Topic 2

Question 1

What are the 3 main biological molecules?

Answer 1

• Carbohydrates
• Lipids
• Proteins

Question 2

What are carbohydrates made up of?

Answer 2

Molecule made from carbon, hydrogen and oxygen.

Question 3

What is the function of carbohydrates?

Answer 3

Carbohydrates provide energy (plants use glucose for cellulose cell walls and starch to store energy. Glycogen is stored as energy in the liver for animals)

Question 4

What are the tests for carbohydrates?

Answer 4

• Benedicts Solution (blue -> red, reverse rainbow simple chains of glucose)
• Iodine test (orange/brown -> blue/black for starch)

Question 5

What are lipids made of?

Answer 5

Molecule made from carbon, hydrogen and oxygen, plus 3 fatty acids joined tot a glycerol molecule.

Question 6

What is the function of lipids?

Answer 6

Energy-dense molecules. Fat stored under skin is adipose tissue (insulates). Used to produce cell membranes and hormones. Plants store oil in seeds.

Question 7

What is the test for lipids?

Answer 7

Ethanol emulsion test (positive result = milky white emulsion)

Question 8

What is a solid fat?

Answer 8

Saturated fats

Question 9

What is a lipid fat?

Answer 9

Oils (unsaturated)

Question 10

What is a protein made of?

Answer 10

Molecule made from carbon, hydrogen, oxygen and nitrogen (sometimes sulfur). Made from long chains of amino acids.

Question 11

What is the function of proteins?

Answer 11

Proteins are used to make new proteins or enzymes. They are used for growth and cell repair of cells. They are used to make antibodies.

Question 12

What is the test for proteins?

Answer 12

Biuret test (blue -> purple)

Question 13

Enzymes:

Answer 13

Made of proteins (folded amino acid chains). Biological catalysts that speed up the rate of a chemical reaction without being used/altered.

Question 14

What determines the shape of the active site?

Answer 14

The folding of amino acid chains.

Question 15

What would happen without enzymes?

Answer 15

Living cells would have reactions that are necessary for the key life processes, take too long, therefore resulting in death.

Question 16

What is the induced fit model?

Answer 16

When the substrate is not complimentary to the shape of the active site, but is very close to the complimentary sites shape. It is still capable of binding to the enzyme and inducing the active site to change.

Question 17

What binds to the active site?

Answer 17

Substrates.

Question 18

What is the structure called when the enzyme is attached to substrates?

Answer 18

Substrate-enzyme complex.

Question 19

Factors affecting enzymes:

Answer 19

• Temperature (higher eK = more chance of binding)
• pH level (active site shape is influenced by pH)

Question 20

What is photosynthesis?

Answer 20

The process by which plants synthesise carbohydrates from raw materials using energy from light.

Question 21

Word equation for photosynthesis:

Answer 21

water + carbon dioxide -> glucose + oxygen (in the presence of light and chlorophyll.

Question 22

Balanced equation for photosynthesis:

Answer 22

6CO2 + 6H2O - > C6H12O6 + 6O2

Question 23

What is chlorophyll?

Answer 23

The green pigment (protein) found in chloroplasts and catalyses the reaction. Chlorophyll transfers energy from light into energy in chemicals, for synthesis of carbohydrates.

Question 24

5 uses of carbohydrates in plants:

Answer 24

1. Stored in plants as starch
2. Used for respiration
3. Cellulose for cell walls
4. Glucose-> sucrose to be transported through phloem vessels
5. Nectar, for pollinators

Question 25

Why is glucose converted to sucrose in plants?

Answer 25

Glucose is highly reactive, may result in immediate reactions, and it is not energy efficient.

Question 26

2 symptoms of magnesium deficient plants:

Answer 26

1. Magnesium needed to produce chlorophyll 2. Magnesium deficient plants turn yellow (chlorosis) near/between veins **VEINS DO NOT TURN YELLOW**

Question 27

4 symptoms of nitrate deficient plants:

Answer 27

1. Stunted growth 2. Tips of leaves turn yellow 3. Old leaves dry out 4. Nitrates needed for ALL proteins

Question 28

What is hydrocarbonate indicator used for?

Answer 28

Used to monitor the net release of CO2 in plants. red = normal, purple = less CO2, Yellow = more CO2

Question 29

What does light do in photosynthesis?

Answer 29

Provides the energy that is used in chlorophyll to produce/convert into chemical energy

Question 30

What is a limiting factor?

Answer 30

Something that is in short supply that restricts a process.

Question 31

What are the 3 factors plants rely on?

Answer 31

1. Light intensity 2. Carbon dioxide concentration 3. Temperature

Question 32

What is the effect of temperature on a plant?

Answer 32

- denatures enzymes - too much transpiration - too little heat reduces enzyme reaction rate

Question 33

What are 5 leaf adaptations for the structure?

Answer 33

1. Large surface area 2. Very thin - aids diffusion 3. Alternating arrangement - more exposure to light 4.Top = shiny, more chlorophyll. Bottom = stomata 5. Sometimes has fenestrations (gaps) to stop ripping in high winds

Question 34

What do the guard cells do?

Answer 34

Open/close stomata

Question 35

What is the stomata?

Answer 35

Tiny holes, allowing gaseous exchange.

Question 36

What does the waxy cuticle do?

Answer 36

Stops water loss, allowing light to pass through, protecting the leaf surface.

Question 37

What does the epidermal cells do?

Answer 37

Protection, but thin to let light in

Question 38

5 features of the palisade mesophyll section of a leaf:

Answer 38

1. Many chloroplasts 2. Packed tightly together 3. Large surface area 4. Vacuole pushes chloroplasts to edges of cell 5. Thin cell walls aid gaseous exchange

Question 39

What is the palisade mesophyll sections optimised for?

Answer 39

Optimized for light exposure

Question 40

What is spongey mesophyll optimised for?

Answer 40

Optimized for gaseous exchange

Question 41

4 features of the spongey mesophyll section:

Answer 41

1. Irregular shaped 2. Fewer chloroplasts 3. Smaller than palisade cells 4. Spaced out with air pockets

Question 42

What does the xylem do?

Answer 42

Carries water and mineral ions up the plant.

Question 43

What does the phloem do?

Answer 43

Carries nutrients around the plant (sucrose)

Question 44

What is a balanced diet?

Answer 44

A dietary course that contains the correct amounts of each group of nutrients.