The university of Bamenda Université de Bamenda

Faculty of Science Faculté des Sciences

Department of Biological Sciences

Département des Sciences Biologique

Part 1: 35 marks

Instructions: Answer the questions by selecting the single letter that best answers the question (N/B the

right answer is 1 mark and the wrong answer is -0.5 mark)

1.the large diversity of shapes of biological molecules is possible because of the extensive presence of ___

(a) carbon (b) oxygen (c) hydrogen (d) nitrogen (e) sulfur

2. Variations in the properties of different organic molecules are most closely associated with __.

(a) the number of carbon atoms comprising the molecule’s skeleton (b) the presence or absence of double

4. plant cell walls consist mainly of ___.

(a) chitin (b) cellulose (c) peptidoglycan (d) chlorophyll (e) none of the above.

5. A shortage of phosphorus in the cell will make it especially difficult for a plant to manufacture ___

(a) cellulose (b) proteins (c) DNA (d) fatty acids (e) sucrose

6. Glycogen is __

(a) the form in which plants store sugars (b) a polysaccharide found in animals (c) a polysaccharide found

in plant cells (d) a transport protein that carries oxygen (e) a source of saturated fat.

9. Tertiary structure is not directly dependent on ___.

(a) hydrophobic interactions (b) peptide bonds (c) hydrogen bonds (d) ionic bonds (e) bonds between

Sulphur atoms

10. A nucleotide is consist of a(n)__

(a) phosphate group, nitrogen-containing base and a hydrocarbon (b) phosphate group, a nitrogen-

containing base and a five-carbon sugar (c) glycerol, nitrogen-containing base and a five-carbon sugar (d)

amino group, a nitrogen-containing base and a five-carbon sugar (e) sulfhydryl group, a nitrogen-containing

base and a five-carbon sugar.

11. The four main categories of macromolecules in a cell are __.

(a) proteins, DNA, RNA, and steroids (b) monosaccharides, lipids, polysaccharides and proteins (c)

proteins, nuclei acids, carbohydrates, and lipids. (d) nucleic acids, carbohydrates, monosaccharides, and

proteins (e) RNA, DNA, proteins and carbohydrates.

12. Steroid hormones have receptors predominantly on:

a)cell surface b)cytoplasm c)both cell surface and cytoplasm d)inside nucleus only

15. The distribution of intrinsic proteins in the cell membrane is

a) symmetrical b)asymmetrical c) random d) uniform.

16. Which component below is not always found in a typical human cell?

(a) cytosol (b) DNA (c) flagellum (d) plasma membrane (e) water.

17. Select the structure that is not located in the cytosol of the cell.

(a) ER (b) Golgi complex (c) lysosome (d) mitochondrion (e) nucleolus

19. The rough ER is a membranous system associated with

(a) vacuoles (b) chromosomes (c) lysosomes (d) microfilaments (e) ribosomes

20. Which of the following is contained within the nucleus?

(a) deoxyribonucleic acid. (b) cytosol (c) plasma membrane (d) endoplasmic reticulum (e) none of these

answers.

21. Smooth ER in liver cells have:

(a) increased number of ribosomes (b) a sarcoplasmic reticulum for storing calcium. (c) enzymes to detoxify

harmful substances. (d) no interactions with any other organelles (e) none of these answers.

produce secretory vesicles (d) they produce proteins using ribosome. (e) they receive transport vesicles

coming from the ER.

24. Extrusion of materials to the exterior of the cell through the plasma membrane is called

(a) endocytosis (b) exocytosis (c) phagocytosis (d) pinocytosis (e) all of these answers are correct.

26. Select the incorrect characteristic of mitochondria?

(a) they have an inner fluid filled space called the cristae. (b) they possess their own DNA (c) they are the

site a cell respiration (d) their inner membranes possess electron carriers. (e) they possess two membranes.

25. The bending movements of cilia and flagella

(a) are accomplished by alternate sclation and gelation of the cytosol. (b) involve the alternate assembly of

actin filaments. (c) are produced by the sliding of adjascent microtubule doublets past each other. (d) are

important in providing motility for many organisms but not for any use in humans. (e) none of these answers

27. Which of the following organelles contain oxidative enzymes?

(a) peroxisomes (b) mitochondria (c) lysosomes (d) both peroxisomes and mitochondria (e) all of these

answers

29. which of the following is not associated with the cytosol?

(a) duplicate of chromosomes (b) enzymatic regulation of intermediary metabolism 9c) storage of fat and

glycogen . (d) synthesis of proteins for use in the cytosol. (e) presence of cytoskeletal elements.

