IB biology 2.8 and 8.2 Respiration

Which statement is true about mitochondrial DNA and ribosomes?

• Mitochondria do not have DNA or ribosomes - they are organelles not cells

• Mitochondria have circular DNA and smaller ribosomes than eukaryotic cells - they evolved from prokaryotes.

• Mitochondria have linear DNA and 80S ribosomes - they are eukaryotic cells

• Mitochondrial DNA codes for all proteins needed in the electron transport chain but they use the ribosomes on the RER of the cell

Which process requires oxygen in aerobic cell respiration?

• Oxidation of triose Phosphate

• Reduction of hydrogen carriers

• Maintaining an oxygen concentration gradient in the mitochondria

• Accepting electrons at the end of the electron transport chain

What happens when pyruvate is converted to Acetyl CoA in the link reaction?

• Decarboxylation

• Phosphorylation

• Hydrolysis

• Reduction of pyruvate

The following processes occur in aerobic cell respiration. Which is the correct sequence for these processes?

• I ---> II ---> III

• I ---> III ---> II

• II ---> III ---> I

• III ---> I ---> II

What is a requirement for the accurate measurements of the rate of respiration using a respirometer?

• CO₂ must be absorbed by water so that only O₂ production is measured

• Temperature must be kept constant so that the volume changes are only due to O₂ use

• Anaerobic organisms are better to use than aerobic ones as they will produce larger volume changes

• Warm-blooded animals are better to use than cold-blooded animals as they do not change the temperature of the container

Which way will the drop of liquid move in this respirometer and how do you explain it?

• Left - Carbon dioxide produced in respiration is absorbed by the soda lime so the volume of gas in the tube decreases

• Right - Carbon dioxide produced in respiration is absorbed by the soda lime so the volume of gas in the tube increases

• No movement - the volume of CO₂ produced in respiration is the same as the volume of O₂ used so there is no net change

• Depends - The movement will be different depending on whether the woodlice respire anaerobically or aerobically

When investigating the effect of temperature on the rate of respiration, why do you need tube Q with glass beads?

• To make sure it is a fair test - the volume of glass beads needs to be the same as the volume of soda lime

• It is a control variable - it allows you to see what happens without the soda lime

• It is a control - changes in temperature could also cause the bubble to move and this allows you to take that into account

• Glass beads have a high specific heat capacity so it makes it easier to maintain a constant temperature in the tubes

The diagram represents the Krebs cycle. What processes are occurring at I and II?

• I: C₄ is being reduced. II: NAD⁺ is being oxidised

• I: NAD⁺ is being decarboxylated. II: C₅ is being oxidised

• I: NADH is being reduced. II: C₅ is being decarboxylated

• I: NAD⁺ is being reduced. II: C₅ is being decarboxylated

The reaction shown occurs in the mitochondria. What explains that this reaction enables energy to be converted into a usable form?

• The oxidised NAD⁺ will transfer energy from the C₆ compound to ATP

• The chemical energy stored in the C₆ compound is used to reduce NAD⁺ allowing ATP production

• Energy stored in the CO₂ molecule will generate and electron gradient

• The C₆ compound is reduced and the energy resulting from the removal of one carbon is used to oxidise NAD⁺

The diagram shows a mitochondrion. Which letter indicates the structure where ATP synthase is located?

• A

• B

• C

• D