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GNB501S - GENERAL BIOLOGY - 1ST Opp - JUNE 2022 |
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NAMIBIA UNIVERSITY
OF SCIENCE AND TECHNOLOGY
FACULTY OF HEALTH, APPLIED SCIENCES AND NATURAL RESOURCES
DEPARTMENT OF NATURAL AND APPLIED SCIENCES
QUALIFICATION: BACHELOR OF SCIENCE (MAJOR AND MINOR)
QUALIFICATION CODE: 07BOSC
LEVEL: 5
COURSE NAME: GENERAL BIOLOGY 1A
COURSE CODE: GNB501S
SESSION: JUNE 2022
PAPER: THEORY
DURATION: 3 HOURS
MARKS: 100
FIRST OPPORTUNITY EXAMINATION QUESTION PAPER
EXAMINER(S) | Mr. Petrus Tuhafeni Paulus
MODERATOR: | Pr. Lamech Mwapagha
INSTRUCTIONS
Write clearly and neatly
Number the answers clearly
All written work MUST be done in blue or black ink
No books, notes and other additional aids are allowed
Mark all answers clearly with their respective question numbers
THIS QUESTION PAPER CONSISTS OF 10 PAGES
(Including this front page)
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QUESTION 1
Multiple choices questions
[20]
1.1 Which is the lowest level of biological organization that biologists consider to be alive?
(1)
(a) A protein
(b) DNA
(c) A cell
(d) A multicellular organism
1.2 What is the total magnification of an object viewed at 40X objectives with a light
compound microscope at NUST’s General Biology 1A laboratory?
(1)
(a) 40X
(b) 100X
(c) 400x
(d) 1000X
1.3 Maltose, sucrose, and lactose differ from one another;
(1)
(a) Because not all of them exist in a ring form.
(b) In the number of carbons in the sugar.
(c) In the number of hexose monomers involved.
(d) By the linkage of the monomers.
1.4 Junctions that permit the transfer of water, ions, and molecules between adjacent
plant cells are;
(1)
(a) tight junctions
(b) desmosomes
(c) gap junction
(d) plasmodesmata
1.5 The different shapes and functions of proteins are determined by
(1)
. (a) the R groups of the amino acids they contain
(b) the amino groups of the amino acids they contain
(c) the carboxyl groups of the amino acids they contain
(d) whether or not they contain any amino acids
1.6 In meiosis;
(1)
(a) Homologous chromosomes pair at prophase II.
(b) Chromosomes segregate from their homologous partners at anaphase I.
(c) The centromeres split at anaphase |.
,
(d) Reduction of chromosome number occurs in meiosis Il.
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1.7 The DNA content in a diploid cell in G2 is X. If that cell goes into meiosis at metaphase
Il, the DNA content will be:
(1)
(a) 0.5X.
(b) X.
(c) 2X,
(d) 4X.
1.8 Which of the following sequences of events describes the general life cycle of an animal?
(1)
(a) 2n — meiosis — 2n — fertilization — 1n
(b) 1n — meiosis — 2n — fertilization — 1n
(c) 2n— meiosis — 1n — fertilization — 2n
(d) 2n — mitosis — 1n — fertilization — 2n
1.9 Which of the following statements about mitosis is incorrect?
(1)
(a) Microtubules from the spindle poles attach to the kinetochores on the
chromosomes.
(b) In anaphase, the spindle separate sister chromatids and pulls them apart.
(c) In metaphase, spindle microtubules align the chromosomes at the spindle midpoint.
(d) Cytokinesis describes the movement of chromosomes.
1.10 Through a microscope, you see a cell plate beginning to develop across the middle of
the cell and nuclei re-forming on either side of the cell plate.
This cell is most likely;
(1)
(a) an animal cell in the process of cytokinesis
(b) a plant cell in the process of cytokinesis
(c) an animal cell in the S phase of the cell cycle
(d) a plant cell in metaphase
1.11 What is the correct scientific name for humans?
(1)
(a) sapiens homo
(b) sapiens Homo
(c) homo sapiens
(d) Homo sapiens
1.12 In macromolecules, lipids that are liquid at room temperature;
(1)
(a) Are fats
(b) Contain more hydrogen atoms that lipids that are solids at room temperature.
(c) If polyunsaturated, contain several double bonds in their fatty acid chains.
(d) Lack glycerol.
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1.13 RNAdiffers from DNA because;
(1)
(a) RNA may contain the pyrimidine uracil, and DNA does not.
(b) RNA is always single-stranded when functioning, and DNA is always double-stranded.
(c) RNA is more stable and is broken down by enzymes less easily than DNA.
(d) RNA is a much larger molecule than DNA.
1.14 Inthe Table below, assume that the setup was left unattended. Which of the
following statements is correct?
(1)
Selectively permeable membrane
Inside a cell
Outside fluids
Solvent 90%
Solvent 95%
Solute 10%
Solute 5%
(a) The retention of the cell to its environment is isotonic.
(b) The cell is in a hypertonic environment.
(c) The net flow of solvent is into the cell.
(d) The cell will soon shrink.
1.15 Phagocytosis illustrate which phenomenon?
(1)
a) Receptor- mediated endocytosis.
b) Bulk-phase endocytosis.
c) Exocytosis.
d) Pinocytosis.
1.16 Chiasmata;
(1)
(a) Form during metaphase II of meiosis.
(b) Occur between two nonhomologous chromosomes.
(c) Represent chromosomes independently assorting.
(d) Are sites of DNA exchange between homologous chromatids.
1.17.
(a)
(b)
(c)
(d)
Which of these best distinguishes a prokaryotic cell from a eukaryotic cell?
