Question 1

Which chromosomal abnormality is indicated by the presence of three copies of chromosome 21 in a human karyotype, as shown in the first image?

Accepted Answer

Down syndrome (Trisomy 21)

Question 2

Gregor Mendel’s experiments with pea plants established that traits are passed from parents to offspring in predictable ways. Which principle did Mendel’s work help to establish?

Accepted Answer

Principle of independent assortment

Question 3

In the Drosophila cross shown in the third image, what is the genotype of the offspring labeled 'Black vestigial'?

Accepted Answer

b b vg vg

Question 4

Which molecule is responsible for carrying genetic information in chromosomes, as demonstrated by Avery, MacLeod, and McCarty in 1944?

Accepted Answer

DNA

Question 5

The structure of DNA is described as a double helix. Which scientists are credited with elucidating this structure in 1953?

Accepted Answer

Watson, Crick, and Franklin

Question 6

Which of the following is NOT a characteristic of RNA compared to DNA?

Accepted Answer

RNA contains deoxyribose as its sugar

Question 7

During gene expression, what is the process called in which DNA is used to construct a complementary RNA sequence?

Accepted Answer

Transcription

Question 8

Which equation correctly represents the diploid number of chromosomes in humans?

Accepted Answer

$$2n = 46$$

Question 9

A mutation in the gene encoding hemoglobin results in sickle-cell anemia. Which amino acid substitution is responsible for this disease?

Accepted Answer

Glutamic acid replaced by valine

Question 10

Which model organism is commonly used to study disorders of the nervous system and cancer, as shown in the images and study materials?

Accepted Answer

Drosophila melanogaster

Question 11

What is the function of transfer RNA (tRNA) during translation?

Accepted Answer

Recognizes mRNA codons and carries the proper amino acid for protein assembly

Question 12

Which of the following best describes the relationship between genotype and phenotype?

Accepted Answer

Genotype is the set of alleles for a trait, and phenotype is the observable expression of those alleles

Question 13

Which equation represents the reduction in chromosome number during meiosis?

Accepted Answer

$$2n \rightarrow n$$

Question 14

Which of the following is a plausible reason why model organisms like Drosophila melanogaster are used in genetic studies?

Accepted Answer

They produce many offspring and are easy to grow

Question 15

Which of the following statements about the Chromosome Theory of Inheritance is correct?

Accepted Answer

Genes reside on chromosomes and are transmitted through gametes

Question 16

Which equation represents complementary base pairing in DNA?

Accepted Answer

$$A = T$$

Question 17

A scientist is studying a mutation in Drosophila that changes eye color from red to white. What term describes the alternate forms of the gene responsible for this trait?

Accepted Answer

Alleles

Question 18

Which model organism is used to study cardiovascular disease, as indicated in the study materials?

Accepted Answer

Danio rerio (zebrafish)

Question 19

Which process involves the synthesis of proteins directed by information encoded in mRNA?

Accepted Answer

Translation

Question 20

A patient with sickle-cell anemia has two mutant copies of the hemoglobin gene. What is the effect of this mutation on red blood cells?

Accepted Answer

Red blood cells become sickle-shaped, deformed, and fragile

Ch1 Introduction to Genetics: Foundations, Key Concepts, and Model Organisms

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