bio1a1e december supplementary exam

BIO1A1E DECEMBER SUPPLEMENTARY EXAM 2014

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FACULTY OF SCIENCE

DEPARTMENT BOTANY AND PLANT BIOTECHNOLOGY

BIO1A1E

BIOLOGY ETENDED 1A

APK CAMPUS

DECEMBER SUPPLEMENTARY EXAM

DECEMBER 2014

DATE: DECEMBER 2014

SESSION:

ASSESSOR: MS J. WILLIAMSON

INTERNAL MODERATOR: DR. A. NEL

DURATION/ TYD: 3 HOURS

TOTAL MARKS: 150

NUMBER OF PAGES: 15 PAGES

Please read the following instructions carefully:

1. Answer all the questions in the question paper.

2. Answer ALL of the questions in the test book.

3. Work neatly

4. Read your questions carefully.

5. Good Luck.


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QUESTION 1 [20]

Choose the alternative that best completes the statement or answers the question. Only write

down the correct letter next to the question number in your answer book.

1.1 In a hypothetical world, every 50 years people over 6 feet tall are eliminated from the

population. Based on your knowledge of natural selection, you would predict that the

average height of the human population will

A) remain unchanged.

B) gradually decline.

C) rapidly decline.

D) gradually increase.

E) rapidly increase.

1.2 What is a hypothesis?

A) the same thing as an unproven theory

B) a tentative explanation that can be tested and is falsifiable

C) a verifiable observation sensed directly, or sensed indirectly with the aid of scientific

instrumentation

D) a fact based on qualitative data that is testable

E) a fact based on quantitative data that is falsifiable

1.3 A group of molecular biologists is trying to synthesize a new artificial compound to mimic

the effects of a known hormone that influences sexual behavior. They have turned to

you for advice. Which of the following compounds is most likely to mimic the effects of

the hormone?

A) a compound with the same number of carbon atoms as the hormone

B) a compound with the same molecular mass (measured in daltons) as the hormone

C) a compound with the same three-dimensional shape as part of the hormone


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D) a compound with the same number of orbital electrons as the hormone

E) a compound with the same number of hydrogen and nitrogen atoms as the hormone

1.4 A covalent bond is likely to be polar when

A) one of the atoms sharing electrons is much more electronegative than the other atom.

B) the two atoms sharing electrons are equally electronegative.

C) the two atoms sharing electrons are of the same element.

D) it is between two atoms that are both very strong electron acceptors.

E) the two atoms sharing electrons are different elements.

1.5 Which of the following is true of cellulose?

A) It is a polymer composed of sucrose monomers.

B) It is a storage polysaccharide for energy in plant cells.

C) It is a storage polysaccharide for energy in animal cells.

D) It is a major structural component of plant cell walls.

E) It is a major structural component of animal cell plasma membranes.

1.6 Which type of interaction stabilizes the alpha (α) helix and the beta (β) pleated sheet

structures of proteins?

A) hydrophobic interactions

B) nonpolar covalent bonds

C) ionic bonds

D) hydrogen bonds

E) peptide bonds

1.7 Which of the following statements correctly describes some aspect of protein disposal

from prokaryotic cells?


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A) Prokaryotes are unlikely to be able to excrete proteins because they lack an

endomembrane system.

B) The mechanism of protein excretion in prokaryotes is probably the same as that in

eukaryotes.

C) Proteins that are excreted by prokaryotes are synthesized on ribosomes that are

bound to the cytoplasmic surface of the plasma membrane.

D) In prokaryotes, the ribosomes that are used for the synthesis of secreted proteins are

located outside of the cell.

E) Prokaryotes contain large pores in their plasma membrane that permit the movement

of proteins out of the cell.

1.8 Which of the following produces and modifies polysaccharides that will be secreted?

A) lysosome

B) vacuole

C) mitochondrion

D) Golgi apparatus

E) peroxisome

1.9 What kinds of molecules pass through a cell membrane most easily?

A) Large and hydrophobic

B) Small and hydrophobic

C) Large polar

D) Ionic

E) Monosaccharides such as glucose

1.10 The mechanism in which the end product of a metabolic pathway inhibits an earlier step

in the pathway is known as _________________________


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A) metabolic inhibition.

B) feedback inhibition.

C) allosteric inhibition.

D) noncooperative inhibition.

E) reversible inhibition.

1.11 During oxidative phosphorylation, H2O is formed. Where does the oxygen for the

synthesis of the water come from?

A) Carbon dioxide

B) Glucose

C) Atmospheric oxygen

D) Pyruvate

E) Lactate

1.12 Why is glycolysis considered to be one of the first metabolic pathways to have evolved?

A) It produces much less ATP than does oxidative phosphorylation.

B) It is found in the cytosol, does not involve oxygen, and is present in most organisms.

C) It is found in prokaryotic cells but not in eukaryotic cells.

