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Neet Biology Cell Structure And Organelle Mcq
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Q.1
Which of the following statements is not correct? [NEET 2019]
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a) Lysosomes have numerous hydrolytic enzymes
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b) The hydrolytic enzymes of lysosomes are active under acidic pH
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c) Lysosomes are membrane bound structures
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d) Lysosomes are formed by the process of packaging in the endoplasmic reticulum
Explanation
Lysosomes originate by budding off from the membrane of the trans-Golgi network, a region of the Golgi complex responsible for sorting newly synthesized proteins, which may be designated for use in lysosomes, endosomes, or the plasma membrane. Answer : (d)
Q.2
The Golgi complex participates in
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a) Respiration in bacteria
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b) Formation of secretory vesicles
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c) Fatty acid breakdown
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d) Activation of amino acid
Explanation
Answer : (b)
Q.3
Nissl bodies are mainly composed of .... ... [ NEET 2018]
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a) Nucleic acids and SER
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b) DNA and RNA
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c) Proteins and lipids
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d) Free ribosomes and RER
Explanation
Answer : (d)
Q.4
All plastids have similar structure because they can ... ... [ CBSE 1992 ]
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a) Store starch, lipids and proteins
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b) Get transformed from one type to another
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c) Perform same function
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d) Be present together
Explanation
plastids are interchangeable in their form. Generally, three types of plastids arepresent in plant cells, i'.e., leucoplasts (storage), chromoplast (coloured) and chloroplasts(synthesis of food green pigment). Depending upon the circumstances, one type of plasmid may be converted into another type. e.g., (i) In Capsicum, the cells of ovary consist of leucoplasts. When ovary changes into fruit, leucoplasts are transformed into chloroplasts. When the fruit ripens chloroplast areconverted into chromoplast. (ii) The leucoplast in stem tubers of potato, on exposure to sunlight transform to chloroplasts. In some cases the chloroplasts gets converted during ripening of fruits, e.g., tomato chili when they change colour from green to red. In occurs because of chlorophyll and degeneration of lamella. Answer : (b)
Q.5
Water protects organism from thermal shock due to its high ... ... [ AMU 1991]
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a) Thermal conductivity
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b) latent heat
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c) Dielectric constant
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d) All the above
Explanation
Water has high specific heat and high heat of Vaporization ( Latent heat) This property ensures slow heating of water; maintain constant temperature of living organisms and environment. Answer : (b)
Q.6
Which organelle is present only in plants .... .. [ Bihar PMT 2001 ]
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a) Glyoxysome
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b) Lysosome
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c) Peroxisome
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d) Ribosome
Explanation
The glyoxysome is a plant peroxisome, especially found in germinating seeds, involved in the breakdown and conversion of fatty acids to acetyl-CoA for the glyoxylate bypass. Since it is also rich in catalase, the glyoxysome may be related to the microbodies or peroxisomes or derived from them. Structurally, plant and animal cells are very similar because they are both eukaryotic cells. They both contain membrane-bound organelles such as the nucleus, mitochondria, endoplasmic reticulum, golgi apparatus, lysosomes,ribosomes and peroxisome Answer : (a)
Q.7
Folding of inner mitochondrial membrane are called ... ... [ JIPMER 1992 ]
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a) Grana
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b) Thylakoids
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c) Cristae
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d) F0 - F1 structures
Explanation
Mitochondria are shaped perfectly to maximize their productivity. They are made of two membranes. The outer membrane covers the organelle and contains it like a skin. The inner membrane folds over many times and creates layered structures called cristae. The fluid contained in the mitochondria is called the matrix. Answer : (c)
Q.8
Centre of phosphorylation is ... ... [ AFMC 2000 ]
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a) Ribosome
