Cell Division, Genetics and Molecular Biology

Mitosis and meiosis, inheritance patterns, and how genes work at the molecular level.

12 questions, free, marked as you go with a worked explanation on every one.

What this covers

A human body cell contains 46 chromosomes. How many chromosomes are in a human gamete?
What is the key difference between mitosis and meiosis?
Crossing over during meiosis occurs at which stage?
Two heterozygous parents (Aa × Aa) have children. What percentage of the offspring are expected to show the recessive phenotype?
In a cross between a heterozygous tall plant (Tt) and a short plant (tt), what percentage of offspring are expected to be tall?
A DNA strand reads 3′-TAC GGA-5′. What is the matching mRNA sequence?
What is the role of transfer RNA (tRNA) in protein synthesis?
Which statements about DNA replication are correct? Select all that apply.
A colour-blind man (X^b Y) has children with a woman who is a carrier (X^B X^b). What proportion of their sons are expected to be colour blind?
Use the table. A is dominant over a. Construct a Punnett square for this cross. What percent of the offspring are expected to be heterozygous carriers (Aa)?
A pea plant of unknown genotype (TT or Tt) for a dominant tall trait is crossed with a known homozygous recessive (tt) plant, and all of the offspring are tall. What is the unknown parent's genotype?
Use the table. In cattle coat colour, R and W alleles are codominant, where RW individuals show a roan (mixed red-and-white) coat. Construct a Punnett square for this cross. What percent of the offspring are expected to be roan?