Biology: Metabolism and Enzymes Quiz

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Questions and Answers

What type of reaction are catabolic reactions classified as?

Metabolic reactions

Anabolic reactions

Endergonic reactions

Exergonic reactions (correct)

Which molecule is produced when ATP loses a phosphate group?

Adenosine Diphosphate (correct)

Glucose

Adenine

Adenosine Triphosphate

Which statement is true regarding anabolic reactions?

They consume energy to build complex molecules. (correct)

They only occur in the presence of oxygen.

They release energy during the process.

They are the same as catabolic reactions.

What do ATP and ADP have in common?

They are both energy carriers in cells. Signup and view all the answers

Which process is an example of a catabolic reaction?

Digesting food Signup and view all the answers

What is the primary reason the human body needs to eat?

To obtain energy and nutrients. Signup and view all the answers

Which of the following correctly describes the function of ATP?

It serves as an immediate source of energy in cells. Signup and view all the answers

In which process do hydrogen ions move across the inner mitochondrial membrane?

Chemiosmosis Signup and view all the answers

What occurs during exergonic reactions?

Energy is released to the environment. Signup and view all the answers

What is one function of electron carriers in cellular respiration?

To transport electrons and protons throughout the processes. Signup and view all the answers

How does feedback inhibition regulate cellular respiration?

By inhibiting the activity of certain enzymes when product levels are sufficient. Signup and view all the answers

What is formed during glycolysis?

Pyruvate and ATP Signup and view all the answers

Which product is generated from lactic acid fermentation?

Lactic acid Signup and view all the answers

What are the starting materials for glycolysis?

1 glucose + 2 ATP + 2 NAD+ Signup and view all the answers

Where does glycolysis occur within the cell?

In the cytoplasm Signup and view all the answers

What is a product of pyruvate oxidation?

2 NADH Signup and view all the answers

What do all processes discussed have in common regarding ATP?

None require oxygen Signup and view all the answers

How many acetyl CoA molecules are generated from one glucose molecule?

2 Signup and view all the answers

Which of the following is NOT a product of the Citric Acid Cycle?

1 glucose Signup and view all the answers

Which enzyme is responsible for ATP synthesis as H+ ions re-enter the mitochondrial matrix?

ATP Synthase Signup and view all the answers

What is the main role of NAD+ in the glycolysis process?

To donate electrons Signup and view all the answers

What is the primary function of the Electron Transport Chain (ETC)?

To transport protons into the intermembrane space Signup and view all the answers

How does ATP synthase produce ATP?

By allowing protons to move back into the mitochondrial matrix Signup and view all the answers

What is the primary function of ATP in cells?

To provide energy through breaking high energy phosphate bonds Signup and view all the answers

What role does oxygen play in oxidative phosphorylation?

It acts as the final electron acceptor Signup and view all the answers

What happens to electrons in the absence of oxygen during the Electron Transport Chain?

They accumulate and lead to carrier reduction Signup and view all the answers

Which process is essential for maintaining cellular function and requires energy?

Building nucleic acids Signup and view all the answers

What characterizes catabolic reactions in metabolism?

They break down large polymers into smaller monomers Signup and view all the answers

How many protons must move through ATP synthase to generate one ATP molecule?

4 protons Signup and view all the answers

How are exergonic and endergonic reactions related?

Endergonic reactions use the energy released from exergonic reactions Signup and view all the answers

Where does glycolysis occur in the cell?

In the cytoplasm Signup and view all the answers

What type of reaction is characterized by the products having less energy than the reactants?

Exergonic reaction Signup and view all the answers

What is proton motive force?

The electrochemical gradient of protons across the membrane Signup and view all the answers

Which part of cellular respiration begins with glucose?

Glycolysis Signup and view all the answers

Which of the following accurately describes enzymes?

They facilitate both anabolic and catabolic reactions Signup and view all the answers

Which of the following statements about food energy is true?

Energy stored in food is released by breaking chemical bonds Signup and view all the answers

What is the role of monomers in metabolic processes?

They are used to build larger polymers in anabolic reactions Signup and view all the answers

Study Notes

Why We Need to Eat

We need to eat food to get energy to survive
Energy from food is stored in food's chemical bonds
Food provides energy for building macromolecules like proteins and nucleic acids
Energy from food is required for life-sustaining processes like active transport

Metabolism

Metabolism is the sum of all chemical reactions in cells that keep us alive
Metabolic reactions can be classified as either:
- Catabolic: Reactions that break down molecules and release energy
- Anabolic: Reactions that build up molecules and require energy
Metabolic reactions can also be classified as either:
- Exergonic: Reactions that release energy, meaning the products have less energy than the reactants
- Endergonic: Reactions that require energy, meaning the products have more energy than the reactants

Enzymes

Enzymes speed up chemical reactions
Without enzymes, reactions would occur too slowly for organisms to function
Enzymes help both anabolic and catabolic reactions
Enzymes work on substrates to produce products

ATP and ADP

ATP (adenosine triphosphate) and ADP (adenosine diphosphate) are the main forms of chemical energy in a cell
Energy is stored in the bonds between phosphate groups in ATP and ADP
ATP has 3 phosphate groups, high energy, and is made when the cell has extra energy
ADP has 2 phosphate groups, some energy, and is made when the cell uses energy from ATP by removing a phosphate group

Cellular Respiration

Cellular respiration is a series of reactions in which glucose is broken down to generate energy
Energy from glucose is transferred to the bonds of ATP
ATP is then used by cells as a source of energy by breaking its high-energy phosphate bonds

Glycolysis

First step of cellular respiration
Breaks down glucose (C6H12O6) into two pyruvate molecules (C3H4O3)
Occurs in the cytoplasm
Requires 2 ATP to start, but produces 4 ATP (net gain of 2 ATP)
Also produces 2 NADH, which is an electron carrier molecule
Does not require oxygen

Pyruvate Oxidation

Second step of cellular respiration
Occurs in the mitochondrial matrix
Pyruvate is transported into the mitochondria
Each pyruvate is converted into an acetyl CoA molecule
Produces 2 CO2 and 2 NADH

The Citric Acid Cycle (Krebs Cycle)

Third step of cellular respiration
Occurs in the mitochondrial matrix
Acetyl CoA is broken down, releasing more energy
Produces 4 CO2, 2 ATP, 6 NADH, and 2 FADH2

Electron Transport Chain (ETC)

Fourth and final step of cellular respiration
Occurs in the inner mitochondrial membrane
Electrons are transferred from NADH and FADH2 to proteins in the ETC
These electrons lose energy along the chain, powering the movement of protons (H+) across the inner membrane
Oxygen is the final electron acceptor

Chemiosmosis

The movement of protons (H+) across the inner mitochondrial membrane creates a proton gradient
This gradient powers ATP synthase to produce ATP
Called oxidative phosphorylation

Fermentation

Occurs in the absence of oxygen
Allows for the production of ATP without oxygen
Two main types:
- Alcoholic fermentation: Pyruvate is converted to ethanol and CO2
- Lactic acid fermentation: Pyruvate is converted to lactic acid

Feedback Inhibition

Controls the rate of cellular respiration
Prevents the overproduction of ATP
When ATP is abundant, it inhibits enzymes involved in earlier steps of cellular respiration

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Description

Test your knowledge on metabolism and the role of enzymes in biological processes. This quiz covers concepts such as catabolic and anabolic reactions, as well as the energy dynamics in metabolic pathways. Perfect for biology students wanting to deepen their understanding of how life sustains itself through chemical reactions.