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b) mitochondria
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c) Peroxisome
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d) Oxisome
Explanation
phosphorylation, chemical process in which a phosphate group is added to an organic molecule. In living cells phosphorylation is associated with respiration, which takes place in the cell's mitochondria, and photosynthesis, which takes place in the chloroplasts. Answer : (b)
Q.9
Microtubules are made of ... ... [ Odisna 2012 ]
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a) Actin
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b) Keratin
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c) Tubulin
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d) Dynein
Explanation
Microtubules are the largest type of filament, with a diameter of about 25 nanometers (nm), and they are composed of a protein called tubulin. Actin filaments are the smallest type, with a diameter of only about 6 nm, and they are made of a protein called actin. Tubulin is the protein that polymerizes into long chains or filaments that form microtubules, hollow fibers which serve as a skeletal system for living cells. Microtubules have the ability to shift through various formations which is what enables a cell to undergo mitosis or to regulate intracellular transport. Defination of Microtubule Microtubules are microscopic hollow tubes made of the proteins alpha and beta tubulin that are part of a cell’s cytoskeleton, a network of protein filaments that extends throughout the cell, gives the cell shape, and keeps its organelles in place. Microtubules are the largest structures in the cytoskeleton at about 24 nanometers thick. They have roles in cell movement, cell division, and transporting materials within cells. Answer : (c)
Q.10
Vacuole is covered by a membrane called ... .. [ BHU 2006 ]
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a) Tonoplast
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b) Plasmalemma
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c) Cell membrane
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d) Cell wall
Explanation
The membrane surrounding the plant cell vacuole is called the tonoplast. This a very active, dynamic membrane. Plant cells use their vacuoles for transport and storing nutrients, metabolites, and waste products. The tonoplast is a lipid bilayer, typical of other cellular membranes. Recall that a lipid is part of the fats, oils, waxes, etc. group. A bilayer indicates that there are two layers, each with the hydrophillic (water loving) head facing out into the cellular cytosol and the vacuolar cytosol. Cytosol is a liquid component of a cell that surrounds organelles like the vacuole. The hydrophobic (water fearing) tails face inwards. The tonoplast is semi-permeable as well. This means that certain molecules and substrates can pass through it but others cannot. This allows the tonoplast to maintain a balance of ions inside and outside of the central vacuole. Answer : (a)
Q.11
Which cell organelle connect nuclear envelope with cells membrane? [ RPMT 2006 ]
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a) Lysosome
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b) Golgi body
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c) Endoplasmic reticulum
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d) Mitochondria
Explanation
The nuclear membrane is a lipid bilayer, meaning that it consists of two layers of lipid molecules. The outer layer of lipids has ribosomes, structures that make proteins, on its surface. It is connected to the endoplasmic reticulum, a cell structure that packages and transports proteins. Answer : (c)
Q.12
Physical basis of life is ... ... [ RPMT 2005 ]
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a) Nucleoplasm
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b) Cytoplasm
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c) Plasmalemma
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d) Protoplasm
Explanation
According to Huxley the protoplasm is the physical basis of life. Inside the cell wall of living cell the living substance is known as protoplasm. The protoplasm is a thick fluid or jelly like substance Answer : (d)
Q.13
rotein synthesis occurs in ... ... [ CBSE 1997 ]
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a) Mitochondria
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b) Chloroplasts
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c) Cytoplasm
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d) All the above
Explanation
Protein synthesis occurs in three subcellular compartments, namely, cytoplasm, plastids( chloroplast is a type of organelle known as a plastid), and mitochondria Mitochondria and chloroplasts are similar in the following ways: 1. Both are thought to have originally been free-living organisms, like bacteria, that were, during the course of evolution, engulfed by a larger cell in which they survived as intracellular symbionts 2. Both mitochondria and chloroplasts have their own genomes and their own protein synthesis machinery. 3. Both mitochondria and chloroplasts are sites of production of ATP, the energy currency of the cell. Answer : (d)
