1. According of fluid mosaic model, plasma membrane is composed of
(a) phospholipids and oligosaccharides
(b) phospholipids and hemicellulose
(c) phospholipids and integral proteins
(d) phospholipids, extrinsic proteins and intrinsic proteins
2. Acetabularia used in Hammerling‘s nucleocytoplasmic experiments is
(a) unicellular fungus
(b) multicellular fungus
(c) unicellular uninucleate green algae
(d) unicellular multinucleate green algae
3. Organelles can be separated from cell homogenate through
(a) chromatography
(b) X-rays diffraction
(c) differential centrifugation
(d) auto-radiography
4. Plasma membrane is made of
(a) proteins and carbohydrates
(b) proteins and lipids
(c) proteins, lipids and carbohydrates
(d) proteins, some nucleic acid and lipids
5. Polyribosomes are aggregates of
(a) ribosomes and rRNA
(b) only rRNA
(c) peroxisomes
(d) several ribosomes held together by string of mRNA
6. Nucleoproteins are synthesised in
(a) nucleoplasm
(b) nuclear envelope
(c) nucleolus
(d) cytoplasm
7. A bivalent consists of
(a) two chromatids and one centromere
(b) two chromatids and two centromeres
(c) four chromatids and two centromeres
(d) four chromatids and four centromeres
8. Magnification of compound microscope is not connected with
(a) numerical aperture
(b) focal length of objective
(c) focal length of eye piece
(d) tube length
9. The latest model for plasma membrane is
(a) lamellar model
(b) unit membrane model
(c) fluid mosaic model
(d) molecular lipid model
10. Hammerling‘s experiments of Acetabularia involved exchanging
(a) cytoplasm
(b) nucleus
(c) rhizoid and stalk
(d) gametes
11. Electron microscope has a high resolution power. This is due to
(a) electromagnetic lenses
(b) very low wavelength of electron beam
(c) low wavelength of light source used
(d) high numerical aperture of glass lenses used
12. Resolution power is the ability to
(a) distinguish two close points
(b) distinguish two close objects
(c) distinguish amongst organelles
(d) magnify image
13. Fluid mosaic model of cell membrane was put forward b
(a) Danielli and Davson
(b) Singer and Nicolson
(c) Garner and Allard
(d) Watson and Crick
14. Ribosomes were discovered by
(a) Golgi
(b) Porter
(c) De Robertis
(d) Palade
15. Cell wall shows
(a) complete permeability
(b) semipermeability
(c) differential permeability
(d) impermeability
16. Addition of new cell wall particles amongst the existing ones is
(a) deposition
(b) apposition
(c) intussusception
(d) aggregation
17. Angstrom (Å) is equal to
(a) 0.01 mm
(b) 0.001 mm
(c) 0.0001 mm
(d) 0.00001 mm
18. Ribosomes are the centre for
(a) respiration
(b) photosynthesis
(c) protein synthesis
(d) fat synthesis
19. Oxysomes of F0 – F1 particles occur on [
(a) thylakoids
(b) mitochondrial surface
(c) inner mitochondrial membrane
(d) chloroplast surface
20. All plastids have similar structure because they can
(a) store starch, lipids and proteins
(b) get transformed from one type to another
(c) perform same function
(d) be present together
21. An outer covering membrane is absent over
(a) nucleolus
(b) lysosome
(c) mitochondrion
(d) plastid
22. Which one is apparatoreticolare?
(a) Golgi apparatus
(b) Endoplasmic reticulum
(c) Microfilaments
(d) Microtubules
23. Experiments on Acetabularia by Hammerling proved the role of
(a) cytoplasm in controlling differentiation
(b) nucleus in heredity
(c) chromosomes in heredity
(d) nucleo-cytoplasmic ratio
24. Glycogen is a polymer of
(a) galactose
(b) glucose
(c) fructose
(d) sucrose
25. Binding of specific protein on regulatory DNA sequence can be studied by means of
(a) ultra centrifugation
(b) electron microscope
(c) light microscope
(d) X-ray crystallography
26. Names of Schleiden and Schwann are associated with
(a) protoplasm as the physical basis of life
(b) cell theory
(c) theory of cell lineage
(d) nucleus functions as control centre of
cell
27. Which is correct about cell theory in view of current status of our knowledge about cell structure
(a) It needs modification due to discovery of subcellular structures like chloroplasts and mitochondria
(b) Modified cell theory means that all living beings are composed of cells capable of reproducing
(c) Cell theory does not hold good because all living beings (e.g., viruses) do not have cellular organisation
(d) Cell theory means that all living objects consist of cells whether or not capable of reproducing
28. In salivary glandchromosomes/polytenechromosomes,pairing is
(a) absent
(b) occasional
(c) formed between nonhologus chromo
29. Cell recognition and adhesion occur due to biochemicals of cell membranes named
(a) proteins
(b) lipids
(c) proteins and lipids
(d) glycoproteins and glycolipids
30. Golgi apparatus is absent in
(a) higher plants
(b) yeast
(c) bacteria and
31. Membranous bag with hydrolytic enzymes which is used for controlling intracellular digestion of macro – molecules is
(a) endoplasmic reticulum
(b) nucleosome
(c) lysosome
(d) phagosome
32. In plant cells, peroxisomes are associated with
(a) photorespiration
(b) phototropism
(c) photoperiodism
(d) photosynthesis
33. Balbiani rings (puffs) are sites of
(a) DNA replication
(b) RNA and protein synthesis
(c) synthesis of polysaccharides
(d) synthesis of lipids
34. Inner membrane convolutions of a mitochondrion are known as
(a) lamellae
(b) thylakoids
(b) grana
(d) cristae
35. Mitochondrial cristae are sites of
(a) breakdown of macromolecules
(b) protein synthesis
(c) phosphorylation of flavoproteins
(d) oxidation-reduction reactions
36. Organelle having flattened membrane bound cisternae and lying near the nucleus is
(a) golgiapparatus
(b) mitochondrion
(c) centriole
(d) nucleolus
37. Series of reactions which can convert fatty acids to sugars in plants but not in animals is
(a) krebs cycle
(b) glyoxylate cycle
(c) ornithine cycle
(d) glycolysis
38. Auxetic growth is
(a) increase in cell volume only
(b) increase in cell number only
(c) increase in fatty tissue
(d) increase in intercellular material
39. The prokaryotic flagella possess
(a) unit membrane enclosed fibre
(b) protein membrane enclosed fibre
(c) ‗9 + 2‘ membrane enclosed structure
(d) helically arranged protein molecule
40. The function of rough endoplasmic reticulum is
(a) fat synthesis
(b) lipid synthesis
(c) protein synthesis
(d) steroid synthesis
41. The point, at which polytene chromosomes appears to be attached together, is called
(a) centriole
(b) centromere
(c) chromomere
(d) chromocentre
42. The desmosomes are concerned with
(a) cytolysis
(b) cell division
(c) cell adherence
(d) cellular excretion
43. Lysosomes have a high content of
(a) hydrolytic enzymes
(b) lipoproteins
(c) polyribosomes
(d) DNA ligases
44. Genes located on mitochondrial DNA
(a) generally show maternal inheritance
(b) are always inherited from the male parent
(c) show biparental inheritance like the nuclear genes
(d) are not inherited
45. Some of the enzymes,which are associated in converting fats into carbhoydrates, are present in
(a) liposomes
(b) golgi bodies
(c) microsomes
(d) glyoxysomes
46. Which of the following organ has single membrane?
(a) Nucleus
(b) Cell Wall
(c) Mitochondria
(d) Spherosomes
47. The proteins are synthesised at
(a) ribosomes
(b) mitochondria
(c) centrosomes
(d) golgi bodies
48. The cell organelle involved in glycosylation of protein is
(a) ribosome
(b) peroxisome
(c) endoplasmic reticulum
(d) mitochondria.
