Biology Forums - Study Force

Biology-Related Homework Help General Biology Topic started by: flower555 on Oct 9, 2011



Title: cellular repiration questions
Post by: flower555 on Oct 9, 2011
Sorry these a bunch of questions but for some i think i have the right answers can u just make sure and check them out ?!? :-[
1) All cells can convert glucose into pyruvate. What cells do next depends on the availability of oxygen. What terms do we use to describe growth in the presence of oxygen and growth in the absence of oxygen?

2) In the presence of oxygen, what do cells do with pyruvate? Where does this occur?
(I think it occurs in the mitrchondria but not sure)

3) In the absence of oxygen, what are two possible processes calls can use to produce ATP?
( I think it's photosynthesis and kreb's cycle not sure either)

4) In alcoholic fermentation, pyruvate is further broken down into what product?

5) When your muscle cells need to make ATP but are running low on oxygen, which process do they use?
(I think it's cellular repiration)

6) Is yeast a prokaryote or a eukaryote? Why?
(Is it a prokaryote cuz it's bacteria)

7) Could pyruvate enter into the Krebs cycle in yeast?

8) Does the krebs cycle/electron transport chain require oxygen?

9) Explain why  beer and wine are typically made in closed containers?


Title: Re: cellular repiration questions
Post by: bio_man on Oct 9, 2011
1) All cells can convert glucose into pyruvate. What cells do next depends on the availability of oxygen. What terms do we use to describe growth in the presence of oxygen and growth in the absence of oxygen?

Anaerobic versus aerobic, the former means cannot grow in the presence of oxygen, whereas the latter means the opposite. Also, a facultative anaerobe is an organism that makes ATP by aerobic respiration if oxygen is present but is also capable of switching to fermentation. In contrast, obligate anaerobes die in the presence of oxygen.


Title: Re: cellular repiration questions
Post by: pppppp on Oct 12, 2011
Do you mean growth or respiration? Respiration with oxygen included is aerobic respiration. Without oxygen is anaerobic(in this case, another element takes up the place oxygen would have been), and fermentation(alcoholic and lactic acid). First stage of either type of respiration is glycolysis(which does not require oxygen). After this, if fermentation is to occur, kreb's cycle and oxidative phosphorylation stages would be skipped. If it is aerobic or anaerobic, kreb's cycle would occur, if aerobic, in oxidative phosphorylation, Oxygen would be the final electron acceptor. If anaerobic, sulfur, for example would be the last electron acceptor.

 In the presence of oxygen, Pyruvate combines with acetyl co-A and then enters the Kreb's cycle. It occurs in the mitochondria.

I've mentioned what happens in the absence of oxygen.

In alcoholic fermentation, pyruvate is broken down to ethanol(the alcohol) and CO2.

Yes, your muscles use cellular respiration.

Yeast are fungi, not bacteria. They are eukaryotes.

Kreb's cycle does not require oxygen. The electron transport chain(oxidative phosphorylation stage I assume) will require oxygen if it is aerobic respiration.\

In a closed container, Oxygen is prevented from entering, and so fermentation can occur. This is how beer and wines are made.

Did i miss anything?


Title: Re: cellular repiration questions
Post by: StudentSS on Oct 16, 2011
2) in the presence of oxygen cells convert pyruvate into CO2 in the citric acid cycle which takes place inside the mitochondrial matrix,
as 1 pyruvate molecule enters 2 CO2 molecules are generated from the citric acid cycle. there is also a small intermediate step before the citric acid cycle that generates 2 total CO2.
Giving you a total of 6 CO2 being generated


Title: Re: cellular repiration questions
Post by: Pisiform on Oct 18, 2011
1) All cells can convert glucose into pyruvate. What cells do next depends on the availability of oxygen. What terms do we use to describe growth in the presence of oxygen and growth in the absence of oxygen?

Aerobic Respiration= Presence of oxygen; Anaerobic Respiration = absence of oxygen

2) In the presence of oxygen, what do cells do with pyruvate? Where does this occur?

Pyruvate goes into mitochondrial matrix where it is oxidized to Acetyl Coenzyme A which later goes into Krebs Cycle and oxidative phosphorylation.

3) In the absence of oxygen, what are two possible processes calls can use to produce ATP?

Fermentation and Glycolysis

4) In alcoholic fermentation, pyruvate is further broken down into what product?

NAD+ and ethanol.

5) When your muscle cells need to make ATP but are running low on oxygen, which process do they use?

Fermentation. Produced NAD+ to keep glycolysis running and produce Lactate which result in muscle fatigue.

6) Is yeast a prokaryote or a eukaryote? Why?

Yeast is a Fungi

7) Could pyruvate enter into the Krebs cycle in yeast?

Yes, yeast can respire both aerobically and anaerobically

 Does the krebs cycle/electron transport chain require oxygen?

Yes ...oxygen is must because the ETC has to give its electrons in the end to oxygen to make water.

9) Explain why  beer and wine are typically made in closed containers?

To make sure there is no aerobic respiration taking place.