Topic 5– A: Photosynthesis and Respiration- 1. Photosynthesis, respiration and energy Flashcards
Why is energy important?
Plant and animal cells need energy for biological processes to occur
Why do plants need energy?
- Photosynthesis
- Active transport
- DNA replication
- Cell division
- Protein synthesis
Why do animals need energy?
- Muscle contraction
- Maintenance of body temperature
- Active transport
- DNA replication
- Cell division
- Protein synthesis
Respiration equation
Glucose + Oxygen= Carbon dioxide + Water + Energy
Anaerobic respiration (animals)
glucose -> lactic acid + energy
Anaerobic respiration (plants/ yeast)
Glucose-> ethanol + carbon dioxide + energy
What is the difference between aerobic and anaerobic respiration?
- aerobic respiration requires oxygen but anaerobic respiration doesn’t require oxygen
What is photosynthesis?
- It’s the process where energy from light is used to make glucose from water and carbon dioxide
- The light energy is converted to chemical energy in the form of glucose
Formula for glucose
C6H12O6
Photoautotroph
- Any organism that carries out photosynthesis
How long is energy stored in the glucose?
Until the plants release it by respiration
How do animals obtain glucose?
- By eating plants
- By eating animals which have eaten plants
How is energy released?
By respiring glucose
What is photosynthesis an example of ?
- metabolic pathway which occurs in a series of small reactions controlled by enzymes
What is respiration ?
Releasing energy from glucose
Examples of metabolic pathways
- aerobic and anaerobic respiration
What does ATP stand for?
Adenosine triphosphate (immediate source of energy in a cell)
Structure of ATP
- Adenine (nucleotide base)
- Ribose sugar
- 3 phosphate groups
How is ATP made?
- In respiration the energy released from glucose is used to make ATP
What does ATP do?
It carries energy around the cell to where it’s needed
Photosynthesis (equation)
Carbon dioxide + water + energy= glucose + oxygen
What is ATP synthesised via?
- A condensation reaction between ADP and inorganic phosphate (using energy from an energy-releasing reaction) e.g. breakdown of glucose in respiration
- Energy is stored as chemical energy in the phosphate bond (bond between phosphates)
- The enzyme ATP synthase catalyses this reaction
What is phosphorylation?
Adding phosphate to a molecule (ADP is phosphorylated to ATP)
What occurs when ATP is made?
- It diffuses to the part of the cell that needs energy
- Then it’s broken down back into ADP and inorganic phosphate where chemical energy is released from the phosphate bond and used by the cell
- ATP hydrolase catalyses this reaction.
(hydrolysis- splitting of a molecule using water
ATP properties
- can be quickly remade
- easily broken down so energy can be easily released
- It can make other molecules more reactive by transferring one of its phosphate groups to them (phosphorylation)
- small, soluble molecule so it can be easily transported around the cell
What is the energy released from glucose used to?
- It’s used to power all the biological processes in a cell
What dependant determines the rate at which photosynthesis takes place?
- Light intensity of the environment that the plant is in
What is the compensation point?
- Particular level of light intensity at which the rate of photosynthesis exactly matches the rate of respiration
How do you work out the compensation point?
- Measure the rate at which oxygen is produced and used by a plant at different light intensities
