Diffusion and cell membranes

HideShow resource information
Why is transport across membranes vital to cells?
1. To obtain glucose 2.To remove carbon dioxide 3.To obtain oxygen 4.To secret urea 5.secrete hormones 5.maintain water potential 6.Maintain concentration gradients for certain ions
1 of 30
Give an example of a cell which secrets hormones
The pituitary gland-secrets ADH. The Pancreas-secrets pancreatic juice. The salivary glands- secrete saliva (contains amylase.
2 of 30
What is the function of glycoprotiens?
Glycoprotiens-hormone recognition - Cell to cell recoginition
3 of 30
Give an example of hormone recoginiton
Glycoprotiens and glycolipids on the surface of cardiac muscle cells bind specificly to adrenaline which makes the heart beat faster.
4 of 30
What is cell to cell recognition?
Glycoprotiens and glycolipids on the surface of cells allow the body to discriminate between self cells and foregin cells.
5 of 30
Give some example of 'foregin cells'
Pathogens-e.g. bacteria. Cells of a transplant organ. Cells of a blood transfusion
6 of 30
What are the two different types of transport proteins?
Carrier protiens. Channel protiens.
7 of 30
Exaplain more on Channel protiens
They are intrinsic, they have a hydrophillic pore/channel filled with water and lined by polar R groups. Fucntion=facilitaed diffusion. They are also specific to a certain ion.
8 of 30
What does intrinsic mean?
Span the whole phospholipid bilayer
9 of 30
Exalain more about Carrier protiens
Extrisic. Have a binding site specific for a certain molecule. When that molecule binds the carrier protien changes shape (undergoes a conformational change) and shuttles the molecule or ion across.
10 of 30
What does extrinsic mean?
Only go through a section of the phospholipid bilayer
11 of 30
What does the phospholipid bilayer do?
Forms a barrier. The hydrophobic region created by the fatty acid tails prevents polar molecules and large protiens from crossing the membrane.
12 of 30
What is the role of cholesterol in the phospholipid bilayer?
It affects the fluidity. More cholesterol=more fluid.
13 of 30
What are the four different types of diffusion?
Osmosis, diffusion, facilitated diffusion, active transport
14 of 30
Are they active or passive? What is the difference?
Osmosis-active, diffusion-passive, facilitated diffusion-passive, active transport-active. Active-requires ATP energy. Passive-Does not require ATP energy.
15 of 30
What factors affect the rate of diffusion?
Concentration gradient, size of the particles, thickness of the membrane, surface area, the distance between the two regions, temprature, lipid solubility, number of protiens in the membrane.
16 of 30
How does concentraion gradient affect the rate of diffusion?
The greater the difference in the concentraion of a substance in two areas the faster the rate of diffusion
17 of 30
How does the size of particles affect the rate of diffusion?
Small particles ten to diffuse faster than large particles
18 of 30
How does the thickness of the membrane affect the rate of diffusion?
Diffusion takes place more quickly through thin membranes as there is is a shorter distance to diffuse across
19 of 30
How does the surface area of the cell membrane affect the rate of diffusion?
Larger surface area= quicker diffusion
20 of 30
How does the distance between 2 regions affect the rate of diffusion?
The shorter the distance the faster the rate.
21 of 30
How does temperature affect the rate of diffusion?
An increase in temprature increase the rate of diffusion because the particles will have greater kinetic energy, and so can move across faster.
22 of 30
How does lipid solubility affect the rate of diffusion?
The more lipid oluble a substance is the greater the rate of diffusion.
23 of 30
How does the number of rotiens in the membrane affect the rate of diffusion?
The more transport protiens there are in the membreane the greater the rate of facilitated diffusion.
24 of 30
What is bulk transport?
An active process. The transport of large particles of solids or liquids across membranes in vesicles. If liquids then smaller vesicles. Solids e.g. protiens or bacteria.
25 of 30
How does the plasma membrane stay the same size?
Portions of the plasma membrane are continuosly added and removed.
26 of 30
What are the two different types of endocytosis?
Pinocytosis-Liquids. Phagolytosis-solids.
27 of 30
What happens in endocytosis?
The plasma membraneinvaginates around the substance and froms a vesicle which pinches off.
28 of 30
What happens in Exocytosis?
Used to secret substances. Vesicle igrates towards the plasma membrane releasing its conten outside the cell.
29 of 30
What is the name of the model of the plama membrane we look at? why?
The fluid mosaic model. Fluid-The phospholipids move around. Mosaic-The protien molecules are randomly arrange in the phospholipid bilayer
30 of 30

Other cards in this set

Card 2

Front

Give an example of a cell which secrets hormones

Back

The pituitary gland-secrets ADH. The Pancreas-secrets pancreatic juice. The salivary glands- secrete saliva (contains amylase.

Card 3

Front

What is the function of glycoprotiens?

Back

Preview of the front of card 3

Card 4

Front

Give an example of hormone recoginiton

Back

Preview of the front of card 4

Card 5

Front

What is cell to cell recognition?

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Human Biology resources:

See all Human Biology resources »See all Cellular processes and structure resources »