Bioenergetics

Question 1

What are autotrophs?

Answer 1

Organisms that can make their own food using light, water, and carbon dioxide

Question 2

Why are plants called producers in food chains?

Answer 2

Because they can make their own food through photosynthesis

Question 3

What type of reaction is photosynthesis?

Answer 3

An endothermic reaction

Question 4

Where does most photosynthesis take place in a plant?

Answer 4

In specialised mesophyll cells packed with chloroplasts

Question 5

What is the function of chlorophyll in plants?

Answer 5

To absorb light energy for photosynthesis

Question 6

What are the main products of photosynthesis?

Answer 6

Sugars used for making substances a plant needs and for respiration

Question 7

List the reactants required for photosynthesis.

Answer 7

• Light
• Water
• Carbon dioxide

Question 8

What factors affect the rate of photosynthesis?

Answer 8

• Light intensity
• Carbon dioxide concentration
• Temperature
• Amount of chlorophyll

Question 9

How does temperature affect photosynthesis?

Answer 9

It affects the kinetic energy of particles, influencing the rate of collisions

Question 10

What happens to enzymes at high temperatures during photosynthesis?

Answer 10

They can be denatured, reducing the overall rate of photosynthesis

Question 11

What is the relationship between light intensity and photosynthesis rate?

Answer 11

More light increases the rate until another factor limits it

Question 12

How does carbon dioxide concentration affect photosynthesis?

Answer 12

More carbon dioxide leads to a faster reaction rate until limited by another factor

Question 13

What role do chloroplasts play in photosynthesis?

Answer 13

They contain chlorophyll, which absorbs light energy

Question 14

What factors can affect the amount of chlorophyll in a plant?

Answer 14

• Diseases
• Lack of nutrients
• Loss of leaves

Question 15

True or False: Water is considered a limiting factor in photosynthesis.

Answer 15

False

Question 16

What is the inverse square law?

Answer 16

It shows the relationship between light intensity and distance

Question 17

Fill in the blank: The equation for light intensity is _______.

Answer 17

1/d²

Question 18

What is the aim of the investigation using an aquatic organism?

Answer 18

To investigate the effect of light intensity on the rate of photosynthesis

Question 19

How can the rate of photosynthesis be measured in aquatic plants?

Answer 19

By measuring the volume of oxygen produced

Question 20

What is one improvement for measuring gas produced in photosynthesis?

Answer 20

Use a gas syringe to collect the volume of gas produced

Question 21

What are the main uses of glucose in plants?

Answer 21

• Used for respiration
• Converted to insoluble starch for storage
• Used to produce fat or oil
• Used to produce cellulose
• Combined with nitrate ions to produce amino acids

Question 22

What reagent is used to test for starch in leaves?

Answer 22

Iodine solution

Question 23

True or False: Plants only photosynthesize during the day.

Answer 23

True

Question 24

What is cellular respiration?

Answer 24

An exothermic reaction continuously occurring in living cells

Question 25

What does cellular respiration release?

Answer 25

Energy

Question 26

What do organisms need energy for?

Answer 26

* Chemical reactions to build larger molecules from smaller molecules * Muscle contraction to allow movement * Keeping warm (to maintain a constant temperature suitable for enzyme activity)

Question 27

What is aerobic respiration?

Answer 27

Respiration using oxygen to transfer energy from glucose

Question 28

What is the word equation for aerobic respiration?

Answer 28

Glucose + Oxygen → Carbon Dioxide + Water + Energy

Question 29

Where does aerobic respiration primarily occur?

Answer 29

In the mitochondria

Question 30

What is anaerobic respiration in animals?

Answer 30

The incomplete breakdown of glucose into lactic acid without oxygen

Question 31

When does anaerobic respiration occur?

Answer 31

When the body can't supply enough oxygen for aerobic respiration, such as during vigorous exercise

Question 32

What is the word equation for anaerobic respiration in animals?

Answer 32

Glucose → Lactic Acid + Energy

Question 33

What is produced during anaerobic respiration in plants and yeast?

Answer 33

Ethanol and Carbon Dioxide

Question 34

What is fermentation?

Answer 34

Anaerobic respiration in yeast cells

Question 35

What is the economic importance of fermentation?

Answer 35

* Manufacture of bread (carbon dioxide makes dough rise) * Production of alcoholic drinks (ethanol)

Question 36

What are the key differences between aerobic and anaerobic respiration?

Answer 36

* Need for oxygen * Differing products * Relative amounts of energy transferred

Question 37

True or False: Cellular respiration is the same as breathing.

Answer 37

False

Question 38

What happens to muscle contractions during exercise?

Answer 38

They increase, leading to greater energy demand

Question 39

How does the body respond to increased oxygen demand during exercise?

Answer 39

* Breathing rate increases * Breath volume increases * Heart rate increases

Question 40

What is created when the body cannot supply sufficient oxygen during vigorous exercise?

Answer 40

An oxygen debt

Question 41

What happens to lactic acid after vigorous exercise?

Answer 41

* It can be oxidised to form carbon dioxide and water * It can be transported to the liver and converted back into glucose

Question 42

What is metabolism?

Answer 42

The sum of all the reactions in a cell or the body

Question 43

What role does energy play in metabolism?

Answer 43

It allows enzyme-controlled reactions to occur inside cells

Question 44

What are the main metabolic reactions?

Answer 44

* Synthesis and breakdown of carbohydrates * Synthesis and breakdown of lipids * Synthesis and breakdown of proteins

Question 45

What is the role of glucose in carbohydrate metabolism?

Answer 45

* Used in the synthesis of starch (energy storage in plants) * Used in the synthesis of glycogen (energy storage in animals) * Broken down during respiration to release energy

Question 46

What is the role of glycerol in lipid metabolism?

Answer 46

Combined with three fatty acids to synthesize lipids for energy storage

Question 47

What is required to produce amino acids in plants?

Answer 47

Glucose and nitrates

Question 48

What happens to excess proteins?

Answer 48

They are broken down to produce urea, which is excreted from the body