Question 1

Which of the following best describes the difference between a genotype and a phenotype?

Accepted Answer

Genotype refers to the genetic makeup of an organism, while phenotype refers to the observable traits resulting from that genetic makeup.

Question 2

A plant with genotype RrTt is crossed with a plant with genotype RRTT. If R = red petals, r = white petals, T = tall plant, and t = short plant, what is the expected phenotypic ratio among the offspring?

Accepted Answer

All offspring will have red petals and be tall, since all offspring will have at least one dominant R and one dominant T allele.

Question 3

Which of the following best explains the difference between incomplete dominance and codominance?

Accepted Answer

Incomplete dominance results in a blending of traits, while codominance results in both traits being fully expressed.

Question 4

Given the DNA template strand TCG, what is the corresponding mRNA codon produced during transcription?

Accepted Answer

$$	ext{AGC}$$

Question 5

If the DNA template TCG mutates to ACG, and the original mRNA codon AGC codes for serine while the mutated codon UGC codes for cysteine, what type of mutation has occurred?

Accepted Answer

Missense mutation

Question 6

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

Accepted Answer

tRNA carries amino acids to the ribosome and matches its anticodon to the mRNA codon.

Question 7

Which of the following is a function of helper T cells in the immune system?

Accepted Answer

They activate B lymphocytes and cytotoxic T cells by releasing cytokines.

Question 8

A pedigree shows a trait that appears in every generation and affects both males and females equally. What is the most likely mode of inheritance?

Accepted Answer

Autosomal dominant

Question 9

Which of the following best describes the difference between DNA and RNA?

Accepted Answer

DNA is double-stranded and contains deoxyribose, while RNA is single-stranded and contains ribose.

Question 10

Which of the following best describes a frameshift mutation?

Accepted Answer

A mutation that results from the insertion or deletion of nucleotides, altering the reading frame of the gene.

Question 11

Which of the following is an example of a nonspecific defense mechanism in the human body?

Accepted Answer

Inflammatory response at the site of injury

Question 12

A patient is diagnosed with an immunodeficiency disease. Which of the following best describes their condition?

Accepted Answer

Their immune system is unable to mount an effective response to pathogens.

Question 13

Which of the following best describes the process of gene therapy?

Accepted Answer

Replacing a defective gene with a functional copy to treat a genetic disorder.

Question 14

Which of the following is the correct sequence of events in protein synthesis?

Accepted Answer

Replication → Transcription → Translation

Question 15

Which of the following best describes the function of perforin in the immune response?

Accepted Answer

It forms pores in the membranes of infected cells, leading to cell lysis.

Question 16

A test cross is performed between a plant with an unknown genotype for a dominant trait and a homozygous recessive plant. If all offspring display the dominant phenotype, what is the genotype of the unknown parent?

Accepted Answer

Homozygous dominant

Question 17

Which of the following best describes recombinant DNA (rDNA)?

Accepted Answer

DNA formed by combining genetic material from two different species.

Question 18

Which of the following is a real-world example of a polygenic trait?

Accepted Answer

Height in humans

Question 19

Which of the following best describes the role of clonal selection in the immune response?

Accepted Answer

It ensures that only B and T cells specific to an antigen are activated and proliferate.

Question 20

Which of the following is the correct complementary base pairing for the DNA sequence 5'-ATCG-3'?

Accepted Answer

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

Unit 4 Study Guide: Genetics, Protein Synthesis, and Immunology

Study Guide - Practice Questions

Study Guide - Flashcards