B2.4 + 5 Organisms & their environment + Proteins Flashcards
Define a habitat
Where an organism lives
Define distribution (of an organism)
Where an organism is found
What environmental factors affect the distribution of organisms? (5)
- Temperature
- Water availability
- Oxygen and carbon dioxide availability
- Mineral availability
- Amount of light
How are quadrats used to sample?
- Place the quadrat on a random area of ground (coordinates = generated by a computer to avoid bias)
- Count all the organisms within the habitat
- Repeat and take an average
How is a line transect used to sample?
- A line is drawn through the area to be examined using a tape measure forming a transect
- Quadrats are placed along the line at regular intervals (e.g every metre)
- The number of species within every quadrat are counted
- This is repeated except with the transect a metre up
What is a line transect used for?
To examine a change in a habitat’s effect on a species’ distribution
How are measurements of distribution made reliable?
- Making them repeatable and reproducible
- Taking a large sample size
- Using random samples (e.g random areas)
How are measurements of distribution made valid?
By controlling all the environmental factors (other variables) other than the one you are testing.
Describe the structure of proteins.
A chain of amino acids folded into a specific shape
Name four types of proteins
- Catalysts
- Structural components of tissues
- Hormones
- Antibodies
Define ‘catalyst’
A substance which increases the speed of a reaction without being changed or used up in the reaction
What are enzymes?
Biological catalysts
What does an enzyme’s shape have to do with its purpose?
- Every enzyme has a unique shape for a specific substrate
- They can only catalyse on reaction
How do high temperatures affect enzymes?
They break the bonds between molecules in an enzyme, meaning its active site changes shape - it is denatured.
What temperature do enzymes work best at in humans?
37 degrees C
How does pH affect enzymes?
If too high/low it can interfere with the bonds between molecules in an enzyme, meaning its active site changes shape - it is denatured.
What is the pH enzymes work best at?
Usually neutral 7, but not always e.g pepsin works best at pH 2 as the stomach is acidic
What do digestive enzymes do?
To break down molecules too big to pass through the wall of the digestive system (e.g proteins/starch/fat) smaller molecules that can (e.g amino acids/glucose/fatty acids/glycerol)
What reaction does amylase act on?
Starch into glucose
Where in the body is amylase produced?
- Salivary glands
- Pancreas
- Small increase
What reaction does lipase act on?
Lipids into fatty acids and glycerol
Where in the body lipase produced?
- Pancreas
- Small increase
Where in the body pepsin produced?
- Stomach
- Pancreas
- Small intestine
What reaction does pepsin act on?
Proteins into amino acids
What effect do fatty acids have which amino acids don’t have?
They lower the pH
What type of enzyme is amylase?
A carbohydrase enzyme
What type of enzyme is pepsin?
A protease enzyme
Name 4 uses of enzymes in the industry.
- Biological detergents
- Baby food
- Making sugar syrup
- Slimming foods
How are enzymes used in biological detergents?
- Protease breaks down proteins in stains e.g grass, blood and sweat
- Lipase breaks down fat in stains e.g oil
How are enzymes used in baby food?
Protease pre-digests the protein in the food as baby digestive systems aren’t fully developed to
How are enzymes used in making sugar syrup?
Starch syrup is harvested cheaply from plants and broken down into sugar syrup
How are enzymes used in slimming foods?
Glucose and fructose contain the same energy but less fructose is needed for the same sweetness.
glucose + isomerase —> fructose
What are the advantages of using enzymes in industry?
- They’re specific, catalysing the reaction you want them to.
- They speed up reactions without the need for high pressures and temperatures, lowering cost and saving energy.
- They work for a long time, after initial cost you can continually use them.
- They are biodegradable (less environmental pollution)
What are the disadvantages of using enzymes in industry?
- Some people can develop allergies to them
- Expensive to produce
- Need tightly controlled conditions as even small changes can denature them
- Contamination with other substances can affect reaction
What are immobilized enzymes?
Enzymes stuck onto a substance to stop them moving around e.g in alginate gel beads
What are the advantages of immobilized enzymes?
- Reuseable
- Can be used at a higher temp.
- Cleaner/no contamination
- Continuous flow
Where do enzymes used in industry come from?
They pass out of the cells of microorganisms
What is a quadrat?
A square frame enclosing a known area
