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nAmIB lA UnIVERSITY OF SCIEnCE AnD TECH n 0 LOGY

Faculty of Natural Resources and Spatial Sciences

Department of Natural Resources and Agricultural Sciences

QUALIFICATION: Bachelor of Agriculture

QUALIFICATION CODE: 07BAGR LEVEL: 1

COURSE: Introduction to General Biology COURSE CODE: IBI511S

DATE: July 2016

DURATION: 3HRS

EXAMINER(S)

MODERATOR:

SESSION:

MARKS: 100

SECOND OPPORTUNITY EXAMINATION QUESTION PAPER

Mr. Oskar Elago

Mrs. Louise Theron

THIS QUESTION PAPER CONSISTS OF _5_ PAGES

(Excluding this front page)

INSTRUCTIONS

1. Answer ALL the questions.

2. Write clearly and neatly.

3. Number the answers clearly.

PERMISSIBLE MATERIALS

1. Examination paper. 2. Examination script.

Question 1

Identify the correct answer.

1.1 An infectious agent that appears to have no nucleic acid is a

(A) bacterium

(B) bacteriophage

(C) viroid

(D) virus

(E) prion

Total marks [1 0]

(1)

1.2 During cytokinesis in an animal cell, a constricting ring pinches the dividing cell into the two daughter cells. This contractile ring is formed by which of the following structures? (1)

(A) Centrioles

(B) Microtubules

(C) Microfilaments

(D) Z discs

(E) The spindle apparatus

1.3 Which of the following regulates the amount of light passing through the slide specimen on the microscope stage? (1)

(A) Nosepiece

(B) Objective lens

(C) Iris diaphragm lever

(D) Fine focus knob

(E) Non of the above

1.4 If an organic acid accumulates in a plant cell in sufficient quantities to affect the cell's pH significantly, then the acid will probably be stored in the (1)

(A) cytosol

(B) vacuole

(C) nucleus

1

(D) mitochondria

(E) chloroplasts

1.5 During meiosis, homologous chromosomes pair up along their lengths. The most plausible explanation for the karyotype structure shown above is that (1)

(A) portions of non-homologous chromosomes have been translocated

(B) one of the two homologous chromosomes has suffered a deletion

(C) one of the two homologous chromosomes has undergone an inversion

(D) the homologous chromosomes have each suffered a gene duplication

(E) one of a pair of homologous chromosomes has been lost via nondisjunction

1.6 Which of the following is NOT a correct statement about the process of meiosis? (1)

(A) Meiosis I separates chromosomes; meiosis II separates chromatids .

(B) Synapsis and crossing-over occur during meiosis I.

(C) Kinetochores are responsible for aligning chromatids during meiosis I.

(D) Karyokinesis occurs before cytokinesis.

(E) Segregation of unlinked alleles occurs during

1. 7 The receptive surface for pollen on an angiosperm flower is the

(A) anther

(B) corolla

(C) ovary

(D) style

(E) stigma

(1)

1.8 The outermost tissue of a tree trunk that is 6 feet in diameter would most likely be (1)

(A) epidermis

(B) cork

(C) cortex

2

(D) phloem

(E) xylem

1.9 Which of the following is the tissue that is most important in plant survival during droughts and why? (1)

(A) Vascular tissue, because the phloem keeps the plant supplied with water

(B) Vascular tissue, because the xylem can store considerable amounts of water

(C) Ground tissue, because water can be stored in the sclerenchyma for use during droughts

(D) Ground tissue, because the parenchymal tissue provides hormonal cues to stop water loss

(E) Epidermal tissue, because it is covered with a waxy cuticle and includes droughtresponsive stomata

1.10 Which of the following cells or tissues are characteristically found in the roots , but not the stems, of angiosperms? (1)

(A) Parenchyma and collenchyma

(B) Epidermis and cork

(C) Pericycle and endodermis

(D) Vessel elements and tracheids

(E) Sieve tube members and companion cells

Question 2

State whether the following statements are TRUE or FALSE. Total marks [1 0]

2.1 Because the natural world includes all energy and matter, it also includes all living organisms. (1)

2.2 Plants obtain their energy directly from the sun and their raw materials from the soil, air, and water in their environment. (1)

2.3 Recent research indicates that humans are not the only mammal capable of standing upright and walking on two legs. (1)

2.4 Approximately 3.5 billion years ago, single-celled organisms arose from non-living chemical elements. (1)

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2.5 The validity of a prediction in the scientific method is determined by experimentation or observation. (1)

2.6 After years of experimentation and testing, it is possible to prove that a hypothesis is true, at which point it becomes absolute truth. (1)

2. 7 Not only does science involve gaining knowledge about the natural world, it also involves the process of obtaining that knowledge. (1)

2.8 Special interest groups are not permitted to post information as "science" on the internet unless it has undergone peer review. (1)

2.9 Our society places a very high value on human life, and thus would not permit humans to be tested experimentally if the end result is deliberate harm. (1)

2.10 Scientific knowledge cannot prove or disprove the existence, or importance to us, of issues that fall outside of the natural world. (1)

Question 3

Total marks [1 0]

3.1 What occurs during the process of translation?

3.2 Where does translation occur?

3.3 What are mutations?

3.4 What forms the backbone of a DNA chain?

3.5 Which type of microscope would you use to study the following?

(a) the changes in shape of a living human white blood cell _____ _

(b) the finest details of surface texture of human hair _______ _

(c) the detailed structure of an organelle in a human liver cell ____ _

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(2)

(1)

(2)

(2)

(1)

(1)

(1)

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Question 4

4.1 Explain the concept of double fertilization .

4.2 What are the five kingdoms into which living beings are divided?

4.3 Name any five parts and their functions of the light microscope.

Question 5

5.1 Name and explain the five modes of pollination.

5.2 Name ten differences between mitosis and meiosis

Question 6

Total marks [20]

(5)

(5)

(1 0)

Total marks [20]

(1 0)

(1 0)

Total marks [30]

6.1 In a certain plant, blue (B) flower color is dominant to white (b). You have a blue flowered plant and a white flowered plant.

a. What do you know about the genotype and phenotype of each plant? (3)

b. Now you cross the plants and all the offspring are blue. What have you learned about the genotypes of the original plants? (1)

c. Consider the blue-flowered plants produced from the above cross: what gamete types will they produce? If you cross two of these blue-flowered plants to produce a large number of offspring, what genotypes and phenotypes will be produced and in what proportions? (6)

6.2 In pepper plants, green (G) fruit color is dominant to red (g) and round (R) fruit shape is dominant to square (r) fruit shape. These two genes are located on different chromosomes.

a. What gamete types will be produced by a heterozygous green, round plant? (4)

b. If two such heterozygous plants are crossed, what genotypes and phenotypes will be seen in the offspring and in what proportions? (16)

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