Unit 7

Question 1

what is a gene

Answer 1

a gene is a sequence of bases in dna, that code for a polypeptide

Question 2

what is an allele

Answer 2

alternate version of a gene at the same locus

Question 3

what is a genotype

Answer 3

the type of alleles an organism has, the genes characteristics

Question 4

what is a phenotype

Answer 4

the expression of a gene, seen in its physical appearance. depends of genotype and enviromental factors

Question 5

What are dominant and recessive alleles

Answer 5

dominant alleles are always expressed, recessive can only be expressed if two copies are present

Question 6

what are codominant alleles

Answer 6

this is when both alleles are dominant, and both are expressed together-

Question 7

what are homozygous and hetrozygous

Answer 7

homozygous contains both of the same type of allele, eg both dominant
heterozygous when they contain different type of alleles. eg one recessive one dominant

Question 8

monohybrid inheritance

Answer 8

definition : looks at one single gene- and the likley hood of different alleles being inherited in an offspring
phenotypic ratio: 3:!

Question 9

monohybrid inheritance and codominant alleles

Answer 9

definition: co dominant alleles are both expressed since neither are recessive.
the phenotypic ratio is 1:2:1 when having two heterozygous parents involving codominant alleles

Question 10

multiple alleles and dihybrid cross

Answer 10

a gene can contain more than two alleles
a common example is blood groups where O is recessive and AB are codominant

Question 11

dihybrid cross and codominance

Answer 11

a dihybrid cross looks at two genes and the likley hood of alleles being inherited
looks at more than one combination of characteristics.
for codominance the phenotypic ratio may differ but the expected is 9:3:3:1

Question 12

sex linkage

Answer 12

some characteristics are sex linked meaning the alleles for that trait are located on a sex chromosome
the Y chromosome is much smaller thus contains less genes. so most genes are carried on the x chromosome. They may only have one allele for sex linked genes. even if males carry one recessive alleles on their X chromosome it will still be expressed. This is because they only have one X chromosome.

Question 13

autosmal genes

Answer 13

any chromosome that isn’t a sex chromosome is called an autosome
genes on the same
autosome are said to be linked.

Question 14

What is epistasis

Answer 14

it is a gene that influences another gene by affecting it or masking it
it effects the typical phenotypic ratio

Question 15

what is chi squared

Question 16

The critical value

Question 17

Expected results

Question 18

Observed results

Question 19

What is a species

Answer 19

A species is a group of similar organisms that can reproduce to produce fertile offspring.

Question 20

What is a population

Answer 20

A population is a group of organisms of the same species that are in a particular geographical location and at a particular time.

Question 21

What is a gene pool

Answer 21

A gene pool is the full range of alleles in a population

Question 22

What is a allele frequency

Answer 22

Allele frequency is how often an allele occurs in a population