Internal Membranes and Enzymes Flashcards
What is an enzyme?
A globular protein that increases the rate of a reaction without being used up itself.
Can a small amount of an enzyme catalyse a large amount of substrate?
Yes
As the concentration of enzymes or substrate increases…
the rate of enzyme action increases
Do enzymes lower the activation energy required for a reaction to take place?
Yes
What is the lock and key hypothesis
The shape of the enzyme is always complimentary to the shape of the substrate.
What is the induced fit hypothesis ?
The substrate doesnt always fit precisely into the active site.
What is the active site of an enzyme?
Where the substrate binds and carries a reaction.
What are factors that can affect the reaction rate of enzymes?
Temperature, pH, concentration.
What biochemical process is controlled by enzymes?
Photosynthesis. It occurs in the chloroplast in plant cells and uses light energy to synthesise organic compounds like glucose.
How do organisms obtain the energy needed to recycle ATP?
From glucose molecules in the process of cellular respiration.
What are the two stages of photosynthesis?
Light- dependent and light- independent reactions.
Explain light- dependent reactions
These take place in the pigment systems within the thykaloid sacs of the chloroplast. The chlorophyll pigment absorbs light energy. energy from sunlight is absorbed by chlorophyll and that energy is converted into stored chemical energy.
Explain light- independent reactions.
It does not need light energy. It occurs in the stroma and need the products of the light- dependent reaction. Hydrogen combines with carbon dioxide. the chemical energy harvested during the light-dependent reactions drives the assembly of sugar molecules from carbon dioxide.
What is the relationship between light- dependent and independent reactions?
The light dependent reactions use energy from the sun to produce ATP, and the light independent reactions use ATP from these light dependent reactions to produce high- energy sugars.
Explain cellular respiration features.
Energy is released. Involves oxidation of sugar through the assistance of enzymes for each step. Cellular respiration can be aerobic or anaerobic. Starts in the cytoplasm.
