Genes and Alleles
Biology ⇒ Genetics and Heredity
Genes and Alleles starts at 7 and continues till grade 12.
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See sample questions for grade 10
Describe what is meant by the term 'dominant allele'.
Explain the difference between autosomal and sex-linked genes.
Explain why some traits do not follow simple dominant-recessive inheritance patterns.
If a gene has two alleles, A (dominant) and a (recessive), what is the phenotype of an individual with genotype Aa?
A plant with genotype Tt is crossed with another plant with genotype Tt. What is the probability that the offspring will have the genotype tt?
A woman with genotype Aa marries a man with genotype aa. What is the probability that their child will have genotype aa?
If a gene has two alleles, A (dominant) and a (recessive), what is the phenotype of an individual with genotype Aa?
If both parents are heterozygous for a gene (Rr), what is the expected genotypic ratio among their offspring?
Which genotype will result in blood type O in humans?
(1) IAIB
(2) IAi
(3) ii
(4) IBi
Which of the following best describes a gene with two identical alleles?
(1) Heterozygous
(2) Homozygous
(3) Dominant
(4) Recessive
Which of the following best describes a recessive allele?
(1) It is always expressed in the phenotype
(2) It is only expressed when two copies are present
(3) It is never expressed
(4) It is always harmful
Which of the following best describes the relationship between genes and alleles?
(1) Genes are made up of alleles
(2) Alleles are different forms of a gene
(3) Alleles are made up of genes
(4) Genes and alleles are unrelated
Fill in the blank: The location of a gene on a chromosome is called its _______.
Fill in the blank: The set of alleles that an individual has is called its _______.
If a person has two different alleles for a gene, they are said to be _______ for that gene.
If a person has two identical alleles for a gene, they are said to be _______ for that gene.
True or False: A person with genotype IAIB will have blood type AB.
True or False: All genes have only two alleles.
True or False: All mutations in genes result in visible changes in the organism.
True or False: Dominant alleles always mask the effect of recessive alleles in a heterozygous individual.
