B4 - The processes of life Flashcards
What is photosynthesis?
A series of chemical reactions that USES ENERGY from SUNLIGHT to PRODUCE FOOD.
What vital role does photosynthesis play in?
Making energy available to organisms through food chains.
What is respiration?
A series of chemical reactions that RELEASE ENERGY by breaking down large FOOD MOLECULES. It happens in EVERY LIVING CELL.
At night, what do plants do?
During the day, what do plants do?
They respire only and give out Carbon Dioxide.
During the the day, plants photosynthesise as well as respire. There will be a net output of oxygen.
What are enzymes?
Proteins that SPEED UP CHEMICAL REACTIONS.
What do enzymes consist of?
Long chains of AMINO ACIDS joined together.
Cells make enzymes according to…?
the INSTRUCTIONS carried in GENES.
What are SUBSTRATES?
The chemicals that enzymes work on.
What are PRODUCTS?
The chemicals produced in a reaction.
What does the Lock and Key Model show?
That molecules (substrates) have to be the correct shape to fit into the ACTIVE SITE of the enzyme.
What two factors affect the performance of enzymes?
pH and TEMPERATURE
If the pH is inappropriate or the temperature is too high, what will happen to the enzymes?
They will DENATURE (stop working).
What is the optimum temperature of MOST enzymes?
37 C
As the temperature increases, what happens to the enzyme activity and why does this happen?
As the temperature increases, enzyme activity INCREASES because the reaction rate INCREASES.
What can high temperatures do to enzymes?
It can change the shape of the active site of the enzyme. At a point where the change in shape is permanent, the enzyme has been denatured.
What can pH do to enzymes?
It also affects enzyme activity by change the shape of the active site. It can either be temporary or permanent.
What is the WORD equation for photosynthesis?
Carbon Dioxide + Water — (light energy) → Glucose + Oxygen
What is the SYMBOL equation for photosynthesis?
6CO2 + 6H2O – (light energy) → C6H12O6 + 6O2
What are the main stages of photosynthesis (3) ?
- Light energy absorbed by the green chemical chlorophyll
- Energy used to bring about the reaction between carbon dioxide and water to produce glucose (sugar)
- Oxygen produced as a waste product
What are 3 uses of glucose in plants?
- Converted into chemicals (e.g. cellulose, proteins, chlorophyll) needed for growth of plant cells
- Converted into starch for storage
- Used in respiration to release energy
What are the 7 components in the structure of a plant cell?
Cell membrane, cell wall, cytoplasm, nucleus, chloroplasts, mitochondria, large vacuole
What do chloroplasts contain in a plant cell?
They contain chlorophyll and the enzymes for the reactions in photosynthesis
What does the cell membrane allow in the cell?
Allow gases and water to pass in and out of the cell freely while presenting a barrier to other chemicals.
What does the nucleus contain in the cell?
DNA which carries the genetic code for making enzymes and other proteins used in the chemical reactions of photosynthesis
What is the cytoplasm represent in the plant cell?
A jelly-like fluid where the enzymes and other proteins are made. It contains enzymes used in anaerobic respiration.
What do the mitochondria do in the cells?
Contains enzymes needed for the reactions of AEROBIC RESPIRATION.