D) It relies on chemiosmosis which is a metabolic mechanism present only in the first

cells-prokaryotic cells.

E) It requires the presence of membrane-enclosed cell organelles found only in

eukaryotic cells.

1.13 In a protein complex for the light reaction (a reaction center), energy is transferred from

pigment molecule to pigment molecule, to a special chlorophyll a molecule, and

eventually to the primary electron acceptor. Why does this occur?


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A) The action spectrum of that molecule is such that it is different from other molecules

of chlorophyll.

B) The potential energy of the electron has to go back to the ground state.

C) The molecular environment lets it boost an electron to a higher energy level and also

to transfer the electron to another molecule.

D) Each pigment molecule has to be able to act independently to excite electrons.

E) These chlorophyll a molecules are associated with higher concentrations of ATP.

1.14 The reaction-center chlorophyll of photosystem I is known as P700 because

A) there are 700 chlorophyll molecules in the center.

B) this pigment is best at absorbing light with a wavelength of 700 nm.

C) there are 700 photosystem I components to each chloroplast.

D) it absorbs 700 photons per microsecond.

E) the plastoquinone reflects light with a wavelength of 700 nm.

1.15 Which of the following statements about genes is incorrect?

A) Genes correspond to segments of DNA.

B) Many genes contain the information needed for cells to synthesize enzymes and

other proteins.

C) During fertilization, both the sperm and the ovum contribute genes to the resulting

fertilized egg.

D) One gene only is used in a specific cell type.

E) Genetic differences can result from changes in the DNA called mutations.

1.16 Asexual reproduction results in identical offspring unless which of the following occurs?

A) Natural selection

B) Cloning


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C) Crossing over

D) Mutation

E) Environmental change

1.17 Pea plants were particularly well suited for use in Mendel's breeding experiments for all

of the following reasons except that _______________

A) peas show easily observed variations in a number of characters, such as pea shape

and flower color.

B) it is possible to control matings between different pea plants.

C) it is possible to obtain large numbers of progeny from any given cross.

D) peas have an unusually long generation time.

E) many of the observable characters that vary in pea plants are controlled by single

genes.

1.18 Cystic fibrosis (CF) is a Mendelian disorder in the human population that is inherited as a

recessive. Two normal parents have two children with CF. The probability of their next

child being normal for this characteristic is which of the following?

A) 0

B) 1/2

C) 1/4

D) 3/4

E) 1/8

1.19 When T2 phages infect bacteria and make more viruses in the presence of radioactive

sulfur, what is the result?

A) The viral DNA will be radioactive.

B) The viral proteins will be radioactive.


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C) The bacterial DNA will be radioactive.

D) both A and B

E) both A and C

1.20 Which enzyme catalyzes the elongation of a DNA strand in the 5' → 3' direction?

A) primase

B) DNA ligase

C) DNA polymerase III

D) topoisomerase

E) helicase

____________________________________________________________________________

QUESTION 2 [20]

Give the correct biological term for each of the following definitions. Only write down the correct

term next to the appropriate question number in your answer book.

2.1 The domain which includes primitive bacteria cells.

2.2 The unit of inheritance that transmits information from parents to offspring.

2.3 Essential elements only needed in minute quantities.

2.4 A measure of how difficult it is to break the surface of a liquid.

2.5 The molecule which forms between one Carbon and four (4) Hydrogen atoms.

2.6 The bond which forms between the monomers of a triglyceride.

2.7 The organelles typically involved in making proteins that function within the cytoplasm.

2.8 The first person to describe a sperm cell.

2.9 The process which include the engulfment of a particle by wrapping a cell membrane

around it, forming a vacuole.


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2.10 When a plant cell in placed in a hypotonic solution it becomes___________.

2.11 The process related to breathing which involves an exchange of gases.

2.12 Organisms which can survive using either fermentation or cellular respiration. (collective

name)

2.13 The plant pigments which absorbs blue-violet and red light and reflects green light.

2.14 The structure found in the leaf of a plant which functions first during photosynthesis,

absorbs light with a wavelength of 680 nm.

2.15 The need for cells to be in contact with a solid surface to divide.

2.16 Cancer which arises in external or internal body coverings.

2.17 A dominant human disorder resulting in dwarfism.

2.18 The phenomenon that occurs when one gene influences many characteristics.

2.19 The base triplets found on m-RNA molecules.

2.20 The enzyme which joins small fragments of DNA into a continuous chain during DNA

replication.

____________________________________________________________________________

QUESTION 3 [11]

3.1 In 1859, Charles Darwin published the book “On the Origin of Species by Means of

Natural Selection”, which articulated two (2) main points. Discuss these points briefly.(5)

3.2 We can think of biology’s enormous scope as having two (2) dimensions. Explain what is

meant by this statement. (4)


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3.3 Study the diagram below and answer the questions that follow.

