Chapter 12

Front 1

Mendel developed true-breeding strains to be used as ____

Back 1

The parental generation, designated P

Front 2

Look at table 12.1

Back 2

:)

Front 3

The progeny from the cross of the P parents are called what?

Back 3

The first filial generation, designated F1

Front 4

When F1 individuals are crossed to each other or self-fertilized what is it called?

Back 4

Their progeny are designated F2

Front 5

A monohybrid cross involves _____

Back 5

One character (seed shape) and different traits (round or wrinkled)

Front 6

Give an example of dominant and recessive traits

Back 6

When crossing P1 pure-breeding round plants with wrinkled plants, the F1 seeds were all round; the wrinkled trait failed to appear at all.
Because the spherical trait completely masks the wrinkled trait when true-breeding plants are crossed, the spherical trait is considered dominant and the wrinkled trait recessive

Front 7

What is the ratio of the F2 generation?

Back 7

3:1

Front 8

Look at figure 12.3

Back 8

:)

Front 9

What conclusions did mendel reach after his experiment?

Back 9

The units responsible for inheritance are discrete particles that exist within an organism in pairs and separate during gamete formation.
Each pea has two units of inheritance for each character.
During production of gametes, only one pair for a given character passes to the gamete.
When fertilization occurs, the zygote gets one unit from each parent, restoring the pair

Front 10

Mendel’s units of inheritance are now called _____

Back 10

Genes

Front 11

Different forms of a gene are called ___

Back 11

Alleles

Front 12

______individuals have two copies of the same allele (i.e., they are homozygous)

Back 12

True-breeding

Front 13

Some smooth-seeded plants are Ss or _______, although they will not be true-breeding

Back 13

Heterozygous

Front 14

What is Mendel’s first law?

Back 14

is called the law of segregation: Each gamete receives one member of a pair of alleles.
They can be determined by means of a Punnett square

Front 15

What is a locus?

Back 15

It is a gene that is at a portion of the chromosomal DNA and resides at a particular site (called a locus) and that gene codes for a particular function

Front 16

Look at figure 12.5

Back 16

:)

Front 17

What does Mendel’s second law state?

Back 17

The law of independent assortment, states that alleles of different genes (e.g., Ss and Yy ) assort into gametes independently of each other

Front 18

What are dihybrid crosses?

Back 18

Hybrid crosses involving additional characters. They produce four possible gametes with a 9:3:3:1 ratio

Front 19

Look at figure 12.7 and 10.8

Back 19

:)

Front 20

What are pedigrees?

Back 20

They show phenotype segregation in several generations of related individuals because humans cannot be studied using planned crosses

Front 21

Look at figure 12.5

Back 21

:)

Front 22

What does Mendel’s second law state?

Back 22

The law of independent assortment, states that alleles of different genes (e.g., Ss and Yy ) assort into gametes independently of each other

Front 23

What are dihybrid crosses?

Back 23

Hybrid crosses involving additional characters. They produce four possible gametes with a 9:3:3:1 ratio

Front 24

Look at figure 12.7 and 10.8

Back 24

:)

Front 25

What are pedigrees?

Back 25

They show phenotype segregation in several generations of related individuals because humans cannot be studied using planned crosses. Pedigree outcomes for small samples fail to follow the expected outcomes closely

Front 26

Look at figure 12.10

Back 26

:)

Front 27

Differences in alleles of genes consist of slight differences in the DNA sequence at the same locus, resulting in what?

Back 27

Different protein products

Front 28

How many allelels can a population have?

Back 28

A population can have more than two alleles for a given gene.
Even if more than two alleles exist in a population, any given individual can have no more than two of them: one from the mother and one from the father

Front 29

Describe incomplete dominance

Back 29

Heterozygotes may show an intermediate phenotype which might seem to support the blending theory.
The F2 progeny, however, demonstrate Mendelian genetics. For self-fertilizing F1 pink individuals the blending theory would predict all pink F2 progeny, whereas the F2 progeny actually have a phenotypic ratio of 1 red:2 pink:1 white

Front 30

Look at figure 12.12

Back 30

:)

Front 31

In codominance ____

Back 31

Two different alleles for a gene are both expressed in the heterozygotes

Front 32

In the human ABO blood group system the alleles for blood type are A, B, and O. What are the possible outcomes?

Back 32

AA, or AO, results in type A.
BB, or BO, results in type B.
OO results in type O (O is completely recessive).
AB results in type AB. The alleles are called codominant

Front 33

Look at figure 12.13

Back 33

:)

Front 34

What two factors determine the phenotype of an organism?

Back 34

Genotype and environment

Front 35

What can affect the translation of genotype into phenotype?

Back 35

Variables such as light, temperature, and nutrition

Front 36

What are controlled by groups of several genes?

Back 36

Complex inherited characteristics. For example, human height

Front 37

Variation is ________________ rather than qualitative

Back 37

Continuous, or quantitative

Front 38

Variation is usually due to what two factors?

Back 38

Multiple genes with multiple alleles, and environmental influences on the expression of these genes

Front 39

What is crossing over?

Back 39

It is when homologous chromosomes exchange corresponding segments during prophase I of meiosis

Front 40

Look at figure 10.19

Back 40

:)

Front 41

In mammals, sex is determined by what?

Back 41

Which sex chromosomes you possess. The sex chromosomes are labeled as X and Y.

Front 42

Describe the sex chromosomes

Back 42

The sex chromosomes are labeled as X and Y.
Females have two X chromosomes.
Males have X and Y.
Females can only produce one type of egg – one containing a X.
Thus, sex of offspring is determined by the sperm – if a sperm containing an X chromosomes fertilizes the egg = female; if sperm contains a Y = male

Front 43

How many genes does the y and x chromosomes have compared to each other?

Back 43

The Y chromosome carries very few genes (about 20 are known), whereas the X carries a great variety of characters

Front 44

Females with XX may be ______for genes on the X chromosome.

Back 44

Heterozygous

Front 45

Males with XY have how many copies of a gene?

Back 45

Only one copy of a gene

Front 46

What is sex-linked inheritance?

Back 46

The transmission to successive generations of traits that are due to alleles

Front 47

Look at figure 12.23

Back 47

:)

Front 48

Pedigree analysis of X-linked recessive phenotypes shows us what?

Back 48

The phenotype appears much more often in males than in females.
A male with the mutation can pass it only to his daughters.
Daughters who receive one mutant X are heterozygous carriers.
The mutant phenotype can skip a generation if the mutation is passed from a male to his daughter and then to her son