Q.14
Lampbrush chromosomes occur inside ... ... [ BHU 2008 ]
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a) Nucleus of human cells
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b) Oocytes of Frog/ amphibian
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c) Salivary glands of Drosophila
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d) Salivary glands of Silk Moth
Explanation
Lampbrush chromosomes are a special form of chromosome found in the growing oocytes (immature eggs) of most animals, except mammals Lampbrush chromosomes have also been found in spermatocytes of several species, Answer : (b)
Q.15
Chromatin is chemically made of ... ... [ WB 2009 ]
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a) Nucleic acid, histone and non-histone proteins
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b) Nucleic acid and histone proteins
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c) Nucleic acid and non-histone proteins
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d) Nucleic acid
Explanation
Chromatin is a complex of nucleic acids (e.g., DNA or RNA) and proteins (histones) and non-histone proteins. Answer : (a)
Q.16
DNA of chloroplast differs from nuclear DNA in ... ... [ Wardha 2002 ]
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a) Absence of histone protein
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b) Fewer bases
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c) Single
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d) All the above
Explanation
Answer : (d)
Q.17
Which one is without an external covering? ... ... [ RPMT 1995 ]
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a) Lysosome
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b) Golgi apparatus
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c) Centrosome
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d) Centriole
Explanation
Organelles lacking any membrane: Ribosomes, Centrioles, Nucleolus. Centrosomes are made of from arrangement of two barrel-shaped clusters of microtubules, called centrioles and a complex of proteins that help additional microtubules to form. Centrosomes are also non-membrane bound Answer : (d)
Q.18
(i) Starch is a polymer if (ii) basic unit of starch is ... ... [ DPMT 1991 ]
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a) Fructose
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b) Glucose
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c) Sucrose
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d) Maltose
Explanation
Starch is a polysaccharide comprising glucose monomers joined in α 1,4 linkages. The simplest form of starch is the linear polymer amylose; amylopectin is the branched form. Answer : (b)
Q.19
Schleiden ( 1838) proposed cell to be structural and functional unit of life . His idea is ... ... [ CPMT 2004 ]
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a) Observation
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b) Assumption
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c) Generalization
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d) Hypothesis
Explanation
Hypothesis is a supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation. In 1838 Schleiden defined the cell as the basic unit of plant structure, idea was a hypothesis based on the observation which had to be experimentally verified by other workers Answer : (d)
Q.20
Lysosomes are called suicidal bags because they have ... ... [ BHU 1992 ]
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a) Hydrolytic enzymes
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b) Parasitic activity
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c) Food vacuole
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d) Catabolic enzymes
Explanation
lysosome is surrounded by a membrane that maintains an acidic environment within the interior via a proton pump. Lysosomes contain a wide variety of hydrolytic enzymes (acid hydrolases) that break down macromolecules such as nucleic acids, proteins, and polysaccharides. Answer : (a)
Q.21
Heterophagosome is ... .... [ Odisha 2012 ]
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a) Lysosome in which only indigestible food is left
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b) Formed by fusion of primary lysosome with degenerating intracellular organelles
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c) Newly pinched out vesicle from Golgi apparatus which fused with endosome to become functional
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d) Formed by fusion of primary lysosome with food containing phagosome
Explanation
heterophagosome. an intracytoplasmic vacuole formed by phagocytosis or pinocytosis, which becomes fused with a lysosome, subjecting its contents to enzymatic digestion. Answer : (d)
Q.22
Fluidity of cell membranes in cold weather is maintained by ... ... [ Pb PMT 2005 ]
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a) Increasing number of phospholipids with unsaturated hydrocarbon tails
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b) Increasing the proportion of integral proteins
