Chapter 22 - Inheritance Flashcards Preview

Human Biology - Unit 2 > Chapter 22 - Inheritance > Flashcards

Flashcards in Chapter 22 - Inheritance Deck (21):

What is pure breeding?

When something is bred and it produces the same characteristic when bred among themselves


What are hybrids?

When an offspring has the genetic information for two traits but only expresses one


What is a mono hybrid cross?

The mating in which one pair of contrasting genes is studied


What is a gene?

The factor that determines an inherited characteristic that is found on a chromosome


What is an allele?

An alternative form of a gene


What is a dominant allele?

An allele that masks the effect of another allele, expresses itself in the heterozygous phenotype


What is a recessive allele?

An allele that is masked by the dominant gene and is only expressed when both genes are expressed in the homozygous condition


What is homozygous?

The situation where and individual has the same alleles for a particular characteristic


What is heterozygous?

The situation where an individual possesses different alleles for a particular characteristic


What is a phenotype?

The physical appearance of an individual as determined by the expression of the alleles for that characteristic


What is a genotype?

The genetic make-up of an individual as determined by the alleles for they characteristic being considered


What is the first filial generation?

The first generation of offspring produced after the cross of two parents


How is sex determined?

- all female eggs contain X chromosomes
- half of male sperm contain an X chromosome and the other half contain a Y chromosome
- it is the chromosomal complement of the fathers sperm that determines the sex of a child


What are autosomes?

The first 22 pairs of chromosomes that are not involved in sex determination


What is incomplete dominance?

- the dominant trait is not fully expressed
- the heterozygote is different from its pure bred parents


What is an example of incomplete dominance?

- snapdragon flowers
- red, white, pink


What is the principle of segregation?

The principle that during the production of gamete each gamete only receives one gene for each trait


What is codominance?

When a pair of different alleles both contribute to the phenotype and are equally expressed (but not blended) in a heterozygote


How are codominant allele written?

Both as capital letters as super scripts with one base letter


What is an example of codominance?

- shorthorn cattle
- red= R, white= W, roan= RW


What alleles make up the ABO blood group system?

A, B, O