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Flashcards in Lesson 3-4 Deck (28)
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1

What is the main components of cell (biological) membrane?

lipoids 40% and proteins 60%

2

Important lipoids in the cell membrane:

Mainly phospolipids: sphingomyelin, lecithin, cephalin.
Cholesterol

3

What is Glycerolphspatide?

If the phospholipids have a glycerol backbone

4

What type of small molecules, usually polar can be linked to the phsophate group?

Lecithine and cephaline. Forms a variety of phospholipids

5

Cephaline is:

if instead of choline there is a cholamine in the molecule

6

Phosphatidic acid is:

When there is neither choline nor cholamine in the structure

7

Sphingolipids is:

A phospholipid.
18-carbon amino alcohol with an unsaturated hydrocarbon chain.

8

Ceramine is:

Sphingosine + fatty acid

9

Sphingomyelin is:

Ceramide + phosphate + choline

10

What is characteristic of an unsatturated fatty acid

Has generally one to three double bonds.
The fatty acid will have a kink in its shape wherever a double bond occurs that result in looser packing and lower melting points.

11

What is the characteristics of cholesterol?

They are steroids.
they are characterized by a carbon skeleton consisting of four fused rings.
Function to stabilize the membrane.
Precursor from witch other steroids are synthesized.
High levels in blood = atherosclerosis.
(NOT in prokaryotes)

12

Types of movement of lipids in the membrane:

- rotation
- lateral diffusion
- transversal diffusion (flip-flop)
- energy is needed, flippase protein is needed.

13

What is Integral proteins?

- Transmembrane proteins with hydrophobic regions that completely span the hydrophobic interior of the membrane.
- Dynamic function, serve as ion-channels.

14

What is Peripheral proteins?

- loosely bound to the surface of the membrane (not embedded in the lipid bilayer)
often to the exposed part of the integral proteins.
- static function, receptor function.

15

What are the membrane carbohydrates?

- branched oligosaccharides with fewer than 15 sugar units (glucose, galactose, mannose, fucose = deoxyhexose and the N-acetylated sugars like N-acetylglucosamine, N-acetylgalactosamine and mannosamine + pyruvate = neuraminic acid.)
- glycolipids
- glycoproteins

16

Oligosaccharides functions as?

markers that distinguish one cell from another.

17

What is Lipid raft?

Spingolipid and cholestrol rich microdomain, ordered assemblies of specific proteins = lipid raft.
- important role in the cellular machinery

18

Membrane fluidity (elasticity) increases if:

- increased temperature
- decreased amount of cholestrol
- increased proportion of cis-unsaturated fatty acids in the phospholipids.

19

Describe Passive transport:

- Direction: down the concentration/electro chemical gradient.
- Energy: no
- Carrier: generally no (but at facilitated yes)
- Specific inhibition: no

20

describe Active transport:

- Direction: Against concentration/electrochemical gradient.
- Energy: yes
- Carrier: yes
- Specific inhibition: yes

21

Types of passive transport:

Simple diffusion, Facilitated diffusio, Osmosis

22

Simple diffusion:

- Molecules can diffuse passively through the lipid components of cellular membranes.
- Oxygen, carbon dioxide, ammonia, ethanol, urea etc.

23

Facilitated diffusion:

- Molecules can diffuse passively through proteins of cellular membranes which act as carrier and transport molecules or produce pores, gates.
- glucose, glucose transportes, carnitine and translocase

24

Osmosis:

Transport of solvent throug the cellular membrnae from the less concentrated solution in the direction of more concentrated solution.

25

Gibbs-Donnan-Equilibrium

Unequal ion distribution on both side of the semipermeable membrane --> membrane potential

26

Types of active transport:

They differ in their source energy:
- Primary active transport: involves a transport protein that directly hydrolyzes ATP to drive the transport process
- Secondary active transport (cotransport): utilizes energy stores in electromechanical gradients of ions to drive transport.

27

Types of primary active transport:

- Sodium-potassium pump
- Proton pump
a) in the respiratory chain
b) in the epithelial cells of stomach mucous membrane
- ABC transporter protein family

28

Types of Secondary active transport:

- SGLT-1 and SGLT-2 transporters