Metabolism and Energy Capture Quiz

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Questions and Answers

What is the primary role of catabolic reactions in metabolism?

To transport electrons between molecules

To break down large substances to release energy (correct)

To synthesize macromolecules from small substrates

To provide ATP directly without any degradation

Which statement best describes the function of ATP in cellular metabolism?

ATP links catabolic and anabolic reactions by providing energy. (correct)

ATP is produced solely during catabolic reactions.

ATP serves only as a substrate for catabolism.

ATP is a byproduct of all metabolic processes.

In a redox reaction, what does the process of oxidation involve?

Gain of electrons from an oxidizing agent

Transfer of protons between two substrates

Gain of hydrogen ions from an electron donor

Loss of electrons to an electron acceptor (correct)

What does the acronym OIL RIG stand for in the context of metabolism?

Oxidation Is Loss and Reduction Is Gain Signup and view all the answers

How do electrons contribute to ATP synthesis?

Electrons transfer energy between molecules during respiration. Signup and view all the answers

What is the primary reason enzymes are necessary for metabolic reactions in cells?

They speed up reactions by lowering activation energy. Signup and view all the answers

What happens to an enzyme when it is denatured?

Its 3-D structure is destroyed. Signup and view all the answers

What defines the active site of an enzyme?

The region where the enzyme binds to its specific substrate. Signup and view all the answers

Which suffix is commonly used to indicate that a molecule is an enzyme?

-ase Signup and view all the answers

What role do coenzymes and cofactors play in enzyme activity?

They are required for some enzymes to achieve full activity. Signup and view all the answers

What occurs in a metabolic pathway when one enzyme is missing or defective?

The entire pathway is halted, preventing product formation. Signup and view all the answers

Which of the following is NOT a characteristic of enzymes?

They are consumed during reactions. Signup and view all the answers

What is the difference between an apoenzyme and a holoenzyme?

An apoenzyme requires a cofactor or coenzyme for activity. Signup and view all the answers

What is the primary function of the Pentose Phosphate Pathway?

Synthesis of 5C sugars for nucleic acids Signup and view all the answers

Which pathway is characterized by producing 1 ATP, NADPH, and G3P from glucose?

Entner Doudoroff Pathway Signup and view all the answers

What is produced during non-cyclic photophosphorylation?

ATP, NADPH, and O2 Signup and view all the answers

Which statement accurately describes the Calvin-Benson Cycle?

It uses ribulose bisphosphate and ATP to produce glucose Signup and view all the answers

What distinguishes chemoheterotrophs from photoautotrophs?

Chemoheterotrophs lack chlorophyll and depend on organic molecules Signup and view all the answers

Which organism is NOT typically classified as a photoautotroph?

Humans Signup and view all the answers

How many ATP are produced in fermentation compared to aerobic respiration?

Fermentation produces 2 ATP while aerobic respiration produces about 38 ATP Signup and view all the answers

What is a key characteristic of cyclic photophosphorylation?

It involves the excitation of chlorophyll electrons Signup and view all the answers

Which enzyme is primarily associated with the Entner Doudoroff pathway?

2-keto-3-deoxy-6-phosphogluconic acid Signup and view all the answers

What protects against malaria in people with G6PD deficiency?

Resistance to oxidative stress Signup and view all the answers

What must be done to pyruvate for it to enter the Krebs Cycle?

It must be converted to acetyl-CoA Signup and view all the answers

What is the terminal electron acceptor of an aerobic electron transport chain?

Oxygen Signup and view all the answers

Which of the following is a product of fermentation?

Ethyl alcohol Signup and view all the answers

What is chemiosmosis primarily responsible for in the electron transport chain?

ATP synthesis Signup and view all the answers

How many ATPs are generated per cycle of β-oxidation?

5 ATP Signup and view all the answers

What is the purpose of the Krebs Cycle?

To generate ATP and electron carriers Signup and view all the answers

What is the main starting molecule for the fermentation process?

Glucose Signup and view all the answers

Which of the following statements best describes a characteristic of the Entner-Doudouroff pathway?