49. Microtubules absent in
(a) mitochondria
(b) centriole
(c) flagella
(d) spindle fibre
50. Element necessary for middle lamella is
(a) Ca
(b) Zn
(c) K
(d) Cu
51. In fluid mosaic model of plasma membrane
(a) upper layer is non-polar and hydrophilic
(b) upper layer is polar and hydrophobic
(c) phospholipids form a bimolecular layer
in middle part
(d) proteins form a middle layer
52. Which of the following occurs more than one and less than five in a chromosome?
(a) Chromatid
(b) Chromosome
(c) Centromere
(d) Telomere
53. Ribosomes are produced in
(a) nucleolus
(b) cytoplasm
(c) mitochondria
(d) golgi body
54. Mitotic spindle is mainly composed of which protein?
(a) Actin
(b) Myosin
(c) Tubulin
(d) Myoglobin
55. In which one of the following is nitrogen not a constituent?
(a) Pepsin
(b) Idioblast
(c) Bacteriochlorophyll
(d) Invertase
56. Flagella of prokaryotic and eukaryotic cells differ in
(a) type of movement and placement in cell
(b) location in cell and mode of functioning
(c) microtubular organization and type of movement
(d) microtubular organization and function
57. In chloroplasts, chlorophyll is present in the
(a) outer membrane
(b) inner membrane
(c) thylakoids
(d) stroma
58. The main organelle involved in modification and routing of newly synthesized proteins to their destinations is
(a) chloroplast
(b) mitochondria
(c) lysosome
(d) endoplasmic Reticulum
59. According to widely accepted ―fluid mosaic model‖ cell membranes are semifluid, where lipids and integral proteins can diffuse randomly. In recent years, this model has been modified in several respects. In this regard, which of the following statements is incorrect?
64. A major break through in the studies of cells came with the development of electron microscope. This is because
(a) the resolving power of the electron microscope is 200 – 350 nm as compared to 0.1 – 0.2 for the light microscope
(b) electron beam can pass through thick materials, whereas light microscopy requires thin sections
(d) the resolution power of the electron microscope in much higher than that of the light microscope
65. Select the wrong statement from the following
(a) Both chloroplasts and mitochondria have an internal compartment, the thylakoid space bounded by the thylakoid membrane
(b) Both chloroplasts and mitochondria contain DNA
(c) The chloroplasts are generally much large than mitochondria
(d) Both chloroplasts and mitochondria contain an inner and an outer membrane.
66. Which one of the following is not a constituent of cell membrane?
(a) glycolipids
(b) proline
(c) phospholipids
(d) cholesterol.
67. Keeping in view the fluid mosaic model for the structure of cell membrane, which one of the following statements is correct with respect to the
movement of lipids and proteins from one lipid monolayer to the other (described as flipflop movement)?
(a) Both lipids and proteins can flip-flop
(b) While lipids can rarely flip-flop, protein can not
(c) While proteins can flip-flop, lipids can not
(d) Neither lipids, nor proteins can flip-flop
68. Polysome is formed by
(a) several ribosomes attached to a single mRNA
(b) many ribosomes attached to a strand of endoplasmic reticulum
(c) a ribosome with several subunits
(d) ribosomes attached to each other in a linear arrangement
69. Cellulose is the major component of cell walls of
(a) Pythium
(b) Xanthomonas
(c) Pseudomonas
(d) Saccharomyces
70. The two sub-units of ribosome remain united a critical ion level of
(a) copper
(b) manganese
(c) magnesium
(d) calcium
71. Vacuole in a plant cell
(a) is membrane-bound and contains storage proteins and lipids
(b) is membrane-bound and contains water and excretory substances
(c) lacks membrane and contains air
(d) lacks membrane and contains water and excretory substances
72. Plasmodesmata are:
(a) locomotary structures
(b) membranes connecting the nucleus with plasmalemma
(c) connections between adjacent cells
(d) lignified cemented layers between cells
73. Cytoskeleton is made up of:
(a) callosedeposits
(b) cellulosic microfibrils
(c) proteinaceous filaments
(d) calcium carbonate granules
74. Stroma in the chloroplasts of higher plant contains:
(a) light-dependent reaction enzymes
(b) ribosomes
(c) chlorophyll.
(d) light– independent reaction enzymes.
75. Middle lamella is composed mainly of:
(a) muramicacid
(b) calcium pectate
(c) phosphoglycerides
(d) hemicellulose
76. Which one of the following structures between two adjacent cells is an effective transport pathway?
(a) Plasmodesmata
(b) Plastoquinones
(c) Endoplasmic reticulum
(d) Plasmalemma
77. Which one of the following has its own DNA?
(a) Mitochondria
(b) Dictyosome
(c) Lysosome
(d) Peroxisome
78. The main arena of various types of activities of a cell is:
(a) plasma membrane
(b) mitochondrian
(c) cytoplasm
(d) nucleus
79. The plasma membrane consists mainly of:
(a) phospholipids embedded in a protein bilayer
(b) proteins embedded in a phospholipid bilayer
(c) proteins embedded in a polymer of glucose molecules
(d) proteins embedded in a carbohydrate bilayer
80. Given below is a sample of a portion of DNA strand. What is so special shown in it? 5‘ —— GAATTC —— 3‘ 3‘ —— CTTAAG —— 5‘
(a) Replication completed
(b) Deletion mutation
(c) Start codon at the 5‘ end
(d) Palindromic sequence of base pairs
81. Important site for formation of glycoproteins and glycolipids is
(a) vacuole
(b) golgi apparatus
(c) plastid
(d) lysosome
82. Peptide synthesis inside a cell takes place in:
(a) chloroplast
(b) mitochondria
(c) chromoplast
(d) ribosomes
83. What are those structures that appear as beads – on- string in the chromosomes when viewed under electron microscope?
