Energy and Respiration
150 questions· page 1 of 15
Different types of respiratory substrate can have different energy values and therefore release different quantities of energy when they are respired.
Complete Table 1.1 to show the energy value of each of the three main types of respiratory substrate.
Use one tick () to identify which of the two possible energy values is correct for each respiratory substrate.
Table 1.1
| type of respiratory substrate | energy value / | |
|---|---|---|
| approximately 17 | approximately 37 | |
| carbohydrate | ||
| lipid | ||
| protein |
State the name of the laboratory apparatus that can be used to determine the RQ value of organisms such as blowfly larvae.
When determining RQ values using the laboratory apparatus stated in (b)(i), chemicals such as soda lime or potassium hydroxide solution are used.
State the reason for using chemicals such as soda lime or potassium hydroxide solution when measuring RQ values.
Calculate how many molecules of oxygen are taken in when one molecule of malic acid is respired aerobically.
number of molecules of oxygen = ______
Describe the trend shown during torpor in Fig. 1.3 and suggest an explanation for this trend.
Deer mice have a daily period of torpor only at certain times of the year.
Suggest reasons why a deer mouse enters torpor only at certain times of the year.
In the link reaction, a two-carbon acetyl group is produced from pyruvate. The acetyl group is transferred to coenzyme A to form acetyl coenzyme A (acetyl-coA).
State the terms used to summarise the two chemical changes that occur in the link reaction to produce an acetyl group from pyruvate.
Acetyl-coA combines with oxaloacetate in the Krebs cycle to form citrate. This reaction is catalysed by the enzyme citrate synthase.
Acetyl-coA has a similar shape to succinyl-coA, one of the compounds made in a later part of the Krebs cycle.
An experiment was carried out to investigate the effect of increasing the concentration of acetyl-coA on the activity of citrate synthase. The experiment was repeated, this time adding a solution of succinyl-coA.
Fig. 8.1 shows the results of these experiments.
With reference to Fig. 8.1, explain how succinyl-coA could help to regulate the Krebs cycle.
The coenzyme NAD plays an important role in respiration.
Describe the role of NAD in the stages of aerobic respiration that occur in a mitochondrion.
Fig. 1.1 shows a molecule of ATP.
Explain the features of ATP that make it suitable to be the universal energy currency of cells.
Identify the type of phosphorylation reaction to synthesise ATP that occurs during glycolysis and the Krebs cycle.
Pyruvate moves into the matrix of the mitochondrion only when a particular inorganic molecule is present.
Name the inorganic molecule that must be present in the cell for pyruvate to enter the matrix of the mitochondrion.
Explain how the presence of the inorganic molecule named in (d)(i) affects the ATP yield from respiration.
Explain how the experimental set-up in Fig. 2.2 allows the rate of respiration of woodlice to be determined.
A student determined the rate of respiration of woodlice at a temperature of and at a temperature of .
Predict and explain how the rate of respiration of woodlice differs at compared to .
The coenzymes NAD and FAD deliver hydrogen atoms to the electron transport chain (ETC).
With reference to Fig. 1.1, state which of the four carriers receives hydrogen atoms from reduced FAD.
______
Hydrogen atoms that are delivered to the ETC by reduced NAD and reduced FAD split into protons and electrons. Energy is released as electrons pass along the ETC.
Describe the events that occur as a result of this release of energy.
Cyanide ions () are highly toxic.
Cyanide ions bind to carrier 4 in Fig. 1.1 and inactivate the carrier.
Suggest and explain how the binding of cyanide ions to carrier 4 can have an effect on respiration.
With reference to Fig. 1.1, name:
the type of membrane transport protein represented by A ______
process B ______
area C ______
The mitochondrial pyruvate carrier (MPC), shown in Fig. 1.1, allows the passage of pyruvate into the mitochondrial matrix. When pyruvate enters the mitochondrial matrix, it takes part in the link reaction.
Describe the link reaction.
Some tumour cells have a greatly reduced ability to transport pyruvate into the matrix of the mitochondrion.
Suggest how a reduction in pyruvate transport could affect respiration in these tumour cells.
Describe the structure of aerenchyma and explain how this is an adaptation that allows roots of rice plants to be submerged in water.
When the unsaturated fatty acid linoleic acid is respired aerobically the equation is:
Calculate how many molecules of oxygen are used when one molecule of linoleic acid is respired aerobically.
answer = ______
Hummingbirds feed on nectar from flowers. Nectar is rich in sugars.
Fig. 10.1 shows a hummingbird.
A study of aerobic respiration in captive hummingbirds was carried out. The hummingbirds were allowed to feed freely and then made to fast for 4 hours. During the fasting period their RQ values were calculated every 40 minutes.
Fig. 10.2 shows the results from this study.
Describe and suggest explanations for the results shown in Fig. 10.2.
Rotenone is a compound that affects oxidative phosphorylation.
Rotenone disrupts the first carrier in the electron transport chain by stopping the transfer of electrons from this carrier.
Suggest and explain how rotenone reduces the production of ATP and water in aerobic respiration.
Rotenone is a compound that affects oxidative phosphorylation.
Rotenone disrupts the first carrier in the electron transport chain by stopping the transfer of electrons from this carrier.
Suggest and explain how rotenone reduces the production of ATP and water in aerobic respiration.