Life Processes

Question 1

What does MRS GREN stand for?

Answer 1

Movement
Respiration
Sensitivity

Growth
Reproduction
Excretion
Nutrition

Question 2

Definition of Homeostasis

Answer 2

The control of the internal environment

Question 3

What do all animal cells contain?

Answer 3

Nucleus - Control centre for cell
Cytoplasm - where chemical reactions take place
Mitochondria - aerobic respiration occurs - Energy
Cell membrane - controls what substances enters or leaves the cell

Question 4

What do all Plant cells contain?

Answer 4

Cell Wall - Made of cellulose providing structural support to the cell giving it its rigid structure

Permanent Vacuole - contains water necessary to provide turgor pressure and a store for ions and molecules

Chloroplasts - contains chlorophyll and the production of glucose by photosynthesis

Question 5

Order of organisation from smallest to largest

Answer 5

Cells —> Tissues —> Organs —> Organ Systems

Question 6

What is Cell specialisation and give one example

Answer 6

Cells become specialised for a particular function for example a sperm cell has been for reproduction as they have a streamlined head so that it can reach the egg quickly

Question 7

Define Tissue

Answer 7

A collection of similar cells that work together to perform a specific function

Question 8

Define organs

Answer 8

Group of tissues working together to perform a specific function

Question 9

Define Organ system

Answer 9

a collection of organs that work together to perform a specific function

Question 10

What are enzymes

Answer 10

They are biological catalysts that increase the rate of reaction without being used up in the process. They are all proteins and convery substrate into product.

Question 11

How do enzymes work?

Answer 11

1) Active Site - substrate fits into active site
2) substrate collides with enzyme randomly
3) substrate is bound to active site due to electrical interactions
4) this stresses the chemical bonds and makes it easier for the substrate to be converted into poducts lowering the activation energy

Question 12

What factors can alter the rate of reaction

Answer 12

pH -

Temperature - greater frequency of collisions = higher rate of reaction

Question 13

What happens if the temperature is too high?

Answer 13

Because their shape is held together by weak internal bonds if temp too high the structure shake apart and the active site changes and the enzyme becomes denatured - no longer functional

Question 14

What happens if pH changes?

Answer 14

It can cause the enzyme to lose its shape which causes the active site to stop working - the enzyme would denature

Question 15

What is diffusion?

Answer 15

Movement of molecules from a region of high concentration to a region of low concentration down a concentration gradient

Question 16

Factors that affect diffusion

Answer 16

Temperature- greater the temperature the greater the kinetic energy between the particles and cause faster diffusion

Surface area- the greater the surface area means the molecules have more surface to diffuse so increase rate of movement

Concentration gradient- the bigger the difference of concentration between the inside and outside of the cell, the more opportunity the molecules have of diffusing

Question 17

What is osmosis?

Answer 17

The net movement of water molecules from a region of high water concentration to a region of low water concentration through a semi-permeable membrane