Biology Inheritance Quiz
Questions: 16 · 10 minutes
1. A person with blood type AB expresses both A and B alleles. Which inheritance pattern does this demonstrate?
Complete dominance, because the A allele masks the B allele
Recessive inheritance, because neither allele affects the phenotype
Incomplete dominance, because the alleles blend into a new antigen
Codominance, because both alleles are distinctly expressed
2. Which statement correctly distinguishes homologous chromosomes from sister chromatids?
Homologous chromosomes are identical copies made during DNA replication
Sister chromatids come from different parents and may carry different genes
Homologous chromosomes carry the same genes but may contain different alleles
Sister chromatids are unrelated chromosomes that pair during fertilization
3. In a flower species with incomplete dominance, RR plants are red, WW plants are white, and RW plants are pink. What phenotype ratio is expected from RW × RW?
All offspring pink
Three red to one white
One red to two pink to one white
One red to one white, with no pink offspring
4. Genetically identical plants develop different leaf sizes when one group receives more light than the other. What is the best conclusion?
Environmental conditions can influence how a genotype is expressed as a phenotype
The plants must have inherited different alleles for leaf size
Dominant alleles function only when plants receive more light
Genetically identical organisms must always develop identical traits
5. In genetics, what is an allele?
A protein that copies DNA before cell division
A visible characteristic produced only by the environment
A complete set of chromosomes within a species
An alternative version of a gene found at a particular locus
6. A mother has a homoplasmic mitochondrial DNA variant, while the father does not. Which inheritance pattern is expected for the variant?
All her children inherit it, but only daughters can pass it to the next generation
Only her daughters inherit it
Approximately half of all children inherit it, regardless of sex
Only her sons inherit it
7. A plant shows a dominant phenotype, but its genotype could be AA or Aa. Which cross would best reveal its genotype?
Self-pollinate it once and examine only the parent plant
Cross it with a homozygous dominant plant, AA
Cross it with another plant showing the same phenotype
Cross it with a homozygous recessive plant, aa
8. Which mutation could be passed biologically from a parent to an offspring?
A mutation in a skin cell caused by ultraviolet exposure
A mutation that enters an egg or sperm cell and is present at fertilization
A mutation in a muscle cell occurring during exercise
A mutation in a lung cell caused by smoke exposure
9. Two heterozygous parents, Aa and Aa, have an offspring. What is the probability that the offspring has genotype aa?
25%
50%
0%
75%
10. In a pedigree, two unaffected parents have a child with a rare autosomal trait. Assuming full penetrance and no new mutation, which inheritance pattern best fits?
Autosomal dominant, with both parents homozygous dominant
Y-linked, regardless of the child's sex
Autosomal recessive, with both parents likely carrying the allele
Mitochondrial, inherited equally from either parent
11. A mother carries one recessive X-linked allele, while the father does not have the condition. What is the probability that any one of their sons inherits the allele?
50%
25%
75%
100%
12. What is the difference between genotype and phenotype?
Genotype is the chromosome number; phenotype is the number of genes
Genotype refers only to dominant traits; phenotype refers only to recessive traits
Genotype is created by the environment; phenotype is inherited unchanged
Genotype is an organism's allele combination; phenotype is an observable or measurable trait
13. Why is meiosis essential for sexual reproduction?
It produces two genetically identical diploid body cells
It produces haploid cells so fertilization can restore the diploid number
It prevents genetic differences among gametes
It doubles the chromosome number before fertilization
14. Researchers find that two genes on the same chromosome are usually inherited together. What best explains this observation?
The genes must contain identical DNA sequences
The genes are linked, especially if their loci are close together
One gene is dominant and permanently suppresses the other
The genes independently assort more often because they share a chromosome
15. For genes that assort independently, an organism with genotype RrYy is crossed with rryy. What is the probability of an rryy offspring?
1/2
1/4
1/8
1/16
16. In pea plants, tallness (T) is completely dominant over shortness (t). What phenotype would a Tt plant have?
Short, because it carries one shortness allele
Intermediate in height between tall and short
Tall, because one dominant allele is present
Tall and short traits in separate parts of the plant