Photosynthesis and Respiration Flashcards
What are the two types of respiration?
- Aerobic: requires oxygen, produces water and ATP
- Anaerobic: Absence of oxygen, produces lactate (in animals) and ethanol + CO2 (in plants), small amount of ATP produced
What are the four stages of aerobic respiration and where do they take place?
- Glycolysis - cytoplasm
- Link reaction - matrix (mitochondria)
- Krebs Cycle - matrix (mitochondria)
- Oxidative Phosphorylation/ETC - cristae (mitochondria)
Explain briefly the process of glycolysis
- Phosphorylation of glucose (6C)
- So 1 molecule of Glucose Phosphate is produced (6C)
- This splits into two Triose Phosphate molecules (3C each)
- For formation of pyruvate (3C) and formation of reduced NAD (by NAD collecting H+ ions)
- Total production 4 ATP / net production 2 ATP
What is the net production of ATP in glycolysis?
2 ATP molecules released
Explain the Link Reaction
- Pyruvate molecules produced in glycolysis are actively transported from cytoplasm to matrix
- The pyruvate (3C) is oxidised by removing hydrogen
- This hydrogen is accepted by NAD to from reduced NAD
- Acetyl group (2C) formed from pyruvate combines with co enzyme A to produce acetylcoenzyme A
- A CO2 molecule is formed
What is the equation for the Link Reaction?
Pyruvate + NAD + CoA > acetyl CoA + reduced NAD + CO2
Summarise the Krebs Cycle
- Acetylcoenzyme A combines with a 4-carbon molecule to form a 6 carbon-molecule
- NAD is reduced to NAD and CO2 is released causes a %-carbon molecule to form
- x2 NAD & x1 FAD is reduced again to form reduced x2 NAD & x1 FAD and a single molecule of ATP is produced
Apart from respiration, give three uses of ATP in a liver cell
- Active Transport
- Phagocytosis
- Mitosis
- Synthesis
Explain what happens to pyruvate in anaerobic conditions
In animals: forms lactate
In plants; forms ethanol and CO2
Both: use reduced NAD regenerated to produce NAD so glycolysis can be continued and small amounts of ATP can be produced
Name the four products of the Krebs Cycle
- ATP
- CO2
- Reduced NAD
- Reduced FAD
Describe the part played by the inner membrane of the mitochondrion in producing ATP
- Electrons are transferred down ETC which provides energy top take protons into space between membranes.
- Protons then pass back through membrane (through ATP Synthase)into matrix and energy is used to combine ADP and phosphate (Pi) to produce ATP
Give two advantages of ATP as an energy-storage molecule in a cell
- Cannot pass out of cell
- Quick, single reaction to release energy
- Releases small, manageable amounts of energy at any one time
Name the two stages in Aerobic Respiration where CO2 is produced
- Links Reaction
2. Krebs Cycle
What is the equation for Photosynthesis?
6CO2 + 6H20 + Energy > C6H12O6 +6o2
What is the process of photosynthesis an example of?
A metabolic pathway- a series of small reactions controlled by enzymes
How do animals obtain glucose?
By eating plants or eating other animals, then respire the glucose to release energy
Why do plants and animal cells need energy?
For biological processes to occur
What is any organism that carries out photosynthesis known as?
As a ‘photoautotroph’ (can make its own food using light energy)
What is the equation for Respiration?
C6H12O6 + 602 > 6CO2 + 6H2O + Energy
What does ATP stand for?
Adenosine triphosphate
How is ATP synthesised?
Ina condensation reaction between ADP and inorganic phosphate (Pi) using energy from an energy-releasing reaction (e.g the breakdown of glucose)
Which enzyme catalyses the synthesis of ATP?
ATP synthase
Give three properties of ATP?
- It’s a small, soluble molecule so it can be easily transported around the cell
- Releases small, manageable amount of energy at a time
- It’s easily broken down, takes a single reaction
What is the ‘Condensation point’ for light intensity?
There’s a particular level of light intensity at which the rate of photosynthesis exactly matches the rate of respiration
What is the unit that can be used when measuring light intensity?
m-2 s-1 (u moles)