bio topic 10

Question 1

What is a result of crossing over in meiosis?

Answer 1

Variation of gametes

Question 2

Bivalent frequency of chromosomes means…

Answer 2

… that there are chromosome pairs

Question 3

When a cell divides by meiosis, chiasmata can be observed. Which are features of chiasmata?

Answer 3

• they occur during meiosis I
• they increase stability of bivalents

Question 4

What is always passed to the next generation as a result of sexual reproduction?

Answer 4

A haploid set of chromosomes from the mother

Question 5

Which process could cause non-disjunction if it occurred during meiosis?

Answer 5

Homologous chromosomes do not separate in anaphase I.

Question 6

What process occurs in both mitosis and meiosis?

Answer 6

Separation of chromatids

Question 7

How does meiosis cause Mendel’s law of independent assortment?

Answer 7

Alleles that are not in the same linkage group are segregated.

Question 8

Maize (Zea mays) contains 20 chromosomes in a diploid cell. How many chromosomes will be in each cell after the first and second division of meiosis?

Answer 8

10 and 10

Question 9

When do chiasmata form in meiosis?

Answer 9

During prophase I

Question 10

How many autosomes are in human sperm?

Answer 10

22

Question 11

When does an unequal division of cytoplasm occur?

Answer 11

During meiosis in human ovary

Question 12

Some of the ratios that Morgan investigated in genetic crosses did not correspond with expected Mendelian ratios. What was the cause?

Answer 12

The genes in the genetic crosses were linked.

Question 13

Skin colour is a trait controlled by polygenic inheritance. Which statement is correct?

Answer 13

Individuals show a wide range of phenotypes for skin colour

Question 14

Which is a statement of Mendel’s law of independent assortment?

Answer 14

Allele pairs for different genes separate independently during gamete formation.

Question 15

In a fruit fly experiment, grey body, normal winged (homozygous dominant) fruit flies were mated with black body, short winged (homozygous recessive) fruit flies. The F1 dihybrid females were then used in a test cross. If the genes are always linked and no crossing over occurs, what would be the predicted ratio in the F2 generation?

Answer 15

1:1

Question 16

Human skin colour shows continuous variation. What does this indicate about the pattern of inheritance of human skin colour?

Answer 16

It is polygenic

Question 17

In a variety of tulips, V is the allele for variegated colour and C is the allele for compound flower. Which cross will give a 1:1:1:1 ratio of phenotypes in the offspring?

Answer 17

Vvcc × vvCc

Question 18

What causes variation in both sexually and asexually reproducing organisms?

Answer 18

Mutations

Question 19

Which of the following processes result in the production of recombinants?

Answer 19

Crossing over between linked genes and reassortment of non-linked genes

Question 20

Which are the possible recombinants in a dihybrid test cross involving the linked genes JQ/jq?

Answer 20

Jq/jq and jQ/jq

Question 21

What is polygenic inheritance?

Answer 21

A character that is controlled by two or more genes

Question 22

In humans, wavy hair is dominant to straight hair and free ear lobes are dominant to fixed ear lobes. A man and a woman are heterozygous for both characteristics. What is the probability that their first child will have straight hair and fixed ear lobes?

Answer 22

1/16

Question 23

What can lead to reproductive isolation after just one generation?

Answer 23

Polyploidy

Question 24

How do the concepts of gradualism and punctuated equilibrium differ?

Answer 24

The timing of evolution

Question 25

What is polyploidy?

Answer 25

Having an extra set of chromosomes

Question 26

The cheetah (Acinonyx jubatus) is a large cat found in Africa. It has been discovered that organs could be transferred between any two individuals without rejection of the organ. What is the probable reason for this?

Answer 26

Cheetahs have a small gene pool.

Question 27

A hunter tends to kill the bigger individuals of a population for their meat or for large ornamental trophies. Therefore, the population tends to have more individuals who are smaller. What is this an example of?

Answer 27

Directional selection

Question 28

Two kinds of wolf spider rub specialized body parts together in order to produce distinct sounds to attract females. Females of both groups will only allow a male of the same kind to mate with them. It has been found through experimentation, however, that offspring can be produced from crossings between the two groups. What can be hypothesized? I. The groups are reproductively isolated. II. They could be the same species. III. This is an example of behavioural isolation.

Answer 28

All 3

Question 29

Many commercially produced bananas are triploid instead of diploid. The nucleus of a triploid cell has three sets of chromosomes. What is the effect of triploidy?

Answer 29

Chromosomes cannot pair in meiosis.

Question 30

Fossil records show that black bears increased in size during the Ice Age and decreased in size with warmer temperatures. What type of selection do these changes in size represent?

Answer 30

Directional