Lecture 6

Question 1

Who created the peas experiment?

Answer 1

Gregor Mendel

Question 2

What is a genetic cross?

Answer 2

The mating of sperm and eggs

Question 3

What does a recessive trait need?

Answer 3

2 copies to exhibit the trait

Question 4

Parents used in a cross are apart of what generation

Answer 4

The Parental generation

Question 5

What generation is the offspring of the P generation called?

Answer 5

The first filial generation (F1)

Question 6

What is the offspring of the F1 generation called?

Answer 6

F2 generation

Question 7

Explain the concept of dominance with regard to the seeds

Answer 7

When two different alleles are present in a
heterozygote, only the trait encoded by the dominant allele is observed in the phenotype. The other allele is recessive.

. 1. P generation: Homozygous round seed plant cross with a homozygous wrinkled seed plant

2. F1: all the F1 generation have round seeds.
   - Round is dominant to wrinkled
3. F2 generation: produced progeny of both phenotypes.
   3 round seeds: one 1 wrinkled
   Recessive trait reappeared- wrinkled is not lost

Question 8

What does each diploid cell carry?

Answer 8

Two alleles per gene on on each homologous chromosomes

Question 9

If both homologous
chromosomes carry the same
allele at a given gene locus,
the organism is called

Answer 9

homozygous

Question 10

If two homologous
chromosomes carry different
alleles at a given locus, the
organism is called

Answer 10

heterozygous

Question 11

What is a genotype?

Answer 11

An indivdual’s genetic makeup. The combination of alleles for a particular gene or genes

Question 12

What is a phenotype?

Answer 12

Appearance or trait that results from the genotype

Question 13

What is the principle of segregation?

Answer 13

Each individual diploid organism possesses two alleles for any given characteristic. These two alleles segregate into gametes with equal proportions.

Question 14

Segregation is to what?

Answer 14

The separation of homologous chromosomes during meiosis I

Question 15

What is the principle of independent assortment?

Answer 15

genes encoding different traits separate independently during gamete formation

Question 16

Pedigree are used to deuce what?

Answer 16

inheritance patterns in people

Question 17

Recessively inherited disorders manifest only in who?

Answer 17

individuals homozygous for recessive allele

Question 18

What are carriers?

Answer 18

heterozygous individuals who carry the recessive allele but are phenotypically normal, most individuals with recessive disorders are born to carrier parents

Question 19

What is Albinism?

Answer 19

A recessive condition characterized by a lack of pigmentation in skin and hair

Question 20

Autosomal recessive trait tent to what?

Answer 20

Skip generations

Question 21

If both parents are unaffected carriers, what percent of the child will be affected?

Answer 21

25%

Question 22

Phenylketonuria is an example of what?

Answer 22

Autosomal Recessive Traits

Question 23

What is Achondroplasia (dwarfism) caused by

Answer 23

A rare dominant allele

Question 24

TRUE OR FALSE: unaffected people do not transmit the trait in autosomal dominant traits

Answer 24

TRUE

Question 25

Define Complete dominance

Answer 25

Phenotype of the heterozygote is the same as the phenotype of one of the homozygotes

Question 26

Define Incomplete dominance

Answer 26

Phenotype of the heterozygote is intermediate between the phenotypes of the two homozygotes

Question 27

Define Codominance

Answer 27

Phenotype of the heterozygote includes the phenotypes of both homozygotes

Question 28

Human Hair texture is influenced by what?

Answer 28

a gene with two incompletely dominant

Question 29

Define Penetrance

Answer 29

The percentage of individual with a particular genotype that express the expected phenotype

Question 30

Define Expressivity

Answer 30

Degree to which trait is expressed

Question 31

Some alleles are BLANK

Answer 31

Lethal, resulting in death of genotypes

Question 32

Four phenotypes of the ABO blood group in humans are determined by What?

Answer 32

Three alleles for the enzyme that attaches A or B carbohydrates to red blood cells

Question 33

People make antibodies to the type of glycoproteins they lack. What do the antibodies do the red bloods that carry foreign?

Answer 33

The antibodies cause the red blood that carry the foreign glycoproteins to clump together and rupture.

Question 34

What is an enzyme?

Answer 34

A biological catalyst that causes a biochemical reaction to occur or increase the rate of a specific biochemical reaction within a cell, tissue, organ

Question 35

Mutations in the genes that encode enzymes can cause human disorders such as

Answer 35

Hyperaminoaciduria: Accumulation of excess amounts of a specific amino acid

Lysosomal Storage disorders: accumulation of percussor in lysosomes, buildup becomes toxic

Question 36

What is Phenylketonuria (PKU)?

Answer 36

A monogenic disorder caused by loss of function mutations in the gene for the enzyme Phenylalanine hydroxylase (PAH)

It is a autosomal-recessive

Question 37

What is the birth rate for PKU?

Answer 37

1 in 10,000

Question 38

What is the pathophysiology of PKU?

Answer 38

Enzyme PAH (Phenylalanine hydroxylase) converts phenylalanine into tyrosine

Question 39

What happens during the loss of PAH?

Answer 39

Build up of phenylalanine, which converted into phenylpyruvic acid, which lowers ph in the blood.

Question 40

Excess amount of PAH cause what?

Answer 40

effects the development of the nervous system and cause brain damage

Question 41

What happens if there is a deficiency of tyrosine leads to?

Answer 41

reduced melanin and skin pigmentation

Question 42

What are the signs of PKU (phenylketonuria)?

Answer 42

Cognitive impairment
small head size
poor motor skills
light skin, hair, and eye color
tremors and seizure activity