Biology 101 Lecture

Front 1

Heredity

Back 1

Tendency for traits to be passed from parent to offspring

Heredity Ft. called Characters

Traits are alternative form of character

Front 2

True-Breeding

Back 2

Allowing Self-Fertilize for several generations ensuring each variety contained only one type of trait. Mendel Called it P Generation

Front 3

Crossed Two Varieties Exhibiting Alternative Traits

Back 3

Named Resulting Offspring F1 Generation

Then allowed the F1 Generation to self-fertilize to self fertilize naming their offspring F2 Generation

Front 4

Dominant and Recessive Genes

Back 4

Dominant Gene expresses completely in the phenotype while recessive gene is not completely expresses in the phenotype.

Front 5

Hypothesis 1

Back 5

Parents do not transmit traits directly to their offspring

Parents transmit information about the trait called Genes

Front 6

Hypothesis 2

Back 6

Each parent contains two copies of the factor governing each trait

Homozygous individuals have 2 similar copies

Heterozygous individuals have 2 different copies

Front 7

Hypothesis 3

Back 7

Alternative forms of a factor lead to alternative traits

Alleles are defined as alternative forms of a factor

Alleles present are the individual's Genotype

Expression of the alleles is the Phenotype

Front 8

Hypothesis 4

Back 8

The two alleles that an individual possesses do not affect each other

Front 9

Hypothesis 5

Back 9

The presence of an allele does not ensure that a trait will be expressed in the individual that carries it

Front 10

Locus

Back 10

The location of a gene on a chromosome

Front 11

Punnet Square

Back 11

List the possible gametes from one individual on one side of the square and the possible gametes from the other individual on the opposite side

Front 12

Mendel's First Law: Segregation

Back 12

The two alleles of a trait separate from each other during the formation of gametes, so that half of the gametes will carry one copy and half will carry the other copy

Front 13

Dihybrid

Back 13

When crossing individuals who are true-breeding for two different characters, the F1 results is a dihybrid

Front 14

Mendel's Second Law: Independent Assortment

Back 14

Genes located on different chromosomes are inherited independently of one another

Front 15

Polygenic

Back 15

Characters can show a range of small differences when multiple genes act jointly to influence a character

Front 16

Pleiotropic Effects

Back 16

An allele that has more than one effect on the phenotype is considered pleiotropic—one gene affects many characters

Front 17

Incomplete Dominance

Back 17

Not all alternative alleles are either fully dominant or fully recessive in heterozygotes

Front 18

Epistasis

Back 18

In some situations, two or more genes interact with each other, such that one gene contributes to or masks the expression of the other gene

Front 19

Codominance

Back 19

A gene may have more than two alleles in a population

Front 20

Sex-Linked

Back 20

A trait determined by a gene on the sex chromosome

Front 21

Linkage

Back 21

The tendency of close-together genes to segregate together

The further two genes are from each other on the same chromosome, the more likely crossing over is to occur between them. This would lead to independent segregation.

The closer that two genes are to each other, the less likely that crossing over will occur between themthese genes almost always segregate together and would, thus, be inherited together.