Question 1

Which of the following best describes homologous chromosomes?

Accepted Answer

They carry the same genes but may have different alleles.

Question 2

A geneticist is studying a trait controlled by multiple genes, such as human skin color. What is the correct term for this type of inheritance?

Accepted Answer

Polygenic

Question 3

A cell with 8 total chromosomes (4 pairs) is described as:

Accepted Answer

Diploid

Question 4

In a dihybrid cross between two RrSs individuals (R = red wings, r = white wings, S = spotted body, s = plain body), what is the expected phenotypic ratio among the offspring?

Accepted Answer

$$9:3:3:1$$

Question 5

If two carrier parents for cystic fibrosis (genotype Cc) have a child, what is the probability that the child will be affected by the disease?

Accepted Answer

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

Question 6

A karyotype reveals an individual with 47 chromosomes, including two X chromosomes and one Y chromosome (XXY). What condition does this indicate?

Accepted Answer

Klinefelter syndrome

Question 7

Which process most likely caused the presence of an extra chromosome in Klinefelter syndrome?

Accepted Answer

Nondisjunction

Question 8

A scientist observes a virus with glycoproteins on its surface. What is the primary function of these glycoproteins?

Accepted Answer

To attach to host cells

Question 9

Which of the following is true about all viruses?

Accepted Answer

They have genetic material and a protein coat.

Question 10

A virus that infects bacteria is called a:

Accepted Answer

Bacteriophage

Question 11

In a cross between Hh and hh individuals, what percentage of the offspring are expected to be heterozygous?

Accepted Answer

50\%

Question 12

Which of the following best defines an allele?

Accepted Answer

A gene version

Question 13

Which of the following is an example of a phenotype?

Accepted Answer

Blue eyes

Question 14

What is the probability that the offspring of a cross between Nn and nn will display the recessive phenotype?

Accepted Answer

$$0.5$$

Question 15

Which of the following best describes a genotype?

Accepted Answer

Genetic makeup of an organism

Question 16

Why does cystic fibrosis persist in human populations despite being a harmful disorder?

Accepted Answer

Carriers show no symptoms.

Question 17

Which of the following best describes the genetic material of a virus?

Accepted Answer

It stores instructions for making new viruses.

Question 18

Symptoms of a viral infection in humans are typically caused by:

Accepted Answer

Both virus damage and immune response

Question 19

If two parents are both heterozygous for a trait (Bb × Bb), what is the probability that their child will be homozygous recessive?

Accepted Answer

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

Question 20

Which of the following is true about homozygous individuals?

Accepted Answer

They have two identical alleles for a gene.

Practice Exam 4: Genetics, Punnett Squares, and Viruses Study Guidance

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