B4

Question 1

The basic processes of life carried out by all living things depend on what?

Answer 1

Chemical reactions within cells that require energy (released by respiration)

Question 2

Describe phtosynthesis

Answer 2

A series of chemical reactions that use energy from sunlight to build large food molecules in plant cells and some micro-organisms (e.g. phytoplankton)

Question 3

Describe respiration

Answer 3

A chemical reaction that release energy by breaking down large molecules in all living things

Question 4

What is an enzyme?

Answer 4

They are biological catalyst that speed up the rate of reactions

Question 5

Where are enzymes made?

Answer 5

In the cytoplasm of the cell

Question 6

Cells make enzymes according to what?

Answer 6

The instructions carried in the genes

Question 7

Describe the lock and key model

Answer 7

Molecules have to be in the correct shape to fit the active sit of an enzyme. (essentially the substrate has to fit the active site)

Question 8

The specific constant temperature that enzymes need to work best is called what?

Answer 8

The optimum temperature

Question 9

If temperature gets too high, what happens to the enzyme?

Answer 9

The enzymes becomes denatured and will permanently stop working

Question 10

What is enzyme activity at different temperatures a balance between?

Answer 10

Increased rate of reaction as temperature increases and changes to the active site at higher temperatures which may lead to denaturing

Question 11

The pH at which the enzyme works best is known as what?

Answer 11

The optimum pH

Question 12

What happens to an enzyme if it is conditions are different to its optimum pH?

Answer 12

The active site can change shape and it may no longer work because the enzyme-substance complex cannot form

Question 13

State the word equation for photosynthesis

Answer 13

carbon dioxide + water and light energy = glucose +oxygen

Question 14

State the balanced symbol equation for photosynthesis

Answer 14

6CO2 +6H20_C6H12O6 +6O2

Question 15

Recall the three main stages of photosynthesis;

Answer 15

• Light energy is absorbed by the green chemical chlorophyll
• energy is used to bring about the reaction between carbon dioxide and water to produce glucose
• Oxygen is produced as a waste product

Question 16

Minerals taken up by the plant roots are used tom make what?

Answer 16

Chemicals needed by cells including nitrogen from nitrates to make proteins.

Question 17

Name the 6 structural features of a plant cell.

Answer 17

• Cell wall
• Vacuole
• Chloroplasts
• Cell membrane
• Cytoplasm
• Nucleus

Question 18

Describe the function of chloroplast

Answer 18

They contain chlorophyll and the enzymes for the reaction in photosynthesis

Question 19

Describe the function of the cell membrane

Answer 19

It allows gases and water to pass in and out of the cell freely while presenting a barrier to other chemicals

Question 20

Describe the function of the nucleus in a plant cell

Answer 20

It contains DNA, which carries the genetic code for making enzymes and other proteins in the chemical reactions of photosynthesis

Question 21

Describe the function of the cytoplasm in a plant cell

Answer 21

This is where the enzymes and other proteins are made

Question 22

Define diffusion

Answer 22

It is the passive overall movement of molecules from a region of higher concentration to a region of their lower concentration

Question 23

Define osmosis

Answer 23

It is the overall movement of water from dilute to more concentrated solution through a partially permeable membrane

Question 24

The movement of water into plant roots occurs by which process?

Answer 24

Osmosis

Question 25

Define active transport

Answer 25

Movement of chemicals across a cell membrane requiring energy from respiration( chemicals move against the concentration of the gradient)

Question 26

How do plant root absorb nitrates?

Answer 26

Using active transport

Question 27

The rate of photosynthesis may be limited by what three factors?

Answer 27

- Temperature - Carbon dioxide - Light intensity

Question 28

How is a light meter used in fieldworks?

Answer 28

A light meter is used to measure light intensity

Question 29

How is a quadrant used in fieldwork?

Answer 29

A quadrant is used to see how many animals or plants are present in a certain area

Question 30

How is identification key used in field works?

Answer 30

An identification key is used to identify species present in the fieldwork

Question 31

How do you take a transect?

Answer 31

A transect is straight line that runs through a location upon which data on organisms distribution can be recorded

Question 32

All living things require energy released by respiration, What are the three men uses of this energy?

Answer 32

- Movement - Synthesis of large molecules - Active transport

Question 33

Describe examples of the synthesis of large molecules

Answer 33

Synthesis of polymers required by plant cells such as starch and cellulose from glucose in plant cells. Synthesis of amino acids from glucose and nirates and then proteins from amino acids in plants , animals and microbial cells

Question 34

Aerobic respiration takes place in animal and plant cells as well as some micro-organisms : what does it require?

Answer 34

Oxygen ( and glucose)

Question 35

State the word equation for aerobic respiration

Answer 35

Glucose + oxygen = Carbon dioxide + water (energy released)

Question 36

Anaerobic respiration take place in condition of low or no oxygen. Give three examples of this.

Answer 36

1. In plant roots in water logged soil 2. In bacteria in puncture wounds 3. In humans cells during vigorous exercise

Question 37

State the word equation for anaerobic respiration in animals cells and some bacteria.

Answer 37

Glucose = lactic acid ( +energy released)

Question 38

What is the word equation for anaerobic respiration in plant cell and some micro-organisms

Answer 38

Glucose = ethanol + carbon dioxide(+ energy released)

Question 39

In terms of energy released per glucose molecule, what is the difference between aerobic and anaerobic respiration?

Answer 39

Aerobic respiration releases more energy per glucose molecule

Question 40

What are the 4 structural features of an animal cell?

Answer 40

- Cytoplasm - Cell membrane - Nucleus - Mitochondria

Question 41

What 5 structural features of a bacteria cell?

Answer 41

- Nucleus - Mitochondria - Cell wall - Cell membrane - Cytoplam

Question 42

What is the function of mitochondria in cells?

Answer 42

They contain enzymes for the reaction in aerobic respiration (in animals ,plants and yeast)

Question 43

What is the function of the cytoplasm?

Answer 43

It is where are made and it also contains the enzymes use in anaerobic respiration

Question 44

Describe the use anaerobic respiration in foods?

Answer 44

Anaerobic respiration takes place in yeast and some bacteria , producing ethanol and carbon dioxide . They have been used in the making of many foods such as bread , yoghurt and vinegar.

Question 45

Describe the use anaerobic respiration in fuels?

Answer 45

When fermentation is performed on larger scale using yeast, water sugar and some nutrients bio-ethanol can be used as a fuel.

Question 46

Describe the use anaerobic respiration in Biogas?

Answer 46

Bio gas is a fuel manufactured using animal manure ( and sometimes human waste) Biodegesters are used to convert the manure into bio gas. Bacteria inside the biodigester break down parts of the manure and produce methane gas. This can be used as a fuel to run generators and heat buildings. This method of fuel production is more commonly used in developing countries