L7 Cell Membrane And Vesicular Transport

Question 1

Why is nucleus stained blue under H&E stain

Answer 1

Nucleus is heavily acidic and reacts with The basic hematoxylin

Question 2

Describe the structure of cell membrane

Answer 2

Two hydrophobic tails and a hydrophilic head
And Cholesterol
Proteins
Carbohydrates

Question 3

Whats the role of cholesterol

Answer 3

Controls fluidity of membrane

Question 4

What are the types of proteins in cell membrane and describe them

Answer 4

Integral proteins: directly incorporated within lipid bilayer
If they protrude from both sides=transmembrane proteins
Peripheral proteins: exhibit looser association with membrane surfaces (protrude from only one side)
Organelle specific membranes: proteins confer unique functions on certain organelles

Question 5

What are integrins

Answer 5

Transmembrane proteins that are linked to cytoplasmic cytoskeletal filaments and to extracellular molecules

Question 6

What is the glycocalyx

Answer 6

Fuzzy carbohydrate rich region

Question 7

Whats the significance of the glycocalyx

Answer 7

Role in cell recognition and attachment to other cells and extra molecular molecules

Question 8

What is endocytosis

Answer 8

Process whereby a cell ingests macromolecules,particulate matter and other substances

Question 9

What are the mechanisms of endocytosis

Answer 9

Phagocytosis
Pinocytosis
Receptor mediated endocytosis

Question 10

Describe phagocytosis

Answer 10

Non selective process of engulfing larger particulate matter

Question 11

Describe pinocytosis

Answer 11

Non selective process where small invaginations of the cell membrane form and entrap extracellular fluid forming a pinocytotic vesicle that may fuse with a lysosome

Question 12

Describe receptor mediated endocytosis

Answer 12

Selective process of engulfment of macromolecules and depends on interaction between 2 structures
1-receptor proteins in cell membrane=transmembrane proteins
2-ligands

Question 13

Whats the fate if the endocytotic vesicle

Answer 13

Lose their clathrin coat and fuse with early endosomes either require degradation and are transferred deeper in to cytoplasm to become late endosome
H+ pumped inside to acidify it

Question 14

What is the fate of the contents inside the vesicle

Answer 14

Receptors are separated from ligand by acidic PH
Endosome may return to cell membrane to be reused
Ligands are typically transferred to late endosomes but some are re used in ECF
Late endosome transferred to lysosome for degradation