B4 Flashcards
What are enzymes?
Proteins - they consist of long chains of amino acids
What do enzymes do?
Speed up reactions. They are biological catalysts
What is the active site of an enzyme and what does it do?
It is where the enzyme breaks down the substrate
Describe how enzymes break down substrates
Each enzyme has an active site designed to breaks down a specific substrate
The substrate goes into the active site (like a key in a lock)
The reaction occurs and breaks down the substrate
The products are then released from the active site and used by the body
What is denaturing?
When the pH or temperature are too high, the active site permanently changes shape, so it cannot perform the reaction as the substrate doesn’t fit
What is the word equation for photosynthesis?
carbon dioxide + water –> glucose + oxygen
Why can photosynthesis only take place during the day?
Light energy is used to turn the two reactants into the products, without the sun the reaction can’t take place
What is glucose used for in plants?
Turned into chemicals so the plant can grow such as cellulose, chlorophyll, protein
Converted into starch for storage
Used in respiration to get energy
What makes up a human cell and what does each part do?
Nucleus - stores genetic information
Cytoplasm - where anaerobic respiration takes place
Cell Membrane - allows gases and water in and out
Mitochondria - where aerobic respiration takes place
What makes up a plant cell what does each part do?
Nucleus - stores genetic information
Cytoplasm - where anaerobic respiration takes place
Cell Membrane - allows gases and water in and out
Mitochondria - where aerobic respiration takes place
Cell Wall - lets water and chemicals into the cell
Vacuole - gives the cell structure
What makes up a bacterium cell what does each part do?
Circular DNA - stores genetic information
Cytoplasm - where anaerobic respiration takes place
Cell membrane - allows gases and water in and out
Cell wall - lets water and chemicals into the cell
Flagella - allows the cell to ‘swim’ around
What is diffusion?
A chemical moves from HIGH concentration to LOW concentration
It’s a passive process
How do plants use diffusion?
Carbon dioxide and oxygen moving in and out of leaves
What is osmosis?
It is a special type of diffusion involving water
Water moves from HIGH concentration to LOW concentration through a partially permeable membrane
It’s a passive process
Describe osmosis in terms of concentration
It is the movement of a DILUTE solution to a CONCENTRATED solution
How do plants use osmosis?
Water into plant roots from soil and across the roots
What is active transport?
The movement of chemicals across membranes into a plant
It requires energy from the plant
How do plants use active transport?
To absorb nitrates from the soil as they are in a higher concentration in the soil than in the plant
How can the rate of photosynthesis be limited?
By temperature, levels of carbon dioxide and light intensity
After identifying the limiting factor, how would you over come it?
You would increase it e.g. if light was the limiting factor for the plants you were growing, you would increase the light again
Why could temperature also end up decreasing rate of photosynthesis?
As it can lead to the enzymes in the plants being denatured
What do ecologist so to assess the effects of light intensity on an area?
Use an identification key to identify plants
Measure how common the plants are
Use a light metre to measure the light intensity
What is a quadrat used for?
To create samples to help ecologist estimate how many plants are in a selected area
What organisms respire?
All organisms respire
Where is the glucose in respiration in humans come from?
Starch broken down into glucose and raw glucose come from our food
Name the respiration that uses oxygen
Aerobic respiration
What is the word equation for aerobic respiration?
glucose + oxygen → carbon dioxide + water (+energy)
How is excess glucose stored?
As starch
How does respiration take place?
As a series of enzyme controlled reactions with energy being release in stages
Name the respiration that does not use oxygen
Anaerobic respiration
What is the word equation for anaerobic respiration?
glucose → lactic acid (+energy)
Which type of respiration is more efficient?
Aerobic
How is lactic acid broken down?
By blood flowing through fatigued musckes and providing enough oxygen to break it down into glucose
What is fermentation?
A type of anaerobic respiration used by micro-organisms
How can fermentation be useful to us?
Yeast fermentation is used to help bread rise
It also creates ethanol which we can use for a preservative, fuel and disinfectant
What is the word equation for fermentation?
glucose → ethanol + carbon dioxide (+energy)
