respiration Flashcards
give 2 structural features of mitochondria that support the endosymbiotic theory
- 70S ribosomes
- double membrane
Explain why early eukaryotes were able to grow more quickly than cells that did not possess
mitochondria.
- respire aerobically
- produce more ATP
A teacher told his students that the human body makes the equivalent of its own mass in ATP every
day.
Explain why, at the end of the day, only a small proportion of the students’ mass was ATP
- hydrolysed to ADP
- used up immediately
Describe two ways in which the structure of mitochondrial membranes is related to the function of
a mitochondrion.
- outer membrane has carrier proteins
- inner membrane has ETC for oxidative phosphorylation
Describe the production of ATP by substrate-level phosphorylation in different stages of respiration with
reference to the number of ATP molecules produced.
- 2 from glycolysis
- when triose (bis)phosphate broken down to pyruvate
- net yield of 2 bcs 4 made but 2 used up in glycolysis
- 1 ATP produced per Krebs
cycle
Suggest one other aspect of the physiology of naked mole rats that explains how they are able to
survive without oxygen for a long time.
- low metabolic rate
Explain how having a larger number of proton pores in the inner mitochondrial membrane would result in
a person being less likely to gain weight.
- larger number of protons pores = protons leaking back into matrix
- reduces yield of ATP from
chemiosmotic gradients - less ATP is made from oxidative phosphorylation
- food not converted to ATP as
efficiently - less excess energy intake in diet
- less deposition of fat
- fat stores may be respired for
energy
What properties of the mitochondrial inner membrane allow chemiosmosis to occur?
- large SA
- impermeable to H+ ions
Describe two quantitative changes in the inter-membrane space which occur as a result of oxidative phosphorylation.
- pH decreases
- becomes positively charged
Describe two practical considerations to ensure the S. cerevisiae (yeast) population grows successfully
when the initial culture is established.
- enough nutrients for growth
- aseptic techniques
Athletic sprinters require large amounts of energy in short periods of time. Many elite sprinters
can run 100 metre races in under 10 seconds.
Suggest how these sprinters can expend so much energy without needing to carry out aerobic
respiration.
- have high phosphocreatine stores
- use the stored ATP from it as an immediate source of short burst of energy
why does cheese have the highest energy content
- cheese is high in fat
- fatty acids have lots of H atoms
- can reduce NAD lots of times
The student planned to allow yeast cells and maggots to respire the cookie powder in
anaerobic conditions and measure the RQ over 2 minutes.
State and explain one problem with the student’s method.
- maggots will not produce CO2 as they use the lactate fermentation pathway
- yeast produce CO2 from ethanol fermentation pathway
- measuring RQ requiers CO2 production therefore for maggots it will be lower
Describe how the student could use 1 cm3 pipettes and 10 cm3 measuring cylinders to
dilute the sample so that it was 10 000 times less concentrated.
- take 1 cm3 of culture and make up to 10 cm3
- make a total of four 1:10
dilutions - mixing of yeast suspension at
each stage