(a) Genes
(b) Nucleotides
(c) Nucleosomes
(d) Base pairs
84. The Golgi complex plays a major roleb
(a) in digesting proteins and carbohydrates
(b) as energy transferring organelles
(c) in post translational modification of proteins and glycosidation of lipids
(d) in trapping the light and transforming it into chemical energy
85. In mitochondria, proteins accumulate in the
(a) outer membrane
(b) inner membrane
(c) intermembrane space
(d) matrix
86. Which one of the following is not considered as a part of the endomembrane system?
(a) Golgi complex
(b) Peroxisome
(c) Vacuole
(d) Lysosome
87. Ribosomal RNA is actively synthesized in
(a) Lysosomes
(b) Nucleolus
(c) Nucleoplasm
(d) Ribosomes
88. Which one of the following does not differ in E.coli and Chlamydomonas
(a) Ribosomes
(b) Chromosomal Organization
(c) Cell wall
(d) Cellmembrane
89. What is true about ribosomes
(a) The prokaryotic ribosomes are 80S, where ―S‖ stands for sedimentation coefficient
(b) These are composed of ribonucleic acid and proteins
(c) These are found only in eukaryotic cells
(d) These are self-splicing introns of some RNAs.
90. Nuclear mebrane is absent in
(a) Penicillium
(b) Agaricus
(c) Volvox
(d) Nostoc
91. Select the correct statement from the following regarding cell membrane.
(a) Na+ and K+ ions move across cell membrane by passive transport
(b) Proteins make up 60 to 70% of the cell membrane.
(c) Lipids are arranged in a bilayer with polar heads towards the inner part.
(d) Fluid mosaic model of cell membrane was proposed by Singer and Nicolson
92. Which one of the following structures is an organelle within an organelle?
(a) Ribosome
(b) Peroxisome
(c) ER
(d) Mesosome
93. Which one of the following cellular parts is correctly described?
(a) Centrioles – Sites for active RNA synthesis.
(b) Lysosomes – Optimally active at a pH of about 8.5.
(c) Thylakoids – Flattened membranous sacs forming the grana of chloroplasts.
(d) Ribosomes – Those on chloroplasts are larger (80s) while those in the cytoplasm are smaller (70s).
94. Stroma in the chloroplasts of higher plant contains:
(a) light-dependent reaction enzymes
(b) ribosomes
(c) chlorophyll.
(d) light– independent reaction enzymes
95. The Golgi complex plays a major role
(a) in digesting proteins and carbohydrates
(b) as energy transferring organelles
(c) in post translational modification of proteins and glycosidation of lipids
(d) in trapping the light and transforming it into chemical energy
96. A major site for synthesis of lipids is:
(a) SER
(b) Symplast
(c) Nucleoplasm
(d) RER
97. The term ‗glycocalyx‘ is used for
(a) A layer surrounding the cell wall of bacteria
(b) A layer present between cell wall and membrane of bacteria
(c) Cell wall of bacteria
(d) Bacterial cell glyco-engineered to possess N-glycosylated proteins
98. Which of the following type of plastids does not contain stored food material?
(a) Amyloplasts
(b) Chromoplasts
(c) Elaioplasts
(d) Aleuroplasts
99. The basic unit of nucleic acid is
(a) Pentose sugar
(b) Nucleoid
(c) Nucleoside
(d) Nucleotide
100. Why is a capsule advantageous to a bacterium?
(a) It allows the bacterium to attach to the surface
(b) It protects the bacterium from desiccation
(c) It provides means of locomotion
(d) It allows bacterium to ―hide‖ from host‘s immune system
101.Select the mismatch.
(a) Gas vacuoles – Green bacteria
(b) Large central vacuoles – Animal cells
(c) Protists – Eukaryotes
(d) Methanogens – Prokaryotes
102. A cell organelle containing hydrolytic enzymes is
(a) lysosome
(b) ribosome
(c) mesosome
(d) microsome
103.Plasmodesmata connections help in
(a) cytoplasmic streaming
(b) synchronous mitotic divisions
(c) locomotion of unicellular organisms.
(d) movement of substances between cells
104. Which one of the following cell organelles is enclosed by a single membrane?
(a) Nuclei
(b) Mitochondria
(c) Lysosomes
(d) Chloroplasts
105. The cells involved in large amount of lipid synthesis,do not possess this orgenelle on Endoplasmicreticulum.
(a) Mitochondrion
(b) Ribosomes
(c) Golgi apparatus
(d) lysosome
106. What is common between chloroplasts, chromoplasts and leucoplasts?
(a) Presence of pigments.
(b) Possession of thylakoids and grana
(c) Storage of starch, proteins and lipids.
(d) Ability to multiply by a fission-like process
107.Nuclear envelope is a derivative of
(a) smooth endoplasmic reticulum
(b) rough endoplasmic reticulum
(c) microtubules
(d) membrane of Golgi complex.
108. The chromosomes in which centromere is situated close to one end are
(a) telocentric
(b) metacentric
(c) submetacentric
(d) acrocentric
109.Which one of the following structures is an organelle within an organelle?
(a) Ribosome
(b) Peroxisome
(c) Mesosome
(d) ER
110. It directs formation of the bipolar spindle during cell division.
(a) Golgi body
(b) Centriole
(c) Ribosome
(d) Cilia
111. Which of the following statements are correct ?
(i) In prokaryotic cells, a special membranous structure formed by the extension of the plasma membrane into the cell is known as polysome.
(ii) The smooth endoplasmic reticulum is the major site for synthesis of glycoproteins.
(iii) RuBisCO is the most abundant protein in the whole biosphere.
(iv) Mitochondria, chloroplasts and
peroxisomes are not considered as part of endomembrane system.
(a) (iii) and (iv)
(b) (ii) and (iii)
(c) (i) and (iv)
(d) (i) and (ii)
112. The structures that are formed by stacking of organised flattened membranous sacs in the chloroplasts are
(a) stroma lamellae
(b) stroma
(c) cristae
(d) grana
113. The main area of various types of activities of a cell is
(a) plasma membrane
(b) mitochondrion
(c) cytoplasm
(d) nucleus
114. Middle lamella is composed mainly of
(a) muramic acid
(b) calcium pectate
(c) phosphoglycerides
(d) hemicelluloses
115. In germinating seeds fatty acids are degraded exclusively in the
(a) peroxisomes
(b) mitochondria
(c) proplastids
(d) glyoxysomes.
116. Organelles can be separated from cell homogenate through
(a) chromatography
(b) Xrays diffraction
(c) differential centrifugation
(d) autoradiography.
