learning outcomes

Question 1

describe the structures present in cell types

Answer 1

1- nucleus: contain DNA, RNA
2-nucleolus: site of ribosomal RNA
3-ER: interconnecting tubules, vesicles and sacs-cisternae
can be smooth ( site of lipid biosynthesis, membrane synthesis) or rough (site of protein synthesis)
4-ribosomes: 2 sub-units. involved in protein synthesis
5- Golgi apparatus: complex of flattened sacs which package secretory proteins and synthesise compex polysaccharides
6-lysosome: contains amourphous granular material which help break down bacteria and debris
7-peroxisome: contains catalase- regulate hydrogen peroxide conc.- and oxidases- involved in beta oxidation of FA
8- mitochondria: permeable outer layer containing porin. folds in inner membrane- Cristae

Question 2

define the role of the cytoskeleton?

Answer 2

1- microfilaments: fine strands of actin which in small intestine form microvilli
2- microtubules; form cilia

Question 3

describe the structure and function of a cell membrane?

Answer 3

function:
-receptor
-enzyme
-cell-cell recognition
-cell-cell adhesion
-transport
structure: phospholipid bilayer with proteins embedded
very flexible, good insulation due to presence of FA.
continuos repair to meet the needs of the cell.

Question 4

Describe the interactions between water molecules and solutes that determine solubility.

Answer 4

water-solute bonds favoured over water-water, solute-solute bonds when H-bonds are involved.

Question 5

describe the different type of membrane proteins?

Answer 5

Integral: they cannot be removed from membrane without altering its function or structure. They are amphipathic and have same orientation as phospholipids.
they can be
-channel
-carrier
-enzymes
-receptors
Peripheral: can be removed from membrane without disturbing it . Not amphipathic. Act as enzymes