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Biology

Bioenergetics

Photosynthesis

Higher Human Biology: Cellular Respiration, Glycolysis, and the Citric Acid Cycle

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Higher Human Biology: Cellular Respiration, Glycolysis, and the Citric Acid Cycle

Isla .

@isla._hrgc

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Higher Human Biology respiration is a complex process that occurs in cells to break down glucose and release energy. This process involves three main stages: glycolysis, the citric acid cycle, and the electron transport chain. These stages work together to produce ATP, the energy currency of cells, through a series of enzyme-controlled reactions.

Key points:

Glycolysis occurs in the cytoplasm and breaks down glucose into pyruvate
The citric acid cycle takes place in the mitochondrial matrix
The electron transport chain on the inner mitochondrial membrane produces the bulk of ATP
Oxidative phosphorylation is the primary method of ATP production in aerobic respiration
Specialized cells like muscle and nerve cells have numerous mitochondria to meet high energy demands

24/04/2023

Stage 1 - Glycolysis

Glycolysis is the first stage of cellular respiration, occurring in the cytoplasm of cells. This process breaks down glucose into pyruvate and can occur in both aerobic and anaerobic conditions.

Key aspects of glycolysis:

Consists of two main stages: Energy Investment and Energy Pay-off
Energy Investment stage uses 2 ATP molecules to phosphorylate glucose
Energy Pay-off stage generates 4 ATP molecules and 2 NADH molecules
Net gain of 2 ATP molecules per glucose molecule
Under aerobic conditions, pyruvate is further broken down to acetyl-CoA

Definition: Glycolysis - The metabolic pathway that breaks down glucose into pyruvate, producing a small amount of ATP and NADH.

Example: In the Energy Pay-off stage, 4 ATP molecules are produced per glucose molecule, resulting in a net gain of 2 ATP molecules after subtracting the 2 ATP used in the Energy Investment stage.

Highlight: Glycolysis can occur in both the presence and absence of oxygen, making it a versatile energy-producing pathway for cells.

K.A.7
Stage 3 - Electron Transport Chain
The electron transport chain is a series of Carrier
proteins attached to the inner mitochondrial me

Cellular Respiration Overview

Cellular respiration is a fundamental process in living organisms that breaks down glucose to release energy in the form of ATP. This energy is essential for various cellular functions and metabolic processes.

Key aspects of cellular respiration:

ATP is the primary energy currency used by cells
Energy from ATP is required for processes such as muscular contraction, nerve impulse transmission, and protein synthesis
Cellular respiration occurs in three main stages: glycolysis, citric acid cycle, and electron transport chain
The process is more efficient when oxygen is present (aerobic respiration)
ATP is regenerated through phosphorylation, adding a phosphate group to ADP

Definition: Cellular respiration - The metabolic process by which cells break down glucose through a series of enzyme-controlled reactions to release energy in the form of ATP.

Example: ATP is used for various cellular processes, including active transport across cell membranes and the synthesis of new proteins.

Highlight: The presence of oxygen allows for more energy to be released during cellular respiration compared to anaerobic processes.

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Stage 2 - Citric Acid Cycle

The citric acid cycle, also known as the Krebs cycle, takes place in the matrix of the mitochondria. This stage is crucial for generating electron carriers and carbon dioxide as a waste product.

Key steps in the citric acid cycle:

Acetyl group from acetyl coenzyme A combines with oxaloacetate to form citrate
A series of enzyme-controlled reactions gradually convert citrate back to oxaloacetate
Dehydrogenase enzymes remove hydrogen ions and high-energy electrons
Hydrogen ions and electrons are passed to NAD+, forming NADH
NADH transfers hydrogen ions and electrons to the electron transport chain

Definition: Citric acid cycle - A series of chemical reactions in cellular respiration that generates electron carriers and carbon dioxide from the breakdown of acetyl groups.

Highlight: The citric acid cycle is an aerobic process, occurring only in the presence of oxygen.

Vocabulary: Oxaloacetate - A four-carbon molecule that combines with the acetyl group to initiate the citric acid cycle.

