17.1 energy cycles

Question 1

The need of energy? 6 points

Answer 1

• Organisms have to be active to survive.
• Grow
• Respond to changes in the environment.
• Deal with threats from other organism
• Reproduce
• Find or make food

Question 2

Examples of metabolic activities

SULC

BM

Answer 2

SULC

S-Selective reabsorption of glucose+ amino acids in kidney.

U-Uptake of nitrates by root hair cells.

L-Loading sucrose into sieve tube elements.

C- Conduction if nerve impulses.

BM

B-Building of polymers like proteins, polysaccharides and nucleus acids essential for growth and repair

M-Movement brought about by cilia,flagella or contractile filaments in muscle cells

Question 3

What do organisms make use of?

Answer 3

The energy in the bonds of organic molecules e.g glucose.

Question 4

What is respiration?

Answer 4

The process by which organic molecules such as glucose, are broken down into smaller inorganic molecules e.g H2O,CO2

Question 5

Why does respiration happen?

Answer 5

Energy stored within bonds of organic molecules, used to synthesise ATP.

Question 6

What is photosynthesis ( in terms of biomass)?

Answer 6

The reaction behind the production of most of the biomass on earth.

Question 7

What is respiration (in terms of biomass)?

Answer 7

The process by which organisms breakdown biomass to produce the ATP,needed to drive the metabolic reactions that take place in cells.

Question 8

What are 3 differences between respiration and photosynthesis?

Answer 8

Respiration Photosynthesis

Glucose+O2 H2O+CO2
Reactants

H2O+CO2 Glucose+O2
Products

Release energy Trap energy
Purpose

Question 9

Describe bond energy.

Answer 9

The same quantity of energy is involved whether a particular bond is being broken or formed.

Question 10

What are features of bonds in inorganic molecules?

3 points

Answer 10

• Joined by strong bonds
• Releases lots of energy when formed.
• Requires lots of energy to break.

Question 11

What are features of bonds between the atoms of organic molecules?

4 points

Answer 11

• Contain many more bonds than inorganic molecules.
• Weaker bonds compared to inorganic bonds.
• Release less energy when formed.
• Requires less energy to be broken

Question 12

Why is less energy required to break bonds in organic molecules?

4 points

Answer 12

• Contains large numbers of c-h bonds.
• carbon and hydrogen share electrons equally in bonds between them.
• Makes the bond non-polar.
• less energy required to break bond

Question 13

Where does excess energy used to synthesis ATP come from?

2 points

Answer 13

• Total energy required to break all the bonds in a complex organic molecule.
• Is less than energy released when bonds in smaller inorganic products form.

Question 14

Explain why it is incorrect to say energy is produced?

2 points

Answer 14

• Energy can not be created or destroyed.

- ATP is produced

Question 15

Why is ATP not a good energy storage molecule, but organic molecules like lipids and carbohydrates are?

3 points

Answer 15

• ATP is not stable.
• Easy to remove phosphate group.
• Organic molecules are more stable.

Question 16

Describe interrelationship between respiration and photosynthesis in organisms?

6 points

Answer 16

• In photosynthesis light energy is converted into chemical energy.
• Inorganic molecules is converted into organic molecules.
• CO2 and H20 converted into 02 and glucose
• Respiration uses 02 produced in photosynthesis.
• Organic molecules broken down into inorganic molecules
• Energy released used to synthesise ATP.
• CO2 produced used in photosynthesis.