Unit 6 - Genetics Flashcards
1
Q
Inheritance/heredity
A
Transfer of genetically determined characteristics (encoded by genes) from one generation to the next
2
Q
What is genetics
A
The study of inheritance
3
Q
What make up our 23 chromosome pairs
A
- 22 homologous pairs - autosomal
- 1 pair of sex chromosomes - XX or XY
4
Q
Alleles
A
- genes occupying the same location on homologous chromosomes
- may be:
1. Homozygous
2. Heterozygous
5
Q
Homozygous alleles
A
- 2 of the same allele
- same allele of a particular gene on homologous chromosomes
- both alleles express the same version of a trait
- ex. BB (black hair), bb (blonde hair)
6
Q
heterozygous alleles
A
- 2 different alleles
- different alleles of the same gene
- alleles code for different expressions of the same trait
- ex. Bb
7
Q
Genotype
A
- genetic makeup of an organism
- which alleles are homozygous and which are heterozygous
- BB, Bb, bb
8
Q
Phenotype
A
- expression of genotype (genes) to give observable characteristics
- ex. Black hair, brown hair, blonde hair
9
Q
Dominant allele
A
- B
- expressed in phenotype regardless of other allele
- ex. BB or Bb: dominant allele is expressed = black hair
10
Q
Recessive allele
A
- b
- expressed in phenotype only if present on both alleles (homozygous recessive)
- bb: homozygous recessive = blonde hair
11
Q
Punnett squares
A
- determines probability of inheritance
- predicts offspring genotype and phenotype
- ex. BB x Bb
12
Q
Are % of genotype and phenotype always the same in a Punnett square?
A
NO!!!
13
Q
X-linked inheritance
A
- inheritance of somatic characteristics determined solely by genes on the X chromosome
14
Q
Medical conditions due to restive alleles on the X chromosome
A
- Hemophilia
- colour blindness
- duchenne’s muscular dystrophy
15
Q
Can x-linked traits be masked by a male (XY)
A
- No!!
- if gene is X-linked its expression is not masked because there is no corresponding allele on Y chromosome
