BMST BMST - Basic Math and Science Genetics and Heredity Questions and Answers 1 — Questions and Answers
Question 1: What is a gene?
- A segment of DNA that codes for a protein (Correct answer)
- A type of RNA molecule
- A chromosome pair
- A cell membrane protein
Correct answer: A segment of DNA that codes for a protein
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?
- Heterozygous
- Homozygous (Correct answer)
- Dominant
- Recessive
Correct answer: Homozygous
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)?
- 1/4 (Correct answer)
- 1/2
- 3/4
- 0
Correct answer: 1/4
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?
- Cytosine
- Guanine
- Thymine (Correct answer)
- Uracil
Correct answer: Thymine
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?
- Dominant
- Codominant
- Recessive (Correct answer)
- Lethal
Correct answer: Recessive
A recessive allele is only expressed in the phenotype when the organism is homozygous recessive.
Question 6: How many chromosomes are found in normal human somatic (body) cells?
- 23
- 46 (Correct answer)
- 48
- 44
Correct answer: 46
Human somatic cells are diploid and contain 46 chromosomes arranged in 23 pairs.
BMST BMST - Basic Math and Science Genetics and Heredity Questions and Answers 1
What is a gene?