BMST BMST - Basic Math and Science Genetics and Heredity Questions and Answers

Question 1

What is a gene?

Accepted Answer

A segment of DNA that codes for a protein

Answer

A gene is a specific segment of DNA that contains the instructions for making a protein.

Question 2

What term describes an organism that has two identical alleles for a trait?

Accepted Answer

Homozygous

Answer

Homozygous means both alleles for a gene are the same (e.g., TT or tt).

Question 3

In a Punnett square cross of Tt × Tt, what fraction of offspring are expected to be TT (homozygous dominant)?

Accepted Answer

1/4

Answer

A Tt × Tt cross produces a 1 TT : 2 Tt : 1 tt ratio, so 1/4 of offspring are TT.

Question 4

Which nitrogenous base pairs with adenine in a DNA molecule?

Accepted Answer

Thymine

Answer

In DNA, adenine always pairs with thymine via two hydrogen bonds.

Question 5

What term describes an allele that is expressed only when two copies are present?

Accepted Answer

Recessive

Answer

A recessive allele is only expressed in the phenotype when the organism is homozygous recessive.

BMST - Basic Math and Science Test Practice Test