chapter 22 - inheritance Flashcards
1
Q
what were mendels two conclusions
A
- law of segregation: two alleles for each trait separate when gametes form; parents pass only one allele for each trait onto offspring
- law of independent assortment: genes of different traits are inherited independently of each other
2
Q
what is a cross / hybrid cross
A
- C: the mating of two organisms
- HC: only one pair of contrasting characteristics is studied
3
Q
what is a gene
A
- the factor that determines an inherited characteristic
- located on chromosomes
4
Q
what is an allele
A
- an alternative form of a gene, an individual only usually has 1 or 2 alleles for each gene
5
Q
what is dominant vs recessive
A
- D: the allele that masks the effect of an alternative allele
- R: the allele that is masked by the effect of an alternative allele
6
Q
what is homozygous, heterozygous and hemizygous
A
- homo: when an individual has the same alleles for a particular characteristic (purebred)
- hetero: when an individual possesses different alleles for a particular characteristic (hybrid)
- hemi: individuals have only one allele for a gene (sex linked)
7
Q
what are genotype vs phenotype
A
- G: genetic makeup of an individual as determined by the alleles for the characteristic being considered
- P: physical appearance of an individual determined by the expression of alleles for that characteristic
8
Q
who was Gregor Mendel
A
- first known geneticist, father of genetics
- Australian monk, born in 1822
- did most of his study on pea plants
9
Q
what is a punnet square
A
- diagram showing the gene combinations that might result from a genetic cross
- used to calculate the probability of inheriting a particular trait
10
Q
what is chromosome 23
A
- sex chromosomes, females have two X’s, males have one X and one Y
11
Q
what are chromosomes 1-22
A
- autosomes, non-sex chromosomes
12
Q
what are sex linked characteristics
A
- traits / genes that are carried / located on the sex chromosomes
13
Q
males and sex-linked traits
A
- males XY
- only men inherit the Y chromosome, only men inherit Y-linked traits
- males is hemizygous for X-linked traits
- men cannot be carrier of X-linked traits, they have it or they don’t
14
Q
females and sex-linked traits
A
- female XX
- pass on X to their sons
- can be carriers of a certain characteristic or trait
15
Q
what are X-linked traits
A
- traits carried on the X chromosome
- males and females can inherit X-linked traits, both inherit an X chromosome
16
Q
what are Y-linked traits
A
- traits carried on the Y chromosome
- Y chromosome is small and doesn’t carry many genes
- y-linked diseases are very rare
- only passed from father to son
17
Q
what is co-dominance
A
- situation in which both alleles of a gene contribute to the phenotype of the organism
- no dominant of recessive genes
18
Q
what are multiple alleles
A
- when there are more than two alleles for a particular characteristic
19
Q
example of co-dominance and multiple alleles
A
- blood types / groups
20
Q
explain the different types of blood groups
A
- A: antigen a, I^A I^A or I^A i, receives from A and O, donates to A and AB
- B: antigen b, I^B I^B or I^B i, receives from B and O, donates to B and AB
- AB: antigens a and b, I^A I^B, receives from A, B, AB and O (universal receiver), donates to AB
- O: no antigens, i i, receives from O, donates to A, B, AB and O (universal donor)
