The importance of protein targeting

Question 1

Light microscopy resolution is limited
by…

Answer 1

the wavelength of light (300 – 900
nm; visible light).

Question 2

Light microscopy wavelength?

Answer 2

300 - 900 nm; visible light

Question 3

the nucleus contains…

Answer 3

… genetic information, chromosomes (23 homologous pairs in
humans)

Question 4

the nucleus is highly structured because…

Answer 4

…double membrane and pores (nuclear envelope)
strict control over nuclear traffic

Question 5

where is the nucleolar organising region located?

Answer 5

in the nucleolus on p arms of chromosomes; 13, 14,
15, 21 & 22 aggregate

Question 6

what does the nucleolar organising region contain?

Answer 6

rRNA and rRNA protein

Question 7

what is the ER encrusted with?

Answer 7

Usually encrusted with ribosomes (rough ER),.

Question 8

the ER is the site of…

Answer 8

…protein translation

Question 9

what is the ER?

Answer 9

The ER is a highly organised folded
membrane structure with a distinct
lumen biochemistry

Post-translational modifications
may occur (cleavage of pro-forms)

Question 10

What may occur in the ER?

Answer 10

Post-translational modifications
may occur (cleavage of pro-forms)

Question 12

what does the ER interface with?

Answer 12

Interfaces with golgi Cis membrane
as part of the secretory pathway

Question 13

what is the golgi?

Answer 13

Folded stack of membrane stack; contains a lumen where post
translational protein modification occurs

Question 14

Function of the golgi?

Answer 14

Packaging system creating vesicles destine for secretion or for proteins
destined to be expressed on plasma membrane

Question 15

Golgi is a central component in…

Answer 15

the cells secretory
pathway

Question 16

The golgi has what faces?

Answer 16

Has Cis and Trans membrane faces

Question 18

mitochondria membrane?

Answer 18

Double membrane, highly folded membrane lumen (cristae)

Question 19

what is mitochondria the site of?

Answer 19

Site of aerobic respiration (citric acid cycle); double membrane
required to generate proton-gradient (proton motive force) for
ATPsynthetase

Question 20

the mitochondria has its own…

Answer 20

…genome (37 genes)

• trna
• NADH dehydrogenase
• Cyt-B

Question 21

Mitochondria arose by…

Answer 21

…endosymbiosis

Question 22

what are the chloroplasts structure?

Answer 22

Double membrane, highly folded and organised inner structure, thylocloid membrane stacks and stromal space

Question 23

How did chloroplasts arise?

Answer 23

Arose through endosymbiosis (cyanobacter ancestor) – own genome

Question 24

What are chloroplasts the site of?

Answer 24

Site of photosynthesis in photo-autotrophs

Question 25

size of chloroplasts?

Answer 25

5-8 um diameter and 1-3 um thick

Question 26

What do the chloroplasts contain?

Answer 26

Contains pigments; chlorophylls, phycobilins and carotenoids

Question 27

What is the lysosome?

Answer 27

The ‘stomach’ of the cell that is formed by the fusing of endosomes and Trans golgi face vacuoles

Question 28

What do lysosomes contain?

Answer 28

Contain acid hydrolases, site of autophagy and hydrolysis of foreign agents

Question 29

What do peroxisomes contain?

Answer 29

Contain NADPH oxidase (NOX) generate an oxidative burst

Question 30

What are peroxisomes important for?

Answer 30

Important for viral / bacterial infections.

Question 31

Functions of the cell membrane?

Answer 31

- Partitions the intracellular matrix from the extracellular matrix - Controls what enters and leaves the cel

Question 32

What do cell membranes differ in?

Answer 32

Cell membranes differ in the protein expression between cell types

Question 33

What are highly specialised membrane receptors also known as?

Answer 33

ligand specific

Question 34

Highly specialised membrane receptors (ligand specific) involved in ...

Answer 34

...extracellular signal perception and channels

Question 35

What do highly specialised membrane receptors do?

Answer 35

Allow signals that are not membrane permeable to be transduced in the cell.

Question 36

What do MHC proteins do?

Answer 36

MHC proteins identify self cells from non-self cells.

Question 37

what does the cell contain an array of?

Answer 37

Thus the cell contains an array of highly specialised compartments (organelles), which have a distinct biochemical properties (proteins)

Question 38

Why do proteins in the cell know where to go?

Answer 38

because they contain signals (amino acid sequences) within the primary and tertiary structure

Question 39

Amino acids are coded for in the...

Answer 39

...genome

Question 40

Mutations in the genome may mean that ...

Answer 40

... a protein targeting signal lost