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Mitochondria and Respiration Key Enzymes

Mitochondria play a crucial role in cellular respiration, particularly in cells with high energy demands. The structure and abundance of mitochondria are adapted to meet these energy requirements.

Key points about mitochondria and respiration enzymes:

Cells with high energy needs (e.g., muscle, liver, nerve cells) have numerous mitochondria
Mitochondria in these cells often have more folds in the inner membrane, increasing surface area for electron transport chains
Dehydrogenase enzymes remove hydrogen ions and high-energy electrons, passing them to NAD+
NAD+ acts as a hydrogen acceptor and carrier, forming NADH
NADH transfers hydrogen to the final stage of respiration, regenerating NAD+

Vocabulary: Dehydrogenase - An enzyme that removes hydrogen ions and high-energy electrons from substrates during cellular respiration.

Definition: NAD+ (Nicotinamide Adenine Dinucleotide) - A coenzyme that acts as a hydrogen acceptor and carrier in cellular respiration.

Highlight: The increased surface area of the inner mitochondrial membrane in cells with high energy demands allows for more frequent and efficient electron transport chain activity.

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Stage 3 - Electron Transport Chain

The electron transport chain is the final stage of cellular respiration, occurring on the inner mitochondrial membrane. This process is responsible for producing the majority of ATP in aerobic respiration.

Key features of the electron transport chain include:

A series of carrier proteins embedded in the inner mitochondrial membrane
Transfer of electrons along the chain, releasing energy
Pumping of hydrogen ions across the membrane, creating a concentration gradient
Flow of hydrogen ions back through ATP synthase, driving ATP production
Combination of hydrogen ions and electrons with oxygen to form water

Vocabulary: ATP synthase - A membrane protein that catalyzes the synthesis of ATP using the energy from the flow of hydrogen ions.

Highlight: The bulk of ATP production occurs due to the action of ATP synthase, which is driven by the return flow of hydrogen ions across the mitochondrial membrane.

Example: The rotation of part of the ATP synthase protein, caused by the flow of hydrogen ions, catalyzes the synthesis of ATP from ADP and inorganic phosphate.

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Can't find what you're looking for? Explore other subjects.

Knowunity is the #1 education app in five European countries

Knowunity has been named a featured story on Apple and has regularly topped the app store charts in the education category in Germany, Italy, Poland, Switzerland, and the United Kingdom. Join Knowunity today and help millions of students around the world.

Download in

Google Play

Download in

App Store

4.9+

Average app rating

13 M

Pupils love Knowunity

#1

In education app charts in 12 countries

950 K+

Students have uploaded notes

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iOS User

I love this app so much, I also use it daily. I recommend Knowunity to everyone!!! I went from a D to an A with it :D

Philip, iOS User

The app is very simple and well designed. So far I have always found everything I was looking for :D

Lena, iOS user

I love this app ❤️ I actually use it every time I study.

Subjects

Biology

Bioenergetics

Photosynthesis

Higher Human Biology: Cellular Respiration, Glycolysis, and the Citric Acid Cycle

Isla .

@isla._hrgc

0 Follower

Key points:

Glycolysis occurs in the cytoplasm and breaks down glucose into pyruvate
The citric acid cycle takes place in the mitochondrial matrix
The electron transport chain on the inner mitochondrial membrane produces the bulk of ATP
Oxidative phosphorylation is the primary method of ATP production in aerobic respiration
Specialized cells like muscle and nerve cells have numerous mitochondria to meet high energy demands

24/04/2023

Stage 1 - Glycolysis

Glycolysis is the first stage of cellular respiration, occurring in the cytoplasm of cells. This process breaks down glucose into pyruvate and can occur in both aerobic and anaerobic conditions.

Key aspects of glycolysis:

Consists of two main stages: Energy Investment and Energy Pay-off
Energy Investment stage uses 2 ATP molecules to phosphorylate glucose
Energy Pay-off stage generates 4 ATP molecules and 2 NADH molecules
Net gain of 2 ATP molecules per glucose molecule
Under aerobic conditions, pyruvate is further broken down to acetyl-CoA

Definition: Glycolysis - The metabolic pathway that breaks down glucose into pyruvate, producing a small amount of ATP and NADH.

