Mendelian Genetics

Question 1

alleles

Answer 1

different forms of same trait

Question 2

true breeding plants

Answer 2

always give same type of offspring when self pollinated

Question 3

hybrid/hybridization

Answer 3

Have two different alleles for a trait

Question 4

Monohybrid cross

Answer 4

tracks the inheritance of single trait

Question 5

P generation-

Answer 5

(parental generation)- two true-breeding parents

with contrasting alleles

Question 6

F1 generation-

Answer 6

(first filial)- hybrid P offspring

Question 7

F2 generation

Answer 7

allowing F1 generation to self pollinate

Question 8

Homozygous

Answer 8

organism having a pair of identical alleles for a character

Question 9

Phenotype-

Answer 9

organism’s appearance (purple or white)

Question 10

Heterozygous

Answer 10

organism having two different alleles for a gene

Question 11

Genotype

Answer 11

genetic makeup (PP, pp, Pp) (homozygous dominant,) (homozygous recessive,) (heterozygous [always dominant])

Question 12

blending inheritance-(false)

Answer 12

fluids of parents, carrying the traits, would blend together during reproduction to form intermediate hybrids.

Question 13

Give an example that proves blending inheritance false

Answer 13

the F1 generation would have pale purple flowers, and it does not

Question 14

Law of segregation

Answer 14

during meiosis, the two alleles of a gene separate into separate gametes

Question 15

If the two alleles differ

Answer 15

dominant allele is fully expressed in the organism’s appearance, while the recessive allele is masked

Question 16

What accounts for variations?

Answer 16

Alternative versions of genes (different alleles)

Question 17

For each gene, an organism inherits…

Answer 17

2 alleles, 1 from each parent ( May be the same, as in true breeding/homozygous individuals; May be different, as in hybrid/heterozygous)

Question 18

Law of segregation…explain results of identical alleles v hybrid alleles in gametes

Answer 18

The two alleles for each character segregate during
gamete production. If organism has identical alleles, that allele will exist in all gametes; If organisms is hybrid, then
50% of gametes receive dominant allele and 50% receive recessive allele.

Question 19

test cross explanation

Answer 19

How can we tell if a purple plant is homozygous or
heterozygous??
If we cross the unknown purple-flowered plant with a white-flowered plant, the offspring will tell us:

All offspring are purple–homozygous dominant
offspring are purple and white–> heterozygous

Question 20

Dihybrid cross

Answer 20

cross that studies the outcome of two different genes

Question 21

possible hypotheses for dihybrid crosses

Answer 21

If alleles travel together, then only two gametes are made for each parent, resulting in 3 yellow smooth:1green wrinkled
Alternative hypothesis- two pairs of alleles segregate
independently of one another, resulting in four gametes- YR, Yr, yR, and yr, giving 16 possible offspring in
a phenotype 9:3:3:1 ratio (this is correct)
phenotype 9DD:3Dd: 3dD:1dd

Question 22

• Mendel’s law of independent assortment

Answer 22

therefore states that by the end of meiosis, each pair of homologous chromosomes (and the genes they carry) have been sorted in the gametes independently of how the other pairs were sorted

Question 23

To find the joint probabilities of independent events-

Answer 23

multiply probabilities of individual events

Question 24

find the probability that an event can occur in two or more different ways–

Answer 24

the sum of the individual probabilities of those 2 ways

Question 25

Incomplete Dominance

Answer 25

one allele of a pair is not fully dominant over its partner, so the phenotype of the heterozygous individual is somewhere in between the phenotype of the two homozygous individuals

Question 26

Complete Dominance

Answer 26

in both heterozygotes and homozygous

dominant individuals, the dominant phenotype occurs

Question 27

Codominance-

Answer 27

both alleles are at same time in phenotype

Question 28

multiple allele system

Answer 28

3+ possible alleles coding for a trait

Question 29

What is polydactyly? Why would one assume that polydactyly is common within the human population? Why isn’t this true?

Answer 29

6 fingers. Bc it’s dominant–but–Just because an allele dominant, does not mean that it is more
common in the population

Question 30

Type O blood

Answer 30

genotype of ii. No coding for sugars. recessive. antibodies against everything.

Question 31

Type A blood

Answer 31

genotype of I^Ai or I^A I^A. antibodies against B. dominant.

Question 32

Type B blood

Answer 32

genotype of I^Bi or I^B I^B. antibodies against A. dominant.

Question 33

Type AB blood.

Answer 33

genotype of I^A I^B. No antibodies. codominant.

Question 34

Polygenic inheritance

Answer 34

when a number of genes, in addition to environmental factors, can affect outcome of expression

Question 35

continuous variation

Answer 35

Polygenic inheritance results in a range of phenotypes called continuous variation- individuals in a population generally exhibit a range of small differences in a trait

Question 36

exes of continuous variation

Answer 36

Ex- eye color- caused by different genes that affect the production + distribution of melanin in eyes; o Height- variations bell curve–majority have intermediate phenotype and minority has extremes
o Height- variations are expressed in a normal distribution curve, or bell curve -

Question 37

bell curve phenotypes

Answer 37

majority have intermediate phenotype and minority has extremes

Question 38

Environmental Effects on phenotype

Answer 38

An individual’s genes provide the potential for developing a particular phenotype but environmental influences may SOMETIMES also shape phenotype