117. Chromosome in which centromere is located at the end is….
(a) Acrocentric
(b) Telo centric
(c) Meta centric
(d) Sub-meta centric
118. Hammerling’s experiments of Acetabularia involved exchanging
(a) cytoplasm
(b) nucleus
(c) rhizoid and stalk
(d) gametes
119. Active and passive transports across cell membrane differ in
(a) passive transport is nonselective
(b) passive transport is along the concentration gradient while active transport is due to metabolic energy
(c) active transport is more rapid
(d) passive transport is confined to anions while active transport in confined to cations
120. Which one of the following is not an inclusion body found in prokaryotes?
(a) Glycogen granule
(b) Polysome
(c) Phosphate granule
(d) Cyanophycean granule
121. Which of the following components provides sticky character to the bacterial cell ?
(a) Nuclear membrane
(b) Plasma membrane
(c) Glycocalyx
(d) Cell wall
122. Which of the following cell organelles is responsible for extracting energy from carbohydrates to form ATP ?
(a) Ribosome
(b) Chloroplast
(c) Mitochondrion
(d) Lysosome
123. Select the incorrect match :
(1) Lampbrush chromosomes – Diplotene bivalents
(2) Allosomes –
Sex chromosomes
(3) Polytene chromosomes – Oocytes of amphibians
(4) Submetacentric chromosomes –
L-shaped chromosomes
123. Which of the following events does not occur in rough endoplasmic reticulum?
(a) Protein folding
(b) Protein glycosylation
(c) Phospholipid synthesis
(d) Cleavage of signal peptide
124. Which of the following is true for nucleolus?
(a) Larger nucleoli are present in dividing cells
(b) It is a membrane-bound structure
(c) It is a site for active ribosomal RNA synthesis
(d) It takes part in spindle formation
125. The shorter and longer arms of a submetacentric chromosome are referred to as
(a) s-arm and l-arm respectively
(b) p-arm and q-arm respectively
(c) q-arm and p-arm respectively
(d) m-arm and n-arm respectively
126. Which of the following statements is not correct?
(a) Lysosomes have numerous hydrolytic enzymes
(b) The hydrolytic enzymes of lysosomes are active under acidic pH
(c) Lysosomes are membrane bound structures
(d) Lysosomes are formed by the process of packaging in the endoplasmic reticulum
127. Which of the following pair of organelles does not contain DNA?
(a) Mitochondria and Lysosomes
(b) Chloroplast and Vacuoles
(c) Lysosomes and Vacuoles
(d) Nuclear envelope and Mitochondria
128. Which of the following statements regarding mitochondria is incorrect?
(a) Outer membrane is permeable to monomers of carbohydrates, fats and
proteins.
(b) Enzymes of electron transport are embedded in outer membrane.
(c) Inner membrane is convoluted with infoldings.
(d) Mitochondrial matrix contains single circular DNA molecule and ribosomes.
129. The concept of “Omnis cellula-e cellula” regarding cell division was first proposed by
(a) Rudolf Virchow
(b) Theodor Schwann
(c) Schleiden
(d) Aristotle
130. In light reaction, plastoquinone facilitates the transfer of electrons from
(a) PS-I to NADP+
(b) PS-I to ATP synthase
(c) PS-II to Cytb6f complex
(d) Cytb6f complex to PS-I
131. Which is the important site of formation of glycoproteins and glycolipids in eukaryotic cells?
(a) Golgi bodies
(b) Polysomes
(c) Endoplasmic reticulum
(d) Peroxisomes
132. Which of the following statements about inclusion bodies is incorrect?
(a) They lie free in the cytoplasm
(b) These represent reserve material in cytoplasm
(c) They are not bound by any membrane
(d) These are involved in ingestion of food particles
134
Match List-I with List-II.
| List I | List II | ||
| (a) | Cristae | (i) | Primary construction in Chromosome |
| (b) | Thylakoids | (ii) | Disc shaped sacs in Golgi apparatus |
| (c) | Centromere | (iii) | Infolding in mitochondria |
| (d) | Cisternae | (iv) | Flatted membranous sacs in stroma of plastids |
Choose the correct answer from the options given below.
(a) (b) (c) (d)
(1) (ii) (iii) (iv) (i)
(2) (iv) (iii) (ii) (i)
(3) (i) (iv) (iii) (ii)
(4) (iii) (iv) (i) (ii)
135. When the centromere is situated in the middle of two equal arms of chromosomes, the chromosome is referred as :
(a) Acrocentric
(b) Metacentric
(c) Telocentric
(d) Sub-metacentric
136. The organelles that are included in the endomembrane system are
(a) Golgi complex, Endoplasmic reticulum, Mitochondria and Lysosomes
(b) Endoplasmic reticulum, Mitochondria, Ribosomes and Lysosomes
(c) Endoplasmic reticulum, Golgi complex, Lysosomes and Vacuoles
(d) Golgi complex, Mitochondria, Ribosomes and Lysosomes
137. Identify the types of cell junctions that help to stop the leakage of the substances across a tissue and facilitation of communication with neighbouring cells via rapid transfer of ions and molecules.
(a) Adhering junctions and Gap junctions, respectively
(b) Gap junctions and Adhering junctions, respectively
(c) Tight junctions and Gap junctions, respectively
(d) Adhering junctions and Tight junctions, respectively.
Solutions :
1.Solution: (d)According to fluid mosaic model proposed by Singer and Nicolson (1972, 74), plasma membrane is composed of phospholipid bilayer and protein. Protein molecules occur at places both inside and outside of lipid bilayer. The internal proteins are called intrinsic proteins and the external proteins are called extrinsic proteins.
2.Solution: (c)
Acetabularia used in Hammerling’s nucleocytoplasmic experiments is
unicellularuninucleate marine green alga.
3.Solution: (c)Centrifuge is an instrument used to crea tea centrifugal force. The homogenate of the cell organelles is allowed to undergo centrifugation by which different cell organelles get separated. The process is known as differential centrifugation.
4. Solution: (c) Plasma membrane is made up of proteins, are covalently linked to both lipid and protein.
5.Solution: (d) Polyribosomes consists of 4-8 ribosomes which are attached to a single strand of mRNA. This mechanism help in synthesis of several copies of the same protein.
6.Solution: (d) Nucleoproteins are conjugated proteins. They are deoxyribonucleoproteins and ribonucleoproteins synthesised in cytoplasm of the cell.
7. Solution: (c) A pair of homologus chromosomes lying together in the zygotene stage of Prophase I of first meiotic division is called a bivalent.
8.Solution: (a)Magnification is defind as the power of enlargement. Magnification of compound microscope is the product of magnification of objective lens and magnification of ocular lens.
9. Solution: (c) Fluid mosaic model is the most recent model of a biomembrane proposed by Singer and Nicolson (1972, 74). According to this model, the membrane does not have a uniform deposition of lipids which are present as highly viscous fluid matrix of two layers of phospholipid moles and proteins arranged in a symetrical pattern.
