C1.2 Cell respiration

What is ATP made of?

Adenine, ribose (RNA), 3 phosphate groups

What is the role of energy?

Supply immediate energy

What is the formula for ADP synthesis?

Hydrolysis: ATP + H₂O → ADP + Pi (inorganic phosphate)

Releases energy

What is the formula for ATP synthesis?

Condensation: ADP + Pi (inorganic phosphate) → ATP + H₂O

Makes ATP (needs energy)

What does ATP power inside cells?

1. Active transport: sodium/potassium pumps

2. Anabolism: synthesis of macromolecules

3. Movement of the whole cell

4. Movement of components within the cell e.g. chromosomes during mitosis and meiosis

What are the differences between aerobic and anaerobic respiration in humans?

• Aerobic requires oxygen, anaerobic doesn’t

• Aerobic happens in mitochondrion, anaerobic in cytosol

• Aerobic produces ~30 ATP, anaerobic produces 2 ATP

• Aerobic produces CO₂ + H₂O, anaerobic produces lactate

What is the difference between RNA nucleotides and ATP molecules?

• Both RNA and ATP contain ribose

• RNA contains 1 phosphate, ATP contains 3

• RNA contains nitrogenous bases A U C G, ATP contains A

What properties of ATP make it suitable for use as the energy currency in cells?

• ATP is soluble in water → it can move freely through cytoplasm and other aqueous solutions

• ATP is stable at pH levels close to neutral (pH 7)

• ATP cannot pass freely through phospholipid bilayer → cannot diffuse out of cell, plasma membrane keeps ATP inside

• Third phosphate group of ATP can easily be removed to produce ADP

• Hydrolysis of ATP into ADP and phosphate releases energy that is enough for many cellular processes

What is the formula for aerobic respiration?

Glucose + Oxygen → Carbon dioxide + Water + ATP

What is the formula for anaerobic respiration in plants/yeast?

Glucose → Carbon dioxide + Ethanol + ATP

What is the formula for anaerobic respiration in humans?

Glucose → Lactic acid + ATP

How to measure respiration?

• Speed = distance food dye travels / time

• Measure carbon dioxide production/oxygen intake

• Bubble/water level

• Absorb carbon dioxide/potassium hydroxide

What variables affect the rate of cell respiration?

• Temperature

• Oxygen availability

• Substrate type/concentration

• pH