Session 9 - Lecture 1 - Protein Targeting / Collagen Biosynthesis Flashcards

Question

25

Answer 1

A

Collagen as a example of a post-translationally modified protein

{quick 1 page brief on the diff processes – don’t need to know in masses amounts of details. all molecular detail – e.g. mitochondrial targeting – Just need to know there are things in the membrane that will transport things across.}

Answer 2

A

Proteins may be delivered to the plasma membrane via a regulated or constitutive pathway

Immunoglobulins
Albumin
Prohormones
Collagen
Fibronectin
Laminin
Receptors

Insulin
Glucagon
b-endorphin
ACTH
a-MSH
b-lipotropin
Trypsin

Golgi apparatus
trans Golgi network
newly synthesised soluble proteins for constitutive secretion
newly synthesised plasma membrane protein
newly synthesised plasma membrane lipids
unregulated membrane fusion
CYTOSOL
EXTRACELLULAR SPACE
CONSTITUTIVE SECRETORY PATHWAY
plasma membrane
intracellular signalling pathway
secretory vesicle storing secretory proteins
regulated membrane fusion
signal such as hormone or neurotransmitter
REGULATED SECRETORY PATHWAY

{diff types of secretion:

constitutive (continuously) being secreted, e.g. collagen – constantly going to be producing collagen [top list]
regulated, e.g. hormones, particular NTs – going to be released at particular times in response to a signal [bottom list]}

Answer 3

A

Collagen
• from the Greek “kolla” meaning glue
• the most abundant protein in the body (25-35%)
• most abundant fibrous protein in connective tissue
- Tendons, ligaments, cartilage, bone
- Loose connective tissue providing structure to
internal organs

{1. Greek derivative

a lot of it
Find it in a lot of things bc it’s got q a lot of strength.
3b. surrounding organs.}

Answer 4

A

Secreted protein produced by fibroblasts in connective tissue

Elastin fiber
Fibroblasts
Collagen fiber
Loose connective tissue
Fibroblast nuclei
Fibroblasts
Collagen fibers
Fibrous connective tissue

{can see it in slightly diff ways
Left: collagen fibres in loose CT – see it’s quite a lot of white blues, q diffused – other proteins as well e.g. elastins, fibroblasts whichj secrete collagen fibres that are here – fibroblast pretty small but collagen fibre is enormous compared to this – will explain later.
Right: Fibrous CT – in this case tend to see things packed full of collagen fibres – meshed between them – see this sort of idea as you look at diff sections.}