10. Hammerling‘s experiments of Acetabularia involved exchanging
(a) cytoplasm
(b) nucleus
(c) rhizoid and stalk
(d) gametes
11. Electron microscope has a high resolution power. This is due to
(a) electromagnetic lenses
(b) very low wavelength of electron beam
(c) low wavelength of light source used
(d) high numerical aperture of glass lenses used
12. Resolution power is the ability to
(a) distinguish two close points
(b) distinguish two close objects
(c) distinguish amongst organelles
(d) magnify image
13. Fluid mosaic model of cell membrane was put forward b
(a) Danielli and Davson
(b) Singer and Nicolson
(c) Garner and Allard
(d) Watson and Crick
14. Ribosomes were discovered by
(a) Golgi
(b) Porter
(c) De Robertis
(d) Palade
15. Cell wall shows
(a) complete permeability
(b) semipermeability
(c) differential permeability
(d) impermeability
16. Addition of new cell wall particles amongst the existing ones is
(a) deposition
(b) apposition
(c) intussusception
(d) aggregation
17. Angstrom (Å) is equal to
(a) 0.01 mm
(b) 0.001 mm
(c) 0.0001 mm
(d) 0.00001 mm
18. Ribosomes are the centre for
(a) respiration
(b) photosynthesis
(c) protein synthesis
(d) fat synthesis
19. Oxysomes of F0 – F1 particles occur on [
(a) thylakoids
(b) mitochondrial surface
(c) inner mitochondrial membrane
(d) chloroplast surface
20. All plastids have similar structure because they can
(a) store starch, lipids and proteins
(b) get transformed from one type to another
(c) perform same function
(d) be present together
21. An outer covering membrane is absent over
(a) nucleolus
(b) lysosome
(c) mitochondrion
(d) plastid
22. Which one is apparatoreticolare?
(a) Golgi apparatus
(b) Endoplasmic reticulum
(c) Microfilaments
(d) Microtubules
23. Experiments on Acetabularia by Hammerling proved the role of
(a) cytoplasm in controlling differentiation
(b) nucleus in heredity
(c) chromosomes in heredity
(d) nucleo-cytoplasmic ratio
24. Glycogen is a polymer of
(a) galactose
(b) glucose
(c) fructose
(d) sucrose
Solution: (b)
Glycogen is an animal starch, stored in the liver and is polysaccharide of a-Glucose. About 30,000 glucose molecules joined by 1-4 a-glycosidic bonds and its branches by 1-6 glycosidic bonds. It gives red colour with iodine solution. • Galactose is a monosaccharide from milk. • Fructose is a monosaccharide from fruit. • Sucrose is a disaccharide (Glucose + Fructose)
25.Solution: (d)
X-ray crystallography is a technique to study the binding of specific protein on regulatory DNA. X-ray crystallography or single-crystal X-ray diffraction is an
analytical technique which uses the diffraction pattern produced by bombarding a single crystal with X-rays to solve the crystal structure. The diffraction pattern is
recorded and then analyzed or ―solved‖ to reveal the nature of the crystal. This technique is widely used in chemistry and biochemistry to determine the structures of an immense variety of molecules, including inorganic compounds, DNA, and proteins.
26.Solution: (b) Cell theory was proposed by Schleiden and Schwann (1839) according to which ―All living organisms are composed of cells.‖ Cell theory is also known as cell principle, cell doctrine etc.
27.Solution: (c)The exceptions of cell theory is viruses which do not possess a cellular machinery. They consists of DNA or RNA core surrounded by a protein sheath and lack cellular organisation.
28.Solution: (d)In salivary gland chromosomes/ polytene chromosomes, somatic pairing is formed between homologous chromosomes and
repeated replication of their chromonemata.
29.Solution: (d)Cell recognition and adhesion occur due to biochemicals of cell membranes named glycoproteins and glycolipids. These are formed due to the small carbohydrate molecules present on lipids and extrinsic protein.
30.Solution: (c) Golgi complex is absent in prokaryotic cell i.e (PPLO, bacteria and blue green algae). It is present in all eukaryotic cells except sieve tubes of plants, sperms of bryophytes and pteridophytes and red blood corpuscles.
31.Solution: (c)Lysosomes are membranous bag with hydrolytic enzymes which is used for controlling intracellular digestion of macromolecules.
32.Solution: (a)In plant peroxisomes are associated with photorespiration. Peroxisomes are ubiquitous organelles in eukaryotes that function to rid the cell of toxic substances. they have a single membrane that separates their contents from the cytosol (the internal fluid of the cell) and that contains membrane proteins critical for various functions, such as importing proteins into the organelles and aiding in proliferation. Unlike lysosomes, which are formed in the secretory pathway, peroxisomes usually self-replicate by enlarging and then dividing, although there is some indication that new ones may be formed directly. Peroxisomes were
discovered by the Belgian cytologist Christian de Duve in 1965
33. Solution: (b) In the region of Balbiani ring the DNA strands uncoil, become active and produce number of copies of messenger RNA.
34. Solution: (d) The inner membrane of mitochondria is infolded to form involutions called cristae. They are meant for increasing the active area of the inner membrane.
35. Solution: (d) Mitochondrial cristae possess small particles called elementary particles which contain ATP- ase. Therefore, they are the centes of ATP synthesis during oxidative – phosphorylation.
36. Soution :(a) Organelle having flattened membrane bound cisternae and lying near the nucleus is Golgi apparatus.
37. Solution: (b) Several plant structures e.g. pollen, seeds contain fats. The fats are hydrolysed and consumed as source of energy. This is accomplished through oxidative degradation called glyoxylate cycle.
38. Solution: (a)101 Three types of growth are present in multicellular animals: (i) Auxetic growth: Increase in cell volume only not in number. (ii) Multiplication growth: Increase in number not in volume. (iii) Accretionary growth: Growth is due to mitotic division of some special type of cells occurring in
specific locations of body.
39. Solution: (d) The prokaryotic flagellum is single stranded made up of several parallel protein fibrils and helical in shape while in eukaryotes it is made up of axonema and sheath.
40. Solution: (c) Rough endoplasmic reticulum bears ribosomes on its outer surface. These ribosomes take part in protein synthesis.
41. Solution: (d) Granules of condensed chromatin (heterochromatin), are found scattered in interphase nuclei. At chromocentre, the polytene chromosomes appear attached.
42. Solution: (c) Desmosomes are cementing substances, which adhere to each other and keep the latter tightly packed and they also prevent leakage of fluid from interphase.
43. Solution: (a) Lysosomes are single membrane bound vesicular organelles rich in acid hydrolases. They are involved in phagocytosis.
44. Solution: (a) Genes located on the mitochondrial DNA are inherited through the cytoplasm. The zygote receives cytoplasm from the female gamete hence it involves maternal inheritance.
45. Solution: (d) Golgi bodies are cytoplasmic organelle which take part in elaboration and secretion of complex biochemical. Microsomes are small single single membraned cell organelles that absorb oxygen and perfom direct oxidation of substrates. Glyoxis contain enzymes for b- oxidation of fatty acids.
50. Solution: (a) Zinc is an activator of enzymes like carbonic anhydrase. Copper takes part in electron transport as plastocyanin. Potassium maintains membrane
permeability.
51. Solution: (c) Fluid mosaic model of plasma membrane proposes that plasma membrane comprises of a phospholipid bilayer wherein icebergs of proteins floating in sea of phospholipids.