3.3.1 Identify the structure in the diagram. (½)

3.3.2 Give the complete name of the nitrogen base which bonds with G. (½)

3.3.3 Give the complete name of the nitrogen base which bonds to T. (½)

3.3.4 What do you call the monomers of the structure in the diagram? (½)

____________________________________________________________________________

QUESTION 4 [11]

4.1. Water is the solvent of life. Discuss this statement. Include suitable examples to aid your

discussion and clearly state why water is a suitable solvent. (8)

4.2 Explain how the gecko in the photo below manage to walk on walls? (3)

____________________________________________________________________________


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QUESTION 5 [11]

5.1 Complete the table below. Only write down the correct word (answer) next to the

appropriate question number in your answer book. (7)

Functional

group

Structure Name of

compound

Functional properties

Hydroxyl 5.1.1 5.1.2 Is polar as a result of the electrons

spending more time near the

electronegative oxygen atom.

5.1.3 5.1.4 Ketones and

aldehydes

A ketone and an aldehyde may be

structural isomers with different

properties.

5.1.5 -NH2 5.1.6 5.1.7

5.2 What are the monomers of Polysaccharides called? Name three (3) different

examples of this monomer. (4 x ½ = 2)

5.3 The structure below represents a type of monomer of one of the organic

compounds. Study this structure and answer the questions that follow.

5.3.1 What monomer is represented in the structure? Give a reason for your answer.

(2 x ½ = 1)

5.3.2 Is this monomer hydrophobic or hydrophilic? Give a reason for your answer.

(2 x ½ = 1)

____________________________________________________________________________


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QUESTION 6 [11]


X

6.1.1 Label structures 1 – 6. (6 x ½ = 3)

6.1.2 What are structures 1,2 and 3 collectively called? (½)

6.1.3 Give the functions of the structures in question 6.1.2. (1½)

6.2 Draw and label the energy converting organelle only found in a plant cell. (6)

____________________________________________________________________________

QUESTION 7 [11]

7.1 A chemical that interferes with an enzyme’s activity is called an inhibitor. Discuss the

different types of enzyme inhibitors and their mode of inhibition. (4)

7.2 What happens when both a plant and animal cell are placed in the following solutions?

(5)


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7.2.1 Hypertonic solution

7.2.2 Isotonic solution

7.3 For the following question, match the labelled (A-E) component of the cell membrane in

the diagram below with its description (1-4). (4 x ½ = 2)

7.3.1 Peripheral protein

7.3.2 Cholesterol

7.3.3 Fibre of the extracellular matrix

7.3.4 Microfilament of the cytoskeleton

____________________________________________________________________________

QUESTION 8 [11]

8.1 Three (3) categories of cellular poisons obstruct the process of oxidative

phosphorylation. Name the three (3) ways of how these poisons work. (3)

8.2 Why are fats excellent cellular fuel? (2)

8.3 Distinguish between: respiration and cellular respiration. (4)


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8.4 What is brown fat and what type of animals benefit from producing brown fat? (2)

__________________________________________________________________________

QUESTION 9 [11]

9.1 What do greenhouse gasses do? (1)

9.2 Explain what happens to C3 plants in hot and dry weather. (5)

9.3 Draw a photosystem II found in the thylakoid membrane. (5)

____________________________________________________________________________

QUESTION 10 [11]

10.1 Give a suitable biological definition of each of the following:

10.1.1 Klinefelter syndrome: (1)

10.1.2 Polyploid (1)

10.1.3 Chronic myelogenous leukemia (3)

10.2 Alterations of chromosome structure can cause birth defects and cancer. Discuss this

statement. (4)



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10.3.1 What is displayed in the diagram? (½)

10.3.2 Are these chromosomes that of a male or female? Give a reason for your answer.(1)

10.3.3 What disease does this person suffer from? (½)

____________________________________________________________________________

QUESTION 11 [11]

11.1 In the breeding season, male Anole lizards court females by bobbing their heads up and

down while displaying a colourful throat patch. Assume for this question that both males

and females bob their heads and have throat patches. Assume also, that both traits are

controlled by single locus genes on separate chromosomes. Now, suppose that anoles

prefer to mate with lizards who bob their heads fast (F) and have red throat patches (R)

and that these two alleles are dominant to their counterparts, slow bobbing and yellow

throats. A male lizard heterozygous for head bobbing and homozygous dominant for the

red throat patch mates with a female that is also heterozygous for head bobbing but is

homozygous recessive for yellow throat patches. How many of the F1 offspring have the

preferred fast bobbing / red throat phenotype (assume 16 young)? Show the entire

genetic cross. (11)

____________________________________________________________________________

QUESTION 12 [11]

12.1 Mutations within a gene can be divided into two (2) general categories. Discuss this

statement. (8)

12.2 Briefly discuss the three (3) steps of elongation during translation of protein synthesis.

(3)

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bio1a1e december supplementary exam

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