Cell Basics
Explain why plant cells have chloroplasts and animal cells don't
Plant cells have chloroplasts because they cannot eat food to obtain energy. Chloroplasts are where photosynthesis takes place to break down light and carbon dioxide into glucose.
Define active transport
Active transport is the movement of substances from an area of low concentration to an area of high concentration (against the concentration gradient). It requires the use of ATP.
Describe what an enzyme is
An enzyme is a globular protein which speeds up the rate of a chemical reaction.
Define homeostasis
Homeostasis is the state of a steady internal environment in response to external factors.
Compare the process of cellular respiration and photosynthesis
Photosynthesis: The process where Chloroplasts in a plant convert light and carbon dioxide to oxygen and glucose
Cellular respiration: Process where glucose is converted to ATP (energy medium for cells to use), oxygen and water
List three organelles present in plant cells and not animal cells
-Chloroplast
-Cell Wall
-Large vacuole
Define passive transport
Passive transport moves substances from an area of higher concentration to an area of lower concentration until equilibrium is reached. Does not require ATP.
Explain what the active site is on an enzyme
The part of an enzyme to which substrates bind and where a reaction is catalysed.
Identify three ways the body reactions to a cold external environment
1). Piloerection (hair muscles contract to pull hair up on arms)
2). Vasoconstriction (blood vessels constrict)
3). Body movement- shivering
Identify which part of this photosynthesis formula is glucose
6CO2 + 6H2O → C6H12O6 + 6O2.
C6H12O6
List three specialised plant cells
Palisade cell
Root hair cell
Storage cell
Enable certain substances to cross through the cell membrane e.g. water soluble substances, ions.
Enzyme and substrate will compliment each other in terms of shape. Substrate will fit into active site.
1). Hair muscles relax- hair lies flat against skin
2). Sweating- sweat excreted by sweat glands
3). Vasodilation: Blood vessels dilate
Name the three stages of cellular respiration.
1). Glycolysis
2). Krebs Cycle
3). Electron Transport Chain/ Oxidation Phosphorylation
Organelles: Eukaryotic cells contain membrane bound organelles
Size: Eukaryotic cells are 100 to 10,000 times larger than Prokaryotic cells
Complexity: Eukaryotic cells are more complex then Prokaryotic
What are the function of Glycoproteins and Glycolipids in the cell membrane?
Glycoproteins: Hydrophilic. Role is to help with cell recognition and communication.
Glycolipids: Lipid with carbohydrate attached. Role is to maintain stability of the cell membrane.
List three factors that affect enzyme activity?
Temperature
pH
Substrate concentration
Define ADH and describe the role it has on osmoregulation
ADH: Anti-diuretic hormone
- Synthesized in the hypothalamus and transported to the pituitary gland where it is stored
- (ADH) increases water reabsorption in the distal tubules and collecting ducts of the kidney
-Increases the permeability of water of the distal tubules and collecting ducts
Explain the difference between light independent and light dependent reactions in photosynthesis
Light Independent: The Calvin cycle takes place in the stroma of chloroplasts. It uses ATP and NADPH to convert carbon dioxide into glucose.
Light dependant: Occur in the thylakoid membrane of chloroplasts. ATP and NADPH are produced and used as energy carriers. They provide the necessary energy for the light-independent reactions.
What is the main function of the cell membrane?
It controls which substances exit and enter the cell
What is the name of the model used to represent the cell membrane structure?
Fluid mosaic model
Explain what enzyme denaturation is
Denaturation occurs when an enzyme loses it's conformation (shape/structure) making it unable to bind to the required substrate and catalyse.
Describe the steps the body takes in response to loss of water (blood volume increases)
Detected by special cells in the hypothalamus
These cells cause the pituitary gland to release more ADH
ADH travels in the blood to the kidney
At the kidney tubules, it causes the collecting ducts to become more permeable to water
This means more water is reabsorbed back into the blood
This makes the urine more concentrated, and the blood becomes more dilute.
Explain what the stromata is responsible for in plants
Gas exchange: Intake of carbon dioxide and disposal of oxygen as well as the loss of water vapour in transpiration