Respiration 2.0 Flashcards by sophie bennett

What is respiration?

Controlled release of energy from food.

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What is aerobic respiration?

Controlled release of energy from food, using oxygen.

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What is anaerobic respiration?

The controlled release of energy from food, without using oxygen.

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What is the respiration equation?

C6H12O6 + 6O2 –→ 6CO2 + 6H20 + Energy

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What is the first stage of respiration?

Glycolysis.

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Where does glycolysis occur?

In the cytosol of the cell.

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Does glycolysis require oxygen?

No, its anaerobic.

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What is the amount of ATP formed during glycolysis?

A small amount of ATP is formed.

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What happens during glycolysis?

A 6-carbon molecule (glucose) breaks down into two, 3 carbon molecules (pyruvic acid). As this process occurs, enough energy is released to form a small amount of ATP by joining ADP & P.

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What does ADP + P equal?

ATP.

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What are the products formed at the end of glycolysis?

• Pyruvic acid - main product
• ATP
• Water

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Where does pyruvic acid move to?

• Mitochondria & change to acetyl co-enzyme A & enter the Krebs cycle.
OR…
• undergo anaerobic respiration.

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What is a 6 carbon molecule?

Glucose.

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What is a 3 carbon molecule?

Pyruvic acid.

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What is stage 2 of respiration?

The Krebs cycle & electron transport chain.

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Does the Krebs cycle require oxygen?

Yes!

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What happens to pyruvic acid in the presence of oxygen?

It moves to the lumen of the mitochondria.

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What is pyruvic acid changed to?

Acetyl Co-enzyme A by losing a carbon dioxide molecule.

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What does Acetyl Co-enzyme A join with in the Krebs cycle?

It joins with a 4 carbon molecule (already in the cycle) to form a 6 carbon molecule.

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What happens as the 6 carbon molecule goes around the Krebs cycle?

C6 molecule is broken down to a 5 carbon molecule.

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What does the breakdown of the C6 molecule to a C5 molecule do?

This releases energy to form ATP, by joining ADP + P.

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What is formed from the energy created when C6 breaks down to C5?

NADH.

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What is C5 broken down to?

A C4 molecule, releasing energy to form NADH & ATP + CO2 is released.

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What does C4 join with?

With another Acetyl Co-enzyme A & the cycle restarts.

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What are the products formed during the Krebs cycle?

• NADH - main product • ATP • CO2

How many carbons does Acetyl Co-enzyme A have?

What is used in the electron transport system?

NADH from the Krebs cycle is used here.

Where does the electron transport system occur?

In the inner membrane of the mitochondria.

What happens in step 1 of the electron transport system?

NADH is broken down into...NAD+ + H+ + 2e-.

What is NAD+ used for?

Make more NADH by picking up H+ & 2e and using the energy provided in the Krebs cycle.

What does H+ take part in?

Formation of water.

What happens to the 2e?

They enter the Electron Transport Chain.

What occurs in stage 2: Electron transport chain?

Electrons pass through the electron transport chain & are losing energy. This energy is used to change ADP & P into ATP, and a large amount of ATP is formed. In the end, the 2e - combine with H+ & half O2 to form H2O.

What are the products formed in the electron transport chain?

• ATP • H2O

Under what condition is lactic acid produced during respiration?

Anaerobic conditions.

What is the role of NADH in the electron transport system?

Breaks down to deliver high energy electrons.

Where does the Krebs cycle occur?

The lumen of the mitochondria.

How is acetyl CoA formed?

If oxygen is present, pyruvic acid will lose a CO2 molecule & change into Acetyl co-enzyme A.

What is the function of oxygen during respiration?

O2 (oxygen) combines with low-energy electrons & H+ to form H2O, at the end of the electron transport chain.

Why is respiration important to humans?

Ethanol = Solvent Carbon dioxide = Baking.

What are two products formed when pyruvic acid is broken down?

CO2 & Acetyl Co-enzyme A.

Describe the fate of pyruvic acid.

Pyruvic acid loses a CO2, forming Acetyl Co-enzyme A & enters the Krebs cycle. NAD+ is converted to NADH & NADH enters the electron transport chain. High-energy electrons are passed through the chain & lose energy. This energy is used to form ATP by joining ADP+P. At the end the low energy electrons join with H+ & 1/2 CO2, to form H2O.

What is the final electron acceptor in aerobic respiration?

Oxygen.

What is the importance of ADP in respiration?

Energy is released by electrons as they move through the electron transport chain & is picked up by ADP & a phosphate is added to form ATP.

Is respiration anabolic or catabolic?

Catabolic, as it's breaking down large molecules (glucose).

What is the fate of ATP?

Breaks down and releases energy.

What is the fate of CO2?

Used in photosynthesis.

What is the fate of NADH?

Breaks down and releases electrons.

What is the method for the production of alcohol by yeast experiment?

• Add 500ml of glucose solution to a conical flask & bring the solution to a boil, then allow to cool. • Once cooled, add half of the solution to conical flask A and half to a conical flask B. • Add 5g of yeast solution to conical flask A & leave B yeast free. • Add a layer of oil to the top of each solution. • Place a fermentation lock on the top of each conical flask with a small amount of lime water in each. • Place both in a water bath, with a thermometer @ 25c for at least 24 hrs. • When complete, filter both solutions using filter paper & save the filtrate.

What is the method for the iodoform test?

• Filter the solution (to remove yeast cells). • Add potassium iodine to the filtrate. • Add sodium hypochlorite. • Heat & then allow to cool. • Yellow crystals form if ethanol is present.

Why boil the glucose solution?

To remove oxygen.

Why is there no yeast in flask B?

As B is the control.

Why add a layer of oil?

Prevents oxygen from re-entering, maintaining anaerobic conditions.

Why add lime water to the fermentation lock?

To test for the presence of carbon dioxide.

Why incubate in a water bath at 25 degrees?

As 25 degrees is the optimum temperature for enzymes.

What is the nitrogenous base in ATP?

Adenine.

What is the sugar in ATP?

Ribose.

What is an advantage of ATP?

Easily broken down.

How would you know when all the glucose is used up?

No more bubbles.

Why is boiled yeast a suitable control?

As the heat denatures the enzymes.

What is another suitable control?

Distilled water.

What is one factor to keep constant except for temperature?

Same concentration of glucose.

What is a storage polysaccharide in humans from which glucose is produced?

Glycogen - Found in the muscles.

From which substance is ethanol produced?

Glucose.

Explain why anaerobic conditions result in a small amount of ATP being formed.

As glucose is not fully broken down.

What is cytosol?

Liquid portion of cytoplasm - No organelles.

What is the function of NAD?

Carries high energy electrons.