Topic 5B: Energy Transfer and Efficiency

Question 1

Where do plants get energy from?

Answer 1

The sun

Question 2

Energy + CO2 =

Answer 2

Glucose

Question 3

What is glucose used for?

Answer 3

• respiration
• biomass
• synthesis of biological molecules

Question 4

What is biomass?

Answer 4

Chemical energy stored in plants

Question 5

Why is energy sometimes lost when light energy is converted to chemical energy?

Answer 5

• wrong wavelength

- light miss the chlorophyll

Question 6

What are producers?

Answer 6

Organisms that make their own food (usually through photosynthesis)

Question 7

Why do we use dry mass over fresh mass?

Answer 7

Because in fresh mass water varies so it makes it unreliable

Question 8

How do you get dry mass from fresh mass?

Answer 8

• place mass in an oven at low temp
• water will evaporate
• measure mass at regular intervals until mass becomes constant.

Question 9

Biomass can be measured using…

Answer 9

• dry mass

- using calOrimeter

Question 10

How can you estimate the chemical energy in biomass?

Answer 10

• burn mass in calorimeter
• the amount of heat given off tells you how much energy is in it
• calculate the change in temperature

Question 11

What is energy measured in?

Answer 11

KJ/J

Question 12

Define GPP

Answer 12

Gross Primary Production

Question 13

What is GPP?

Answer 13

The overall chemical energy that is converted from light energy in plants which they gain from photosynthesis

Question 14

Define RL?

Answer 14

Respiratory Loss

Question 15

What is respiratory loss?

Answer 15

Most of the GPP is lost through heat to the environment and this is because plants respire.

Question 16

Define NPP

Answer 16

Net Primary Production

Question 17

What is NPP?

Answer 17

The energy that is used for growth and respiration

Question 18

How much energy is lost to the environment?

Answer 18

around 90%

Question 19

How is energy lost?

Answer 19

• movement
• respire
• faces and waste

Question 20

How do you calculate NPP

Answer 20

GPP - RL

Question 21

What is the typical unit for rate of primary production?

Answer 21

• kj ha^-1 year^-1

- kj m^-2 year^-1

Question 22

Net product in consumers =

Answer 22

I -(R+F)

Question 23

What are the two ways energy is lost?

Answer 23

• The energy lost to other organisms eg pests

- The energy lost through respiration

Question 24

How do farmers reduce energy loss through pests?

Answer 24

By using Chemical and Biological reagents

Question 25

Chemical Reagents used to reduce pests are…

Answer 25

• Insectides - kill animals that feed on/ damage crops

- Herbicides- Kills weeds that compete with plants for light energy from the sun

Question 26

Biological Reagents used to reduces pests are…

Answer 26

• Parasites- makes animals that feed on crops not function properly
• Pathogenic bacteria-release toxins to kill

Question 27

How do farmers reduce energy loss through respiration?

Answer 27

• Constrict movement because when they move they respire and release energy so farmers keep them indoors
• Control Temperature- they also respire to maintain body temp so farmers provide radiators and heaters

Question 28

How is restricting movement and temperature raise ethical concerns?

Answer 28

Putting animals in pain/distress/removing them from their natural environment.