Cell Membranes, Cell Biology - Biology - Quiz, Exercises for Cell Biology
sanaka
sanaka

Cell Membranes, Cell Biology - Biology - Quiz, Exercises for Cell Biology

3 pages
7Number of download
1000+Number of visits
100%on 1 votesNumber of votes
Description
These are the notes of Cell Biology. Key important points are: Cell Membranes, Cell Biology, Cell Surface Membrane, Plasma Membrane, Carbohydrate Side Chain, Cell Recognition, Phospholipid Bilayer, Groups of Phospholipid...
30 points
Download points needed to download
this document
Download the document
Preview3 pages / 3

1. The table below refers to components of the cell surface membrane (plasma membrane) and to their roles in transporting substances across the membrane.

Complete the table by inserting an appropriate word or words in the empty boxes.

Component

Phospholipid

Carbohydrate side chain

Protein

Fatty acids, glycerol and phosphate

monosaccharide/ named e.g. of a monosaccharide/ ref. to pentose/hexose;

ester;

glycosidic;

Peptide

Role in transportChemical bond between subunits

Subunits

Ref. to vesicle formation/cytosis/ chylomicrons/ref.to diffusion;

Receptor

Ref. to channels/pores allowing passage/ facilitated diffusion/ receptor/enzyme/ carrier/active transport;

amino acids;

[Total 6 marks]

2. Write an essay on the following topic.

The structure and functions of cell surface membranes (Bio, Hbio) structure and function of cell surface membranes:

Introduction could include: outline of fluid mosaic model - communication with external medium, barrier - controls exchange of material -

fluid mosaic model: phospholipids and orientation - proteins, glycocalyx, channels - microvilli -

passage through the membrane: diffusion, facilitated diffusion, Na/K - osmosis, active transport, ATPase - lipid soluble molecules, adrenaline polar molecules through pores, channels -

Vesicles: cytosis - endocytosis, phagocytosis, pinocytosis - exocytosis, secretory vesicles others: glycosides as receptors, insulin- adhesion between cells - immunological response S = 13, B = 2,C = 2

[Total 15 marks]

Docsity.com

3. (a) (i) A = glycerol 1

B = fatty acid (residue) 1

(ii) hydrolysis 1

(b) polar (molecules) / hydrophilic heads/eq & hydrophobic tails/eq 1form a bilayer / bimolecular double layer [accept from clear diagram] 1(polar/hydrophilic) heads outside / (non–polar/hydrophobic) tails inside 1

[6]

4. (a) A phospholipid ; B protein ; C glycoprotein ; 3

(b) act as a marker / antigen / recognition site ; other molecules combine with it / detecting similar / non-self cells ;

OR reference to receptor / binding site ; other (specific) molecules / named e.g. / combine with it ; 2

[5]

5. (a) Phospholipid ; 1

(b) A Glycerol / propan 1,2,3 triol ;

B Ester bond / ester linkage ; 2

(c) Insoluble in water / does not dissolve in water / non-polar ; 1

(d) (Fluid because) phospholipids move (around membrane) ;

(Mosaic because) membrane contains proteins / glycoproteins (lying amongst phospholipids) / eq ; 2

[6]

6. (a) {Fatty acid / tails} are {hydrophobic / non-polar} ; (so orientate themselves) away from {water / polar environment} ; {Phosphate / heads} are {hydrophilic / polar} ; (so can) interact with {water / polar environment} ; 3

(b) Correct measurement ; [27 mm or 37 / 38 mm] Divide by magnification ; Correct conversion to µm ; [answer = 0.009 or 0.012 / 0.013] 3

(c) Carbohydrate: Cell recognition / cell adhesion / eq ; 1

Protein: Transport of molecules / eq OR receptor for hormone / eq OR enzymes ; 1

[8]

Docsity.com

7. Accept points only in correct context

1. phospholipid bilayer ; 2. polar / phosphate / hydrophilic (groups of phospholipids) face outwards ; 3. nonpolar / hydrophobic / fatty acid tails face inwards ; 4. reference to cholesterol ; 5. molecules can move around ; 6. proteins present in membrane ; 7. qualification of the location of these proteins ; 8. glycosidic / carbohydrate side chains on lipids / proteins / glycolipids / glycoproteins / glycocalyx ; 9. involvement of proteins in transport (across membrane) ; 10. by active transport / facilitated diffusion described (e.g. reference to attachment / change in shape) ; 11. some proteins are enzymes ; 12. partially / selectively permeable / eq ; 13. reference to cell-cell interaction / recognition / antigens ; 14. reference to receptors for hormones / neurotransmitters ; 15. vesicle fusion / formation / description of membrane involvement in exo- or endo-cytosis ;

[10]

Docsity.com

no comments were posted