Quiz 1 (Ch. 2, 3, & 4)

Question 1

Where are genes found?

Answer 1

Within chromosomes

Question 2

How many sets of chromosomes do humans have? How many do pea plants have?

Answer 2

Both humans and pea plants have two sets of chromosomes

Question 3

Where do the two sets of human chromosomes come from?

Answer 3

One set of chromosomes is inherited via the sperm, and the other set is inherited via egg

Question 4

What do the genes that offspring inherit affect?

Answer 4

Genes affect the traits of the offspring

Question 5

What is an allele?

Answer 5

A version of a gene; Can be dominant or recessive

Question 6

What is a haploid cell?

Answer 6

A cell which contains only one set of chromosomes

Question 7

What occurs during the formation of a haploid cell?

Answer 7

i) The alleles of a gene segregate from each other

ii) The alleles of two different genes assort independently of each other

Question 8

What three ideas of inheritance did Mendel’s experiments refute?

Answer 8

i) Pangenesis
ii) Preformation
iii) Blending hypothesis of inheritance

Question 9

What organism did Mendel use for his experimental organism? Why did he choose this organism?

Answer 9

• Pea plants
• This organism was ideal because:
• –i) It existed in several varieties with distinct characteristics
• –ii) Its structure allowed for easy crosses where the choice of parental plants could be controlled

Question 10

Definition: Hybridization

Answer 10

The mating or crossing between two individuals that have different characteristics
—Ex: Purple-flowered plant x White-flowered plant

Question 11

Definition: Hybrids

Answer 11

The offspring that result from a hybridization mating

Question 12

What does the anther of a plant contain?

Answer 12

The anther contains the pollen grains, where the male gametes (sperm) are produced

Question 13

What does the ovule of a plant contain?

Answer 13

The ovule contains the female gametes (eggs)

Question 14

What does the endosperm nucleus of a plant do?

Answer 14

The endosperm nucleus provides storage material for the developing embryo

Question 15

Describe self-fertilization in pea plants

Answer 15

• Pollen & egg are derived from the same plant

- Naturally occurs in peas because a modified petal isolates the reproductive structures

Question 16

Describe cross-fertilization

Answer 16

• Pollen & egg are derived from different plants
• Required removing & manipulating anthers
• Fig. 2.3

Question 17

Definition: Characters

Answer 17

The morphological characteristics of an organism

Question 18

Definition: Trait / Variant

Answer 18

Describes the specific properties of a character

—Ex: Eye color is a character, Blue eyes are a trait

Question 19

Definition: True-Breeder

Answer 19

A variety of organism which produces the same trait over several generations

Question 20

What seven characters did Mendel study?

Answer 20

i) Height (tall v. dwarf)
ii) Flower color (purple v. white)
iii) Flower position (terminal v. axial)
iv) Seed color (yellow v. green)
v) Seed shape (round v. wrinkled)
vi) Pod color (green v. yellow)
vii) Pod shape (smooth v. constricted)

Question 21

Definition: Empirical approach ; How did Mendel use this?

Answer 21

• Using quantitative analysis to determine mathematical relationships
• In Mendel’s case, he believed that the he could find the mathematical relationships which govern hereditary traits

Question 22

Definition: Single Factor Cross

Answer 22

• An experiment involving two variants of the same characteristic
• Only one characteristic of the organism is being observed

Question 23

What are the four parts of Mendel’s Law of Segregation?

Answer 23

i) A pea plant contains two discrete hereditary factors for a given character, one from each parent
ii) These two factors may be identical or different
iii) When the two factors of a single character are different and present in the same plant, one is dominant and the other is recessive
iv) During gamete formation, the paired factors for a given character segregate randomly so that half of the gametes receive one factor and half of the gametes receive the other factor

Question 24

Describe the term ‘Homozygous’ as it relates to alleles

Answer 24

An individual with two identical alleles

Question 25

Describe the term ‘Heterozygous’ as it relates to alleles

Answer 25

An individual with two different alleles

Question 26

Definition: Genotype

Answer 26

Refers to the specific allelic composition of an iindividual

Question 27

Definition: Phenotype

Answer 27

Refers to the outward appearance of an individual

Question 28

Punnett square

Answer 28

A grid that enables one to predict the outcome of simple genetic crosses
—Proposed by Reginald Punnett