52. Solution: (a) A chromatid is one of two identical strands of DNA making up a chromosome that are joined at their centromeres, for the process of nuclear division (mitosis or meiosis). The term is used so long as the centromeres remain in contact. When they separate (during anaphase of mitosis and anaphase
2 of meiosis), the strands are called daughterchromosomes.The tips of the chromatid are called telomeres.They are there to prevent the ends of the
chromosome from attaching to other chromosomes. It has been said that after repeated cell replication, the telomeres gets shorter resulting in cell death. Thus, this
mean that the way telomeres work could play a role in determining the lifespan of a cell.
53. Solution: (a) Golgi bodies take part in elaboration and secretion of complex biochemicals.Mitochondria are the site of ATP synthesis.Ribosomes are produced in nucleolus.
54.Solution: (c)Mitotic spindles are composed of microtubules which are made of tubulin dimers. Actin and myosin are the contractile proteins of muscle fibres.
Myoglobin is oxygen carrying pigment found in muscle.
55.Solution: (b)Raphides are needle-shaped crystals of calcium carbonate or calcium oxalate found in specialized plant cells called idioblasts. It is believed that the raphides are a defense mechanism against plant predators, as they are likely to tear the soft tissues of the throat or esophagus of a plant predator chewing on the plant‘s leaves. They are non-nitrogenous substances.
56.Solution: (c)Prokaryotes have simple flagella without microtubules whereas eukaryotes have complex cilia and flagella which consists of microtubules arranged in 9+2 fashion (an outer ring of nine pairs surrounding 1 center pair). Further in prokaryotes the arrangement is 9+0.
57.Solution: (c)The thylakoid membranes possess the chlorophylls. The outer membrane is permeable to a number of solutes. Inner membrane has a number of carrier proteins. Stroma forms the matrix containing the enzyme for Calvin cycle.
58.Solution: (d)Endoplasmic reticulum transport proteins and enzymes to their destinations i.e. within the cell and outside the cell.
59.Solution: (b) Flip-Flop movement is due to migration of lipid molecules from one lipid monolayer to other monolayer of lipid bilayer.
60.Solution: (a)Resolving power or limit of resolution is the ability of the eye to distinguish two close objects as separate. Its value is calculated by Abbe‘s equation,
61.Solution: (a)During anaphase APC (anaphase promoting complex) develops. It degenerates proteins binding the two chromatids in the region of centromere. As
a result the centromere of each chromosome divides. This converts the two chromatids into daughter chromosomes.
62.Solution: (d)Protein synthesis in an animal cell occurs on ribosomes present in cytoplasm as well as in mitcohondria because mitochondria and chloroplast also have their own DNA, RNA and ribosome so can synthesize half of their required proteins.
63.Solution: (a)The enzymes of electron transport system are present in inner mitochondrial membrane.
64.Solution: (d)A major break through in cell studies came with the development of EM having great resolution power due to which we can see the ultrastructures of cell organelles.
65.Solution: (a)Both chloroplasts and mitochoridria have an internal compartment, the thylakoid space bounded by double membrane
66.Solution: (b)
67.Solution: (b)Keeping in view the ‗Fluid mosaic model‖ for the structure of cell membrane, the movement of lipids and proteins from one lipid monolayer to the other, lipid can rarely flip-flop, protein can not. The fluid mosaic model is the most important and widely accepted latest model for plasma membrane was given by Singer and Nicolson in 1972. According the them it is ― protein iceberg in a sea of lipids‖.
68.Solution: (a)Polysome (Polyribosome) is a complex formed by several ribosomes attached to a single mRNA molecule in the process of translation.
69.Solution: (a)Cellulose is a major component of cell wall of Pythium. Pythium is a genus of parasitic Oomycete. Because this group of organisms were once classified as fungi, they are sometimes still treated as such. Pythium, like others in the family Pythiaceae, are usually characterized by their production of coenocytic hyphae, hyphae without separations. Oogonia generally contain a single Oospore. Antheridia contain an elongated and club shaped antheridium.
70.Solution: (c)The two subunits of ribosome remain united at a critical ion level of magnesium. The presence of magnesium and its amount plays an important role in the appearance and structure of the ribosomes. If magnesium is absent in medium, the large particles fall apart to present a group of smaller particles.
71.Solution: (b) Vacuole in a plant cell is membrane bound and contains water and excretory substance. Vacuole is a space within the cytoplasm of living cell that is filled with air, water or other liquid, cell sap or food particles. In plant cells, there is usually one large vacuole bounded by a single layered membrane (tonoplast or vacuole membrane); animal cells usually have several small vacuoles.
72.Solution: (c) Plasmodesmata are connections between adjacent cells. Plasmodesmata are narrow channels that act as intercellular cytoplasmic bridges to facilitate communication and transport of materials between plant cells. Plasmodesmata are formed during cell division, when traces of the endoplasmic reticulum become caught in the new wall that divides the parent cell.
73.Solution: (c) The cytoskeleton is made up of three kinds of protein filaments actin filaments (also called microfilaments), intermediate filaments and microtubules whose major constituents are actin and tubulin respectively.
74.Solution: (d)Stroma in the chloroplasts of higher plant contains light independent reactions enzymes. Within the stroma are stacks of thylakoids, the sub-organelles which are the site of photosynthesis.
75.Solution: (b)Middle lamella is mainly composed of calcium pectate. Calcium is deposited in plants cell walls during their formation – it is required for the stability and function of cell membranes and acts as a type of ‗cementing agent‘ in the cell walls in the form of calcium pectate‘. Calcium pectate is like a glue binding adjacent cells together so if inadequate calcium is not transported during cell formation, tissues become less
stable and prone to disintegration.
76.Solution: (a)Plasmodesmata are the structure between two adjacent cells that permits the transport and communication between them. They are the fine cytoplasmic strands that connect the protoplasts of adjacent plant cells by passing through the cell walls.
77. Solution: (a) Mitochondria has its own DNA. It is as structure within cytoplasm of eukaryotic cells that carries out aerobic respiration. It is the site of Kreb‘s cycle and ETS.Therefore, it is also called as cell‘s energy production site.
78. Solution: (c)The main arena of various types of activities of a cell is cytoplasm. It forms the living protoplasm of a cell excluding the nucleus. It consists of proteins, fats, carbohydrates, nucleic acids, vitamins, waste metabolites and all organelles.
79.Solution: (b)Plasma membrane comprises mainly proteins embedded in a phospholipid bilayer. Protein molecules occur at places both inside and outer side of the lipid bilayer.
80. Solution: (d)The sample of a portion of DNA strand shown in the figure is palindromic sequence of base pairs.
81.Solution: (b)Golgi apparatus is the important site for formation of glycoprotein and glycolipid.
82.Solution: (d)Peptide synthesis takes place in ribosome inside a cell.
