Question 1

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

Accepted Answer

A chromosome is a single DNA molecule with associated proteins, while a centromere is the region where sister chromatids are joined.

Question 2

During which phase of meiosis does crossing over occur, and what is its biological significance?

Accepted Answer

Crossing over occurs during prophase I, increasing genetic diversity among gametes.

Question 3

What is the function of the maturation promoting factor (MPF) in the cell cycle?

Accepted Answer

MPF triggers the cell's entry into mitosis by phosphorylating key proteins.

Question 4

Which of the following best defines a metaphase plate?

Accepted Answer

The imaginary plane where chromosomes align during metaphase.

Question 5

A cell with 46 chromosomes undergoes mitosis. How many chromosomes will each daughter cell have after division?

Accepted Answer

Each daughter cell will have 46 chromosomes.

Question 6

Which of the following best describes the molecular makeup of a nucleotide in DNA?

Accepted Answer

A nucleotide consists of a phosphate group, a deoxyribose sugar, and a nitrogenous base.

Question 7

What is the role of DNA polymerase during DNA replication?

Accepted Answer

DNA polymerase synthesizes new DNA strands by adding nucleotides to the template strand.

Question 8

Which of the following statements about homologous chromosomes is correct?

Accepted Answer

Homologous chromosomes carry the same genes but may have different alleles.

Question 9

What is the difference between introns and exons in eukaryotic genes?

Accepted Answer

Exons are coding regions that remain in mRNA, while introns are non-coding regions that are removed.

Question 10

A frameshift mutation occurs when:

Accepted Answer

A nucleotide is inserted or deleted, altering the reading frame of the genetic code.

Question 11

Which of the following best describes the function of a chaperonin?

Accepted Answer

A chaperonin assists in the proper folding of newly synthesized proteins.

Question 12

If a somatic cell has a diploid number of $$2n = 46$$, what is the haploid number in the gametes?

Accepted Answer

The haploid number is $$n = 23.$$

Question 13

Which site on the ribosome is responsible for holding the tRNA carrying the growing polypeptide chain during translation?

Accepted Answer

The P site holds the tRNA carrying the growing polypeptide chain.

Question 14

What is the purpose of a stop codon during translation?

Accepted Answer

A stop codon signals the termination of protein synthesis.

Question 15

Which of the following best describes the difference between cell plate formation and cleavage furrow formation?

Accepted Answer

Cell plate formation occurs in plant cells, while cleavage furrow formation occurs in animal cells during cytokinesis.

Question 16

Which phase of the cell cycle is characterized by DNA replication?

Accepted Answer

S phase of interphase is characterized by DNA replication.

Question 17

What is a locus in genetics?

Accepted Answer

A locus is the specific physical location of a gene on a chromosome.

Question 18

During which stage of mitosis do chromosomes align at the metaphase plate?

Accepted Answer

Chromosomes align at the metaphase plate during metaphase.

Question 19

Which of the following best describes the function of the centrosome?

Accepted Answer

The centrosome organizes microtubules and is the site of spindle formation during cell division.

Question 20

How many daughter cells are produced at the end of meiosis, and how do they differ from those produced by mitosis?

Accepted Answer

Meiosis produces four genetically unique daughter cells, while mitosis produces two genetically identical daughter cells.

Unit 4 Biology Test Review – Step-by-Step Study Guidance

Study Guide - Practice Questions