Genetics 2 Exam

Front 1

Polygenic inheritance gives rise to quantitative traits that vary along a continuum or a gradient.

Back 1

True

Front 2

In polygenic inheritance, the phenotype of an allele of one gene depends on the action of alleles of other genes.

Back 2

False

Front 3

In polygenic inheritance, genes are typically equivalent in their contributions.

Back 3

True

Front 4

Quantitative traits that can be counted and expressed in whole numbers are called _______ traits.

Back 4

Meristic

Front 5

A graph of the number of individuals in each arbitrary phenotypic class for a quantitative trait is called a(n) ___________ _____________.

Back 5

Frequency Distribution

Front 6

Which of the following statements is TRUE about a quantitative trait locus (QTL)?

a) It contains a single gene which affects a polygenic trait.

b) It controls all of the variation for a polygenic trait.

c) Both A and B

d) Neither A nor B

Back 6

d) Neither A nor B

Front 7

Which of the following statements is TRUE about a normal distribution?

a) Equal numbers of individuals are found above and below the mean

b) The mean is also the most frequent value.

c) Both A and B

d) Neither A nor B

Back 7

c) Both A and B

Front 8

Assuming a case of polygenic inheritance with additive alleles, where there are seven genes involved, how many phenotypic classes are expected?

a) 7

b) 10

c) 13

d) 15

e) NOTA

Back 8

d) 15

Front 9

In a certain plant, branch length is under the control of three genes. Branches can be absent or 1-6 cm long. Which of the following genotypes are possible for branches that are 3 cm?

a) AaBbCc

b) aaBBcc

c) AABBcc

d) AAbbCC

e) More than one above

Back 9

a) AaBbCc

Front 10

In a certain plant, branch length is under the control of three genes. Branches can be absent or 1-6 cm long. In a cross of AaBbcc x AAbbCc plants, what proportion of the progeny will have NO branches?

a) 1/2

b) 1/4

c) 1/8

d) 1/16

e) choose this answer if all of the offspring will have branches

Back 10

e

Front 11

In a particular animal, horn length is an example of continuous variation, under polygenic control. Horns could be = 1, 3, 5, 7, 9, 11, 13, 15 or 17 centimeters long. How many genes are involved?

a) 2

b) 3

c) 4

d) 5

e) 6

Back 11

c) 4

Front 12

In a particular animal, horn length is an example of continuous variation, under polygenic control. Horns could be = 1, 3, 5, 7, 9, 11, 13, 15 or 17 centimeters long. How many different genotypes code for horns that are 3 centimeters long?

a) 4

b) 5

c) 6

d) 7

e) 8

Back 12

a) 4

Front 13

The weight of a particular animal is controlled by four genes. Individual animals can be 10, 20, 30, 40, 50, 60, 70, 80 or 90 kilograms. Garfield has genotype AABbCcdd, and Pluto has genotype aabbCCDD. Who is heavier?

a) Garfield

b) Pluto

c) Both have the same weight of 30 kg

d) Both have the same weight of 40 kg

e) none of the above is true

Back 13

e) none of the above is true

Front 14

In a certain plant, branch length is under the control of three genes. Branches can be absent or 1-6 cm long. Which of the following crosses can produce a plant having branches of 6 cm?

a) AaBBcc x AAbbcc

b) AABBcc x AaBbCC

c) AaBbCC x AAbbCC

d) AaBbCC x AaBBCc

e) NOTA

Back 14

d) AaBbCC x AaBBCc

Front 15

The weight of a particular animal is controlled by four genes. Individuals can be 10, 20, 30, 40, 50, 60, 70, 80 or 90 kilograms. What proportion of the offspring of the cross of AabbccDd x aaBbccDd animals are expected to weigh 10 kg?

a) 1/4

b) 1/8

c) 1/16

d) 1/32

e) 1/64

Back 15

c) 1/16

Front 16

What are quantitative genetics?

Back 16

the study of trait that can be measured or described numerically

Front 17

What considered quantitative traits?

Back 17

heart disease, cancer, and diabetes

Front 18

What are the four main categories of quantitative traits?

Back 18

Anatomical, Physiological, Behavior and Disease

Front 19

What are continuous traits?

Back 19

quantitative traits that do not fall in discrete categories such as height and weight

Front 20

What are meristic traits?

Back 20

quantitative traits that can be counted and expressed in whole numbers

Front 21

What are threshold traits?

Back 21

traits that are inherited quantitatively due to the contributions of many genes; a certain threshold must be reached in which the number of disease causing alleles results in the development of the disease

For example: heart disease, diabetes and cancer -- the alleles of SEVERAL different genes contribute to the likelihood the disease will develop

Front 22

What are discontinuous traits?

Back 22

when offspring can be put in discrete categories ex: red eyes or white eyes in drosophila

Front 23

What is the shape of normal distribution on a graph?

Back 23

bell-shaped and symmetric

Front 24

How do geneticists describe traits that show a continuum of phenotypes since most quantitative traits dont fall into discrete categories?

Back 24

using a frequency distribution

Front 25

What does QTL stand for and what is it?

Back 25

Quantitative Trait Locus; the location on a chromosome that harbors one or more genes that effect the outcome of a quantitative trait

Front 26

Humans have ____ homologs?

Back 26

22; because X and Y are not homologs

Front 27

What are homologous chromosomes?

Back 27

Two chromosomes with the same length, centromere position, and staining pattern

Front 28

When does crossing over occur?

Back 28

Prophase 1 of Meiosis

Front 29

What stage of mitosis does the nuclear membrane break down?

Back 29

prophase

Front 30

Where is the centromere in a metacentric chromosome?

Back 30

MIDDLE

Front 31

Where is the centromere in a submetracentric chromosome?

Back 31

OFF CENTER

Front 32

Where is the centromere in a acrocentric chromosome?

Back 32

CLOSE TO THE END

Front 33

Where is the centromere in a telocentric chromosome?

Back 33

VERY VERY END

Front 34

What are the three criteria of characterizing chromosomes?

Back 34

1. size 2. centromere location 3. banding patterns (identified by staining procedures)

Front 35

What stage of the cell cycle are centroSOMES replicted?

Back 35

Interphase

Front 36

What phase of the cell cycle does the pindle apparatus form?

Back 36

Prophase

Front 37

Which stage of the cell cycle do centrosomes migrate to opposite poles?

Back 37

Prophase

Front 38

What phase of the cell cycle have chromosomes not yet taken shape?

Back 38

Interphase

Front 39

What are the three types of microtubles in cell division?

Back 39

1. aster 2. polar 3. kinetochore

Front 40

Which microtubules help to PUSH?

Back 40

polar microtubules

Front 41

Which microtubules help to PULL?

Back 41

kinetochore microtubules

Front 42

Which microtubles are important for positioning the spindle apparatus?

Back 42

aster microtubules

Front 43

Which part of the cell cycle do chromosomes uncoil and become diffuse chromatin again?

Back 43

Telophase

Front 44

Which part of the cell cycle does the nuclear membrane reform?

Back 44

Telophase

Front 45

Which part of the cell cycle does the spindle fibers disappear?

Back 45

Telophase