Unit 2 - Final Review

Question 1

Gregor Mendel

Answer 1

father of genetics. Studied pea plants.

Question 2

Gene Pool

Answer 2

all the genes in a given population

Question 3

Allele

Answer 3

alternate forms of a gene controlling a characteristic.
Found in the same position (locus) of homologous chromosomes

Question 4

Pure

Answer 4

homozygous dominant or homozygous recessive

Question 5

Heterozygous

Answer 5

genotype with 1 dominant and 1 recessive. Hybrid.

Question 6

Genotype

Answer 6

alleles that make up a trait

Question 7

Phenotype

Answer 7

observable characteristics of an organism.

Question 8

Monohybrid cross

Answer 8

cross involving a single traits

Question 9

Dihybrid cross

Answer 9

cross involving two traits

Question 10

Generations naming

Answer 10

P1 = parents
F1 = first generation (filial)
F2 = 2nd generation

Question 11

Mendels ratios (2 x heterozygous)

Answer 11

making two heterozygotes = 3:1 phenotype ratio, dominant: recessive

Question 12

Mendel’s Laws of Heredity

Answer 12

1. Law of Dominance
2. Law of Segregation
3. Law of Independent Assortment

Question 13

Law of Dominance

Answer 13

In heterozygotes, the dominant alleles will mask the recessive allele; the dominant allele will be expressed exclusively.

Question 14

Law of Segregation

Answer 14

during the formation of gametes, the two alleles responsible for a trait will separate. Offspring will receive one allele from each parent, which are recombined during fertilization = offspring genotype.

Question 15

Law of Independent Assortment

Answer 15

alleles are randomly distributed to gametes. the allele that a gamete receives for one gene does not affect the allele that it receives for a different gene.

Question 16

Genotypic ratios

Answer 16

homozygous dominant: heterozygous: homozygous recessive

Question 17

Phenotypic ratios

Answer 17

dominant: recessive

Question 18

test cross

Answer 18

performed between a homozygous individual and an unknown individual

Question 19

Autosomal dominant

Answer 19

Both males and females are equally affected.
Unaffected parents cannot produce an affected child

Question 20

x-linked recessive

Answer 20

Mostly males affected
No transmission of trait from father to son

Question 20

autosomal recessive

Answer 20

Both males and females are equally affected.
Trait tends to skip generations
Unaffected parents can produce an affected child

Question 20

x-linked dominant

Answer 20

Affected sons must inherit from affected mother

Question 21

Pleiotropy

Answer 21

one gene affects more than one phenotypic characteristic

Question 22

Multiple alleles

Answer 22

more than two alleles for a specific trait (dominance hierarchy)

Question 23

Incomplete dominance

Answer 23

having an appearance between phenotypes of the two parental varieties

Question 24

codominance

Answer 24

both alleles are expressed at the same time. (e.g. blood type)

Question 25

# of gametes that can be produced

Answer 25

2^n (where n = # of heterozygotes)

Question 26

Mendel - dihybrid crosses

Answer 26

used this to develop the law of independent assortment

Question 27

9:3:3:1

Answer 27

2 heterozygote traits x2

Question 28

Selective breeding

Answer 28

used to improve domestic varieties of plants and animals

Question 29

purebred (inbred)

Answer 29

similar phenotypes are selected for breeding

Question 30

hybridization

Answer 30

desirable, but different traits are bred, creating new varieties

Question 31

Epistatis

Answer 31

multiple genes affect a single trait (one gene may mask/interfere with the expression of another gene)

Question 32

Complementary interaction

Answer 32

when 2 different genotypes interact to produce a phenotype that neither is capable of producing by itself.

Question 33

T.H. Morgan

Answer 33

studied fruit flies. Discovered sex linked traits. Discovered that some genes do not segregate independently (linked genes)

Question 34

Males cannot be ____ for sex linked traits

Answer 34

carriers/heterozygous

Question 35

Barr bodies are...

Answer 35

small dark spots of chromatin that can be seen in somatic cells of female mammals during interphase.

Question 36

Barr bodies (info)

Answer 36

females only need one of their x chromosomes to produce the proteins that their cell needs. One of the x chromosomes (random) goes dormant, becomes a barr body. Some will either display maternal/paternal x chromosome, so not all female cells will be identical.

Question 37

Barr bodies (lethal genes)

Answer 37

heterozygous females who carry a lethal gene. Gene may only be active in 50% of cells.

Question 38

Testes determining factor

Answer 38

lies on the y chromosome. When activated, it stimulates testes to start releasing male hormones.

Question 39

Testicular feminizing syndrome (TFS)

Answer 39

XY embryo develops testes which secretes testosterone. Nearby tissues are insensitive to testosterone, and external female genitals form.

Question 40

Linked genes

Answer 40

genes located on the same chromosome tend to be transmitted together. They move together during meiosis, resulting in fewer combinations of alleles

Question 41

Non-recombinants/parental types

Answer 41

offspring that have the same genes as parents

Question 42

Recombinants

Answer 42

offsprings with new combinations of alleles

Question 43

crossing over

Answer 43

occurs during meiosis --> greater combinations

Question 44

crossing over frequency

Answer 44

(recombinants/total offspring) x100

Question 45

which genes are most likely to end up on the same chromosome?

Answer 45

those located closest to each other. The farther genes are, the more likely they will be affected by crossing over.

Question 46

cross over % =

Answer 46

map unit

Question 47

Transposons

Answer 47

specific segments of DNA that can move/jump along a chromosome

Question 48

Gene Therapy

Answer 48

process by which defective genes are replaced with normal genes, in order to cure genetic diseases (gene insertion, gene modification, gene surgery)