It generates metabolic intermediates for diagnostic purposes Signup and view all the answers

What is the primary process by which fatty acids are catabolized?

Beta-oxidation Signup and view all the answers

How many ATP are produced per cycle of beta-oxidation?

14-17 ATP Signup and view all the answers

Which of the following processes is involved in removing amino groups from amino acids?

Deamination Signup and view all the answers

Which disease results from a defect in enzymes involved in metabolizing branched-chain amino acids?

Maple syrup urine disease Signup and view all the answers

What is removed from amino acids during decarboxylation?

Carboxyl group Signup and view all the answers

Which molecules are routed to the Krebs cycle after amino acid processing?

C2 molecules Signup and view all the answers

What is the main distinction between catabolism and anabolism in metabolic pathways?

Catabolism releases energy, while anabolism consumes energy. Signup and view all the answers

Which group is commonly cleaved from amino acids by proteases?

R group Signup and view all the answers

Study Notes

Metabolism

All chemical reactions in a cell, both catabolic and anabolic reactions.
Catabolic reactions break down large molecules to release energy and building blocks, while anabolic reactions use that energy to build larger molecules.
ATP is the main energy supplier, linking catabolic and anabolic processes.
Cells need ATP for biosynthesis, motility, and active transport.

Energy Capture

Electrons carry energy.
Electron transfer can involve naked electrons or hydrogen atoms (H+ + e-).
Electron transfer plays a key role in ATP synthesis.
Oxidation: Loss of electrons to an electron acceptor.
Reduction: Gain of electrons from an electron donor.
OIL RIG: Oxidation Is Losing electrons Reduction Is Gaining electrons.
Electron carriers like NAD+, NADP, and FAD are frequently involved in redox reaction.

Enzymes

Protein or RNA catalysts that accelerate reactions by lowering activation energy.
Enzymes are named based on their substrate and/or action.
Enzyme activity can be regulated by factors like competitive inhibition, non-competitive inhibition, and feedback inhibition.

Coenzymes & Cofactors

Coenzymes are organic molecules that help enzymes.
Cofactors are inorganic molecules that improve substrate fit.

Metabolic Pathways

Series of chemical reactions where the product of one acts as the substrate for the next.
Each step requires specific enzymes.
If one enzyme is missing or defective, it can cause metabolic diseases.

Pentose Phosphate Pathway

Uses glucose to produce 5-carbon sugars (pentoses) for nucleic acid synthesis.
Produces ATP and NADPH, which are essential for various anabolic processes.
G6PD deficiency can lead to favaism but offers protection against malaria.

Entner-Doudoroff Pathway

Catabolizes glucose differently than glycolysis.
Produces ATP, NADPH, and G3P.
Used by certain bacteria and can be diagnostically detected by its unique intermediate.

Comparison of Fermentation & Aerobic Respiration

Fermentation: Does not require oxygen, produces 2 ATP/glucose.
Aerobic Respiration: Requires oxygen, produces ~38 ATP/glucose.
Anaerobic Respiration: Does not require oxygen, can produce up to 36 ATP/glucose.

Photosynthesis

The process by which photoautotrophs use light energy to convert CO2 and H2O into glucose and oxygen.
Occurs in two stages: light-dependent reactions and light-independent reactions.
Light-dependent reactions capture light energy to generate ATP and NADPH.
Light-independent reactions utilize ATP and NADPH to reduce CO2 into glucose via the Calvin-Benson Cycle.
Photoautotrophs are the producers in the food chain, providing energy for chemoheterotrophs.

Lipid Catabolism

Fatty acids are broken down through beta-oxidation, producing ATP.

Protein Catabolism

Proteins are cleaved into amino acids.
Deamination, decarboxylation, and various enzymes remove amino groups, carboxyl groups, and R groups.
The resulting C2 molecules enter the Krebs cycle.
Maple syrup urine disease results from defects in the enzymes that metabolize branched-chain amino acids.

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Description

Test your knowledge on metabolism, energy capture, and enzyme functions. This quiz covers both catabolic and anabolic processes, the role of ATP, and the intricacies of electron transfer in energy synthesis. Additionally, understand the function of enzymes and their importance in biochemical reactions.