30. Which characteristic regarding microfilaments is incorrect? a) they serve as a mechanical stiffener for

microvilli. (b) they are composed of actin subunits. (c) they are the smallest elements of the cytoskeleton. (d)

they are involved in cell locomotion. (e) they form mitotic spindles.

31. At which pH would pancreatic enzymes work at maximum activity?

33. Which of the following describes the fluid-mosaic model of the plasma membrane structure?

(a) phospholipid monolayer with embedded proteins (b) phospholipid trilayer with embedded proteins (c)

phospholiplid bilayer with embedded proteins (d) triglyceride bilayer with embedded proteins (e)

triglyceride monolayer wit embedded proteins.

34. Which of the following statements regarding the biochemical activities of the cell is not correct:

(a) it is basically controlled by genetic regulation and enzyme regulation (b) the attachment of the RNA

polymeral to the promoter is essential for the processing transcription (c) it can be controlled by the positive

feedback initiated by the amount of the synthesized product (d) the structural genes found at the special

portion of the DNA strand called operon are involved in the production of special protein enzymes (e) it is

Part 2: 35 Marks

SECTION A: Multiple Choice questions. Write down the letter that corresponds to the most correct

answer. Each question is 0.75 mark.

1. Mitosis proceeds in the order:

(A) cytokinesis prophase, prometaphase, telophase, metaphase, and anaphase. (B) telophase, anaphase,

prophase, prometaphase, metaphase and cytokinesis. (C) prophase, prometaphase, metaphase, anaphase,

telophase and cytokinesis (D) prophase, prometaphase, metaphase, cytokinesis, anaphase, and telophase. (E)

prophase, prometaphase, cytokinesis, metaphase, anaphase and telophase.

2. Paired chromatids separate and begin to move towards the spindle poles in mitotic

(A) prophase (B) prometaphase (C) metaphase (D) anaphase (E) telophase.

3. Meiosis differs from mitosis in that:

(A) the centrioles do not separate during the first meiotic division. (B) meiotic divisions are always

asymmetric. (C) meiosis generates cells with half as much DNA as the progeny of mitotic division have. (D)

movement of chromosomes toward the spindles is slower. (E) All of the above

4) This molecule:

(A) contains three peptide bonds (B) contains methionine with a free α-amino group (C) contains

phenylalanine with a free α-carboxyl group (D) contains cysteine with a free α-carboxyl group (E) contains

tyrosine with a free α-amino group.

pH range is due to which amino acid?

(A) amino acid #1 (B) amino acid #2 (C) amino acid #3 (D) amino acid #4 (E) amino acid #5

7). Which of the amino acids can combine to give cystin?

(A) amino acid #1 (B) amino acid #2 (C) amino acid #3 (D) amino acid #4 (E) none of the above

For questions 8-10 use this information: A fragment of DNA purified from hellcobacter pylori contain 370

bases and is 40% adenine by composition.

8). What are the percentages of Cytosine?

(A) 360 (B) 400 (C) 120 (D) 100 (E) none of the above

11). A reversible inhibitor that only binds to the ES complex is referred to as a ___

(a) competitive inhibitor. (b) non-competitive inhibitor (c) uncompetitive inhibitor (d) suicide inhibitor (e)

irreversible inhibitor.

12. Enzymes cofactors that bind convalently at the active site of an enzyme are referred to as –

(a) cosubstrates (b) prosthetic groups. (c) apoenzymes. (d) vitamins (e) A and C

13). Which of the following is characteristic of an enzyme catalyst?

(a) it positions reactants in the correct orientation. (b) it lowers the activation energy barrier. (c) it binds the

transition state tighter than the substrate. (d) all of the above (e) none of the above.

14). Which one of these is not a phospholipid?

(A) lecithin (B) Plasinalogen (C) sphingomyelin (D) Gangliosides (E) A and D

(A) Cerebroside (B) Ceramide (C) Sphingomyelin (D) lecithine (E) Ganglioside

17). In sickle cell disease,

(A) lysine replaces glutamic acid at position 6 (B) glutamic acid is replaced by valine at position 6 (C)

valine replaces histidine at position 6 (D) valine is replaced alanine at position 6. (E) none of the above

18). Isomers differing as a result of variation in configuration of the –OH and –H on carbon atoms 2,3 and 4

of glucose are known as

(A) Epimers (B) Anomers (C) Optical isomers (D) Steroisomers (E) None of the above