1.3. Mendelian Genetics

Question 1

differentiate: gene and alleles

Answer 1

gene is the unit of inheritance; known as mendel’s unit factors
vs.
alleles are the alternative forms of a single gene that determines the phenotype of an organism; can be dominant or recessive

Question 2

differentiate: phenotype and genotype

Answer 2

phenotype is the observable physical trait
vs.
genotype is the genetic makeup of an individual for the trait it describes

Question 3

differentiate: homozygote and heterozygote

Answer 3

homozygotes have identical alleles at one or more loci
vs.
heterozygotes have different alleles at one or more loci

Question 4

why did mendel use pisum sativum in his experiments?

Answer 4

(1) easy to grow
(2) matures in a single season
(3) reproduces well
(4) self-fertilizing
(5) easy to cross-breed experimentally
(6) easy to hybridize artificially
(7) only has one or very few pairs of contrasting traits in each experiment
(8) faithful and accurate quantitative data recording

Question 5

a type of cross having one pair of contrasting traits

Answer 5

monohybrid cross; one-factor cross

Question 6

individuals that only produce offspring with the same traits when self-fertilized

Answer 6

true-breeding individuals

Question 7

1/3 observation in the monohybrid cross: describe the trait expressed by F1 offspring in a monohybrid cross

Answer 7

all F1 offspring expressed the same trait exhibited by one of the parents

Question 8

1/3 observation in the monohybrid cross: ratio of F2 offsprings

Answer 8

3:1

Question 9

1/3 observation in the monohybrid cross: a female plant with dominant green pods was crossed with a male plant with recessive yellow pods, and vice versa. will all F1 offspring exhibit the dominant trait in both crosses? will all F2 offspring show 3:1 ratio? why or why not?

Answer 9

yes. the results are not sex dependent

Question 10

a mendelian principle stating that genetic characters are controlled by unit factors existing in pairs in individual organisms

Answer 10

principle of unit factors in pairs

Question 11

a mendelian principle stating that when two unlike unit factors responsible for a single character are present in a single individual, one unit factor is dominant to the other, which is said to be recessive

Answer 11

principle of dominance

Question 12

a mendelian principle stating that during gamete formation, paired unit factors segregate randomly so that each gamete receives one or the other with equal likelihood

Answer 12

principle of segregation

Question 13

a diagram used to easily visualize the genotypes and phenotypes resulting from the recombination of gametes during fertilization

Answer 13

punnet square

Question 14

who came up with the punnett square?

Answer 14

reginald punnett

Question 15

a test used to distinguish the genotypes of F2 offsprings showing the dominant phenotypes

Answer 15

test cross

Question 16

who came up with the test cross?

Answer 16

gregor mendel

Question 17

in a test cross, the unknown is crossed with ___.

Answer 17

known homozygous recessive

Question 18

a mendelian principle stating that during gamete formation, segregating pairs of unit factors or alleles assort independently of each other such that each gamete receives one member of every pair of unit factors

Answer 18

principle of independent assortment

Question 19

during the independent assortment of segregating alleles, all possible combinations of gametes should be formed in equal frequency. true or false?

Answer 19

true

Question 20

a cross used to examine two characters simultaneously

Answer 20

dihybrid cross; two-factor cross

Question 21

formula for number of different types of gametes formed

Answer 21

2^n

Question 22

formula for number of different types of genotypes formed

Answer 22

3^n

Question 23

formula for number of different types of phenotypes formed

Answer 23

2^n

Question 24

when an event is certain not to occur, it is denoted by ___.

Answer 24

0

Question 25

when an event is certain to occur, it is denoted by ___.

Answer 25

1

Question 26

the probability of two or more independent events occurring simultaneously is equal to the product of their individual probabilities

Answer 26

product law

Question 27

free earlobe is ___; attached is ____

Answer 27

dominant; recessive

Question 28

dimples are ____; no dimple is ____

Answer 28

dominant; recessive

Question 29

bent little fingers are ____; straight ones are ___

Answer 29

dominant; recessive

Question 30

widow’s peak: ____; straight: ____

Answer 30

dominant; recessive

Question 31

connected eyebrow shape: _____; not connected: _____

Answer 31

recessive; dominant

Question 32

a dominant human genetic condition characterized by abnormal bone growth; dwarfism

Answer 32

achondroplasia

Question 33

a dominant human genetic condition characterized by shortening of fingers and toes

Answer 33

brachydactyly

Question 34

a recessive human genetic condition characterized by lack of pigment

Answer 34

albinism

Question 35

a recessive human genetic condition characterized by black urine

Answer 35

alkaptonuria