Exam questions from previous years

Question 1

• The following figure shows the nutrient cycling process in a grassland from which large herbivores have been excluded by overhunting. Draw a similar diagram showing what the nutrient cycling would look like if large herbivores were reintroduced to the system. Indicate and explain the main differences between the two schemes.

Question 1 continuation

• 
• What are the differences between the two schemes?

Question 2a

• What are the five major mechanisms of evolutionary change?
• 1. Mutation
• 2. Migration
• 3. Sex/recombination
• 4. Genetic Drift
• 5. Natural Selection

Question 2b

• Which mechanism(s) produce random and non-random change?
• Reproductive success

Question 2c

• Which mechanism results in adaptation?

Question 3

• On the following two phylogenic trees, identify one character that defines the clades for each labelled branch.
• A =
• B =
• C =
• D =
• E =

Question 4

• Choose a plant to consider for the following questions. You do not need to know the scientific name of the plant.
• a.) Describe your chosen plant, both its habitat and its 'natural' habitat?
• b.) What is special about your plant that makes it suited to its environment?

Question 5a

• Discus one factor that would limit the maximum size of a prokaryotic cell?

Question 5b

• Discuss three (3) differences between prokaryotic and eukaryotic cells?

Question 6

• What are the similarities and differences between
• a.) Aerobic and anaerobic respiration?
• b.) Anaerobic respiration and fermentation?
• c.) C4 and CAM photosynthesis?
• d.) Mitochondria and chloroplasts?

Question 7

• a.) List 4 functions of membrane proteins?
• b.) What is the main function of membrane carbohydrates?
• c.) What are the differences between facilitated diffusion and active transport?
• d.) Why do leafy vegetables wilt after picking?

Question 8

• The diagram below shows a DNA replication bubble with the origin of replication and two advancing replication forks marked.
• Indicate on the diagram the leading and lagging strands of DNA synthesis

Question 9

• In pea plants, an allele for round peas (R) is dominant to the allele for wrinkled peas (r). An allele for an independently assorting gene produces yellow peas (Y) and is dominant to the allele for green peas (y).
• The following cross was set up: RrYy x RrYy
• a.) what type of cross is this and what generation (progeny) results from this cross?
• b.) What are the types of gametes and their expected frequencies produced by the double heterozygote RrYy?
• c.) what would be the expected phenotypes and their respective ratios in the progeny of this cross?

Question 10

• Mutation is a basic mechanism for evolutionary change, the results of which can be beneficial, neutral or deleterious.
• Phenotypic mutation (proton coding genes) is able to introduce new variation; it is, however, regarded as random and its occurrence is relatively low.
• Using the Information and Inheritance lectures as a guide, outline and briefly explain four (4) factors that can contribute to why these mutations occur rarely.

Question 11

• A plant breeder claims to have developed a bonsai eucalyptus tree that does not need to be pruned constantly.
• a.) Briefly describe two 'ingredients for evolution' that must have been present to allow the plant breeder to develop this particular plant.
• b.) Briefly describe which mechanism(s) of evolution would have been necessary for the plant breeder to develop this particular plant.

Question 12

• For each of the following animals, identify their body symmetry, tissue organisation, whether there is a defined mouth and anus and whether the mouth and anus are shared or separate.
• a.) Sponge - Phylum Porifera
• b.) Jellyfish - Phylum Cnidaria
• c.) Earthworm - Phylum Annelida

Question 13

• Select one (1) of the five (5) stages of Mitosis and describe the cellular events that are taking place in that stage

Question 14

• What are the main functions of:
• a.) Lysosomes
• b.) Golgi body
• c.) Vacuoles

Question 15

• Acid phosphatase is an enzyme that is executed by plants when they are phosphate deficient to break down organic phosphates in the soil into usable inorganic phosphate. The genes for these enzymes are located on nuclear DNA. List the sequence of events that is needed to synthesise the enzyme and transport it into the soil.

Question 16

• Ultimately, all energy for growth and maintenance of plant and animal cells come from the sun. The overall pathway can be traced as follows:
• A. Light reactions in the Chloroplast
• B. Carbon Fixation
• C. Glycolysis
• D. Citric Acid Cycle
• E. Electron Transport Chain
• F. Chemiosmosis = ATP
• Write brief notes on what happens in each of these stages.
• A.
• B.
• C.
• D.
• E.
• F.

Question 17 Part 1

• Emery-Dreifuss muscular dystrophy is a disorder caused by mutation in exon 1 of the LMNA gene and leads to progressive muscle weakness
• In an individual without the disease, the DNA sequence from the first ATG is as follows:
• 5' ATG GAG ACC CCG TCC TAG CGG CGC GCC 3'
• The sequence of the same region from DNA from an Individual with Emery-Dreifuss muscular dystrophy is as follows
• 5' ATG GAG ACC CCG TCC TAG CGG CGC GCC 3'
• a.) For the individual without the disease?
• i. write down the mRNA sequence transcribed from this DNA segment
• ii. What is the amino acid sequence produced after translation of this mRNA

Question 17 Part 2

• b.) For the individual with the disease
• i.) write down the mRNA sequence transcribed from this DNA segment
• ii. What is the amino acid sequence produced after translation of this mRNA?
• 

Question 18

• A pure breeding doubly homozygous tall pea plant that produces yellow peas was crossed with a pure-breeding doubly homozygous dwarf pea plant that produces green peas.
• The tall allele, T, is dominant to the dwarf, t, recessive allele, while the yellow allele, Y, is dominant to the green, y recessive allele. Note also that the 2 genes are on different chromosomes: i.e. independent assortment applies
• a.) what are the genotypes and their respective frequencies of the gametes produced by the F1 progeny of the above cross?
• b.) Indicate which of the gametes are parental and which are recombinant?
• c.) What is the minimum number of meioses needed to produce both parental and recombinant gametes?
• The F1 plants where then self-crossed as follows, TtYy x TtYy to produce the F2 generation
• d.) What are the expected phenotypes and their respective ratios recovered in the F2 generation?