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c) Increasing concentration of cholesterol in membrane
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d) Increasing the number of phospholipids with saturated hydrocarbon tails
Explanation
Cholesterol acts as a bidirectional regulator of membrane fluidity because at high temperatures, it stabilizes the membrane and raises its melting point, whereas at low temperatures it intercalates between the phospholipids and prevents them from clustering together and stiffening.Cholesterol acts as a buffer, increasing fluidity at low temperatures and decreasing fluidity at high temperatures. And the last are unsaturated fatty acids in our phospholipid. When we increase the amount of unsaturated fatty acids in our cell membrane, the fluidity also increases. Answer : (a)
Q.23
Fluid mosaic model of plasma membrane purposes that ... ... [ CBSE 2002 ]
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b) Upper layer is polar and hydrophobic
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a) Upper layer is non-polar and hydrophobic
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c) Phospholipids produce a bilayer in the middle
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d) Proteins form the middle layer
Explanation
Phospholipids are a class of lipids that are a major component of all cell membranes. They can form lipid bilayers because of their amphiphilic characteristic. Phospholipids are the primary molecules found in the plasma membrane. A phospholipid is unique in that it has a hydrophilic region called the head, and a hydrophobic region known as the tail. The interior of the cell is primarily made of water. Likewise, the exterior of the cell is usually surrounded by watery fluid. This means that the plasma membrane could not possibly consist of just one layer of phospholipids. This is because the hydrophobic (or water fearing) tail region would have to interact with one of the watery regions inside or outside of the cell. So instead, the cells have evolved to have two layers of phospholipids. Answer : (c)
Q.24
Phagosomes and pinosomes are collectively called .... .... [ DPMT 2005 ]
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a) Residual bodies
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b) Autophagic bodies
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c) Digestive vacuoles
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d) Endosomes
Explanation
a vacuole in the cytoplasm of a cell, containing a phagocytosed particle enclosed within a part of the cell membrane. Pinosome: A tiny fluid-filled vesicle (bubble) within a cell. Phagosomes, macropinosomes and autophagosomes mature in a manner similar to endosomes, and may require fusion with normal endosomes for their maturation. Answer : (d)
Q.25
All are membrane bound cell organelles except ... .... [ MPPMT 1997 ]
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a) Mitochondria
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b) Lysosomes
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c) Sphaerosomes
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d) Ribosomes
Explanation
Non-membrane bound organelles are more solid structures that are not fluid-filled, so they have no need for a membrane. Examples of non-membrane bound organelles are ribosomes, the cell wall, and the cytoskeleton Answer : (d)
Q.26
Prokaryotic and eukaryotic flagella differ in ... ... [ CBSE 2004 ]
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a) Type of movement and placement
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b) Location and mode of functioning
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c) Microtubular structure and function
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d) Microtubular organisation and type movement
Explanation
Prokaryotic Flagella- They are single stranded. A covering membraneous sheath is absent. The size is smaller. They are narrower. Each flagellum has three parts: basal body, hook and filament. Basal body bears rings. They are formed of protein flagellin. They perform rotatory movements. Eukaryotic Flagella- They are 11 stranded. Flagella are covered by sheath derived from plasmalemma. The size is larger. They are thicker. Each flagellum has two parts: basal body and shaft. Basal body bears rootlets. The strands are formed of protein tubulin. They perform lashing or undulatory movements. Answer : (d)
Q.27
An enucleated plant cell is ... ... [ KCET 2001 ]
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a) RBC
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b) Sieve tube cell
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c) Companion cell
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d) Xylem parenchyma
Explanation
seive tube cells of vascular plants and RBCs are enucleated Answer : (b)
Q.28
Out of peroxisomes, lysosomes and mitochondria, single membrane covering occurs in ... ... [ JKCMEE 2003 ]
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a) Both peroxisomes and lysosomes
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b) only peroxisomes
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c) All the above
