Enzymes
What is an enzyme and what type of molecule is it?
An enzyme is a biological catalyst made of protein. It speeds up chemical reactions in the body without being used up.
What is the overall word equation for photosynthesis.
Carbon dioxide + water → glucose + oxygen
Write the overall word equation for aerobic respiration.
Glucose + oxygen → carbon dioxide + water
This organelle is the site of protein synthesis, reading mRNA to assemble amino acid chains. What is it?
A ribosome.
What does "selectively permeable" mean in relation to the cell membrane?
Selectively permeable means the membrane allows some substances to pass through but not others. This helps the cell control its internal environment.
What is meant by an enzyme's "active site"?
The active site is the specific region of an enzyme where the substrate binds. Its shape is complementary to a particular substrate.
6CO2 + 6H2O --> C6H12O6 + 6O2
What is the difference between aerobic and anaerobic respiration?
Aerobic respiration uses oxygen.
Anaerobic respiration occurs without oxygen.
This organelle is where aerobic respiration occurs, What is it?
Mitochondira
What is the difference between diffusion and osmosis?
Diffusion is the movement of any substance from high to low concentration. Osmosis is specifically the movement of water across a selectively permeable membrane from high to low water concentration.
What happens to enzyme activity if the temperature rises well above the optimum?
The enzyme denatures — the active site changes shape so the substrate can no longer bind. The enzyme permanently loses its function.
In which part of the chloroplast does the light-dependent stage occur?
The light-dependent reactions occur in the thylakoid membranes
What happens during glycolysis?
Glycolysis occurs in the cytoplasm and breaks one glucose molecule into two pyruvate molecules.
What is the function of the cell vacuole?
The vacuole stores water, nutrients, and waste products
How does facilitated diffusion differ from active transport?
Facilitated diffusion uses channel or carrier proteins to move substances down their concentration gradient — no energy needed. Active transport uses protein pumps and ATP to move substances against their concentration gradient.
Explain how competitive inhibition differs from non-competitive inhibition.
A competitive inhibitor binds to the active site, directly blocking the substrate. A non-competitive inhibitor binds elsewhere on the enzyme, changing the active site's shape so it works less effectively.
What are the two stages of photosynthesis and what happens at each stage?
The light-dependent stage - light energy is captured and used to split water.
The light-independent stage converts H and CO₂ into glucose.
What are the different products of anaerobic respiration in humans compared to yeast?
This organelle is found only in plant cells and photosynthesis occurs here. What is it?
Chloroplast
Explain what happens to an animal cell placed in a very hypotonic solution.
Water moves into the cell.
Describe and explain the shape of the graph that would show enzyme activity as the concentration of substrates increases.
Where do the different stages of photosynthesis occur?
Dependent - Thylakoid
Independent - Stroma
What does ATP stand for and what does it do?
Adenosine Tri Phosphate - Provides useful energy to cells.
This organelle uses digestive enzymes used to break down waste materials, damaged organelles, and foreign substances. What is it?
A lysosome.
What is the main component of the cell membrane?
Phospholipids.