Example: In the Energy Pay-off stage, 4 ATP molecules are produced per glucose molecule, resulting in a net gain of 2 ATP molecules after subtracting the 2 ATP used in the Energy Investment stage.

Highlight: Glycolysis can occur in both the presence and absence of oxygen, making it a versatile energy-producing pathway for cells.

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Cellular Respiration Overview

Key aspects of cellular respiration:

ATP is the primary energy currency used by cells
Energy from ATP is required for processes such as muscular contraction, nerve impulse transmission, and protein synthesis
Cellular respiration occurs in three main stages: glycolysis, citric acid cycle, and electron transport chain
The process is more efficient when oxygen is present (aerobic respiration)
ATP is regenerated through phosphorylation, adding a phosphate group to ADP

Definition: Cellular respiration - The metabolic process by which cells break down glucose through a series of enzyme-controlled reactions to release energy in the form of ATP.

Example: ATP is used for various cellular processes, including active transport across cell membranes and the synthesis of new proteins.

Highlight: The presence of oxygen allows for more energy to be released during cellular respiration compared to anaerobic processes.

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Stage 2 - Citric Acid Cycle

The citric acid cycle, also known as the Krebs cycle, takes place in the matrix of the mitochondria. This stage is crucial for generating electron carriers and carbon dioxide as a waste product.

Key steps in the citric acid cycle:

Acetyl group from acetyl coenzyme A combines with oxaloacetate to form citrate
A series of enzyme-controlled reactions gradually convert citrate back to oxaloacetate
Dehydrogenase enzymes remove hydrogen ions and high-energy electrons
Hydrogen ions and electrons are passed to NAD+, forming NADH
NADH transfers hydrogen ions and electrons to the electron transport chain

Definition: Citric acid cycle - A series of chemical reactions in cellular respiration that generates electron carriers and carbon dioxide from the breakdown of acetyl groups.

Highlight: The citric acid cycle is an aerobic process, occurring only in the presence of oxygen.

Vocabulary: Oxaloacetate - A four-carbon molecule that combines with the acetyl group to initiate the citric acid cycle.

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Mitochondria and Respiration Key Enzymes

Mitochondria play a crucial role in cellular respiration, particularly in cells with high energy demands. The structure and abundance of mitochondria are adapted to meet these energy requirements.

Key points about mitochondria and respiration enzymes:

Cells with high energy needs (e.g., muscle, liver, nerve cells) have numerous mitochondria
Mitochondria in these cells often have more folds in the inner membrane, increasing surface area for electron transport chains
Dehydrogenase enzymes remove hydrogen ions and high-energy electrons, passing them to NAD+
NAD+ acts as a hydrogen acceptor and carrier, forming NADH
NADH transfers hydrogen to the final stage of respiration, regenerating NAD+

Vocabulary: Dehydrogenase - An enzyme that removes hydrogen ions and high-energy electrons from substrates during cellular respiration.

Definition: NAD+ (Nicotinamide Adenine Dinucleotide) - A coenzyme that acts as a hydrogen acceptor and carrier in cellular respiration.

Highlight: The increased surface area of the inner mitochondrial membrane in cells with high energy demands allows for more frequent and efficient electron transport chain activity.

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Stage 3 - Electron Transport Chain

Key features of the electron transport chain include:

A series of carrier proteins embedded in the inner mitochondrial membrane
Transfer of electrons along the chain, releasing energy
Pumping of hydrogen ions across the membrane, creating a concentration gradient
Flow of hydrogen ions back through ATP synthase, driving ATP production
Combination of hydrogen ions and electrons with oxygen to form water

Vocabulary: ATP synthase - A membrane protein that catalyzes the synthesis of ATP using the energy from the flow of hydrogen ions.

Highlight: The bulk of ATP production occurs due to the action of ATP synthase, which is driven by the return flow of hydrogen ions across the mitochondrial membrane.

Example: The rotation of part of the ATP synthase protein, caused by the flow of hydrogen ions, catalyzes the synthesis of ATP from ADP and inorganic phosphate.