1 - Basics

Question 1

What is homeostasis?

Answer 1

The maintenance of a stable internal environment

Question 2

Which three things is it important to keep constant during homeostasis?

Answer 2

Temperature
PH
Blood Glucose Concentration

Question 3

What happens when your body temperature gets too high (e.g.. over 40 degrees)?

Answer 3

The metabolic reactions taking place will stop as the enzymes molecules will vibrate more meaning the vibrations will break the hydrogen bonds that hold the enzymes 3D shape, therefore the active site will change shape and so the sublate will no longer fit the enzyme and so the enzyme is denatured.

Question 4

What happens when your body temperature gets too low?

Answer 4

The rate of metabolic reactions taking place will slow down

Question 5

What is the optimum temperature for enzyme activity to take place at?

Answer 5

37 degrees

Question 6

Why is homeostasis important?

Answer 6

It is important as temperature and PH affect the rate of metabolic reactions, and blood glucose concentration should be kept regular as cells need glucose for energy and it affects water potential levels

Question 7

What happens if PH levels are too high or low? why?

Answer 7

Enzymes will become denatured as the ionic and hydrogen bonds holding the enzymes 3D shape will be broken and so the specific shape of the active site will change and so the substrate will no longer fit

Question 8

What is the optimum PH level?

Answer 8

PH7 - neutral

Question 9

How is PH calculated?

Answer 9

It is calculated based on the concentration of hydrogen ions in the environment
The greater the concentration of H+ in the environment the the lower the PH

Question 10

What is the equation for working out PH?

Answer 10

PH = log10 [H+]

Question 11

What is the logarithmic scale?

Answer 11

A scale that uses a logarithm of a number instead of the number itself each value using Log10 is 10 times larger than the value before

Question 12

What happens if the blood glucose concentration is too high?

Answer 12

The water potential of blood is reduced to a point where water molecules diffuse out of the cells into the blood by osmosis, which can cause the cells to shrivel up and die

Question 13

What happens if the blood glucose concentration is too low?

Answer 13

Cells are unable to carry out normal activities as there is not enough glucose for respiration to provide energy

Question 14

What is a negative feedback mechanism?

Answer 14

A mechanism that restores a level back to normal in a system

Question 15

Describe a negative feedback loop

Answer 15

Normal level > Level changes from normal > Receptors detect change > Communication via nervous or hormonal system > Effectors respond > Loops back to Normal level

Question 16

Why does homeostasis involve multiple negative feedback loops?

Answer 16

Because it allows for more control over changes in your internal environment rather than just having one. It means you can actively change a level so it returns to normal again.

Question 17

What would happen if you only have one negative feedback mechanism?

Answer 17

You would only be able to change a level in one direction so it returns to normal. There would be a slower response and less control

Question 18

What is a positive feedback mechanism?

Answer 18

A mechanism that amplifies a change away from a normal level in a system

Question 19

Describe a positive feedback mechanism?

Answer 19

Normal level > Normal level changes > Receptors detect change > Communication via nervous or hormonal system > effectors respond > (Back to normal level) (change amplified)

Question 20

Why isn’t positive feedback used in homeostasis?

Answer 20

Because it doesn’t keep your internal environment stable

Question 21

What is positive feedback used for?

Answer 21

It is used to rapidly activate processes in the body and can also happen when a homeostatic system breaks down