Gaokao Exam Biology: Genetics and Evolution

Question 1

In a monohybrid cross between two heterozygous parents (Aa × Aa), what is the expected phenotypic ratio in the offspring?

Accepted Answer

3:1

Answer

1:1

Answer

1:2:1

Answer

2:1

Question 2

Which molecule carries the genetic instructions from the nucleus to the ribosome during protein synthesis?

Accepted Answer

mRNA

Answer

tRNA

Answer

rRNA

Answer

DNA

Question 3

Darwin's theory of natural selection is best described as:

Accepted Answer

Individuals with favorable traits survive and reproduce more successfully

Answer

Organisms acquire traits by use or disuse during their lifetime

Answer

Evolution occurs through random genetic mutations only

Answer

All members of a species evolve simultaneously

Question 4

A sex-linked recessive trait is carried on the X chromosome. If the mother is a carrier (X^A X^a) and the father is unaffected (X^A Y), what percentage of their sons will be affected?

Accepted Answer

50%

Answer

0%

Answer

25%

Answer

100%

Question 5

Which term describes a mutation that changes a single nucleotide base in the DNA sequence?

Accepted Answer

Point mutation

Answer

Frameshift mutation

Answer

Chromosomal deletion

Answer

Translocation

Question 6

Which structure within the cell contains most of an organism's genetic material?

Accepted Answer

Nucleus

Answer

Mitochondria

Answer

Ribosome

Answer

Cell membrane