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d) None of the above
Explanation
organelles are bounded by a single membrane. For example, vacuole, lysosome, Golgi Apparatus, Endoplasmic Reticulum, peroxisomes Double membrane bound cell organelles are bounded by two unit membranes- Mitochondria, Chloroplasts, Nucleus Non-membrane bound cell organelles are not bounded by membranes- Ribosomes (70S & 80S), Centrosomes, Cilia and flagella, Microtubules Answer : (a)
Q.29
living cell contains 60 -70% water, Water present in human body is ... ... [ CBSE 1992]
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a) 60-65%
0%
b) 55-60%
0%
c) 75 - 80%
0%
d) 65 - 70%
Explanation
The average adult male is about 60% water. The average adult woman is about 55% water because women naturally have more fatty tissue than men Answer : (b)
Q.30
Point at which polytene chromosomes appear attached in ... ... [ CBSE 1995 ]
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a) Centriole
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b) Chromocenter
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c) Centromere
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d) Cell reproduce by mitosis and meiosis
Explanation
Polytene chromosomes are infact formed by pairing of two somatic homologous chromosomes which undergo repeated endomitosis, forming a number of strands. These strands remain attached to a common large chromocentre of all polytene chromosomes and are rich in heterochromatin. Answer : (b)
Q.31
An outer covering membrane is absent over ... ... [ AFMC 2002 ] Explanation is provided please click on
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a) Nucleolus
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b) Lysosome
0%
c) Mitochondrion
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d) Plastid
Explanation
The outer covering membrane made up of the lipid bilayer is absent over the nucleolus. The boundary of the nucleus is called the nuclear envelope.It consists of two phospholipid bilayers: an outer membrane and an inner membrane. Nucleolus is present as a dark spherical spot inside the nucleus. It helps in the formation of the ribosomes proteins which help in the translation proc Answer : (a)
Q.32
olgi bodies produce .... ....
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a) Vesicles
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b) Lysosomes
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c) Centrosomes
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d) Both A and B
Explanation
The Golgi apparatus produces specialist vesicles or vessels for the transport of its products. Some of these have special wrappings or coatings that help identify the contents. Some vesicles are recyclable. Lysosomes are manufactured and budded into the cytoplasm by the Golgi apparatus with enzymes inside. Answer : (d)
Q.33
Assertion: Eukaryotic cells have the ability to adopt a variety of shapes and carry out directed movements. Reason: There are three principal types of protein filaments - microfilaments, micro-tubules and intermediate filaments which constitute the cytoskeleton ... ... [ AIIMS 2006 ]
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a) Both Assertion and Reason are true and Reason is the correct explanation of Assertion
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b) The Assertion and Reason are true but Reason is not correct explanation of Assertion
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c) Assertion is true but, Reason is false
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d) Assertion is false but, Reason is true
Explanation
Eukaryotic cells contain three types of filaments as microtubules, microfilaments and intermediate filaments which give definite shape to cell and also helps in directional movements Answer : (a)
Q.34
Virchow and Schleiden were ... ....
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a) Dutch biologist
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b) English biologists
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c) Austrian biologists
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d) German biologists
Explanation
Answer : (d)
Q.35
Histone octamer possesses ... .. [ JKCMEE 2011 ]
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a) 8 histones of 4 types
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b) 8 types of histones
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c) 6 types of histones
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d) 5 types of histones
Explanation
Histone octamer. A histone octamer is the eight protein complex found at the center of a nucleosome core particle. It consists of two copies of each of the four core histone proteins (H2A, H2B, H3 and H4). The octamer assembles when a tetramer, containing two copies of both H3 and H4, complexes with two H2A/H2B dimers. Answer : (a)
Q.36
on Q107) Which of the following pair lack the unit membrane?
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a) Nucleus and E.R.
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b) Mitochondria and chloroplast.
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c) Ribosome and nucleolus.
0%
d) Golgi body and lysosome.
