Biology Exam

80. This item is based on the following course of human evolution.

Use of fire and other tools
Increase in brain size
Emergence of Homo sapiens
Bipedal walking and arboreal life

Which of the following is the correct order of the above evolutionary time line markers?

A. 3, 2, 4, 1
B. 4, 2, 1, 3
C. 1, 3, 4, 2
D. 2, 1, 3, 4

81. This item is based on the following diagram, which illustrates the occurrence of mutation in a certain sequence of nucleotides.

Sequence	Codon 1	Codon 2	Codon 3	Codon 4	Codon 5
Original	GAC Aspartic acid	GGG Glycine	ATT Isoleucine	GAG Glutamic acid	GAG Glutamic acid
Mutated	GAC Aspartic acid	GGG Glycine	ATG Methionine	GAG Glutamic acid	GAG Glutamic acid

The type of mutation that occurred in the above sequence of nucleotides is

A. Addition
B. Substitution
C. Inversion
D. Deletion

82. Which is NOT a common cause of mutation?

A. Extensive physical exercise
B. Chemical substances
C. Errors in DNA replication
D. Exposure to UV radiation

83. Which genetic phenomenon is common for both bottleneck and founder effects

A. Gene flow that increases inbreed and disease's resistance
B. Natural selection that results from gradual evolutionary changes
C. Genetic drift that reduces diversity in the populationt
D. High mutation rate that enhances adaptation

84. In a scenario where a male black lion population left its terrestrial territory and joined a white female lion population in an isolated Island to mate, there would be a

A. Random introduction of new alleles inti the Island population
B. Change in allele frequencies of terrestrial population but not in Island.
C. Genetic variation in terrestrial population due to immigration.
D. Decrease in island black lions

85. Which of the following is an example of anthropogenic driving factor that contributes to species extinction?

A. Expansion of agriculture
B. Wild fire
C. Volcanic eruption
D. Earthquake

86. In a hypothetical scenario where photosynthesis ceased to occur on the earth, the long-term consequences on the continuity of life would be

A. Balanced CO₂ and O₂
B. Disordered although animal life flourishes
C. Collapse leading to mass extinction
D. No effect on life

87. What are the roles of grana and stroma in the process of photosynthesis? Grana is a site for

A. Generation of sugar while stroma is a site for photolysis of water.
B. Production of NADPH while stroma is a site for chemiosmosis.
C. Photolysis of water while stroma is a site for carbon fixation.
D. Cyclic pathway while stroma is a site for non-cyclic pathway.

88. Which one of the following comparisons between cyclic and non-cyclic photophosphorylation is correct? Non-cyclic photophosphorylation

A. Uses photosystem I as electron donor, but cyclic uses water as an electron donor
B. Involves both photosystems I and II, but cyclic uses only photosystem I.
C. Uses oxygen as the final electron acceptor, but cyclic uses cytochrome b-cl complex.
D. Produces ATP, NADPH and Oxygen, but cyclic produces ATP and NADPH.

89. Which does NOT occur in reduction phase of Calvin cycle?

A. Conversion of 3-PGA to sugar
B. Donation of electrons to a 3C-intermediates to form G3P
C. Use of ATP and NADPH molecules
D. Combining CO₂ with RuBP

90. Reaction in mitochondria during photorespiration

A. Glycerate is converted to GP
B. Phosphoglycolate is converted to glycolate
C. Glycolate is converted to glyoxylate
D. Glycine is converted to serine

91. Correct statement about enzymes

A. Alter themselves at the end of biochemical reactions.
B. Increase the energy required to start a reaction.
C. Allow reactions in cells to take place quickly.
D. Change the overall nature of the products.

92. Four students draw four different big protein structure posters. The contents of each of their structure are displayed in the following table.

Student	Main contents indicated in the structure
I	Polypeptide folded into α-helix and β-sheet, stabilized by hydrogen bonds
II	Amino acid sequence linked by peptide bonds
III	Multiple folded protein subunits forming a multi-subunit complex with haem group
IV	Side-chain interactions and overall three-dimensional structure of a protein

Based on the above information, which student draw secondary and quaternary structures, respectively?

A. I and III
B. II and IV
C. II and III
D. I and IV

93. How does the induced-fit model explain enzyme specificity? They

A. have multiple active sites that can fit to different substrates.
B. bind to whatever the shape of substrate that fits to allosteric site.
C. change the shape of active site slightly to fit substrates precisely.
D. have a rigid active site that can just bind to single substrate.

94. What happens to the substrate molecule when competitive inhibitor binds with an enzyme? It

A. Binds allosteric site temporarily
B. Easily binds with the active site
C. Cannot bind with the active site
D. Changes conformation

95. What will happen to the reaction if you add a certain inhibitor or activator to the substrate having allosteric enzyme set up?

A. Activator binds active site to initiate the reaction.
B. Activator binds regulatory site to activate the reaction.
C. Inhibitor binds to regulatory site to increase rate of reaction.
D. Inhibitor bind to activ site speeds up to reaction

96. Photosynthesis ensures life continuity by

A. Constantly removing oxygen from the atmosphere
B. Adding natural gas and absorbing methane from the atmosphere
C. Maintaining carbon dioxide and oxygen balance in the atmosphere
D. Constantly adding carbon dioxide to the atmosphere₂

97. Which of the following is the difference between substrate level phosphorylation and oxidative phosphorylation? Substrate level phosphorylation

A. has the same source of energy as oxidative phosphorylation.
B. occurs in aerobic respiration while oxidative phosphorylation in anaerobic respiration.
C. occurs during glycolysis and Kreb's cycle while oxidative phosphorylation occurs during electron transport chain.
D. occurs in the inner mitochondrial membrane while oxidative phosphorylation occurs in the cytosol.

98. Which one of the following is correct about the energy liberation phase of glycolysis pathway? It

A. releases one water molecule and dihydroxyacetone phosphate molecule.
B. produces four ATP, two NADH and two molecules of pyruvate.
C. breaks six carbon molecules into two glyceraldehyde-3-phosphate molecules.
D. hydrolyses two ATP molecules and raises the free energy of glucose.

99. Which one of the following statements describes an event of the process of electron transport system correctly?

A. More than 90% of the total ATP is produced by substrate-level phosphorylation.
B. It happens due to the difference in pH as the inside mitochondrial membrane is more acidic.
C. Thirteen ATP molecules are invested when electrons are transferred from NADH/FADH2 to 02.
D. Oxygen serves as a terminal electron acceptor in the production of ATP

100. In a complete oxidation of glucose molecule, how many net ATP molecules are produced by substrate level phosphorylation?

A. 8
B. 10
C. 4
D. 2

Biology Exam: Part 4

Exam Results