Quiz 1 (SQ): Topic 1 Molecules of Life

Quiz 1: Topic 1 Molecules of Life

WATER

WATER

• 1.   FIGURE 1 shows the interaction between water molecules.

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a) Name the bonds labelled A and B. [1 mark]

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b) What is the property of water which allows aquatic organisms to survive during winter? [1 mark]

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c) Water achieves its highest density at 4^OC. What is the benefit of

this property of water to the aquatic organisms? [2 marks]

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a) Why water is a versatile solvent? [2 marks]

CARBOHYDRATES

CARBOHYDRATES

2. FIGURE 2 shows the structures of two types of polysaccharide. Polysaccharide S is found in plant and polysaccharide K is found in animal.

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a) Name polysaccharide S and K. [1 mark]

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b) State the specific bonds labelled C and D. [1 mark]

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c) State the function of polysaccharide K. [1 mark]

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d) Why human intestine is unable to digest polysaccharide S? [1 mark]

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e) Name the molecule that has the same function as starch but

can be found in animal. [1 mark]

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f) In which tissue or organ, molecule in (e) can be found. [1 mark]

LIPIDS

LIPID

3. FIGURE 3 represent organic molecules.

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a) Name the molecule S and K. [1 mark]

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b) Identify X and Y. [1 mark]

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c) What is the by-product released in the formation of Molecule S? [1 mark]

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d) Lipid is an important molecule to store energy. State other importance of lipid in human. [1 mark]

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e) State ONE feature of the molecules in FIGURE 3 that make them suitable for the function in (d). [1 mark]

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f) Give ONE reason why fats are stored in the humps of camels.

[1 mark]

PROTEIN

4. FIGURE 4 shows a structural formula for a polypeptide molecule.

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(a) State the name and the number of monomers that form the polypeptide in FIGURE 4. [2 marks]

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b) State the name of the bond formed in the synthesis of the polypeptide above. Draw arrows in FIGURE 4 to show the bonds that you named. [2 marks]

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c) Name the reaction involved when one monomer is eliminated from polypeptide FIGURE 4. [1 mark]

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d) What is the importance of proteins for living beings? [1 mark]

NUCLEIC ACID:

DNA & RNA

5. FIGURE 5 shows the structure of nucleic acid.

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a) Give TWO structural differences between Molecule W and X.

[2 marks]

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b) Differentiate between G and T bases. [1 mark]

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a) If the percentage of cytosine in a DNA strand is 42%, what is the percentage of Thymine? Give a reason for your answer. [2 marks]

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d) State the impact on protein synthesis if Molecule X is destroyed in the cytoplasm. [1 mark]