B2.4 + 5 Organisms & their environment + Proteins

Question 1

Define a habitat

Answer 1

Where an organism lives

Question 2

Define distribution (of an organism)

Answer 2

Where an organism is found

Question 3

What environmental factors affect the distribution of organisms? (5)

Answer 3

• Temperature
• Water availability
• Oxygen and carbon dioxide availability
• Mineral availability
• Amount of light

Question 4

How are quadrats used to sample?

Answer 4

• 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

Question 5

How is a line transect used to sample?

Answer 5

• 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

Question 6

What is a line transect used for?

Answer 6

To examine a change in a habitat’s effect on a species’ distribution

Question 7

How are measurements of distribution made reliable?

Answer 7

• Making them repeatable and reproducible
• Taking a large sample size
• Using random samples (e.g random areas)

Question 8

How are measurements of distribution made valid?

Answer 8

By controlling all the environmental factors (other variables) other than the one you are testing.

Question 9

Describe the structure of proteins.

Answer 9

A chain of amino acids folded into a specific shape

Question 10

Name four types of proteins

Answer 10

• Catalysts
• Structural components of tissues
• Hormones
• Antibodies

Question 11

Define ‘catalyst’

Answer 11

A substance which increases the speed of a reaction without being changed or used up in the reaction

Question 12

What are enzymes?

Answer 12

Biological catalysts

Question 13

What does an enzyme’s shape have to do with its purpose?

Answer 13

• Every enzyme has a unique shape for a specific substrate

- They can only catalyse on reaction

Question 14

How do high temperatures affect enzymes?

Answer 14

They break the bonds between molecules in an enzyme, meaning its active site changes shape - it is denatured.

Question 15

What temperature do enzymes work best at in humans?

Answer 15

37 degrees C

Question 16

How does pH affect enzymes?

Answer 16

If too high/low it can interfere with the bonds between molecules in an enzyme, meaning its active site changes shape - it is denatured.

Question 17

What is the pH enzymes work best at?

Answer 17

Usually neutral 7, but not always e.g pepsin works best at pH 2 as the stomach is acidic

Question 18

What do digestive enzymes do?

Answer 18

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)

Question 19

What reaction does amylase act on?

Answer 19

Starch into glucose

Question 20

Where in the body is amylase produced?

Answer 20

• Salivary glands
• Pancreas
• Small increase

Question 21

What reaction does lipase act on?

Answer 21

Lipids into fatty acids and glycerol

Question 22

Where in the body lipase produced?

Answer 22

• Pancreas

- Small increase

Question 23

Where in the body pepsin produced?

Answer 23

• Stomach
• Pancreas
• Small intestine

Question 24

What reaction does pepsin act on?

Answer 24

Proteins into amino acids

Question 25

What effect do fatty acids have which amino acids don’t have?

Answer 25

They lower the pH

Question 26

What type of enzyme is amylase?

Answer 26

A carbohydrase enzyme

Question 27

What type of enzyme is pepsin?

Answer 27

A protease enzyme

Question 28

Name 4 uses of enzymes in the industry.

Answer 28

• Biological detergents
• Baby food
• Making sugar syrup
• Slimming foods

Question 29

How are enzymes used in biological detergents?

Answer 29

• Protease breaks down proteins in stains e.g grass, blood and sweat
• Lipase breaks down fat in stains e.g oil

Question 30

How are enzymes used in baby food?

Answer 30

Protease pre-digests the protein in the food as baby digestive systems aren’t fully developed to

Question 31

How are enzymes used in making sugar syrup?

Answer 31

Starch syrup is harvested cheaply from plants and broken down into sugar syrup

Question 32

How are enzymes used in slimming foods?

Answer 32

Glucose and fructose contain the same energy but less fructose is needed for the same sweetness.
glucose + isomerase —> fructose

Question 33

What are the advantages of using enzymes in industry?

Answer 33

• 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)

Question 34

What are the disadvantages of using enzymes in industry?

Answer 34

• 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

Question 35

What are immobilized enzymes?

Answer 35

Enzymes stuck onto a substance to stop them moving around e.g in alginate gel beads

Question 36

What are the advantages of immobilized enzymes?

Answer 36

• Reuseable
• Can be used at a higher temp.
• Cleaner/no contamination
• Continuous flow

Question 37

Where do enzymes used in industry come from?

Answer 37

They pass out of the cells of microorganisms

Question 38

What is a quadrat?

Answer 38

A square frame enclosing a known area