Topic 12 - Respiration Flashcards
What is the purpose of respiration?
To release energy from glucose
To produce ATP
What is the general equation for aerobic respiration?
6O2 + C6H12O6 –> 6H20 + 6CO2 + energy
What do plants need energy for? (name 5)
Photosynthesis
Active transport of minerals via roots
DNA replication
Cell division
Protein Synthesis
What do animals need energy for? (name 6)
Muscle contraction
Maintaining a constant body temperature
Active transport
DNA replication
Cell division
Protein synthesis
What is the chemical name for ATP?
Adenosine triphosphate
What are the 3 components of ATP
1 molecule of adenine
1 molecule of ribose
3 molecules of phosphate ions
How is ATP formed?
Condensation reaction between ADP and Pi
Catalysed by ATP synthase
Which enzyme catalyses the condensation reaction between ADP and Pi
ATP synthase
What is phosphorylation
Adding phosphate to a molecule
How does ATP move through the cell
Diffusion
Which enzyme catalyses the hydrolysis of ATP?
ATP hydrolase
What are the 6 properties of ATP
1) Stores and releases small amount of energy so none wasted as heat
2) Small, soluble molecules so easily transported
3) Easily hydrolysed so energy releases instantly
4) Quickly resynthesised
5) Make other molecules more reactive (phosphorylation)
6) Can’t pass out of cell so immediate energy supply
What is the compensation point?
The level of light intensity (in plants) where the rate of respiration and photosynthesis are the same
How could you find a plants compensation point
Plot a graph of light intensity against net oxygen production. Find the light intensity when the new oxygen production = 0
What are 3 differences between aerobic and anaerobic respiration?
- Aerobic uses oxygen, anaerobic doesn’t
- Aerobic has 4 stages, anaerobic just has glycolysis
- Aerobic produces CO2 and H2O , anaerobic produced lactic acid (animals) and ethanol (yeast)
Where does glycolysis occur?
Cell cytoplasm
Which 3 coenzymes are used in aerobic respiration?
NAD, FAD, coenzyme A
Which stage of respiration is an anaerobic process and why?
Glycolysis
Uses no O2
What are the 2 stages of glycolysis?
- Phosphorylation of glucose
- Oxidation of triose phosphate
What is the purpose of glycolysis?
To produce pyruvate from glucose
Describe what happens when glucose is phosphorylated? (3 stages)
- ATP donates Pi to glucose to from glucose phosphate (and ADP)
- ATP donates Pi to glucose phosphate to form hexose bisphosphate (and ADP)
- Hexose bisphosphate split to form 2 molecules of triose phosphate
Describe what happens when 2 molecules of triose phosphate is oxidised?
2 molecules of triose phosphate are oxidised to 2 molecules of pyruvate
2 molecules of NAD are reduced to form reduced NAD
4 molecules of ATP are produced from 4 molecules of ADP/Pi
What is the net production of ATP in glycolysis?
2 ATP
2 used and 4 produced
What is the reduced NAD produced in glycolysis used for?
Oxidative phosphorylation
What is the pyruvate produced in glycolysis used for?
Actively transported into the mitochondrial matrix
Link reaction
Why does glycolysis take place in the cytoplasm?
Glucose can’t cross the mitochondrial membrane because it is too big
Describe the process after glycolysis in yeast/plants (2 stages)
- Pyruvate loses CO2 to form ethanal
- Ethanal reduced to ethanol and reduced NAD oxidised to NAD
What is the purpose of anaerobic respiration?
To produce ATP by glycolysis
Oxidises reduced NAD from glycolysis to NAD to allow glycolysis to continue
Describe the process of glycolysis in animal cells / some bacteria
Pyruvate reduced to lactate (lactic acid)
Reduced NAD oxidised to form NAD
Where does the link reaction occur?
Matrix of the mitochondria
What is the purpose of the link reaction
To convert pyruvate to acetyl coenzyme A
Describe what happens during the link reaction
- Pyruvate is decarboxylated to form acetate
2a. Pyruvate is oxidised to acetate
2b. NAD is reduced to reduced NAD - Coenzyme A combines with acetate to form acetyl coenzyme A
Where is the acetyl coenzyme A used
Krebs cycle
Where is the reduced NAD used?
Oxidative phosphorylation
What happens to the CO2 produced in the link reaction
lost as a waste product
What happens in the Krebs cycle
ATP and reduced coenzymes are produced in a series of redox reactions
CO2 is lost as a waste product
Where does the Krebs cycle take place
Matrix of the mitochondria
Describe what happens in the Krebs cycle
- Acetyl CoA reacts with 4 carbon compound to form a 6 carbon compound and coenzyme A
- The 6 carbon compound forms a 5 carbon compound
- The 5 carbon compound reforms the 4 carbon compound
What is substrate level phosphorylation?
When a phosphate group is directly transferred from one molecule to another
e.g. the production of ATP in the Krebs cycle
What is the CoA produced in the Krebs cycle used for?
The link reaction
What are the reduced enzymes produced in the Krebs cycle used for?
Oxidative phosphorylation
What is oxidative phosphorylation
The process where energy from electrons form reduced coenzymes is used to synthesise ATP
Describe the stages of oxidative phosphorylation
- NAD/FAD release H atoms (split to H+ and e-)
- Electrons move down the ETC and lose energy at each electron carrier
- Energy used to actively transport protons into inter membrane space from mitochondria matrix (forms electrochemical gradient)
- Protons move down electrochemical gradient into matrix via ATP synthase
- The protons and electrons combine with oxygen to form water
What is the importance of oxygen in aerobic respiration
Final electron acceptor in oxidative phosphorylation