(1)
Prokaryotic cells have a cell wall, but eukaryotic cells never do.
Prokaryotic cells are much larger than the eukaryotic cells.
Prokaryotic cells have flagella, but eukaryotic cells do not have.
Prokaryotic cells do not have a membrane-bounded nucleus, but eukaryotic cells do
have such a nucleus.
1.18 In an experiment you cross a true-breeding orange-flowered plants and white-
flowered plants. The phenotypic ratio of the F2 generation will be?
(1)
(a) 3:1
(b) 1:3
(c) 1:2:1
(d) 4:0
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1.19 The percentage of A in a double-stranded DNA is 20. What is the percentage of C in
that DNA molecule?
(1)
(a) 20%
(b) 40%
(c) 60%
(d) 30%
1.20
it?
Forthe DNAtemplate below, what would be the sequence of an RNAtranscribed from
(1)
3’ -CAAATTGGCTTATTACCGGATG- 5’
(a) 3’ -CAAATTGGCTTATTACCGGATG- 5’
(b) 3’-GUUUAACCGAAUGGCCUAC-S’
(c) 5’-GTTTAACCGAATGGCCTAC-3’
(d) 5’°-GUUUAACCGAAUGGCCUAC-3’
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QUESTION 2: FILL IN THE BLANK
[10]
2.1 When cells use nutrient molecules to make their [arts and products, they carry out a
sequence of chemical reactions.
is all the chemical reactions that
occur in the cell.
(1)
2.2
have enzymes for oxidizing small organic molecules with the
formation of hydrogen peroxide.
(1)
2.3 A component of the plasma membrane that is responsible for reducing the permeability
and maintains fluidity of the membrane to most biological molecules is called
(1)
2.4 The specific type of protein that has a shape that allows a specific molecule to bind to it
is called a
protein.
(1)
2.5 Genetics refers to characters
meaning that they many factors, both genetic
and environmental, collectively affect phenotype.
(1)
2.6 The entire complex of DNA and proteins that is the building material of chromosomes is
referred to as
;
(1)
2.7 A mother chimpanzee 48 chromosomes its somatic cells. How many chromosomes will
the offspring inherit from the father chimpanzee?
chromosomes
(1)
2.8 During which stage of the cell cycle does each of the sister chromatids become an
independent chromosome?
(1)
2.9 All cells of the body except the gametes and their precursors are called
cells.
(1)
2.10 Non-sex chromosomes are called
.
(1)
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QUESTION 3: Short answer questions
[20]
3.1 During DNA replication, what is the function of helicases and DNA ligase?
(2)
3.2 Fill in the terms (A-L) associated with the diagram of the light and dark reactions.
(6)
3.3 If two organisms, both with the genotype AaBb, are mated, what is the probability that of
obtaining the genotypes AABB and AaBb in the F2 generations?
(2)
3.4 Distinguish the following terms
(6)
3.4.1 Aquaporins and Amphipathic
(2)
3.4.2 Glycolipids and Glycoproteins
(2)
3.4.3 Decarboxylases; dehydrogenases
(2)
3.5 State any four (4) substances that a plant cell can make from G3P, the product of the
Calvin cycle.
(2)
3.6 In terms on independent assortment of chromosomes, say an organism has a diploid
number of 24. The number of possible combinations in the resulting gametes is
(2)
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QUESTION 4: TRUE OR FALSEE
[20]
4.1 The sequence of amino acids in a polypeptide determines its final shape because various
R groups interact differently. The function of a protein is dependent onitsshape.
(2)
a. True
b. False
4.2 The nucleic acids DNA and RNA are polymers of nucleotides. DNA is the genetic material
and RNA is an intermediary during the process of protein synthesis.
(2)
a. True
b. False
4.3 Small cells, not large cells, are likely to have an adequate surface area for the exchange
of wastes for nutrients.
(2)
a. True
b. False
4.4 When using a 100x objective in laboratory to observe a specimen, oil is added. The oil is
placed between the sample and the objective lens of the light microscope, the revolving
power is decreased to hence provide the great details to be seen.
(2)
a. True
b. False
4.5 The swelling of a plant cell in a hypotonic solution creates turgor pressure. The cytoplasm
expands because the large central vacuole gains water and the plasma membrane pushes
against the rigid cell wall. Turgor pressure is important is extremely important to the
maintenance of the plant’s erect position. Suppose you forget to water your plants; they
will die due to increased turgor pressure.
(2)
a. True
b. False
4.6 Fermentation, anaerobic respiration, and aerobic respiration are three alternative cellular
pathways for producing ATP by harvesting chemical. All these pathways produce the same
amount of ATP.
(2)
a. True
b. False
4.7 Photorespiration uses light and oxygen to produce CO2 thereby generating ATP. It
increases the photosynthetic output by investing energy and CO>2 to the Calvin cycle.
(2)
a. True
b. False
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4.8 Before the cell can divide to form genetically identical daughter cells, all of its DNA must
be replicated, and then the two copies of must be separated so that each daughter cell
ends up with a complete genome.
(2)
a. True
b. False
4.9 After duplication or replication, the cell is still said to be diploid, 2n. Because it has only
two sets of information regardless of the number of chromatids, which are merely copies
of the information in one set.
(2)
a. True
b. False
4.10 Homologous chromosomes are the same as sister chromatids.
(2)
a. True
b. False
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QUESTION 5: Essay Questions
[30]
5.1 Distinguish between the four levels of organization of protein molecules.
(8)
5.2 Meiosis
(15)
a)
Define meiosis.
(3)
b)
Discuss the main stages involved in meiosis.
(12)
THE END
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