Mendelian Genetics

Question 1

Genetics

Answer 1

The study of inheritance (genes passed down from parent to offspring)

Question 2

Gregor Mendel

Answer 2

Gregor Mendel is an Austrian monk who performed experiments on pea plants and formulated the modern theory of inheritance

Question 3

Why peas though?

Answer 3

1. Easy to grow, produces many seeds
2. He could control the parents
3. have several pairs of contrasting traits

Question 4

True breeding plants

Answer 4

When a plant is self-fertilized and produces offspring that has traits identical to itself

Question 5

P
F1
F2

Answer 5

P = Parental (true breed x true breed)
F1 = First filial generation 
F2 = Second filial generation

Question 6

YY x yy

Answer 6

4: 0 for F1
3: 1 for F2

Question 7

Law of Independant Assortment

Answer 7

Genes for one trait are not inherited together with another trait

Question 8

Law of Segregation

Answer 8

Alleles separate into separate gametes so that each gamete has 1 allele. Upon fertilization, the offspring receives 2 alleles; whether it is dominant or not determines the trait.

Question 9

Chromosome Theory of Inheritance

Answer 9

Traits determined by genes are inherited through the movement of chromosomes during Meiosis (genes on chromosomes, chromosomes have alleles, chromosomes segregate and independently assort during meiosis)

Question 10

Alleles

Answer 10

Alternative forms of a gene; Mendel referred to them as factors

Question 11

Phenotype

Answer 11

Expression of the genotype or observable trait

Question 12

Genotype

Answer 12

Combination of alleles an organism has

Question 13

Hybrid

Answer 13

Two different true breeding plants’ offspring

Question 14

Dominant trait

Answer 14

Trait that is expressed in the hybrid

Question 15

Recessive trait

Answer 15

Trait that is masked in the hybrid

Question 16

Homozygous

Answer 16

2 alleles that are the same

Question 17

Heterozygous

Answer 17

2 alleles that are different

Question 18

Monohybrid Crosses

Answer 18

1. Identify the trait
2. Let statement (what is dominant)
3. Write genotype, phenotype, and gametes of parent plants
4. Make Punnett square with the gametes from each parent on either side
5. Fill in the square; dominant letter goes first

Question 19

Dihybrid Crosses

Answer 19

1. Identify traits
2. Let statement (what is dominant)
3. Write genotype, phenotype, and gametes of parent plants
4. Make Punnet square (FOIL)
5. Fill in square
6. Determine ratio

Question 20

BbRr x BbRr

Answer 20

9:3:3:1

Question 21

BbRr x bbrr

Answer 21

4:4:4:4 (don’t reduce)

Question 22

BBRR x bbrr

Answer 22

16:0:0:0

Question 23

Pedigree

Answer 23

A flowchart that uses symbols to show the inheritance patterns of traits in a family over many generations

Question 24

Autosomal Inheritance

Answer 24

Inheritance of traits determined by genes on autosomal chromosomes

Question 25

Autosomal Dominant

Answer 25

- Disease-causing allele is dominant | - Eg. child is not diseased even when both parents are (if recessive, child would have it)

Question 26

Why is a pedigree useful?

Answer 26

By studying a pedigree, you can determine whether the inheritance pattern of a disorder is autosomal dominant or autosomal recessive; 2 parents are affected but child isn’t means autosomal dominant.

Question 27

Incomplete Dominance

Answer 27

A condition in which neither allele for a gene completely conceals that presence of the other; results in intermediate expression of trait

Question 28

Codominance

Answer 28

The condition in which both alleles for a trait are equally expressed in a heterozygote; both alleles are dominant

Question 29

Multiple Alleles

Answer 29

A gene with more than 2 alleles (versions)

Question 30

Linked Genes

Answer 30

Genes that are on the same chromosome and that tends to be inherited together

Question 31

Sex-Linked Trait

Answer 31

A trait controlled by genes on X or Y chromosome (generally X)

Question 32

X and Y homologous?

Answer 32

X has 2000 genes, Y has 78. They have very little homologous DNA.

Question 33

Eg. Thomas Hunt Morgan crossed a white eyed male fly with a red eyed female fly.

Answer 33

All daughters had red eyes, ½ males had red eyes. Therefore, the gene for eye colour is on the X chromosome.

Question 34

Cross

Answer 34

Fertilization of female gamete of specific origin with a male gamete of a specific origin

Question 35

Test Cross

Answer 35

Cross between a parent of unknown genotype and a homozygous recessive parent

Question 36

Autosomal Recessive

Answer 36

- Disease causing allele is recessive | - Eg. child is diseased but parents are not (they are carriers)

Question 37

Blood type

Answer 37

- Multiple Alleles - O is recessive - IA and IB are dominant - Antigens (markers) and antibodies (killers) - O is universal donor, AB is universal reciever