LECTURE 2 - STUDY GUIDE

Question 1

What is the definition of a gene?

Answer 1

DNA nucleotide sequence

Question 2

What is the definition of an allele?

Answer 2

varying genetic traits

Question 3

What is the definition of a locus?

Answer 3

Particular location of a gene on a chromosome

Question 4

What is the difference between a homozygous and heterozygous individual?

Answer 4

Homozygous- same type of allele. Homo means the same
Heterozygous- one of each type of allele, varying alleles. Think Hh. Hetero means different.

Question 5

What is the difference between a genotype and phenotype?

Answer 5

Genotype- alleles

Phenotype- physical representation that you are going to display
(Words of the possibilities)

Question 6

What does it mean that Mendelian genetics are considered “discrete” genetics?

Answer 6

Discrete Genetics-
- Discrete genetics: the dominant will always show up if present (one or the other)

Question 7

Which statement does not describe Mendel’s First Law of Heredity: Segregation?

Answer 7

Alternative alleles of character segregate from each other in heterozygous individuals and remain distinct

during miosis

Question 8

What is the difference between completing a monohybrid verses dihybrid test cross?

Answer 8

Monohybrid-produce 4 possibilities
Dihybrid: mixing 2 different set of alleles (use foil to determine outsides)

Question 9

21. Which statement does not describe how Mendel found his phenotype ratio for the 𝐹1 and 𝐹2 generations from dihybrid crosses? (know all experimental design and which genotypes he breed)

Answer 9

1)Took purebreeds of RRYY he mixed that with rryy

2)Every single offspring would be carriers like RrYy

3)Then he did self-fertilization to breed RrYy with RrYy

4)He always got a 9:3:3:1 ratio all the time
9→RRYY
3→RRyy
3:rrYY
1:rryy

Question 10

Which statement describes the results of Mendel’s experiments for dihybrid crosses?

Answer 10

9:3:3:1

Question 11

What do the letters on the outside of the Punnett square stand for?

Answer 11

The parent’s genotypes

Question 12

What do the letters on the inside of the Punnett square stand for?

Answer 12

They represent the possible genotypes for offspring.

Question 13

What is the (a) genotypic and (b) phenotypic ratio of the offspring of a dihybrid cross of a homozygous tall and green male and homozygous short and yellow female plant? H = tall, h = short, G = green, and g = yellow

Answer 13

genotypic ratio: 1HhGg (100% HhGg)

phenotypic ratio: 100% tall and green

Question 14

What is the phenotypic ratio of the offspring of a dihybrid cross of a heterozygous male and a heterozygous female plant? H = tall, h = short, G = green, and g = yellow

Answer 14

phenotypic ratio: 9:3:3:1

19% short and Green

19% tall and yellow

6% short and yellow

Question 15

Hornless (H) in cattle is dominant over horned (h). A homozygous hornless bull mated with a homozygous horned cow. What will be the genotype and phenotype of the first generation?

Answer 15

p1: HH x hh
f1: Hh

Question 16

In tomatoes, red fruit (R) is dominant over yellow fruit (r). A plant that is homozygous for red fruit is crossed with a plant that has yellow fruit. What would be the genotypes and phenotypes of the P1 and F1 generations?

Answer 16

Phenotype: 100% will be red fruit

Genotype: Rr

Question 17

In humans, being a tongue roller (R) is dominant over non-roller (r). A man who is a non-roller marries a woman who is heterozygous for tongue rolling. What is the probability of this couple having a child who is a tongue roller?

Answer 17

Phenotype: 50% of offspring becoming tongue rollers

Genotypes: Rr, rr

Question 18

Brown eyes in humans are dominant over blue eyes. A brown-eyed man, whose mother was blue-eyed, marries a brown-eyed woman whose father had blue eyes. What is the probability that this couple will have a blue-eyed child?

Answer 18

Phenotype: 25% of offspring becoming blue-eyed

Genotype: BB, Bb, bb

Question 19

What is the Law of Independent Assortment regarding genetics?

Answer 19

Genes located on different chromosomes assort independently of one another