Bio Unit 6 Test Flashcards
Where do alleles come from?
one from mom, one from dad
What is a recessive allele?
gene that is overpowered and doesn’t show up
an allele that when present alone can’t effect the individual
If an DD individual is crossed with a dd individual, then _____% of the offspring will be dominant and _____% of the offspring will be recessive.
100%, 0%
All squares are Dd. “D” is dominant, therefore all of the offspring are dominant.
What percentage is filled in the square?
75%
What is incomplete dominance?
a lack of dominance in either of two different alleles in heterozygotes resulting in a phenotype that is intermediate
Example: red rose (RR) with a white rose (rr) equals a pink rose (Rr)
What is genotype?
the letters that represent the different forms of a trait
Example: dd / DD
What does homozygous mean?
having 2 identical alleles
BB / bb
What does heterozygous mean?
having 2 different alleles
Bb
The following is an example of what type dominance?
a) incomplete
b) complete
c) codominant
a) incomplete
How many alleles do we have for each trait?
two
What is a carrier?
the dominant gene shows up, but carriers the recessive gene
an individual who “carries” and can pass on an allele associated with a disease (or trait) that is inherited and who does not show symptoms of that disease (or features of that trait)
Why are more men colorblind than women?
only need a mutation to be present in the singular X chromosome
colorblindness is a recessive gene, so males only need to inherit one gene for color blindness because they only have one X chromosome.
If 2 parents have a 1 in 4 chance of having a child with hemophilia, what percentage chance do they have EACH TIME they have a child of having one with hemophilia?
25%
What is complete dominance?
heterozygous condition where the allele that is dominant completely masks the effect of the allele that is recessive.
if the individual carries two alleles in a manner that one is dominant and the other one is recessive, (e.g. Aa), the dominant allele will be expressed while the recessive allele will be suppressed.
What is a dominant allele?
a gene that overpowers and shows up in the living thing
What is codominance?
When two alleles for a trait are equally expressed with neither being recessive or dominant, it creates codominance.
“fighting for control”
What percentage is filled in the square?
50%
How does epistasis inheritance work?
An allele of one gene
a gene that determines whether or not a trait will be expressed
a circumstance where the expression of one gene is modified (masked, inhibited or suppressed) by the expression of one or more other genes
What percentage is filled in the square?
25%
Black (B) is dominant
White (b) is recessive
What percentage of the offspring are homozygous black?
0%
Black (B) is dominant
White (b) is recessive
What percentage of the offspring will homozygous white?
50%
If an Bb individual is crossed with an bb individual, then ____% of the offspring will be heterozygous and _____% of the offspring will be homozygous.
50%, 50%
