Question 1

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

Accepted Answer

Anaphase

Question 2

A researcher observes a cell with two nuclei forming, each with a complete set of chromosomes, but the cytoplasm has not yet divided. Which stage is this cell most likely in?

Accepted Answer

Telophase

Question 3

Which of the following best explains why X-linked recessive disorders are more common in males than in females?

Accepted Answer

Males have only one X chromosome, so a single recessive allele will cause the disorder.

Question 4

A plant with genotype $$RrYy is $$crossed with a plant with genotype $$rryy. $$What is the probability that an offspring will have the genotype $$Rryy$$? (Assume independent assortment.)

Accepted Answer

$$\frac{1}{4}$$

Question 5

Which enzyme is responsible for unwinding the DNA double helix during DNA replication?

Accepted Answer

Helicase

Question 6

A woman who is a carrier for sickle cell disease (heterozygous) and a man who is also a carrier have a child. What is the probability that their child will have sickle cell disease?

Accepted Answer

$$\frac{1}{4}$$

Question 7

Which of the following best describes the difference between mitosis and meiosis?

Accepted Answer

Mitosis produces two genetically identical cells; meiosis produces four genetically different cells.

Question 8

Which process increases genetic variation during meiosis by exchanging genetic material between homologous chromosomes?

Accepted Answer

Crossing over

Question 9

A patient is diagnosed with Down Syndrome. Which chromosomal abnormality is responsible for this condition?

Accepted Answer

Trisomy 21

Question 10

Which of the following statements about the genetic code is TRUE?

Accepted Answer

The genetic code is universal, meaning it is shared by almost all organisms.

Question 11

Which molecule is responsible for adding RNA primers during DNA replication?

Accepted Answer

Primase

Question 12

A mutation changes a codon from $$UAC ($$tyrosine) to $$UAA ($$stop codon). What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 13

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

Accepted Answer

tRNA brings amino acids to the ribosome and matches them to the mRNA codon.

Question 14

A cell is observed to have a Barr body. What does this indicate about the cell?

Accepted Answer

It is a female cell with an inactivated X chromosome.

Question 15

Which of the following is an example of incomplete dominance?

Accepted Answer

A pink snapdragon flower resulting from a cross between red and white flowers

Question 16

Which scientist(s) demonstrated that DNA, not protein, is the genetic material using bacteriophages?

Accepted Answer

Hershey and Chase

Question 17

If a DNA sample contains 30% adenine, according to Chargaff’s rules, what percentage of the sample is cytosine?

Accepted Answer

20%

Question 18

Which of the following best explains why mitochondrial disorders are inherited only from the mother?

Accepted Answer

Sperm mitochondria are destroyed after fertilization.

Question 19

A cell fails to pass the G1 checkpoint due to DNA damage. What is the most likely outcome for this cell?

Accepted Answer

It will enter the G0 phase and stop dividing.

Question 20

Which of the following is a real-world example of pleiotropy?

Accepted Answer

Sickle cell disease affecting multiple organs

BIO 101 Exam 3 Study Guide: The Cell Cycle, Meiosis, Mendelian Genetics, Chromosomal Inheritance, Molecular Genetics, and Gene Expression

Study Guide - Practice Questions

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