The primary function of the smooth endoplasmic reticulum is to synthesize proteins destined for secretion or insertion into membranes.
Correct Answer
False
The smooth endoplasmic reticulum is primarily involved in lipid synthesis, detoxification of drugs and poisons, and storage of calcium ions. Protein synthesis for secretion or membrane insertion occurs on ribosomes of the rough endoplasmic reticulum.
Question 2
Both prokaryotic and eukaryotic cells contain membrane-bound organelles such as mitochondria and endoplasmic reticulum.
Correct Answer
False
Prokaryotic cells do not contain membrane-bound organelles like mitochondria or endoplasmic reticulum. These organelles are characteristic features of eukaryotic cells.
Question 3
Plant cells use chloroplasts to perform photosynthesis and mitochondria to perform cellular respiration.
Correct Answer
True
Plant cells contain chloroplasts for photosynthesis, which converts light energy into chemical energy, and mitochondria for cellular respiration, which breaks down glucose to produce ATP.
Question 4
During prophase of mitosis, the nuclear envelope completely reforms around the separated chromosomes.
Correct Answer
False
During prophase, the nuclear envelope breaks down. The nuclear envelope reforms around the two sets of separated chromosomes during telophase, not prophase.
Question 5
Lysosomes are responsible for breaking down waste materials and cellular debris using hydrolytic enzymes.
Correct Answer
True
Lysosomes are membrane-bound organelles containing a variety of hydrolytic enzymes that digest macromolecules, old organelles, and cellular debris.
Question 6
During cellular respiration, the majority of ATP is generated during glycolysis.
Correct Answer
False
Glycolysis produces a small net amount of ATP (2 ATP molecules). The majority of ATP during cellular respiration is generated during oxidative phosphorylation through chemiosmosis in the electron transport chain.
Question 7
Water molecules cross the cell membrane exclusively through specialized protein channels called aquaporins.
Correct Answer
False
While aquaporins significantly increase the rate of water transport across cell membranes, water molecules can also slowly diffuse directly through the lipid bilayer, although at a much slower rate.
Question 8
During anaphase of mitosis, sister chromatids separate and move to opposite poles of the cell.
Correct Answer
True
Anaphase is characterized by the separation of sister chromatids, which are then considered individual chromosomes, and their movement towards opposite poles of the cell.
Question 9
Ribosomes are responsible for synthesizing lipids and steroids in the cell.
Correct Answer
False
Ribosomes are the sites of protein synthesis (translation). The synthesis of lipids and steroids primarily occurs in the smooth endoplasmic reticulum.
Question 10
Facilitated diffusion requires ATP to move molecules across the cell membrane down their concentration gradient.
Correct Answer
False
Facilitated diffusion is a type of passive transport that uses transport proteins to move molecules across the membrane down their concentration gradient without the direct expenditure of ATP.
Question 11
Chloroplasts contain their own DNA and ribosomes, suggesting an endosymbiotic origin.
Correct Answer
True
Chloroplasts, like mitochondria, possess their own circular DNA and ribosomes, which are similar to those found in bacteria. This supports the endosymbiotic theory, suggesting they originated from free-living prokaryotes engulfed by ancestral eukaryotic cells.
Question 12
In the cell cycle, DNA replication occurs during the G1 phase of interphase.
Correct Answer
False
DNA replication, where the cell synthesizes an exact copy of all its DNA, occurs during the S (synthesis) phase of interphase, not the G1 phase.
Question 13
The Golgi apparatus modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles.
Correct Answer
True
The Golgi apparatus is a complex of flattened sacs that functions to modify, sort, and package proteins and lipids synthesized in the ER, preparing them for secretion from the cell or delivery to other cellular destinations.
Question 14
The Calvin cycle of photosynthesis directly produces oxygen as a byproduct.
Correct Answer
False
Oxygen is produced as a byproduct during the light-dependent reactions of photosynthesis when water molecules are split. The Calvin cycle uses ATP and NADPH to fix carbon dioxide into sugar.
Question 15
The movement of water across a selectively permeable membrane from an area of lower solute concentration to an area of higher solute concentration is called osmosis.
Correct Answer
True
Osmosis is the net movement of water molecules across a selectively permeable membrane from a region of higher water potential (lower solute concentration) to a region of lower water potential (higher solute concentration).
Question 16
Microtubules are primarily responsible for anchoring organelles in place within the cytoplasm.
Correct Answer
False
While microtubules are part of the cytoskeleton and contribute to cell shape, intermediate filaments are primarily responsible for anchoring organelles and providing structural reinforcement, resisting tension. Microtubules are more involved in intracellular transport and cell division.
Question 17
Photosynthesis converts light energy into chemical energy stored in glucose molecules.
Correct Answer
True
Photosynthesis is the process by which light energy is captured by chlorophyll and converted into chemical energy, which is then used to synthesize organic compounds like glucose from carbon dioxide and water.
Question 18
The electron transport chain in cellular respiration is located in the cytoplasm.
Correct Answer
False
The electron transport chain, a crucial component of oxidative phosphorylation in cellular respiration, is located on the inner mitochondrial membrane, not in the cytoplasm.
Question 19
Active transport mechanisms always move substances against their concentration gradient.
Correct Answer
True
Active transport mechanisms require energy to move substances across a cell membrane from a region of lower concentration to a region of higher concentration, against their concentration gradient.
Question 20
The primary purpose of lactic acid fermentation is to produce a large amount of ATP in the absence of oxygen.
Correct Answer
False
Lactic acid fermentation's primary purpose is to regenerate NAD+ from NADH so that glycolysis can continue to produce a small amount of ATP in the absence of oxygen. It does not produce a large amount of ATP itself.
Question 21
The inner mitochondrial membrane is highly folded into cristae to increase the surface area for oxidative phosphorylation.
Correct Answer
True
The inner mitochondrial membrane is extensively folded into cristae, which significantly increases its surface area, providing more space for the electron transport chain components and ATP synthase required for oxidative phosphorylation.
Question 22
Cytokinesis is the division of the cytoplasm, which typically occurs concurrently with the final stages of mitosis.
Correct Answer
True
Cytokinesis is the process by which the cytoplasm of a single eukaryotic cell divides into two daughter cells, usually following nuclear division (mitosis).