Cell Compnonents And Microscopes

Question 1

Outline the structural features that identify the Golgi body from the RER

Answer 1

Flattened sacks have layered appearance/ no connection between membranes (Connection between membranes in RER)
Not contiguous with the nuclear envelope (RER is contiguous with nuclear envelope)
Swellings at end of sacs - for vesicles formation/ vesicles at end of sacs
No ribosomes

Question 2

How is it possible to deduce that this figure is a transmission electron micrograph and not a scanning electron micrograph

Answer 2

Can see internal structures

Cannot see surface contours

Question 3

Describe the fluid mosaic model of membrane structure

Answer 3

• phospholipid bilayer
• fatty acid core/ fatty acid tails orientated inwards
• proteins within the membrane
• hydrophobic and hydrophilic regions
• proteins scattered in phospholipid bilayer
• integral and peripheral proteins

Question 4

Suggest why the inner membrane of the mitochondrion is less permeable than the outer membrane

Answer 4

Reduced gaps between membrane molecules
Higher proportion of phospholipids with saturated fatty acids
Fewer unsaturated fatty acids, so fewer kinks in tails
Channel/ carrier proteins
Higher proportion of cholesterol molecules