Question 1

true breeding

Accepted Answer

if an organism has a certain characteristic that is always passed on to its offspring, we say that this organism bred true with respect to that characteristic

Question 2

allele

Accepted Answer

one of a pair of genes that occupies the same position on homologous chromosomes

Question 3

recessive allele

Accepted Answer

an allele that will not determine the phenotype unless the genotype is homozygous in that allele

Question 4

monohybrid cross

Accepted Answer

a cross between two individuals, concentrating on only one definable trait

Question 5

dihybrid cross

Accepted Answer

a cross between two individuals, concentrating on two definable traits

Question 6

autosomal inheritance

Accepted Answer

inheritance of a genetic trait not on a sex chromosome

Question 7

know the principles of Mendelian genetics using   updated terminology. Here are 2

Accepted Answer

1. the traits of an organism are determined by its genes; 
2.Each organism has 2 alleles that make up the genotype for a given trait;

Question 8

Here are the other 2 principles of Mendelian genetics

Accepted Answer

3.in sexual reproduction, each parent contributes only one of its alleles to its offspring; 
4.in each genotype, there is a dominant allele. If it exists in an organism, the phenotype is determined by that allele.

Question 9

The factor for producing yellow peas ("Y") is dominant over the factor for producing green peas ("y"). Suppose a pea plant produces yellow peas. What possible combination(s) of factors can it have?

Accepted Answer

"YY"  or  "Yy" (since yellow peas are dominant, the plant needs to only have one yellow factor)

Question 10

for a given trait, how many alleles does a normal gamete have?

Accepted Answer

a gamete has only one allele for each trait

Question 11

for a given trait, how many alleles does a non-gamete cell have?

Accepted Answer

normal cells have 2 allele's for each trait

Question 12

a pea plant which is homozygous in the dominant, axial flower allele ("A")is crossed with a pea plant that is heterozygous in that allele. What are the possible genotypes and phenotypes, along with their percentage chances, for the offspring?

Accepted Answer

dominant parent is genotype AA. The other is heterozygous so it is Aa so 50% of offspring will have AA and 50% will have Aa. Each has at least one dominant allele so 100% have the axial flower phenotype

Question 13

a woman is heterozygous in the ability to roll her tongue when extended. If she marries a man who cannot roll his tongue, what percentage of their children will be able to roll their tongues? (tongue rolling alleles are dominant)

Accepted Answer

the woman is Rr. The man is rr. 50% of the children will be able to roll their tongue (if the woman was homozygotus in her ability to roll her tongue, what is her genotype?  RR)

Question 14

**know the difference between heterozygous and homozygotus genotypes

Accepted Answer

in "homo", both alleles are identical where in "hetero" both are different

Question 15

a person carries a genetic disorder but does not have the disorder. How is that possible?

Accepted Answer

the genetic disorder must be recessive, that way as long as you carry the dominant allele, you will not have the disease.

Question 16

do sex linked genetic disorder affect men and woman the same? if not, which sex is affected more and why?

Accepted Answer

sex linked disorder affect men more than woman because men only have one allele

Question 17

so if a man does not have a sex linked recessive disease but has children with a woman who carries it but doesnt have it, what do their alleles look like?

Accepted Answer

He can only carry it on his X chromosome and since he doesn't have the disease, and its recessive, he must carry the dominant allele - XD. She has 2 chromosomes but doesn't have the disease so she would have an XD and an Xd.

Question 18

name four means by which genetic disorders arise

Accepted Answer

autosomal inheritance, sex linked inheritance, change in chromosome structure, allele mutation, change in chromosome number

biology 8

test

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