Higher Biology - Unit 2.2

​Unit 2.2

Cellular respiration​

​A T P

​Adenine Triphosphate

​ATP is an energy carrying molecule used in cells. It can release energy very quickly.

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​Energy is released from ATP when the end phosphate is removed. Once it has released energy it becomes ADP (adenine diphosphate) which is a low energy molecule.

​Tip: The phosphate has Died, so it becomes (Adenine)Diphosphate

​A T P & A D P

​ADP can be transferred back into ATP, however energy will be required.

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​These molecules can be recycled so that a constant stream of energy rich ATP is available for all metabolic pathways in the cell.

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​ATP can transfer energy to other molecules in processes such as muscle contraction, DNA replication, Active transport, and Synthetic pathways

Multiple Choice

When ATP becomes ADP...

• Energy is released

• Energy is required

Multiple Choice

What happens when ATP releases energy?

• It gains a phosphate molecule

• It looses a phosphate molecule

• It becomes ACP

Multiple Choice

When ADP becomes ATP...

• Energy is required

• Energy is released

Fill in the Blanks

How many phosphate molecules does Adenine Triphosphate (ATP) have?

Fill in the Blanks

How many molecules does Adenine Diphosphate (ADP) have?

​Respiration

​ Respiration (a metabolic pathway) can be split up into 3 stages:

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-Glycolysis

-Citric acid cycle

-Election transport chain ​

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​Respiration

​Glycolysis occurs in the cell's cytoplasm

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Citric acid​ cycle occurs in the matrix of the mitochondria

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Electron transport chain ​occurs in the inner membrane of the mitochondria

Fill in the Blanks

Which stage of respiration occurs in the Matrix of the mitochondria?

Fill in the Blanks

Which stage of respiration occurs in the Cytoplasm?

Fill in the Blanks

Which stage of Respiration occurs in the inner membrane of the Mitochondria?

​Glycolysis

​Glycolysis is the breakdown of glucose into 2 pyruvate molecules.

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​During this process, several intermediate molecules are produced and ATP molecules in an energy investment stage are required

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​Glycolysis

​After the energy investment stage, more ATP is then regenerated than what was used in the production of the intermediates.

Therefor their is a net gain ​of ATP molecules.

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​Dehydrogenase enzymes hydrogen ions and electrons from intermediates of the cycle, which are then past on to the co-enzyme NAD. This forms NADH.

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The hydrogen ions and electrons are then passed on to the electron transport chain on the inner mitochondrial membrane.​

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​Fermentation - Citric cycle

​If oxygen is available: The pyruvate molecules will progress to the citric acid cycle stage.

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​If oxygen is not available: The pyruvate molecules will undergo fermentation in the cytoplasm of the cell.

​Fermentation

​There are 2 types of Fermentation:

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​​Alcoholic Fermentation - The pyruvate is converted into ethanol and CO2. This occurs in plant cells and fungi

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Lactace Fermentation - The pyruvate is converted into lactate. This occurs in animal cells

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Fermentation produces a lot less ATP than aerobic respiration​

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​Cirtic Acid Cycle

​The pyruvate enters the matrix of the mitochondria and the carbon dioxide is removed.

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​Carbon is removed to form an acetyl group, which is combined with an enzyme to form acetyl coenzyme A.

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​The acetyl from the coenzyme A combines with a molecule called Oxaloacetate to form Citrate (hence the name of this stage).

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​Citric Acid Cycle

​Intermediate molecules are formed from this process because the enzymes remove carbon and hydrogen/electrons. Carbon dioxide is released as a by-product, and ATP is produced.

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​These intermediate steps gradually convert Citrate back into Oxaloacitate, which is then able to combine into another acytel group.

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​Electron Transport Chain

​The last stage of respiration, produces the most ATP, occurs in the inner membrane of the mitochondria where a collection of proteins are found.

