Question 1

Which statement best describes the difference between assimilative and dissimilative reduction processes in microbial metabolism?

Accepted Answer

Assimilative reductions incorporate inorganic nutrients into biomass, while dissimilative reductions use inorganic compounds as electron acceptors and excrete the reduced products.

Question 2

In the context of anabolic pathways, what is the primary reason why biosynthesis requires much energy?

Accepted Answer

Because biosynthesis involves the formation of complex cellular structures from simple precursors, which is energetically unfavorable.

Question 3

Which of the following is a principle governing biosynthesis in cells?

Accepted Answer

Most cell structures are assembled from a limited set of small precursors.

Question 4

Which metabolic pathway is responsible for the synthesis of glucose from non-carbohydrate precursors?

Accepted Answer

Gluconeogenesis

Question 5

During fatty acid biosynthesis, which molecule acts as the carrier for the growing fatty acid chain?

Accepted Answer

Acyl carrier protein (ACP)

Question 6

Which of the following statements about peptidoglycan synthesis is correct?

Accepted Answer

Peptidoglycan synthesis involves uridine diphosphate and bactoprenol as carriers.

Question 7

Which process is most important for assimilative nitrogen acquisition in microbes?

Accepted Answer

Nitrogen fixation

Question 8

Nitrogenase, the enzyme complex responsible for nitrogen fixation, is inhibited by which environmental factor?

Accepted Answer

Oxygen ($$O_2)$$

Question 9

Which of the following is a key difference between cyclic and non-cyclic photophosphorylation in photosynthetic organisms?

Accepted Answer

Non-cyclic photophosphorylation involves the reduction of NADP$$^+ to $$NADPH and the production of $$O_2$$ from water.

Question 10

In the Calvin Cycle, which enzyme catalyzes the fixation of $$CO_2 to $$ribulose-1,5-bisphosphate?

Accepted Answer

Ribulose-1,5-bisphosphate carboxylase/oxygenase (RUBISCO)

Question 11

Which of the following best explains why carboxysomes are important in some bacteria?

Accepted Answer

They protect RUBISCO from oxygen, increasing the efficiency of $$CO_2$$ fixation.

Question 12

Which pigment is primarily responsible for light absorption in oxygenic photosynthesis?

Accepted Answer

Chlorophyll a

Question 13

A bacterium growing in deep water with very low light intensity is most likely to possess which adaptation?

Accepted Answer

Chlorosomes containing bacteriochlorophyll arrays for efficient light capture

Question 14

Which of the following is true regarding the reverse citric acid cycle (reductive TCA pathway)?

Accepted Answer

It requires unique enzymes such as $$	ext{2-oxoglutarate synthase}$$ and $$	ext{ATP-citrate lyase}.$$

Question 15

Which of the following is a correct equation for the overall Calvin Cycle for the synthesis of one glucose molecule?

Accepted Answer

$$6CO_2 + 18ATP + 12NADPH + 12H^+ + 12H_2O \rightarrow glucose + 18ADP + 18P_i + 12NADP^+$$

Question 16

Which of the following is a plausible consequence of a mutation that disables the acyl carrier protein (ACP) in a bacterium?

Accepted Answer

Fatty acid biosynthesis would be impaired, affecting membrane formation and energy storage.

Question 17

Which of the following best describes the role of phycobilisomes in cyanobacteria?

Accepted Answer

They act as giant antenna systems, capturing light and transferring energy to reaction centers.

Question 18

In purple non-sulfur bacteria, what is the primary electron source for photosynthetic electron flow?

Accepted Answer

Organic compounds such as succinate or malate

Question 19

Which of the following is a key feature of amphibolic enzymes?

Accepted Answer

They function in both anabolic and catabolic pathways, allowing for efficient use of resources.

Metabolic Diversity and Anabolism in Microorganisms

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