Cycle 5 Flashcards
1
Q
How did mendel complete his experiment?
A
- manipulated one variable at a time
- used a pea plant because it was easy to grow, short generation time, distinct phenotypic characteristics and easy to mate
- used two plants to have sexual reproduction
- cut off the anther so that the flower could not self pollinate
- chose pollination
plants growing reveal dominant and recessive traits
2
Q
What were mendel’s conclusions
A
- variation in traits is due to different alleles
- alleles segregate randomly into gametes
appearance if heterozygotes is determined by the dominant allele - homozygous alleles can be carried in heterozygous and passed onto generations having the phenotype reappear
- 2 alleles determine the trait
3
Q
What are alleles?
A
- they are differences in gene sequences
- changes the phenotypic expression
4
Q
How does eye color work?
A
- polygenic
- oca2 allele plays role
- helps mature p-protein structure
- more mature p protein means high melanosomes and more melanin (brown eyes)
5
Q
monohybrid crosses
A
- simple 2 by 2 punnet square
6
Q
Dihybrid crosses
A
- 4 by 4
- make total combination of the two different alleles
7
Q
incomplete dominace
A
- intermediate expression
- ex. red (full protein production) , pink (half), and white flower (none)
8
Q
codominance
A
- both alleles are expressed
- ex. ABO system
9
Q
how ABO system works
A
- glycoprotein is structures with a protein and sugar component
- type a or b depends on the terminal sugar group (terminal = the antigen)
- glycsotransferase works by transferring sugar groups to the chain to make glycoproteins
- AB has two different glycotrasnferase working
- 4 sequence amino acid difference is what chooses the antigen
- o is mutated with no functional transferase
- big difference on system
10
Q
what are sex linked characteristics?
A
- father can not be carrier
- y chromosome is smaller
- usually more frequent in males
- higher frequency than autosomal diseases
- Ex. Red green colourblinds in 1:12 men vs 1:200 female, autosomal recessive inheritance 1:380
11
Q
what is epistasis?
A
- traits like height and eye colour that do not have a fixed number of expression
- there is a range and variation
- intermediate is the most common one to appear in the population
12
Q
what traist show the continuous variation of epistasis?
A
- polygenic traits
- determined by the influence of multiple genes acting across many chromosomes
13
Q
formal definition of epistasis
A
- form of non-mendelian inheritance in one gene capable of interfering with the expression of another
14
Q
What does the example of epistasis in labradors explain?
A
- B makes pigment; b makes no pigment
- E deposits pigent, e does not
- Black: BB EE, Bb EE
- Brown: bb Ee
- Golden: Bb ee, bb ee
- lead to different phenotypic ratio
