B 9.2 Inheritance Flashcards
(15 cards)
What is a chromosome?
A long strand of DNA found in the nucleus that contains many genes.
What is a gene?
A short section of DNA that codes for a specific protein.
What is an allele?
A different version of a gene.
What is the difference between dominant and recessive alleles?
Dominant alleles are always expressed if present; recessive alleles are only expressed if both copies are recessive.
What is meant by homozygous?
Having two identical alleles for a particular gene (e.g., BB or bb).
What is meant by heterozygous?
Having two different alleles for a particular gene (e.g., Bb).
What is a genotype?
The genetic makeup of an organism — the alleles it possesses.
What is a phenotype?
The observable characteristics of an organism.
What is a genetic cross?
A diagram used to show the possible combinations of alleles inherited from parents.
What are the chances of a child having a dominant trait if both parents are heterozygous (e.g., Bb x Bb)?
75% (3 in 4)
What is cystic fibrosis caused by?
A recessive allele — both copies must be faulty for the disorder to appear.
What is polydactyly caused by?
A dominant allele — only one copy is needed to inherit the condition.
What is a carrier?
A person who has one copy of a recessive allele for a genetic condition but does not show symptoms.
What are some ethical issues with embryo screening?
Concerns include cost, discrimination, and the potential for ‘designer babies.’
Why might embryo screening be considered useful?
It can identify embryos with genetic disorders, helping parents make informed choices.
