Biology Final Exam: Chapter 16, Lecture 3

Front 1

Gregor Mendal (1822-1884)

Back 1

Experiment on pea plants

Advantageous: self fertilizing (shows true breeding lines), many character traits

Front 2

What are the traits Mendel studied of the pea plants?

Back 2

1. Pea shape

2. Pea color

3. Flower Color

4. Flower Piston

5. Pod Shape

6. Pod Color

7. Plant Height

Front 3

Dominant and Recessive trait for pea shape

Back 3

Round (R) &

Wrinkled (r)

Front 4

Dominant and Recessive for pea color

Back 4

Yellow (Y) &

Green (y)

Front 5

Dominant and Recessive for flower color

Back 5

Purple &

White

Front 6

Dominant and Recessive for flower position

Back 6

Axial flowers &

Terminal flowers

Front 7

Dominant and Recessive for pod shape

Back 7

Inflated &

Pinched

Front 8

Dominant and Recessive for pod color

Back 8

Green &

Yellow

Front 9

Dominant and Recessive for plant height

Back 9

Tall & Short

Front 10

What is a Single-Factor cross?

Back 10

Experimenter follows the variants of only 1 trait

Front 11

P generation

Back 11

True-breeding parents (First parents in tree)

Front 12

F1 Generation

Back 12

Offspring of P cross

Monohybrids: When one parent has a different allele than the other parent

Front 13

F2 Generation

Back 13

Offspring from F1 Generation

Front 14

What is one point that Mendel concluded from a single factor cross?

Back 14

1. Dominant & recessive traits: Dominant is displayed but recessive is "masked" by dominant

Front 15

What is the second point Mendel concluded from a single factor cross

Back 15

2. Genes & Alleles

- Mechanism of inheritance

- "unit factors" = Genes

- Every individual has 2 genes for a trait

- Gene has two variant forms or alleles

Front 16

What is Mendel the father of?

Back 16

He is the father of genetics

Front 17

What is a hybrid?

Back 17

A hybrid is the offspring of two plants with different alleles of the same trait

Front 18

Mendel's 1st Law of Segregation

Back 18

One sperm or egg carries only one allele. (Explains the 3:1 ratio of dominant to recessive phenotype)

T x t & T xt = TT, Tt, Tt, (3 dominant), tt (recessive)

Front 19

Genotype

Back 19

Genetic composition

Front 20

Phenotype

Back 20

Observable Characteristics

Front 21

What is a Test Cross?

Back 21

Testing for genotype of an organism

Front 22

Two-factor cross

Back 22

Inheritance of two different traits

- linked or unlinked

- 9:3:3:1 = independent assortment

Front 23

Law of Independent assortment

Back 23

Alleles of different genes assort independently during gamete formation

Front 24

What are Dihybrid offspring?

Back 24

Offspring are hybrids with respect to both traits

Front 25

Why are the behavior of chromosomes and genes similar?

Back 25

- 2 copies

- Unchanged complements from parent to offspring

-Segregate indepedently

-1/2 from mom, 1/2 from dad

Front 26

Who was Walter Sutton?

Back 26

Studied grasshopper spermatocytes.

Parent cells contained 22 chromosomes plus an X and a Y

Determined XX = females

Determined XY = Males

Front 27

Sex Chromosomes

Back 27

X-Y = males XY and females XX (mammals)

Z-W = male ZZ and female ZW (Birds)

X-O = males X or XO, female XX (insects)

Front 28

What is incomplete dominance?

Back 28

Neither trait is dominant

(Ex: Red X White = Pink)

Front 29

What is Pleiotrophy?

Back 29

Mutation in a single gene has multiple effects

Front 30

Co-dominance

Back 30

Blood types: A and B express both genes equally

Front 31

What is PKU?

Back 31

Increased levels of phenyalanine in the blood.