Chapter 3

Question 1

When did Gregor Mendel study pea plants?

Answer 1

From 1856 - 1868

Question 2

Why did Gregor Mendel choose pea plants?

Answer 2

Fast growing, many individuals can grow at once, have clear phenotypic traits, and are easy to cross/breed.

Question 3

Define trait/trait versions

Answer 3

Physical characteristics and their variants

Question 4

Define selfing

Answer 4

When an individual plant pollinates itself

Question 5

Define cross

Answer 5

When one plant is bred with another

Question 6

Define hybridization

Answer 6

Pea plant with one trait version is bred with a pea plant with a different trait version.

Question 7

Define P1 Generation

Answer 7

Parental generation

Question 8

Define F1 Generation

Answer 8

First filial generation. Children of parents

Question 9

Define F2 generation

Answer 9

Second filial generation. Grandchildren of parents.

Question 10

Define monohybrid crosses

Answer 10

Hybridization in which individuals only differ in 1 trait.

Question 11

In monohybrid crosses of homozygous plants, what phenotypes will the F1 and F2 generation have?

Answer 11

F1 - only one trait version / phenotype (dominant allele shows)
F2 - mix of both trait versions

Question 12

What are unit factors?

Answer 12

What Mendel called alleles.

Question 13

Define homozygous

Answer 13

Organism with the same 2 unit factors /alleles

Question 14

Define heterozygous

Answer 14

Organism that has 1 of EACH unit factor / allele

Question 15

Define dominant

Answer 15

One trait version masks the other when both are present.

Question 16

Define recessive

Answer 16

One trait version is masked when the other is present.

Question 17

Define phenotype

Answer 17

An organism’s observable characteristics.

Question 18

Define genotype

Answer 18

Organism’s underlying alleles

Question 19

How many unit factors do diploid somatic cells have?

Answer 19

2 unit factors - corresponding to the 2 homologous chromosomes.

Question 20

What is a punnet square?

Answer 20

Way to visual crosses. Shows what could happen if you cross 2 parents together.

Question 21

Define testcross

Answer 21

Allows you to determine the genotype of a dominant individual.
Done by crossing the unknown dominant individual with a homozygous recessive individual.

Question 22

What would the results of a test cross tell us?

Answer 22

If offspring all have the dominant phenotype, then the unknown’s genotype is homozygous dominant.
If offspring have a mix of dominant-phenotype and recessive-phenotype, the unknowns genotype is heterozygous dominant.

Question 23

Define dihybrid cross

Answer 23

Crossing individuals that differ in 2 traits.

Question 24

Define trihybrid cross

Answer 24

Cross between individuals that differ in 3 traits.

Question 25

Define product law

Answer 25

Probability of multiple independent events is co-occurring. Is the product of their individual probabilities

Question 26

Define independent assortment

Answer 26

Each homologous chromosome randomly picking a side in metaphase I

Question 27

What are the odds that all maternal chromosomes end up on the same side in metaphase I?

Answer 27

1 / (2^23) (incredibly low)

Question 28

Define a chi squared test

Answer 28

Determines if the actual ratio differs from the expected ratio, or if the difference is due to chance. Statistical test comparing observed and expected results.

Question 29

What are the steps to a chi squared test?

Answer 29

1) Establish a null hypothesis 2) Obtain data 3) determine expected results 4) Find the chi squared value 5) determine degrees of freedom 6) Use df and chi square value to find probability (using given table) 7) Determine if you can reject the null hypothesis

Question 30

Define null hypothesis

Answer 30

Default hypothesis assumed to be true (Ex. no real difference between expected and observed offspring ratios)

Question 31

How can you determine the expected results?

Answer 31

What is the expected offspring ratio? Use product law.

Question 32

What is the chi-squared equation?

Answer 32

chi-square value = the sum of [((O - E)^2) / E ] E = expected O = observed

Question 33

What symbol is a female

Answer 33

circle

Question 33

Define pedigree charts

Answer 33

Charts that reveal the distribution of phenotypes in a family. Helps to keep track and predict heritable diseases/conditions.

Question 33

How do you know if you can reject the null?

Answer 33

If the p-value is less than or equal to 0.05 THEN you can reject the null.

Question 33

What symbol is a male

Answer 33

Square

Question 34

What symbol is when sex is unknown

Answer 34

Diamond

Question 35

What symbol is for affected individuals

Answer 35

Shaded in / colored

Question 36

What symbol is for parents who are unrelated to each other

Answer 36

(circle) - (square)

Question 37

What symbol is for parents who are related to each other

Answer 37

(circle) = (square)

Question 38

How are offspring of parents labeled/ordered?

Answer 38

By birth order. Oldest is on the left ---> youngest to the right

Question 39

What symbol is for fraternal twins?

Answer 39

A branch that stems into 2.

Question 40

What symbol is for identical twins?

Answer 40

A branch that stems into 2 that has a second horizontal line (denoting =)

Question 41

What does the "p" mean?

Answer 41

Proband.

Question 42

Define consanguineous parents

Answer 42

Parents related to eachother

Question 43

Define dizygotic twins

Answer 43

Fraternal. Not identical. Formed from 2 distinct zygotes

Question 44

Define monozgotic twins.

Answer 44

Identical. Formed from same zygote.

Question 45

Define proband

Answer 45

(p). Person who was first noticed to have the condition. FIRST CASE.

Question 46

Define carrier

Answer 46

Someone who has the allele for a disease but does NOT have the disease. Generally heterozygous for it

Question 47

What are the odds that an offspring is both yellow and round if 1 parent is GgWw and the other parent is GgWw?

Answer 47

9/16 odds for yellow and round

Question 48

With a GgWw X GgWW cross, what is the probability of a GgWW offspring?

Answer 48

1/8 probability

Question 49

Assuming a GGww x GgWw cross what are the odds of: a) yellow, wrinkled b) yellow, round c) green, wrinkled d) GGWw offspring e) Ggww offspring ?

Answer 49

a) 1/2 b) 1/2 c) 0 d) 1/4 e) 1/4

Question 50

With a cross between DdGgWw x DdGgWw , what are the odds for: a) tall, yellow, and round b) tall, green, and round c) ddGGWw

Answer 50

a) 27/64 b) 9/64 c) 1/32