Question 1

Which phase of the cell cycle is characterized by DNA replication, and what is the main enzyme responsible for this process?

Accepted Answer

S phase; DNA polymerase

Question 2

A cell with 46 chromosomes undergoes mitosis. How many chromosomes will each daughter cell have after cytokinesis, and what is their genetic relationship to the parent cell?

Accepted Answer

46 chromosomes; genetically identical

Question 3

During which stage of mitosis do sister chromatids separate and move toward opposite poles of the cell?

Accepted Answer

Anaphase

Question 4

Which of the following best describes the difference between chromatin and chromosomes?

Accepted Answer

Chromatin is uncondensed DNA for normal function; chromosomes are condensed DNA for cell division.

Question 5

Which of the following cells is most likely to be found in the G₀ phase?

Accepted Answer

Mature neuron

Question 6

What is the main function of checkpoints in the cell cycle?

Accepted Answer

To maintain the integrity and proper regulation of the cell cycle by monitoring for errors

Question 7

Which of the following statements about meiosis is correct?

Accepted Answer

Meiosis produces four haploid cells that are genetically unique.

Question 8

A mutation that adds or deletes a nucleotide from a gene is likely to cause a frameshift. Why are frameshift mutations usually more damaging than substitutions?

Accepted Answer

They change the reading frame, altering every amino acid downstream.

Question 9

Given the DNA sequence $$5'	ext{-}ATGCGT-3'$$ , what is the corresponding mRNA sequence produced during transcription?

Accepted Answer

$$5'	ext{-}UACGCA-3'$$

Question 10

Which of the following best describes the role of tRNA during translation?

Accepted Answer

tRNA brings specific amino acids to the ribosome by matching its anticodon to the mRNA codon.

Question 11

A woman with genotype $$X^R X^r ($$carrier for red-green color blindness) and a man with genotype $$X^R Y$$ have children. What is the probability that a son will be color blind?

Accepted Answer

$$25\%$$

Question 12

Which of the following is a correct statement about autosomes and sex chromosomes in human somatic cells?

Accepted Answer

Somatic cells have 44 autosomes and 2 sex chromosomes.

Question 13

Which of the following best explains why sex-linked conditions are more common in men than in women?

Accepted Answer

Men have only one X chromosome, so a single recessive allele will be expressed.

Question 14

Which of the following is an example of polygenic inheritance?

Accepted Answer

Height in humans

Question 15

If a cell fails a checkpoint and cannot repair the damage, what is the most likely outcome?

Accepted Answer

The cell will undergo apoptosis (programmed cell death).

Question 16

Which of the following best describes the difference between a gene and a chromosome?

Accepted Answer

A gene is a segment of DNA that codes for a protein; a chromosome is a long DNA molecule containing many genes.

Question 17

Which of the following best describes the function of mRNA?

Accepted Answer

It carries the DNA code from the nucleus to the ribosome for protein synthesis.

Question 18

A person with genotype $$I^A i$$ and a person with genotype $$I^B i$$ have a child. What is the probability that the child will have blood type O?

Accepted Answer

$$25\%$$

Question 19

Which of the following is a function of proteins in the human body?

Accepted Answer

Speeding up chemical reactions as enzymes

Question 20

Which of the following best describes a karyotype and its use?

Accepted Answer

A karyotype is an arrangement of all chromosome pairs by size and structure, used to detect chromosomal abnormalities.

BIO 231 Exam 3 Study Guide: Cell Cycle, Genetics, and Protein Synthesis

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