Fuels and Biofuels: Cellular Biosystems; Cellular Respiration Flashcards
What is the word equation of aerobic respiration? Where does this occur?
- Glucose + Oxygen —> Carbon dioxide + Water + ATP
- Mitochondria
How is aerobic respiration controlled?
By a sequence of enzyme controlled reactions
How many ATP molecules are produced per molecule of glucose metabolised?
38 ATP molecules
What percent of the energy extracted from aerobic respiration is wasted and as what?
60% is wasted as heat
What is anaerobic respiration? Where does it occur?
- Cellular respiration where there is no O2
- Cytosol
What kind of reaction is aerobic respiration? Explain why it is this kind of reaction
- Redox reaction
- Glucose gets oxidised (loses electrons and hydrogens) and forms CO2 and Oxygen is reduced (gaining electron and hydrogens) to from H2O
What is the importance of O2 in cellular respiration?
It neutralises the H+ that is created from the breakdown of glucose preventing the cell from increasing in pH and denaturing its proteins
What are the three main cycles of cellular respiration? Outline each one
- Glycolysis: break down of glucose into two pyruvic acid molecules (FYI 2 ATP produced)
- Krebs cycle: breaks down pyruvic acid (FYI 2 ATP)
- Electron transfer: energy from electrons, produced by breakdown of pyruvic acid produce bulk of ATP (FYI 34 ATP)
What does glyco and lysis mean? How does it relate to the process it undertakes?
- Sugar split
- It is the breaking down of glucose
What are the two main phases of glycolysis?
Energy investment phase and energy harvest phase
What is the energy investment phases?
Where the glucose uses 2 ATP molecules to slit into a 3-carbon phosphate sugar
What is the energy harvest phase?
When the NADH (high energy electron carriers) transfer the H+ into the mitochondria to form H2O
What are the inputs and outputs of glycolysis?
Input: 2 ATP, 2 NAD+
Output: 2 pyretic acid, 4 ATP (∴ 2 net), 2 NADH
What is the function of the krebs cycle?
It completes the energy extraction of glucose
What is the step before the krebs cycles but after glycolysis? What is the purpose of this?
- The transition stage
- To produce acetic acid acetyl-CoA (Acetyl coenzyme A)
What happens to acetyl-CoA in the krebs cycle?
It bonds with oxaloacetic acid to form citric acid
What is extracted from citric acid that is useful for respiration?
ATP (final product, FYI 2 of them), NADH (6 of them FYI) and FADH2 (2 of them FYI)
What are the products of the krebs cycle that go to what final step in aerobic respiration?
The NADH and FADH2 go into the electron transfer step
What occurs in the electron transfer stage?
High energy electrons are passed form molecule to molecule (in a series of redox reactions) that then energise protein pumps to pump hydrogen ions against the concentration gradient into the space between the inner and outer membrane of mitochondria
How are the high energy electrons released?
NADH is converted into NAD+ (releasing a hydrogen and two electrons) and FADH2 is converted into FAD (releasing two protons and two electrons) by a series of redox reactions controlled by enzymes
How does pumping hydrogen ions against the concentration gradient produce energy?
The hydrogen ions have potential energy and are forced through an enzyme complex on the inner mitochondrial membrane that then uses the energy of this ion gradient to generate ATP from ADP
How many ATP are produced per NADH and FADH2?
3 per NADH
2 per FADH2
What process in anaerobic respiration that is different from aerobic respiration?
Pyruvate is broken down into lactic acid (instead of acetyl-CoA
Why does pyruvate turn into lactic acid?
In order to free up the NADH, that transferred electron to form lactic acid, to turn back into NAD+ allowing for continual production of ATP
What property of anaerobic respiration makes it limited?
As lactic acid builds up the pH decreases which causes other cellular reactions to stop (e.g. acidifies the cell)
How is lactic acid removed from the body?
Once oxygen is available the lactic acid is converted back into pyruvate where it is then used for aerobic respiration