section a n b

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Section A

60 Marks

Answer all questions in this section.

1. Diagram 1 shows the structure of a cell as seen using an electron microscope.

Diagram 1

(a) On Diagram 1, name the structures labelled K,L,M and N. [4 marks]

(b) (i) Where could this cell be found?

___________________________________________________

(ii) Explain your answer in (b) (i). [2 marks]

________________________________________________________________

________________________________________________________________________________________________________________________________

(c) What is structure K made of? [1 mark]__________________________________________________________

(d) State the function of [2 marks]

(i) a mitochondrion__________________________________________________________

(ii) structure N__________________________________________________________

(e) (i) What is the most important constituent of structure M? [2 marks]

__________________________________________________________

(ii) State the function of structure M.____________________________________________________________________________________________________________________

(f) Explain the role of L in maintaining cell turgidity. [2 marks]

_____________________________________________________________________________________________________________________________________________________________________________________________________________________


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2. Diagram 2.1 and Diagram 2.2 show two different types of transport processes across theplasma membrane. [10 marks]

(a) On Diagram 2.1, label the following structures: Phospholipid bilayer with letter X Pore protein with letter Y [2 marks]

(b) State two features of the phospholipid bilayer. [2 marks]______________________________________________________________________________________________________________________________________________________________________________________________________________________________

(c) Name each transport process across the plasma membrane as shown in Diagram 2.1and Diagram 2.2. (2 marks)

Process in Diagram 2.1: _________________________________________________Process in Diagram 2.2: _________________________________________________

(d) What is the characteristic displayed by the plasma membrane in both processes? [1 mark]__________________________________________________________________

(e) If substance in diagram 2.2 are sodium ion. Describe how they are transported out of the cell.[3 marks]____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

3. The Diagram 3 shows the organelles involved in the production of extracellular enzymes.

Diagram 3


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By giving an example, explain the term extracellular enzyme. [1 mark]_____________________________________________________________________________________________________________________________________________

Based on the organelles shown, explain how extracellular enzymes are produced.

________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________[4 marks]

(b) The Diagram 3.2 shows the action of an enzyme and its substrate.

Diagram 3.2

If the substrate used is lipid, name the part labelled P, Q and R. [3 marks](i)

P : _______________________________________________Q : _______________________________________________R : _______________________________________________

(ii) What is the principles of enzymatic reaction shown in Diagram 3.2 [1 mark]______________________________________________________

(iii) State three characteristic of enzyme shown in Diagram 3.2 [3 marks]__________________________________________________________________________________________________________________________________________________________________

4. The Diagram 4.1 shows the various structures of protein.

Diagram 4.1

(a) Name the structure P, Q, R and S. [4 marks]P : _____________________________________________________________________Q : _____________________________________________________________________R : _____________________________________________________________________S : _____________________________________________________________________


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(b) Explain how

a dipeptide is formed. [1 mark]

________________________________________________________________________________________________________________________________________________

structure S is formed from structure R. [1 mark]________________________________________________________________________________________________________________________________________________

(c) Give one example of a substance for each of the protein structures of R & S. [2 marks]R : _____________________________________________________________________S : _____________________________________________________________________

What is denaturation? [1 mark]______________________________________________________________________________________________________________________________________

What is the result of denaturation of proteins? [1 mark]___________________________________________________________________

(e) State the differences between essential amino acids and non-essential amino acids. [2 marks]

5. Diagram 5.1 shows three stages of meiosis X, Y and Z in an animal cell.

X Y ZDiagram 5.1

a) Name the stages X, Y and Z in diagram 1.1. (3 marks)X:________________________________________________________________Y:________________________________________________________________Z:________________________________________________________________

b) Explain what happens at stage Z. (3 marks)

_______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________


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c) State the chromosomal behavior at the following stages: (2 marks)i) Stage X: ____________________________________________________ii) Stage Y:____________________________________________________

d) Explain the role of mitosis in the cloning of banana plant. [3 marks]

___________________________________________________________________________________________________________________________________________________________________________________________________________________________________

e) Diagram 5.2 shows a cell at a certain phase. If chromosome P is not separated,draw the diagrams of two daughter cells which will be formed in the next phase inthe spaces provided below.

Daughter cell I Daughter cell II

Diagram 5.2(2 marks)

Section B[40 marks]

Answer only two questions from this section.

6 (a) Diagram 6 .1 and Diagram 6.2 show the condition of erytrocytes and an onion cell after30 minutes being immersed in distilled water.

Diagam 6.1 Diagram 6.2

Based on Diagram 6 .1 and 6.2, give a brief explanation of the process occurs in both cellsthat result in the above observation. [4 marks]

P


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(b) (i) A group of students carry out an experiment to investigate the concentration of sucrosesolution that is isotonic to the potato strip cell sap by weighing the initial and final massof the potato strip.

Graph 6.3 shows the changes in mass of the potato strips.

Graph 6.3

Based on Graph 6.3, what is the concentration of the potato cell sap that is isotonic to thesucrose solution . Explain how the concentration of the potato strip cell sap being determined.[3 marks]

(ii) A certain type of herbicide was sprayed on the weed plants to control their population.The herbicide causes the proteins and ATPase enzyme in the cell to denature.Explain the effect of this herbicide to the transport of potassium ions in the weedplants. [3 marks]

c) Diagram 6.4 and Diagram 6.5 show two types of transport in the movement of moleculesacross the plasma membrane.

R Transport S Transport

Diagram 6.4 Diagram 6.5

Based on Diagram 6.4 and Diagram 6.5, explain the similarities and differences between Rand S transport. [10 marks]


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section a n b

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