B13 Reproduction

Question 1

Asexual reproduction needs only one…

Answer 1

parent.

Question 2

Asexual reproduction does not involve production of a…

Answer 2

gamete.

gamete = sex cell, e.g. sperm or egg

Question 3

In asexual reproduction, the daughter plant is called a…

[Hint: begins with ‘c’]

Answer 3

clone.

Question 4

A red flowered plant is bred with a white flowered plant. All the offspring are red flowered. This shows that the red colour is due to:

a) A dominant allele
b) A recessive allele
c) An environmental factor

Answer 4

a) A dominant allele

The red flowered parent must have been RR and the white flowered parent must have been rr. The offspring would all be Rr meaning the dominant R allele for red flowers is still expressed.

Question 5

A red flowered plant is bred with a white flowered plant. All the offspring are red flowered. The offspring are then bred and the second generation offspring have a mixture of red and white flowered plants. This shows that the white colour is due to:

a) A dominant allele
b) A recessive allele
c) An environmental factor

Answer 5

b) A recessive allele

The red flowered parent must have been RR and the white flowered parent must have been rr. The offspring would all be Rr. When the offspring are bred their second generation offspring would have been a mixture of RR, Rr and rr, meaning the recessive r allele for white flowers is now expressed in the rr offspring.

Question 6

How are genes from parents passed to their offspring in sexual reproduction?

Answer 6

The parents produce gametes (sex cells) that contain DNA from each parent (a half set of chromosomes). The gametes fuse to form a zygote containing DNA from both parents (a full set of chromosomes) which divides and grows to form the baby.

Question 7

How many chromosomes does a human gamete (sex cell) contain?

Answer 7

23 chromosomes

Question 8

How many chromosomes does a normal human cell contain?

Answer 8

46 chromosomes (23 pairs)

Question 9

How many chromosomes does a human zygote (fertilised egg) contain?

Answer 9

46 chromosomes (23 pairs)

Question 10

How many chromosomes does a diploid human cell contain?

Answer 10

46 chromosomes (23 pairs)

Question 11

How many chromosomes does a haploid human cell contain?

Answer 11

23 chromosomes (half a diploid cell)

Question 12

The sex chromosomes for a male are:

a) XX
b) XY

Answer 12

b) XY

Question 13

The sex chromosomes for a female are:

a) XX
b) XY

Answer 13

a) XX

Question 14

If a couple already have three sons, what is the probability their next child will be a girl?
a) 0%, b) 25%, c) 50%, d) 75%, e) 100%

Answer 14

c) 50%

Question 15

A fertilised egg (zygote) has ____ of genetic information.

Complete the sentence with:

a) one set
b) two sets
c) half a set

Answer 15

b) two sets

Question 16

A fertilised egg (zygote) divides to form an embryo by a process called…

Answer 16

mitosis.

Question 17

Give one environmental factor and one other factor that might affect the number of peas in a pod on a pea plant.

Answer 17

Physical: e.g. light, temperature, rain, nutrients/minerals

Other: e.g. genes, disease

Question 18

Are the sex chromosomes YY possible?

Answer 18

No.

Question 19

The number of chromosomes in a gamete (sex cell) is ____ in body cells.

Complete the sentence with:

a) the same number as
b) half the number
c) twice the number

Answer 19

b) half the number

Question 20

Gametes are produced by ____.

Complete the sentence with:
meiosis / mitosis / fertilisation

Answer 20

a) meiosis

Question 21

Our understanding of how genes are inherited is mostly due to the work of ____.

a) Darwin
b) Lamarck
c) Mendel
d) Galileo
e) Bieber

Answer 21

c) Mendel

Question 22

A tall plant is bred with a short plant of the same species. All the offspring are tall.

T = allele for tall (dominant)
t = allele for short (recessive)

This shows that the original tall plant was

a) TT
b) Tt
c) tt

Answer 22

a) TT

Question 23

T = allele for tall (dominant)
t = allele for short (recessive)

Draw a punnet square for a Tt tall plant crossed with a tt short plant.

What is the ratio of tall to short offspring?

a) 1:1
b) 2:1
c) 3:1
d) 1:2

Answer 23

a) 1:1

Question 24

T = allele for tall (dominant)
t = allele for short (recessive)

Two short plants were crossed. This cross produced 100 offspring.

The expected offspring would be

a) 100 short plants
b) 50 tall plants and 50 short plants
c) 75 tall plants and 25 short plants

Answer 24

a) 100 short plants