​NADH will release the hydrogen ions and electrons into the transport chain. The electrons transfer their energy to the proteins in the membrane.

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This provides energy for the hydrogen ions to be pumped across the inner mitochondrial membrane. The flow of ions across the membrane synthesises a protein calls ATP synthase

El​ectron Transport Chain

​The oxygen then combines with the hydrogen Ions and electrons to form water.

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​38 ATP molecules are produced in total from this process.

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​Glucose and Respiration

​If glucose isn't available in the respiration pathway, other respiratory substrates can be used via alternative metabolic pathways.

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​Starch , glycogen , proteins (amino acids) , and fats can all be broken down into intermediate molecules during glycolysis or the citric acid cycle.

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​This provides alternative metabolic pathways to make ATP!

Fill in the Blanks

Name the process which comes before citric acid cycle and electron transport chain in respiration

Fill in the Blanks

In which part of the cell does Glycolysis take place?

Fill in the Blanks

In which part of the cell does citric acid cycle take place?

Fill in the Blanks

In which part of the cell does electron transport chain take place

Multiple Choice

During glycolysis, what is the glucose broken down into?

• Glycogen

• Ethanol

• CO2

• 2 Pyruvate molecules

• 5 Pyruvate molecules

Multiple Choice

After glycolysis, there is a ... of ATP

• net gain

• loss

• breaking down

• production

Fill in the Blanks

Which enzyme is formed (during glycolysis) after the intermediates are past on to the co-enzyme NAD?

Multiple Choice

Fermentation will take place instead of respiration if the conditions are...

• Aerobic

• Anaerobic

Fill in the Blanks

Citric acid cycle: Name the enzyme formed when the acetyl group is combined with coenzyime A

Multiple Choice

Citric acid cycle: Which molecule does the acetyl from the coenzyme A combine with to form citrate?

• Pyruvate

• Hydrogen

• Phospholipids

• Oxaloacitate

Fill in the Blanks

The citric acid cycle produces ATP, but what is the bi-product that is released?

Fill in the Blanks

Which respiration stage occurs in the inner membranes of the mitochondia?

Multiple Choice

Which respiration stage produces the most ATP? (38 ATP)

• Glycolysis

• Fermentation

• Citric acid cycle

• Electron transport chain

Fill in the Blanks

NADH will release hydrogen and ... into the chain

Multiple Choice

Where in the membrane do the electrons transfer their energy to?

• The phospholipids

• The nucleus

• The proteins

• The pores

Fill in the Blanks

Which protein does the flow of ions across the membrane form

Fill in the Blanks

The combining of the oxygen and hydrogen ions forms what?

​List of Terms

​Acetyl group - Produced by the breakdown of pyruvate, joins with oxaloacetate in the citric acid cycle

ATP synthase - Enzyme produced during the electron transport chain by the flow of ions in the mitochondrial membrane

Citrate - Substance produced in the citric acid cycle

Glycolysis - First stage in respiration which occurs in the cytoplasm

Citric acid cycle - Second stage in respiration which occurs in the matrix of the mitochondria

Electron transport chain - Third stage in respiration which occurs in the inner membrane of the mitochondria

Oxaloacetate - Combines with acetyl group to form citrate in the citric acid cycle

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Fill in the Blanks

Produced by the breakdown of pyruvate, joins with oxaloacetate in the citric acid cycle

Fill in the Blanks

Enzyme produced during the electron transport chain by the flow of ions in the mitochondrial membrane

Fill in the Blanks

Substance produced in the citric acid cycle

Fill in the Blanks

First stage in respiration which occurs in the cytoplasm

Fill in the Blanks

Second stage in respiration which occurs in the matrix of the mitochondria

Fill in the Blanks

Third stage in respiration which occurs in the inner membrane of the mitochondria

Fill in the Blanks

Combines with acetyl group to form citrate in the citric acid cycle

​END OF KEY AREA

Thank goodness!​