Biology Chapter 8 Flashcards Preview

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Flashcards in Biology Chapter 8 Deck (22):
1

Metabolic rate varies between

Different species: temperature and size main factor

2

Catabolism

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

3

Anabolism

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

4

Types of energy:

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

5

ATP (Adenosine Tri Phosphate)

Stores Chemical energy.

Has 3 phosphate groups attached to adenine and ribose.

Mainly produced in mitochondria.

6

First law of thermodynamics

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

7

Second law of thermodynamics

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

8

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

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

9

Enzymes

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

10

Enzymes are specific

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.

11

The speed of enzymes can be affected by

Environmental conditions (temp, pH)

Coenzymes (vitamins)

Inhibitors (toxins)

12

What temperature do human enzymes work best at?

37 degrees Celsius

13

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

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

14

What pH do most human enzymes work best at?

Close to pH 7

15

Trypsin in the intestines works best around pH 8.

Pepsin in the stomach works best around pH 2.

Acids act as preservatives, as they slow or stop enzymes

16

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

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

17

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

Folate deficiency

18

Competitive inhibitors

Attach to the active site of the enzyme

19

Non-competitive inhibitors

Attach away from the active site

20

Enzyme inhibitors are important in pesticides

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

21

Metabolism

All of the chemical reactions in an organism

22

There is ATP mainly produced?

In mitochondria.