83.Solution: (c)Under electron microscope the nucleosomes appear as beads on string in chromosome, due to a short length of DNA wrapped around a core of histone proteins.
84.Solution: (c)Golgi apparatus plays a major role in post translational modification of proteins forming glycoprotein and glycosidation of lipid forming glycolipids. A number of proteins and lipids synthesised on endoplasmic reticulum (rough and smooth respectively) are modified in the cisternae of the Golgi apparatus before they are released from it trans face.
85.Solution: (b) The inner membrane of mitochondria contains more than 151 different polypeptides, and has a very high proteinto- phospholipid ration.
86.Solution: (b) Except peroxisome the remaining three and ER are the parts of endomembrane system.
87.Solution: (b)Ribosomal RNA is actively synthesized in nucleolus. Nucleolus is also known as ribosomal factory.
88.Solution: (d)Cell membrane of E.coli, a bacteria and Chlamydomonas a unicellular green alga does not differ. As in both cell membrane is composed of lipids and proteins.
89.Solution: (b) Ribosomes are amembraneous (ie. without membrane) cell organelle composed of rRNA and protein. These are found in both prokaryotic and eukaryotic cells. In prokaryotes, ribosomes are 70S type while in eukaryotes, it is 80S type.
90.Solution: (d) Nostoc is prokaryote while rest are eukaryotes. Nuclear membrane is absent in prokaryotes.
91.Solution: (d) Fluid mosaic membrane model was proposed by Singer and Nicholson in 1972. It is most accepted model of structure of biomembrane.
92.Solution: (a) Ribosome are small naked (non membrane bound) particles made of r-RNA and proteins. Ribosomes are also seen in the organelles like itochondria and chloroplasts. They are the cell‘s protein factories and are found on RER and scattered in the cytoplasm as polyribosomes. Ribosomes are the sites at which information carried in the genetic code is converted into protein molecules.
93.Solution: (c)Centrioles serve as basal bodies for cilia and flagella. They are concerned with spindle formation during cell division. Lysosomes are membrane-bound organelles containing many hydrolytic enzymes, which are optimally active at an acid pH (near pH 5). Thylakoids are membrane-bound organelles found within chloroplasts. The thylakoid membrane, forms many flattened, fluid-filled tubules that enclose a single convoluted compartment. These tubules tend to stack on top of each other to forma structure called a granum.
94.Solution: (d)Stroma in the chloroplasts of higher plant contains light independent reactions enzymes. Within the stroma are stacks of thylakoids, the sub-organelles which are the site of photosynthesis.
95. Solution: (c) Golgi apparatus plays a major role in post translational modification of proteins forming glycoprotein and glycosidation of lipid forming glycolipids. A number of proteins and lipids synthesised on endoplasmic reticulum (rough and smooth respectively) are modified in the cisternae of the Golgi apparatus before they are released from it trans face.
96.Solution: (a)The smooth endoplasmic reticulum is the major site for synthesis of lipid. In animal cells lipid like steroidal hormones are synthesised in SER.
97. Solution: (a) Glycocalyx or mucilage is the outermost coating of bacterial cells/cell wall which is rich in polysaccharides. A thick and tougher mucilage is called capsule which gives gummy or sticky trait to cells. It protects the cells from dessication, toxins and preventing attachment to foreign invaders.
98. Solution: (b)Chromoplasts are non-photosynthetic coloured plastides which synthesise and stored carotenoid pigmentes. They, therefore, appear orange red and yellow where as amyloplast (store starch), aleuroplast (store proteins) and elaioplast (store oil droplets and fats) are leucoplasts, colourless plastids.
99. Solution: (d)Nucleic acid (DNA and RNA) comprises of polynucleotides. Each nucleotide consist of nitrogenous bases, pentose sugar and phosphoric acid.
100.Solution: (d)Capsule is a layer that lies outside the cell wall of bacteria. The capsule can protect cells from engulfment by eukaryotic cells, such as macrophages. They also exclude bacterial viruses and most hydrophobic toxic materials such as detergents
101.(b) Large central vacuoles are present in plant cell.
102.(a) A lysosome is a membrane-bound cell organelle that contains hydrolytic enzymes. Lysosomes are involved with various cell processes. They break down excess or worn-out cell parts. They may be used to destroy invading viruses and bacteria.
103.(d) Plasmodesmata (singular, plasmodesma) are small channels that directly connect the cytoplasm of neighboring plant cells to each other, establishing living bridges between cells.
104.(c) Nuclei, mitochondria and chloroplasts are all double membrane bound organelles. Lysosomes are single membrane bound organelle.
105.(b) Ribosomes
106.(d) The common among all the three organelles are that they have ability to multiply by a fission like process because these organelles contain there own genetic material and protein synthesizing machinery, i.e., DNA, RNA and ribosomes
107.(b) Recent developments have shown that nuclear membrane is derived from rough endoplasmic reticulum. During cell division, nuclear membrane is disintegrated. The nuclear envelope transmembranc proteins are absorbed in the RER. Once the division is completed, RER reassembles the nuclear envelope.
108.(d) In acrocentric chromosomes, centromere appears subterminal, ie, with a very small and a very long arm. In metacentric chromosome, centromere is median and chromosome appears V-shaped during anaphasic movement. submetacentric chromosome, centromere is submedian, ie, one arm smaller and one arm Larger. In telocentric chromosome, centromere is Tuely terminal.
109(a) Ribosomes are small membrane-less, granular organelles which normally occur in prokaryotes.In prokaryotes, they remain spread in the cytoplasm. This makes it an organelle. In the eukaryotes, they are present over RER. RER stands for rough endoplasmic reticulum. Since RER is itself an organelle ribosome are called as organelles within the organelle.
110.(b) Centriole
111.(a) The special membranous structure formed by the extension of prokaryotic plasma membrane is known as mesosome. While polysome is a structure formed by combination of many ribosomes. SER is the major site of synthesis of lipids. The site of protein synthesis is RER.
112.(d) A chloroplast is a vesicle, bound by an envelope of two unit membranes and filled with a fluid matrix called stroma. The lamellae, after separation from the inner membrane, usually take the form of closed, flattened, ovoid sacs, the thylakoids, which lie closely packed in piles, the grana.
113.(c) Cytoplasm is the gelatinous liquid that fills the inside of a cell. It is composed of water, salts, and various organic molecules. Some intracellular organelles, such the nucleus and mitochondria, are enclosed by membranes that separate them from the cytoplasm. What is the important function of cytoplasm? The cytoplasm is responsible for holding the components of the cell and protects them from damage. It stores the molecules required for cellular processes and is also responsible for giving the cell its shape.
114(b) The middle lamella is a layer which cements the primary cell walls of two adjoining plant cells together. It is the first formed layer which is deposited at the time of cytokinesis. The cell plate that is formed during cell division itself develops into middle lamella or lamellum. The middle lamella is made up of calcium and magnesium pectates. In a mature plant cell it is the outermost layer of cell wall. In plants, the pectins form a unified and continuous layer between adjacent cells.
