Biology: Genetics and Evolution Flashcards
6 cards from real GAOKAO practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Biology: Genetics and Evolution flashcards as text
In a monohybrid cross between two heterozygous parents (Aa × Aa), what is the expected phenotypic ratio in the offspring?
Answer: 3:1
A Punnett square for Aa × Aa yields AA, Aa, Aa, aa — a 3:1 dominant-to-recessive phenotypic ratio.
Which molecule carries the genetic instructions from the nucleus to the ribosome during protein synthesis?
Answer: mRNA
Messenger RNA (mRNA) transcribes the DNA code in the nucleus and carries it to ribosomes for translation.
Darwin's theory of natural selection is best described as:
Answer: Individuals with favorable traits survive and reproduce more successfully
Natural selection states that heritable traits increasing survival and reproduction become more common over generations.
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?
Answer: 50%
Sons receive either X^A (unaffected) or X^a (affected) from the mother with equal probability, so 50% of sons are affected.
Which term describes a mutation that changes a single nucleotide base in the DNA sequence?
Answer: Point mutation
A point mutation involves the substitution, insertion, or deletion of a single nucleotide in the DNA sequence.
Which structure within the cell contains most of an organism's genetic material?
Answer: Nucleus
The nucleus houses the cell's chromosomal DNA, which carries the majority of the organism's genetic information.