Question 1

Which of the following best describes the relationship between catabolic and anabolic reactions in cellular metabolism?

Accepted Answer

Catabolic reactions break down complex molecules into simpler ones, releasing energy, while anabolic reactions build complex molecules from simpler ones, requiring energy.

Question 2

According to the endosymbiont theory, which organelles are believed to have originated from free-living prokaryotes?

Accepted Answer

Chloroplasts and mitochondria

Question 3

Which of the following is the correct balanced chemical equation for cellular respiration?

Accepted Answer

$$\mathrm{C_6H_{12}O_6$ + 6O_2 \rightarrow 6CO_2 + 6H_2O + Energy}$$

Question 4

During glycolysis, which molecule is the initial substrate and what are the main products?

Accepted Answer

Glucose; pyruvate, ATP, and NADH

Question 5

Where in the cell does the citric acid cycle occur, and what is its primary function?

Accepted Answer

Mitochondrial matrix; to oxidize acetyl CoA and produce NADH, FADH2, and ATP

Question 6

Which process directly generates the most ATP during cellular respiration?

Accepted Answer

Oxidative phosphorylation (electron transport and chemiosmosis)

Question 7

How is the proton gradient across the inner mitochondrial membrane generated during cellular respiration?

Accepted Answer

By the pumping of protons by the electron transport chain using energy from electron transfer

Question 8

In the absence of oxygen, how do cells maintain redox balance during glycolysis?

Accepted Answer

By converting NADH back to NAD+ through fermentation pathways

Question 9

Which of the following statements about the versatility of catabolism is correct?

Accepted Answer

Proteins, fats, and carbohydrates can all be broken down and their products fed into cellular respiration.

Question 10

Which structure is responsible for photosynthesis in plant cells, and what is its main function?

Accepted Answer

Chloroplast; conversion of light energy to chemical energy

Question 11

What distinguishes autotrophs from heterotrophs?

Accepted Answer

Autotrophs produce their own food from inorganic sources, while heterotrophs obtain energy by consuming other organisms.

Question 12

Which of the following best describes the two stages of photosynthesis?

Accepted Answer

Light reactions in the thylakoid membrane produce ATP and NADPH; Calvin cycle in the stroma uses ATP and NADPH to fix carbon dioxide.

Question 13

Which photosystem is responsible for splitting water and releasing oxygen during the light reactions?

Accepted Answer

Photosystem II

Question 14

What is the main purpose of the electron transport chain in both respiration and photosynthesis?

Accepted Answer

To generate a proton gradient used to synthesize ATP

Question 15

Which enzyme is responsible for carbon fixation in the Calvin cycle?

Accepted Answer

RuBisCO

Question 16

Under which conditions does photorespiration occur, and how is it minimized in C4 and CAM plants?

Accepted Answer

Photorespiration occurs under high O2 and low CO2; C4 and CAM plants minimize it by spatial and temporal separation of carbon fixation.

Question 17

Which of the following best explains the similarities and differences between electron transport and chemiosmosis in respiration and photosynthesis?

Accepted Answer

Both processes use an electron transport chain to generate a proton gradient, but the sources of electrons and the final electron acceptors differ.

Question 18

A patient with a genetic defect in ATP synthase would most likely experience which of the following?

Accepted Answer

Decreased ability to harness the proton gradient for ATP synthesis

Question 19

If a plant is exposed to light but deprived of CO2, which stage of photosynthesis will be directly affected?

Accepted Answer

Calvin cycle

Study Guide: Respiration and Photosynthesis (BIOL101)

Study Guide - Practice Questions

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