Explanation
Answer:(c)
Q.37
Which in view of fluid mosaic model is correct with respect to the movement of lipids and proteins from one lipid monolayer to the other ? .... ... [ CBSE 2008 ] Explanation is provided, please click on
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a) Proteins can flip-flop, lipids cannot
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b) Neither proteins nor lipids can flip-flop
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c) Both lipids and proteins can flip-flop
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d) Lipids can rarely flip-flop, proteins cannot
Explanation
Transverse diffusion or flip-flop involves the movement of a lipid or protein from one membrane surface to the other. Unlike lateral diffusion, transverse diffusion is a fairly slow process due to the fact that a relatively significant amount of energy is required for flip-flopping to occur. Most large proteins do not flip-flop due to their extensive polar regions, which are unfavorable in the hydrophobic core of a membrane bilayer. This allows the asymmetry of membranes to be retained for long periods, which is an important aspect of cell regulation. Also because hydrophilic parts lipid or protein molecules would have to cross the membrane's hydrophobic core, lipid or protein molecules rarely flip transversely (flip-flop) across the membrane Answer : (d)
Q.38
Chromosomes present in prolonged prophase in the salivary gland of Drosophila are ... .... [ CPMT 1991]
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a) Polytene
0%
b) Lampbrush
0%
c) B - chromosomes
0%
d) Supernumerary chromosomes
Explanation
Polytene chromosomes are found during the interphase stage of the cell division in the nuclei of the salivary gland cells of the larvae of Diptera (fruitfly or Drosophila melanogaster). Polytene chromosomes are formed due to endoduplication, duplication without separation and replication of DNA without cell division Answer : (a)
Q.39
A chromosome carrying centromere at one end is ... ... [ AIIMS 2002 ]
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a) Acrocentric
0%
b) Telocentric
0%
c) Metacentric
0%
d) Submetacentric
Explanation
Depending on the position of the centromere, chromosomes are of the following types: Metacentric chromosome: The centromere is present right in the middle of the chromosome. It forms two equal arms of the chromosome. Submetacentric chromosome: The centromere is present a little away from the middle of the chromosome. It forms two unequal arms of the chromosome. Acrocentric chromosome: The centromere is present close to one of the ends of the chromosome. It forms one short and another quite long arm. Telocentric chromosome: A terminal centromere. There is only one arm of the chromosome with the centromere at the end. Answer : (b)
Q.40
membrane permeability is controlled by ... ... [CPMT 1992 ]
0%
a) Na+
0%
b) K+
0%
c) Both A and B
0%
d) Ca2+
Explanation
Permeability of cell membranes to sodium and potassium is regulated by internal calcium, which in turn is controlled by a calcium pump that utilizes ATP. Answer : (d)
Q.41
Disappearance of tadpole tail during metamorphosis is brought about by ... ... [ AMU 2010 ]
0%
a) Lysosomes
0%
b) Golgi bodies
0%
c) Peroxisomes
0%
d) Endoplasmic reticulum
Explanation
Disintegration of tadpole tail requires digestion of tail tissue, which is achieved by very high lysosomal enzymatic activity. Explanation: Lysosomes are single membrane bound small vacuole shaped organelles. These are formed from Golgi bodies. Lysosome stores a lot of digestive and hydrolysing enzymes. Lysosomal enzymes help macrophagic cells to digest cell debris that they remove. The enzymes could also be released inside the cell to achieve cell lysis. Answer : (a)
Q.42
Microfilaments are mainly composed of ... ... [ DPMT 2010 ]
0%
a) tubulin
0%
b) Myosin
0%
c) Actin
0%
d) Keratin
Explanation
