chapter 4-Genetics

Question 1

what are Mendel’s 3 Laws?

Answer 1

1. Inherited characteristics are controlled by factors known as genes
2. One factor or gene masks the effect of another
3. a pair of factors or genes separate or segregate during the formation of sex cells

Question 2

what is a genotype?

Answer 2

The genes of an organism

Question 3

what is a phenotype?

Answer 3

The visible traits of an organism

Question 4

homozygous?

Answer 4

Two genes that are the same

ex. TT

Question 5

heterozygous?

Answer 5

two different genes

ex.Tt

Question 6

Gene?

Answer 6

A code of heredity

Question 7

allele?

Answer 7

An alternate form of genes

ex.T= tall and t= short

Question 8

mono hybrid cross?

Answer 8

A gene with contrastic traits

ex.Tt from TTxtt

Question 9

dihybrid cross?

Answer 9

A hybrid that is heterozygous for alleles of two different genes
ex. TT tt x TT tt

Question 10

multiple alleles?

Answer 10

three or more alternative forms of a gene that occupy the same place.
ex. Ee in a square of a Punnett square

Question 11

Incomplete dominance?

Answer 11

blending of the dominant & recessive traits so that the third phenotype is something in the middle
ex. red x white = pink

Question 12

What is probability?

Answer 12

the study of outcomes of events and occurrences

Question 13

rule of independent events?

Answer 13

chance has no memory

Question 14

product rule?

Answer 14

probability of independent events occurring simultaneously= product of these events occurring separately

ex. the chances of tossing heads after two tosses =1/2, but the chances of tossing it three times in a row=1/2x1/2x1/2=1/8

Question 15

polygenic inheritance?

Answer 15

traits are inherited characteristics that are affected by one or more gene

Question 16

pleiotropic genes?

Answer 16

genes that affect many characteristics

ex. sickle-cell anemia

Question 17

chromosomal theory of inheritance?

Answer 17

• chromosomes carry genes
• paired chromosomes segregate during meiosis
• chromosomes assort independently during meiosis
• each chromosome contains many different genes

Question 18

what is a somatic cell?

Answer 18

the cells of an organism except the sex cells

Question 19

sex linked trait?

Answer 19

crontrolled by genes located on the sex chromosomes

ex.eye colour in Drosophilia controlled by X chromosome

Question 20

zygotes?

Answer 20

a cell resulting from the Union of male and female sex cells

Question 21

gene pool?

Answer 21

all of the genes that occur within a specific population

Question 22

what is the Hardy Weinberg principle?

Answer 22

A principle indicating conditions under which allele and gene frequencies will remain constant from generation to generation

Question 23

what are the 4 conditions in the Hardy Weinberg principle?

Answer 23

1. Large populations
2. no selection
3. No net mutations
4. No net migration

Question 24

gene equilibrium?

Answer 24

the condition of an alleged or genes type in a gene pool where the frequency does not change from generation to generation

Question 25

genetic drift?

Answer 25

the process in which allele frequencies in a population change randomly overtime because of chance

Question 26

what did Mendel experiment on?

Answer 26

pea plants

Question 27

codominance?

Answer 27

where in the offspring both dominant and recessive genes appear
ex.AB blood type