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Biology for IGCSE & O level - Biological Molecules (Section 2)

1
Which molecule is used as a building block in the formation of starch?
Answer
(A)
Glucose
2
What is the process by which plants convert light energy into chemical energy?
Answer
(B)
Photosynthesis
3
Which of the following describes a peptide bond?
Answer
(C)
The bond between two amino acids.
4
What is a common characteristic of both starch and glycogen?
Answer
(B)
They are storage forms of glucose.
5
What type of molecule is a triglyceride?
Answer
(B)
A lipid
6
Which type of bond is present in the sugar-phosphate backbone of a DNA molecule?
Answer
(B)
Covalent bonds
7
How do unsaturated fatty acids differ from saturated fatty acids?
Answer
(C)
Unsaturated have double bonds between carbon atoms.
8
What does the DCPIP test measure?
Answer
(D)
Vitamin C concentration
9
Which of the following is true about complex carbohydrates?
Answer
(C)
They are made by joining many simple sugar molecules together.
10
What is a saturated fatty acid?
Answer
(B)
A fatty acid with no double bonds.
11
Which of the following is a monosaccharide?
Answer
(B)
Glucose
12
Which of the following is a type of simple sugar (monosaccharide)?
Answer
(C)
Glucose
13
Which of the following represents the correct order of the process of making an extract in a food sample for testing
Answer
(A)
Grind the food, add water, mix in blender
14
What will be the result of a DCPIP test if vitamin C is present?
Answer
(C)
The blue solution becomes colorless
15
Which biological molecule is tested by the Biuret test?
Answer
(C)
Protein
16
What type of reaction is used to create complex molecules from smaller ones?
Answer
(B)
Dehydration synthesis
17
What is the primary function of the sugar and phosphate backbone in a DNA molecule?
Answer
(D)
To provide structural support.
18
Which of the following results would indicate a positive test result for reducing sugars when using Benedict's solution?
Answer
B
C
D
19
Which of the following are the bases found in a DNA molecule?
Answer
A
C
D
20
What is the expected outcome of the emulsion test when performed on a sample containing lipids?
Answer
(B)
A white emulsion forms.
21
What is the basic building block of a protein?
Answer
(B)
An amino acid
22
Which of the following is the correct base pairing rule?
Answer
(C)
A-T and C-G
23
What is the primary function of a protein in the body?
Answer
(D)
All of the above
24
What does the term 'hydrolysis' mean?
Answer
(A)
Adding water to break a bond.
25
What would be the expected color change if Benedict's test is positive for a large amount of glucose?
Answer
(D)
Orange/Red
26
What is the function of enzymes?
Answer
(A)
To speed up chemical reactions
27
What is the name for the long chain of amino acids that forms a protein?
Answer
(B)
Polypeptide
28
Which component is common in the structure of fats?
Answer
(A)
Glycerol
29
What is the role of nucleotides in a DNA molecule?
Answer
(D)
To make up the individual building blocks of DNA.
30
What type of sugar is found in a DNA molecule?
Answer
(B)
Deoxyribose
31
Which of the following best describes the structure of a DNA molecule?
Answer
(C)
A double helix
32
In which form is glucose transported in the blood?
Answer
(C)
Glucose
33
Which of the following is a disaccharide?
Answer
(C)
Sucrose
34
Which of the following statements best describes the structure of DNA?
Answer
(C)
A molecule with a double helix structure.
35
Which of the following best describes the chemical test for proteins?
Answer
(C)
Biuret solution is used and a color change to purple or violet occurs.
36
What is the general term for a molecule made up of a chain of amino acids?
Answer
(C)
Polypeptide
37
What are the major elements found in proteins?
Answer
(B)
Carbon, hydrogen, oxygen, and nitrogen
38
Which of the following is a key characteristic that distinguishes saturated fats from unsaturated fats?
Answer
(C)
Presence of double bonds in the hydrocarbon chain.
39
Which of the following is the correct sequence for the chemical test for reducing sugars?
Answer
(A)
Add Benedict's solution, heat, observe for color change.
40
If a sample turns from blue to yellow in the iodine test, what does that indicate?
Answer
(B)
The absence of starch
41
Which of the following solutions is used in the test for proteins?
Answer
(C)
Biuret solution
42
What type of bond connects the fatty acids to the glycerol in a triglyceride?
Answer
(B)
Ester bond
43
Which of the following is the role of hydrogen bonds in a DNA molecule?
Answer
(C)
Joining the base pairs
44
What type of bond joins amino acids together to form a protein?
Answer
(B)
Peptide bond
45
Which of the following is an example of a polymer?
Answer
(C)
Starch
46
Which of the following is NOT a function of fats in the human body?
Answer
(D)
Facilitating gas exchange
47
What is the chemical test used to identify a reducing sugar?
Answer
(C)
Benedict's Test
48
What is the most appropriate test to use to determine the presence of lipids in a sample?
Answer
(D)
Emulsion test
49
What is the name of the process in which monomers are joined together to form polymers?
Answer
(B)
Dehydration synthesis
50
Which of the following bonds are involved in holding together the two strands of DNA?
Answer
(C)
Hydrogen bonds