115.(d) Glyoxysomes are small, spherical vesicles enclosed by a single unit membrane. Glyoxysomes are generally found in cells of yeast, Neurospora and in germinating fatty seeds where fat is being converted into carbohydrates, i.e., glyoxylate cycle (gluconeogenesis).
116.(b) Organelles can be separated from cell homogenate through differential centrifugation. The basic principle involved here is sedimentation of particles in a suspension by centrifugal force. In a centrifuge, the particles sediment at different rates when an accelerating force is subjected. The rate of sedimentation depends upon the size of the particles, its shape and density.
117.(b) A telocentric chromosome’s centromere is located at the terminal end of the chromosome. A telocentric chromosome has therefore only one arm. Telomeres may extend from both ends of the chromosome, their shape is similar to letter “i” during anaphase.
118.(b) A major breakthrough in the studies of cells came with the development of electron microscope. This is because the resolving power of the electron microscope is 200 350 nm as compared to 0.1 0.2 nm for the light microscope
119.(b) Active and passive transports across cell membrane differ in passive transport is due to metabolic energy. There is always expenditure of energy in active transport.
120.(b) Polysome is a not an inclusion body. It is an aggregation of ribosomes formed under conditions of high concentration of magnesium. An inclusion body is any of various particulate structures, usually proteins, formed after viral infections in a prokaryotic or eukaryotic cell.
121 (c)The glycocalyx is a carbohydrate-enriched coating that covers the outside of many eukaryotic cells and prokaryotic cells, particularly bacteria . When on eukaryotic cells the glycocalyx can be a factor used for the recognition of the cell. On bacterial cells, the glycocalyx provides a protective coat from host factors. The possession of a glycocalyx on bacteria is associated with the ability of the bacteria to establish an infection.
122. (c)The mitochondrion (plural mitochondria) is a membrane-bound organelle found in the cytoplasm of eukaryotic cells. It is the power house of the cell; it is responsible for cellular respiration and production of (most) ATP in the cell. Mitochondria are organelles – ‘small organs’ within each cell. They produce energy in the form of a molecule called ATP (adenosine triphosphate) which gets used throughout the cell to power the different jobs it has to do.
123 (c)Lampbrush chromosomes (LBCs) are transitory structures that exist during an extended diplotene of the first meiotic division in female gametocytes of most animals, except mammals allosome (genetics) A sex chromosome that differs from an ordinary autosome in form, size, or behaviour. The human sex chromosomes are a typical pair of allosomes.Polytene chromosomes are large chromosomes which have thousands of DNA strands. They provide a high level of function in certain tissues such as salivary glands of insects. Polytene chromosomes develop from the chromosomes of diploid nuclei by successive duplication of each chromosomal element (chromatid) without their segregation. The newly formed chromatids remain associated lengthwise and together form a cable-like structure, referred to as polytene chromosomes.A submetacentric chromosome is a chromosome whose centromere is located near the middle. As a result, the chromosomal arms are slightly unequal in length and may also form an L-shape. A chromosome with equal chromosomal arms is termed metacentric chromosome
124 (c)Rough endoplasmic reticulum is an organelle found in eukaryotic cells. Its main function is to produce proteins. It is made up of cisternae, tubules and vesicles. The cisternae are made up of flattened membrane disks, which are involved in the modification of proteins.
125 (c)Within the cell nucleus there’s a very specific part called the nucleolus. This does not contain the chromosomes. What this contains is the machinery necessary to assemble the cell’s ribosomal RNAs. Ribosomal RNAs then are transported through the nuclear pores into the cytoplasm where they become part of the ribosome, which is the protein machinery. These ribosomal RNAs guide the messenger RNAs through the ribosomes and help in the protein translation, but they themselves are RNA’s that do not become proteins. They’re non-coding RNAs that help the messenger RNAs to undergo the protein translation process. These RNAs, like the other messenger RNAs, are made in the nucleus, but ribosomal RNAs are made in the nucleolus which is a very specific part of the cell nucleus.
126 (b)submetacentric chromosomes. A chromosome with a centromere located sub-median resulting in slightly unequal length of chromosomal arms. Supplement. The centromere is the dense, constricted region in a chromosome.Each chromosome has a constriction point called the centromere, which divides the chromosome into two sections, or “arms.” The short arm of the chromosome is labeled the “p arm.” The long arm of the chromosome is labeled the “q arm.
127 (d)A lysosome is a membrane-bound cell organelle that contains digestive enzymes. Lysosomes are involved with various cell processes. They break down excess or worn-out cell parts. Lysosomes bud off from trans face to Golgi bodies. Precursor of lysosomal enzymes are synthesized by RER and then send to Golgi bodies for further processing.
128 (a)Mitochondria and Lysosomes do not contain DNA Mitochondria and lysosomes are critical to every cell in the body, where they play distinct roles. Mitochondria produce energy for the cell, while lysosomes recycle waste material.
129 (b)enzyme for electron transport are present in the inner membrane.
130 (a)Omnis cellula e cellula, that each cell derives from a pre-existing cell by division, is the culmination of a profound insight of the late 19th century and a dictum articulated by the German pathologist Rudolf Virchow.
131(a)Plastoquinone (PQ) is an isoprenoid quinone molecule involved in the electron transport chain in the light-dependent reactions of photosynthesis In the reaction , plastoquinone facilitates transfer of electron from PS-II to Cytb6f complex.
132(a)Golgi apparatus, also called Golgi complexor Golgi body, membrane bound organelle of eukaryotic cells (cells with clearly defined nuclei) that is made up of a series of flattened, stacked pouches called cisternae. The Golgi apparatus is responsible for transporting, modifying, and packaging proteins and lipids into vesicles for delivery to targeted destinations. It is located in the cytoplasm next to the endoplasmic reticulum and near the cell nucleus. While many types of cells contain only one or several Golgi apparatus, plant cells can contain hundreds.
133 (d)Inclusion bodies are aggregates of protein associated with many neurodegenerative diseases, accumulated in the brain cells either in the cytoplasm or cell nucleus.
134(d)Cristae – Infoldings in mitochondria (inner membrane) Thylakoids – Flattened membranous sacs in stroma of plastids Centromere – Primary constriction in chromosome Cisternae – Disc shaped sacs in Golgi apparatus
135 (b)A typical angiospermic embryo sac has seven cells that are three antipodals, one central cell, one egg cell and two synergids. The central cell has two polar nuclei, hence the embryo sac is eight nucleated.
136 (c)Endomembrane system includes Endoplasmic Reticulum, Golgi complex, Lysosomes and Vacuoles
137 (c) Three types of junctions are found in tissues Tight junctions stop leakage of substances from leaking across a tissue.Adhering junctions cement and keep neighbouring cells together. Gap junctions or communication junctions facilitate communication between cells by connecting the cytoplasm of adjoining cells.
