Respiration Flashcards
What is ATP?
Adenosine Triphosphate
- universal energy currency which can be hydrolysed to form ADP + Pi to release manageable amounts of energy
How is ATP made?
- Substrate level phosphorylation (glycolysis + krebs cycle)
- Oxidative Phosphorylation (ETC)
What are the 4 steps of Respiration?
- Glycolysis
- Link Reaction
- Krebs Cycle
- OxPhos (ETC)
What is the role of oxygen in aerobic respiration?
Final electron acceptor - if oxygen is not present, whole system collapses
Where does Glycolysis occur?
cytoplasm
What are the 3 stages of glycolysis?
- Phosphorylation - Glucose phosphorylated to form hexose bisphosphate (6C) forms 2 ADP
- Splitting - hexbis forms 2TP
- Oxidation - 4ATP made ,2 NADH made from 2 NAD (done via dehydrogenase enzymes)
forms 2xPYRUVATE
(technically 4ATP made from the 2TP but since 2 were put in at the start that means there is only a net gain of 2ATP)
Where does link reaction occur?
mitochondrial matrix
What are the products of link reaction?
- 1 NADH
- 1 CO2
- Acetyl Coenzyme A
(Acetyl CoA)
(Pyruvate dehydrogenase is the enzyme responsible for decarboxylating and then dehydrogenating the pyruvate so it becomes an acetyl group)
(despite the acetyl coA complex being formed, only acetyl enters the krebs cycle
Where does Krebs Cycle occur?
mitochondrial matrix
What are the products of the Krebs Cycle (1 turn)
- 1 ATP
- 3 NADH
- 1 red. FAD
- 2 CO2
What occurs during OxPhos?
- H+ ion are pumped into intermembrane space via electron transport chain
- Create an H+ gradient for chemiosmosis to occur
- H+ ions move via a channel protein to an ATP synthase molecule where ADP and Pi are condensed to form ATP
Whats the difference between aerobic and anaerobic respiration?
- Aerobic = presence of oxygen, includes link, krebs and OxPhos
- Anaerobic = no presence of oxygen, doesn’t include link, krebs, and OxPhos
GLYCOLYSIS for both though
What is the product of anaerobic respiration in animals ?
lactate
What is the product of anaerobic respiration in fungi / plants?
ethanol
What is the progression of molecules being formed in the krebs cycle?
acetyl group (2C) - (add oxaloacetate (4C) ) citrate (6C) - (loses CO2 + form NADH) 5C compound - (loses CO2 + forms NADH) 4C compound - form ATP (ADP + Pi) 4C compound - (form red. FAD) 4C compound - form NADH oxaloacetate (4C)
6C compound for 1 step
5C compound for 1 step
4C compound for 3 steps
What is the definition of oxidative phosphorylation?
the formation of ATP by oxidising reduced NAD AND FAD in the presence of oxygen and the proteins of the electron transport chain
What is the definition of chemiosmosis?
the flow of protons down a concentration gradient through an ATP synthase molecule
Why is water formed after OxPhos ?
The excess H+ ions from the chemiosmosis part react with the final electron acceptor O2 to form H2O
What is the word equation for anaerobic respiration in animals?
pyruvate + NADH -> lactace + NAD
What is the word equation for anaerobic respiration in plants?
pyruvate -> ethanal (CO2 given off)
ethanal + NADH -> ethanol + NAD
what is a special property of yeast?
it is a facultative anaerobe
- can respire aerobically or anaerobically depending on surroundings
Experiment for Yeast
- Grow Yeast in 2 conditions- with oxygen and without
- leave for 1 day
- measure cell density
- use a haemocytometer to count how many yeast cells are in it
Why is a double respirometer used instead of a single respirometer?
Acts to control external variables such as temperature
- if you were to increase temperature, pressure would also increase, therefore making the fluid in the respirometer move differently.
- however, with a double respirometer setup, both tubes expand / contract pressure equally, negating this change entirely.
How do you calculate RQ?
respiratory quotient
CO2 given out / O2 taken in
What is RQ value of carbohydrates?
1
RQ value of protein?
0.9 (roughly)
RQ value of lipid?
0.7 (roughly)
What happens to RQ value when anaerobic respiration is occuring?
It increases to more than 1
