Biology 12 – membranes

Cell structures

Is this eukaryotic?

Why?

Is this a plant or animal cell?

Why?

Label the structures

Cell structures

Is this eukaryotic?

Why?

Is this a plant or animal cell?

Why?

Label the structures

Yes

It has a nucleus

Plant

Chloroplasts, cell wall, large vacuole

Cell wall

Cell membraneChloroplast

Lysosome

Golgi body Nucleus Nucleolus

DNA

Magnification and field of view 1

magnification x 40 magnification x 400

field of view 4000 m field of view 400 m

Magnification has increased by a factor of 10

Field of view has decreased by a factor of 10

Magnification and field of view 2

magnification x 100 magnification x 400

field of view 1600 m field of view 400 m

Magnification has decreased by a factor of 4

Field of view has increased by a factor of 4

Size of objects under the microscope 1

Magnification x100, field of view 1600 m

~ 4 cells fit across diameterEach cell ~ 400 m

Size of objects under the microscope 2

Magnification x400, field of view for x100 = 1200 m

Field of view for x400 = 300 m ~ 2 cells fit across diameterEach cell ~ 150 m

Cells exchange matter and energy

In: Out:Processes:

Cells exchange matter and energy

In:

Oxygen

Nutrients eg glucose

(carbon dioxide and light energy in plants)

Water

Ions

Out:

Carbon dioxide

Wastes eg urea

(oxygen in plants)

Water

Ions

Heat energy

Processes:

Respiration

Synthesis

Growth

Division

Photosynthesis (in plants)

Unicellular responses to the environment

Give one example that demonstrates unicellular organisms respond to their environment

Unicellular responses to the environment

Give one example that demonstrates unicellular organisms respond to their environment

Engelmann’s experiment

Paramecia and Amoeba changing the rate of their contractile vacuoles depending on salt concentration

Euglena movement towards food & light

Cell membranes

Sketch a typical cell membrane according to the Fluid Mosaic model

Describe the roles of:• Phospholipids

• Proteins

• Carbohydrates

CellsSketch a typical cell membrane according to the Fluid Mosaic model .

Describe the roles of:Phospholipids = A – waterproof, flexible layer, that lets in small particles

Proteins = B – provides channels for larger particles (facilitated diffusions), acts as pumps (active transport), acts as receptor sites

Carbohydrates = C - acts as receptor sites

A

B

C

Diffusion

Draw a diagram to show how materials are exchanged by diffusion

Movement of particles - diffusion

Occurs without energy

Particles will move from higher concentrations to lower concentrations

Osmosis

Draw a diagram to show how materials are exchanged by osmosis

OsmosisMovement of waterThis occurs from areas of high water concentration (low

concentration of solute) to areas of low water concentration (high concentration of solute)

Active transport

Draw a diagram to show how materials are exchanged by active transport

Active transport

Movement against a concentration gradient.Energy is needed

Exchange of material

Show the movements of water and ions that would occur in both these cases

Distilled water Sea water

Water moves in

Water moves out Ions move inIons move out

Determining the components of the cell membrane

Beetroot lab – part A

acid base

water Distilled water

detergent

Beetroot lab part A

Beetroot experiment part A

• What hypothesis is being tested?

• What is the control?

• What is the independent variable?

• What is the dependent variable

• What variables are controlled?

• How will this tell you about the components of the cell membrane?

Beetroot lab results – part A

After 1 hour After 24 hours

Beetroot lab results – part A

After 1 hourAfter 24 hours

Detergent has broken down cell membranes

Detergent has broken down cell membranesThe osmotic difference between distilled water and the cells has caused water to enter and burst cellsAcidic and basic conditions starting to damage cell membranes

Beetroot experiment part B

Beetroot lab – part B• How will you change the temperature? • How many different temperatures will

you test?• How many slices of beetroot will you

use in each test tube?