Question 1

Which statement best explains why the electron transport chain in cellular respiration is considered spontaneous?

Accepted Answer

Electrons are transferred from species with lower redox potential to those with progressively greater redox potential, releasing energy.

Question 2

In photosynthesis, what is the primary role of light energy in the electron transport chain?

Accepted Answer

To excite electrons in photosystems, enabling electron transfer through the photosynthetic ETC.

Question 3

What is the main end product of cellular respiration, and how is it generated?

Accepted Answer

ATP, generated by dissipating the proton gradient via ATP synthase.

Question 4

During photosynthesis, which molecule is reduced as a result of electron transfer, and what is its significance?

Accepted Answer

NADP$$^+ is $$reduced to NADPH, which is then used in the Calvin Cycle for carbon fixation.

Question 5

Which equation best represents the overall process of cellular respiration?

Accepted Answer

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

Question 6

How is the energy from electron transfer used to generate ATP in both photosynthesis and cellular respiration?

Accepted Answer

By creating a proton gradient across a membrane, which is dissipated via ATP synthase to produce ATP.

Question 7

Which of the following is NOT a type of intercellular signaling described in the study materials?

Accepted Answer

Mitochondrial signaling

Question 8

A signaling molecule that binds to a receptor and triggers a cellular response is called a:

Accepted Answer

Ligand

Question 9

Which type of receptor is most likely to be activated by neurotransmitter binding for rapid signal transmission between neurons?

Accepted Answer

Ion-channel linked receptor

Question 10

What is the role of second messengers such as cAMP and Ca$$^{2+} in $$cell signaling?

Accepted Answer

They amplify the strength of the signal received from the receptor.

Question 11

Which process describes the conversion of an external signal into an intracellular response?

Accepted Answer

Signal transduction

Question 12

Which feedback mechanism increases the production of an effector protein in response to its own activation?

Accepted Answer

Positive feedback

Question 13

What is the function of Receptor Tyrosine Kinases (RTKs) upon ligand binding?

Accepted Answer

They dimerize and autophosphorylate tyrosine residues, activating intracellular signaling cascades.

Question 14

Which molecule acts as a 'molecular switch' in many signaling pathways, toggling between active and inactive states depending on whether it is bound to GDP or GTP?

Accepted Answer

Ras

Question 15

A mutation that causes uncontrolled cell signaling can lead to which of the following outcomes?

Accepted Answer

Evading growth suppressors and resisting cell death

Question 16

Which type of signaling involves a cell releasing a molecule that acts on itself to promote its own growth?

Accepted Answer

Autocrine signaling

Question 17

Which of the following best describes the role of ATP and NADPH produced in the light-dependent reactions of photosynthesis?

Accepted Answer

They are consumed in the Calvin Cycle to fix atmospheric carbon dioxide.

Question 18

Which of the following is a correct sequence of events in G-protein coupled receptor (GPCR) signaling?

Accepted Answer

Ligand binds GPCR, G-protein is activated, cAMP is produced, PKA is activated.

Question 19

Which of the following changes in cellular response can result from cell signaling pathways?

Accepted Answer

Altered metabolism, gene expression, or cell shape and movement

Photosynthesis vs. Cellular Respiration: Electron Transport and Energy Conversion

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