Cells - contents and membranes

Cytoplasm includes:

• cytosol

• organelles

• membrane

• extracellular fluid

How can you speed up movement of particles across a membrane?

• Smaller molecules

• Increase the temperature

• Have a bigger concentration difference one side to the other

• A shorter distance to travel

What membrane crossings need ATP to provide the energy.

• ions because they are charged

• particles moving against their concentration gradient

• Large movements involving membrane deformation such as exocytosis

• Diffusion where a protein channel is required.

Cell membranes are made up of:

• Phospholipids

• Cholesterol

• Protein channels

• Carbohydrates (sugar sprinkles)

What do lysosomes do?

• Construct proteins

• Digest cellular rubbish and recycle the bits

• Wrap membranes around vesicles

• Extend the surface area of the cell.

What is the difference between flagellar and cillia in animals?

• Cillia increases the surface area, flagella moves the cell

• Cillia moves the cell, flagella moves substances across the cell surface.

• Flagella moves the cell, cillia moves substances across the cell surface.

• Flagella moves the cell, cillia form fresh membrane

What does the Golgi apparatus do?

• Packages proteins made in the endoplasmic reticulum for transport.

• Packages lipids for transport.

• Synthesises proteins

• digests cell rubbish

Why is the rough endoplasmic reticumum rough?

• Studded with proteins

• Studded with carbohydrates

• Pitted ragged surface (has greater surface area)

• Studded with ribosomes

Osmosis is the movement of water and best described as

• Flowing from an area of high solute concentration to low solute concentration.

• Flowing from an area of low water concentration to high water concentration.

• Flowing from an area of high water concentration to low water concentration.

• Flowing from an area of low solute concentration to high solute concentration.

Given that osmosis is about the movement of water molecules - what would happen to a cell if the solution it was bathed in had a higher concentration of solutes than the inside of the cell?

• Water would move out of the cell and it would srhink (crenate)

• Nothing at all the cell membrane takes care of everything

• Water would enter the cell and it would swell, may even burst

• Water would leak everywhere.