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Unit-3 The cell

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A. ribosomes
B. chromosomes
C. lysosomes
D. vacuoles
Answer: Chromatin threads condense and coil into distinct chromosomes when the cell divides.
A. passage of the cell wall
B. movement of chloroplasts
C. exchange of materials between the nucleus and cytoplasm
D. entry of all organelles into the nucleus
Answer: Nucleopores permit the movement of molecules such as RNA and proteins between nucleus and cytoplasm.
A. lack a nucleus
B. contain two nuclei
C. have no plasma membrane
D. are filled with chloroplasts
Answer: Mammalian red blood cells are enucleated, lacking a nucleus to make room for hemoglobin.
A. ribosomes
B. lysosomes
C. centrioles
D. mitochondria
Answer: Mitochondria are the site of aerobic cellular respiration where energy is released.
A. cisternae
B. cristae
C. grana
D. tonoplasts
Answer: The inner mitochondrial membrane is folded into cristae, which increase the surface area for respiration.
A. a single membrane
B. three membranes
C. two membranes
D. no membrane
Answer: A mitochondrion has an outer and an inner membrane enclosing the matrix.
A. DNA
B. cell wall
C. starch grains
D. chlorophyll
Answer: Mitochondria possess their own DNA and ribosomes, supporting their semi-autonomous nature.
A. lysosomes
B. ribosomes
C. vacuoles
D. mitochondria
Answer: Mitochondria generate ATP during cellular respiration.
A. stroma
B. matrix
C. cytosol
D. nucleoplasm
Answer: The matrix is the fluid filling the inner space of the mitochondrion.
A. lysosomes
B. centrioles
C. ribosomes
D. vacuoles
Answer: Ribosomes read mRNA to build proteins, so they are the sites of protein synthesis.
A. RNA and proteins
B. lipids and sugars
C. DNA and cellulose
D. starch and proteins
Answer: Each ribosome is formed of ribosomal RNA and proteins arranged in two subunits.
A. smooth endoplasmic reticulum
B. lysosome
C. vacuole
D. rough endoplasmic reticulum
Answer: Ribosomes stud the surface of the rough ER, giving it a granular appearance.
A. only outside the cell
B. within the cell itself
C. only inside the nucleus
D. in the cell wall
Answer: Free ribosomes make proteins needed inside the cell, whereas ribosomes on rough ER make proteins for export.
A. lipid synthesis
B. photosynthesis
C. protein synthesis
D. digestion of waste
Answer: The rough ER carries ribosomes that synthesize proteins for transport out of the cell.
A. lipids
B. proteins
C. DNA
D. cellulose
Answer: The smooth ER lacks ribosomes and is involved in lipid and steroid synthesis.
A. storage of water
B. production of ATP
C. digestion of food
D. transport of materials within the cell
Answer: The ER network transports materials inside the cell and connects different organelles.
A. chlorophyll inside it
B. ribosomes on its surface
C. peptidoglycan in its wall
D. lysosomes attached to it
Answer: Ribosomes attached to the outer surface give the rough ER its granular look.
A. Lipids
B. Enzymes
C. Ribosomes
D. Membranes
Answer: The smooth ER has no ribosomes, so it does not synthesize proteins.
A. nuclear membrane
B. cell wall
C. chloroplast
D. nucleolus
Answer: The ER extends from the nuclear membrane to the cell membrane, forming a connected network.
A. photosynthesis
B. cellular respiration
C. protein synthesis on ribosomes
D. packaging and secretion of materials
Answer: The Golgi apparatus modifies, packages, and secretes proteins and other materials.
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