1. What is the main purpose of the Krebs cycle?
A. To produce glucose
B. To generate ATP and electron carriers for the electron transport
chain
C. To produce oxygen
D. To synthesize proteins
Answer: B) To generate ATP and electron carriers for the electron
transport chain
Rationale: The Krebs cycle (citric acid cycle) generates high-energy
electron carriers (NADH, FADH2) and a small amount of ATP, which
are used in the electron transport chain to produce large amounts of
ATP.
2. Which of the following is the function of the cytoskeleton?
A. Protein synthesis
B. Energy production
C. Cell shape and movement
D. DNA replication
Answer: C) Cell shape and movement
Rationale: The cytoskeleton provides structural support to the cell,
helping maintain its shape and enabling cellular movement.
,3. What is the result of crossing over during meiosis?
A. The production of genetically identical gametes
B. The exchange of genetic material between homologous
chromosomes
C. The formation of four daughter cells
D. The replication of DNA
Answer: B) The exchange of genetic material between homologous
chromosomes
Rationale: Crossing over occurs during meiosis, where homologous
chromosomes exchange segments of their genetic material, leading to
genetic variation in the offspring.
4. Which macromolecule serves as the primary energy source for living
organisms?
A. Carbohydrates
B. Proteins
C. Lipids
D. Nucleic acids
Answer: A) Carbohydrates
Rationale: Carbohydrates are the primary energy source for most living
organisms because they are easily broken down into glucose, which is
used to produce ATP.
, 5. During which stage of cellular respiration is the majority of ATP
produced?
A. Glycolysis
B. Krebs cycle
C. Electron transport chain
D. Fermentation
Answer: C) Electron transport chain
Rationale: The majority of ATP in cellular respiration is produced in
the electron transport chain through oxidative phosphorylation.
6. Which molecule carries the genetic code from the nucleus to the
ribosome?
A. mRNA
B. tRNA
C. rRNA
D. DNA
Answer: A) mRNA
Rationale: Messenger RNA (mRNA) carries the genetic code
transcribed from DNA to the ribosome for protein synthesis.
7. Which structure in the cell is responsible for packaging and shipping
proteins?
A. To produce glucose
B. To generate ATP and electron carriers for the electron transport
chain
C. To produce oxygen
D. To synthesize proteins
Answer: B) To generate ATP and electron carriers for the electron
transport chain
Rationale: The Krebs cycle (citric acid cycle) generates high-energy
electron carriers (NADH, FADH2) and a small amount of ATP, which
are used in the electron transport chain to produce large amounts of
ATP.
2. Which of the following is the function of the cytoskeleton?
A. Protein synthesis
B. Energy production
C. Cell shape and movement
D. DNA replication
Answer: C) Cell shape and movement
Rationale: The cytoskeleton provides structural support to the cell,
helping maintain its shape and enabling cellular movement.
,3. What is the result of crossing over during meiosis?
A. The production of genetically identical gametes
B. The exchange of genetic material between homologous
chromosomes
C. The formation of four daughter cells
D. The replication of DNA
Answer: B) The exchange of genetic material between homologous
chromosomes
Rationale: Crossing over occurs during meiosis, where homologous
chromosomes exchange segments of their genetic material, leading to
genetic variation in the offspring.
4. Which macromolecule serves as the primary energy source for living
organisms?
A. Carbohydrates
B. Proteins
C. Lipids
D. Nucleic acids
Answer: A) Carbohydrates
Rationale: Carbohydrates are the primary energy source for most living
organisms because they are easily broken down into glucose, which is
used to produce ATP.
, 5. During which stage of cellular respiration is the majority of ATP
produced?
A. Glycolysis
B. Krebs cycle
C. Electron transport chain
D. Fermentation
Answer: C) Electron transport chain
Rationale: The majority of ATP in cellular respiration is produced in
the electron transport chain through oxidative phosphorylation.
6. Which molecule carries the genetic code from the nucleus to the
ribosome?
A. mRNA
B. tRNA
C. rRNA
D. DNA
Answer: A) mRNA
Rationale: Messenger RNA (mRNA) carries the genetic code
transcribed from DNA to the ribosome for protein synthesis.
7. Which structure in the cell is responsible for packaging and shipping
proteins?