Microfilaments are polymers of the protein actin and are 7 nm in diameter. Microtubules are composed of tubulin and are 25 nm in diameter. Microfilaments, also called actin filaments, are protein filaments in the cytoplasm of eukaryotic cells that form part of the cytoskeleton. They are primarily composed of polymers of actin, but are modified by and interact with numerous other proteins in the cell Answer : (c)
Q.43
A rrangement of ciliary microtubules is ... ... [ RPMT 2006 ]
0%
a) 9 + 2
0%
b) 9 + 4
0%
c) 9 + 3
0%
d) 9 + 9
Explanation
Flagella and cilia have a 9 + 2 arrangement of microtubules. This arrangement refers to the 9 fused pairs of microtubules on the outside of a cylinder, and the 2 unfused microtubules in the center Answer : (a)
Q.44
From the following select the statements that is true ... ... [ JKCET 2012 ]
0%
a) All cells have a cell wall
0%
b) Animal cells contain microtubules but plant cells do not have microtubules
0%
c) Golgi apparatus is found only in animal cells
0%
d) Chloroplasts are found in plant cells but not in prokaryotic or animal cells
Explanation
A prokaryote is a unicellular organism that lacks a membrane-bound nucleus, mitochondria, or any other membrane-bound organelle Cyanobacteria classified as prokaryotic, derive their energy through photosynthesis, but lack a nucleus or membrane bound organelles, like chloroplasts. In cyanobacteria, there are other membranous extensions into the cytoplasm called chromatophores which contain pigments. Chromatophores are light sensitive organelles where certain photoreceptor pigments are present whereas Chloroplast is an organelles that houses as a site for photosynthesis Option "d" correct Answer : (d)
Q.45
Circular DNA occurs in .... ... [ MPPMT 1995 ]
0%
a) Bacteria only
0%
b) Bacteria and chloroplasts
0%
c) All viruses
0%
d) Bacteria, chloroplasts and mitochondria
Explanation
A circular DNA occurs as a bacterial DNA, chloroplast and mitochondria DNA. Which forms a closed loop or a circle with no ends and contains the entire genome Answer : (d)
Q.46
Schleiden and Schwann proposed ... ..... [ JKCMEE 2004 ]
0%
a) Brownian movement
0%
b) Cell theory
0%
c) Protoplasm as physical basis of life
0%
d) None of the above
Explanation
Answer : (b)
Q.47
Assertion: A cell membrane shows fluid behavior Reason: A membrane is mosaic of diverse lipids and proteins. .... .... [ AIIMS 2008 ]
0%
a) Both Assertion and Reason are true and Reason is the correct explanation of Assertion
0%
b) The Assertion and Reason are true but Reason is not correct explanation of Assertion
0%
c) Assertion is true but, Reason is false
0%
d) Assertion is false but, Reason is true
Explanation
Answer : (a)
Q.48
When a lysosome fuses with a phagosome, it results in the formation of ... .. [ KCET 2003 ]
0%
a) Secondary lysosome
0%
b) Primary lysosome
0%
c) Autophagic vacuole
0%
d) Residual body
Explanation
Lysosomes are membrane-bound organelles which contain acid hydrolases or digestive enzymes that digest excess or worn out organelles, food particles, engulfed viruses or bacteria and macromolecules. Phagosome can be defined as the vesicle which is formed around the material engulfed by a phagocyte through phagocytosis. The fusion of a lysosome with a phagosome gives rise to secondary lysosomes Answer : (a)
Q.49
Respiratory enzymes occur in ... .... [ WB 2009 ]
0%
a) Chloroplasts
0%
b) Mitochondria
0%
c) Lysosome
0%
d) Peroxisomes
Explanation
The enzymatic reactions of cellular respiration begin in the cytoplasm, but most of the reactions occur in the mitochondria. Cellular respiration occurs in the double-membrane organelle called the mitochondrion. The folds in the inner membrane are called cristae. Answer : (b)
Q.50
lampbrush chromosomes found in oocytes occur in ... ... [ AFMC 1999 ]
0%
a) Leptotene
0%
b) Zygotene
0%
c) Pachytene
0%
d) Diplotene
Explanation
Lampbrush chromosome (immature eggs) of most animals, except mammals. Chromosomes transform into the lampbrush form during the diplotene stage of meiotic prophase I due to an active transcription of many genes. They are highly extended meiotic half-bivalents, each consisting of 2 sister chromatids. Answer : (d)
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