Question 1
1
The drawing shows part of a Thunbergia grandiflora plant. It has been widely cultivated as an ornamental garden plant.
7 marks
Question 1(c)
1(c)
After fertilization, seeds of T. grandiflora form in a small pod. If you were provided with Petri dishes, absorbent cotton balls and seeds, suggest how one variable affecting germination of these seeds could be investigated.
Mediumpractical3 marks
Answer
a. different values for the named independent variable b. large / equal number of seeds in each Petri dish c. control of other variables «than seeds» d. mentions how germination will be determined OR how germination rate/percentage will be measured e. includes a control giving seeds all factors needed Possible factors include water, oxygen, temperature, pH, light, salt concentration. Name of the independent variable must be included, eg temperature. eg appearance of radicle. eg number germinated over time/in a set time. Do not accept measurement of growth of stem/number of leaves. 3 max
Question 2
2
Concerns have been raised about the effect of rising pollution levels on sperm production in men. To investigate the possible effects of pollution on spermatogenesis, sperm samples from men of similar ages were collected in Kolkata in the 1980s and 2000s. The box plot represents the mean and range of sperm counts in the 1980s and 2000s.
0 marks
Question 2(b)
2(b)
The light micrograph shows a cross section of seminiferous tubules.
0 marks
Question 2(b)(ii)
2(b)(ii)
Identify the type of cell labelled Z .
Mediumstructured1 marks
Answer
spermatogonium OR primary spermatocyte
Question 2
2
Hemophilia is a sex-linked disease that affected some members of royal families in Europe during the 19th and 20th centuries.
0 marks
Question 2(d)
2(d)
Explain the mechanism that prevents polyspermy during fertilization.
Mediumstructured2 marks
Question 11
11
Which diagram(s) represent(s) processes used in asexual reproduction?
Mediummcq1 marks
Question 11
11
The micrograph shows a cross section of a lily (Lilium longiflorum) anther. What can be found in X ? A. Haploid nuclei produced by meiosis B. Diploid nuclei produced by fertilization C. Haploid nuclei produced by mitosis D. Diploid nuclei produced by pollination
Mediummcq1 marks
Answer
A
Question 3
3
This redwood tree (Sequoia sempervirens) was blown over in 1936, but five side branches formed new roots and are now separate trees. Three of the new trees formed from side branches of the original tree
structured0 marks
Question 3(b)
3(b)
If the genomes of the five new trees were sequenced, predict with a reason how similar they would be to each other.
Mediumstructured2 marks
Answer
a. identical/the same; b. (because of) asexual reproduction/vegetative propagation/mitosis/DNA replication; c. clones/produced by cloning; d. any differences would be due to mutation; 2 max
Question 12
12
What term describes genetically identical organisms derived from a single parent? A. Species B. Clone C. Family D. Twins
Easymcq1 marks
Answer
B
Question 3
3
A broad bean is the seed of a species, Vicia faba, in the Fabaceae, a family of flowering plants. This family contains many species that are used as sources of food.
0 marks
Question 3(a)
3(a)
On the diagram, label the testa and the radicle.
Easystructured2 marks
Answer
a. testa labelled b. radicle labelled (must point to the bottom half of the embryo or the tip) [图片]
Question 3(b)
3(b)
An experiment was done to test the hypothesis that temperature affects the rate of germination of the broad bean. Outline two factors apart from temperature that should be controlled in this experiment.
Mediumstructured2 marks
Answer
a. same amount/type of soil/substrate / pH of soil b. same amount of water / humidity \(\boldsymbol{}\) c. oxygen/aeration d. same measurement of germination / time e. same number/source/age of seeds e.g.: heater Accept discussion of light only in as much as it relates to temperature; e.g.: emergence of radicle 2 max
Question 13
13
A cloning method used for livestock involves in vitro fertilization (IVF) with selected male and female gametes. The diagram shows the steps followed after in vitro fertilization. What does X represent? A. A group of eggs B. An embryo C. A follicle D. A group of zygotes
Easymcq1 marks
Answer
B
Question 14
14
Which diagram(s) represent(s) processes used in asexual reproduction? I only I and II only II only I, II and III
Mediummcq1 marks
Answer
C