Biology Chapter 8

Question 1

Metabolic rate varies between

Answer 1

Different species: temperature and size main factor

Question 2

Catabolism

Answer 2

Breaking down large molecules to small molecules (usually releases energy)

Question 3

Anabolism

Answer 3

Building up large molecules from small ones (usually requires energy)

Question 4

Types of energy:

Answer 4

Chemical (eg in food),
Light,
Heat,
Electrical (nerves),
Kinetic (energy of movement).

Question 5

ATP (Adenosine Tri Phosphate)

Answer 5

Stores Chemical energy.

Has 3 phosphate groups attached to adenine and ribose.

Mainly produced in mitochondria.

Question 6

First law of thermodynamics

Answer 6

Energy can be changed from one form to another, it cannot be created or destroyed

Question 7

Second law of thermodynamics

Answer 7

Entropy (disorder) is always increasing. So things fall apart and break down, because the general trend is towards disaster.

Question 8

In living things, chemical energy (ATP) is used for:

Answer 8

Mechanical work. Eg muscles.
Chemical work. Eg anabolism.
Active transport. Eg sodium/potassium pump.

Question 9

Enzymes

Answer 9

Control chemical reactions in the cell.
Are proteins.
Act as catalysts. (Speed up chemical reactions by lowering the activation energy)

Question 10

Enzymes are specific

Answer 10

Each affects a particular substrate.
They have an active site that the substrate molecule fits.
Work very rapidly (up to 100,000 Chemical reactions per min) so are only needed in tiny quantities.

Question 11

The speed of enzymes can be affected by

Answer 11

Environmental conditions (temp, pH)

Coenzymes (vitamins)

Inhibitors (toxins)

Question 12

What temperature do human enzymes work best at?

Answer 12

37 degrees Celsius

Question 13

Above 40 degrees C enzymes become denatured. Cold temps slow enzymes.

Answer 13

By cooling down a patient’s body, surgeons can do heart surgery without a heart/lung machine

Question 14

What pH do most human enzymes work best at?

Answer 14

Close to pH 7

Question 15

Trypsin in the intestines works best around pH 8.

Pepsin in the stomach works best around pH 2.

Answer 15

Acids act as preservatives, as they slow or stop enzymes

Question 16

Vitamins are needed in small amounts. Large amounts can be toxic. Vitamin E supplements may increase death risk.

Answer 16

Some vitamins are antioxidants that protect cells from damage. Coffee contains antioxidants

Question 17

During pregnancy, what deficiency increases the risk of birth defects?

Answer 17

Folate deficiency

Question 18

Competitive inhibitors

Answer 18

Attach to the active site of the enzyme

Question 19

Non-competitive inhibitors

Answer 19

Attach away from the active site

Question 20

Enzyme inhibitors are important in pesticides

Answer 20

Some medications, such as HIV drugs and aspirin, are inhibitors

Question 21

Metabolism

Answer 21

All of the chemical reactions in an organism

Question 22

There is ATP mainly produced?

Answer 22

In mitochondria.