Bioenergetics

Question 1

What type of reaction is photosynthesis?

Answer 1

Endothermic - requires energy

Question 2

What is the word equation for photosynthesis?

Answer 2

Water + Carbon dioxide ->(light energy)-> Oxygen + Glucose

Question 3

What is the symbol equation for photosynthesis?

Answer 3

6CO² + 6H²O ->(Light energy)-> 6C12H6O, 6O²

Question 4

What are the key factors affecting the rate of photosynthesis?

Answer 4

• Chlorophyll concentration
• Light intensity
• Carbon dioxide concentration
• Temperature

Question 5

Why can’t the temperature be more than 45°C for photosynthesis?

Answer 5

The enzymes thst catalyse the reaction denature.

Question 6

What are some of the consequences for plants growing in mineral-deficient soil?

Answer 6

Low absorption of minerals
Low production of chlorophyll
Low rate of photosynthesis

Question 7

What could be a limiting factor for photosynthesis on a warm, sunny day?

Answer 7

CO² concentrations

Question 8

What products can glucose be converted into?

Answer 8

Starch
Proteins
Cellulose
Fats and oils

Question 9

What is the equation for light intensity?

Answer 9

Light intensity = light intensity at source (1) / distance²

Question 10

Light intensity can affect the rate of which process in plants such as pond weed?

Answer 10

Photosynthesis

Question 11

What are the reasons why organisms need energy?

Answer 11

• Contraction (for muscles, allowing them to move)
• Homeostasis (for keeping body temperature of warm-blooded animals relatively constant)
• Growth (for making larger molecules from smaller molecules)

Question 12

What is respiration?

Answer 12

Respiration is an exothermic reaction (releases energy) that supplies all energy needed by organisms.

Question 13

What is the equation for aerobic respiration?

Answer 13

Glucose + Oxygen -> carbon dioxide + water (+energy)

C6H12O6 + 6O2 -> 6CO2 + 6H2O (+energy)

Question 14

What happens to glucose in plant and yeast cells?

Answer 14

Glucose is converted into ethanol and carbon dioxide

Question 15

What is the equation for anaerobic respiratory in plants?

Answer 15

Glucose -> ethanol + carbon dioxide

Question 16

What is the equation for anaerobic respiration in animals?

Answer 16

Glucose -> lactic acid

Question 17

When does anaerobic respiration occur in animals?

Answer 17

When insufficient oxygen reaches the muscles during periods of intense activity.

Question 18

What is metabolism?

Answer 18

Metabolism refers to all the chemical reactions that happen in an organism. Many of these chemical reactions create new molecules with the help of enzymes.

Question 19

What are the features of metabolic reactions?

Answer 19

• Breaking down excess proteins (to form urea, excreted in urine)
• Converting glucose (into starch-plants, glycogen-animals and cellulose-plants)
• Making amino acids (combining glucose and nitrate ions make amino acids)
• Making lipids (combining glycerol and fatty acids to make lipid molecules)

Question 20

What is the equation for volume of has consumed per minute?

Answer 20

Volume of gas consumed per minute = gas intake per breath x breaths per minute

Question 21

What are the main responses to increase rate of respiration?

Answer 21

• Blood vessels dilate (to ensure more blood reaches the muscles)
• Increased heart rate (to deliver more blood to the muscles)
• Increase in breathing rate (increases has exchange in lungs for more oxygen taken in)
• Increase in breath volume (also increases rate of gas exchange)

Question 22

What is lactic acid?

Answer 22

Lactic acid is a by-product of anaerobic respiration. Lactic acid is toxic, when it builds up in muscles, it can cause muscular pain and fatigue.

It may also stop muscles from contracting efficiently.

Question 23

What is oxygen debt?

Answer 23

Oxygen debt refers to the extra oxygen that is needed after exercise to oxidise lactic acid and get it out of cells.

Question 24

How do you repay oxygen debt?

Answer 24

Blood transport lactic acid to the liver, where it reacts with oxygen to produce carbon dioxide and water.

Heavy breathing helps to repay the pxygen debt by taking more oxygen into the lungs.

Question 25

What economically important process require yeast?

Answer 25

Alcohol production and manufacture of bread