Chapter 9 Patterns Of inherintance Part 1

Question 1

Gene

Answer 1

Definition: region of DNA that contains information about a specific trait.

Example: Flower Color

Question 2

Allele

Answer 2

Definition: a version of a gene

Example: Purple or Yellow

Question 3

Heterozygous

Answer 3

Definition: Having two different alleles for a particular trait.

Example: Pp

Question 4

Homozygous

Answer 4

Definition: Having two identical alleles for a particular trait.

Example: PP or pp

Question 5

Genotype

Answer 5

Definition: The actual allele combination that is present on the chromosome.

Example: PP, Pp or pp

Question 6

Phenotype

Answer 6

Definition: The physical characteristic that can be detected.

What the actual visible trait is.

Example: Purple Kernel or Yellow Kernel

Question 7

Dominant

Answer 7

Definition: The allele that is expressed in a heterozygote (written as an uppercase letter)

Example: Purple (P)

Question 8

Recessive

Answer 8

Definition: The allele that is not expressed in a heterozygote (written as a lowercase letter)

Example: Yellow (p)

Question 9

Heredity

Answer 9

The transmission of traits from one generation to the next.

Question 10

Genetics

Answer 10

The scientific study of heredity.

Question 11

Gregor Mendel

Answer 11

Began the field of genetics in the 1860s

Deduced the principles of genetics by breeding garden peas

Relied upon a background of mathematics, physics, and chemistry

Question 12

Character

Answer 12

A heritable feature that varies among individuals, such as flower color. Genes code for characters

Question 13

Trait

Answer 13

Each variant of character. Eg purple or white flowers.

Question 14

True breeding

Answer 14

When self fertilization produces offspring all identical to the parent.

Question 15

Hybrids

Answer 15

Offspring of two different varieties are hybrids.

Question 16

Cross fertilization

Answer 16

The fusion of male and female gametes (sex cells) from different individuals of the same species.

Question 17

P generation

Answer 17

True-breeding parental plants

Question 18

F1 generation

Answer 18

Hybrid offspring of the parental generation.

Question 19

F2 Generation

Answer 19

Cross of F1 plants produces an F2 generation.

Question 20

Monohybrid cross

Answer 20

A cross between two individuals in a single character is a monohybrid cross.

Eg. Plant with purple flowers x Plant with white flowers.

Question 21

Cross between a plant with Purple Flowers and a Plant with Whote flowers.

Answer 21

The F1 generation produces all plants with Purple flowers.

A cross of F1 plants with each other produced an F2 generation with 3/4 purple and 1/4 white flowers.

Purple is a dominant trait and white is a recessive trait for the character of flower color in this particular plant.

Question 22

Mendel’s 1st Law of Inheritance

Answer 22

Law of Dominance

states that in a heterozygous condition, the dominant expression of the trait will appear and the recessive condition will be unexpressed.

Question 23

Mendel’s 2nd Las of Inheritance

Answer 23

Law of Segregation: during gamete formation there is a random separation (segregation) of dominant and recessive alleles.

Inheritance of a single character ( which in the case of purple and white flowers was purple flower).

Not the blending Hypothesis, ( light purple flowers).

Question 24

3:1 ratio of the F2 generation

Answer 24

The F1 hybrids all have a Pp genotype.

When these plants cross, they end up with a 3:1 ratio where 75% of the plants in the F2 generation have the dominant phenotype and 25% have the recessive phenotype.

Question 25

Locus (plural, loci)

Answer 25

The specific location of a gene in a chromosome.

For a pair of homologous chromosomes, alleles of a gene are at the same locus.

Question 26

Homologous

Answer 26

Pairing of chromosomes at Meiosis that have the same structural features and pattern of genes.

Question 27

Mendel’s 3rd Law of Inheritance

Answer 27

Law of Independent Assortment states that the factors for different characteristics are transmitted independently.

Inheritance of flower color is not affected by inheritance of seed color

Question 28

Dihybrid Cross

Answer 28

A mating of parental varieties that differ in two characters.

Eg. Color of corn kernel and texture of corn kernel.

Question 29

Testcross

Answer 29

A testcross is the mating between individual of unknown genotype and a homozygous recessive individual.

For example, if between green and yellow pea color green is dominant, we know that a testcross has a recessive allele if 50% of the plants in the next generation have yellow peas, when it is crossed with a homozygous recessive plant.

Question 30

Pedigree

Answer 30

A diagram showing the lineage or genealogy of an individual and all the direct ancestors, usually to analyze or follow the inheritance of trait.