Exam 2

Question 1

Artificial selection

Answer 1

the purposeful control of mating by choosing parents for the next generation.

Question 2

How was Mendel different from scientists before him

Answer 2

• He studied garden peas; each pea had both male and female organs which allowed self or cross fertilization
• He studied discrete traits
• He collected and perpetuated lines of peas that bred true (pure-breeding)
• He made reciprocal crosses
• He studied inheritance in a quantitative manner
• He was a good experimentalist

Question 3

Self-fertilization (selfing)

Answer 3

Fertilization in which both egg and sperm come from the same plant or animal; mendels peas self-fertilized since they had both egg and pollen within the same plant/flower and they would self-fertilize because of proximity

Question 4

How did Mendel cross-fertilize

Answer 4

Mendel removed the male sex organs from the flowers of one plant (to prevent selfing) and then brushed pollen from another plant onto the female organs of the first plant

Question 5

Discrete traits

Answer 5

an inherited trait that exhibits an either/or status (that is, purple versus white flowers). Synonymous with discontinuous trait.

Question 6

Continuous traits

Answer 6

Opposite of discrete traits; has intermediates (height, skin color,etc)

Question 7

Pure breeding

Answer 7

organisms that produce offspring with specific parental traits that remain constant from generation to generation; synonymous with true-breeding (lines); these lines are also called inbred

Question 8

Inbred

Answer 8

describes individuals or a population of organisms produced by matings of close genetic relatives; inbreeding results in homozygosity (plants with white flowers only produce white flowers, etc)

Question 9

Antagonistic pairs

Answer 9

Constant but mutually exclusive alternatives (purple vs white flower or yellow vs green seeds)

Question 10

Hybrids

Answer 10

offspring of genetically dissimilar parents; often used as synonym for heterozygotes (yellow and green parents, round and wrinkled, etc)

Question 11

What are reciprocal crosses and what did they prove in mendel’s experiments

Answer 11

Reversed characteristics of male vs female when crossing thus controlling whether a trait was transmitted via egg or sperm (use pollen from purple flower to fertilize egg of white flower and then use pollen from white flower to fertilize egg of purple flower); proved that two parents contributed equally to inheritance since the progeny of reciprocal crosses were similar

Question 12

Parental (P) generation

Answer 12

individuals whose progeny in subsequent generations will be studied for specific traits.

Question 13

Monohybrid crosses

Answer 13

crosses between parents that differ in only one trait.

Question 14

Gene

Answer 14

a specific segment of DNA in a discrete region of a chromosome that serves as a unit of function by encoding a particular RNA or protein.

Question 15

Monohybrid

Answer 15

individuals having two different alleles for a single trait.

Question 16

Mendel’s law of segregation

Answer 16

Mendel’s first law, which states that the two alleles for each trait separate (segregate) during gamete formation and then unite at random, one from each parent, at fertilization.

Question 17

Product rule

Answer 17

the probability of two or more independent events occurring together is the product of the probabilities that each event will occur by itself (fertilization to make egg and sperm are independent events)

Question 18

Sum rule

Answer 18

the probability that any of two or more mutually exclusive events will occur is the sum of their individual probabilities (punnet square demonstrates)

Question 19

Test cross

Answer 19

(1) a cross used to determine the genotype of an individual showing a dominant phenotype by mating with an individual showing the recessive phenotype; and (2) a cross used to determine whether genes are linked and the distance (recombination frequency) between linked genes.

Question 20

Dihybrid

Answer 20

an individual that is heterozygous at two different genes.

Question 21

recombinant types

Answer 21

phenotypes reflecting a new combination of alleles that occurred during gamete formation.

Question 22

Parental types

Answer 22

phenotypes that reflect a previously existing parental combination of alleles that is retained during gamete formation.

Question 23

What were the parental types in mendels peas

Answer 23

Yellow round or green wrinkled