Cell

Question 1

Plasma membrane is made up of

Answer 1

Phospholipid bilayer - hydrophobic groups face inwards, polar groups externa

Transporters, receptros, invaginations and evaginations

Question 2

What size are mitochondria

Answer 2

2 um

Question 3

What occurs at the outer membrane of mitochondria?

Answer 3

Lipid syntehsis
Largen channel forming proteins

Question 4

What happens in the intermembrane space?

Answer 4

Proteins responsible for transport of metabolites between cytosol and outer comparmtnetWha

Question 5

t happens at the innermembrane of mitochondria? Structure?

Answer 5

FOlds / cristae

Electron traensport chain
ATP synthesis
TRanport proteins that allow metabolites in and out of matrix

Question 6

What are the functions of mitochondria

Answer 6

ATP sytnehsis
ATP breakdown
Calcium store
Involved in apoptosis

Question 7

What cells have no nucleus

Answer 7

Red blood cells

Question 8

What is chrmoatin?
What is a nucleosome?

Answer 8

Long strands of DNA, RNA and associated nucleoproteins

Nucleosome = DNA assocaited with 8 histones

Question 9

What is heterochromatin

Answer 9

Electron dense and distributed around the periphery of the nucleus in discrete masses within the nucleus - DNA assocaited with nucleoproeints but not actively undergoing RNA synthesis.

INACTIVE

Question 10

What is euchromatin

Answer 10

Euchormatin - electron translucent - DNA is actively undergoing RNA synthesis

ACTIVE

BEads on string
Activated by acetylation

Question 11

What is the endoplasmic retinculum

Answer 11

Bilatyered phospholipid membranes

Question 12

What is the rough ER? Function?

Answer 12

Bilayered phospholipd membrane with ribosomes (RNA and protein)

Secretory, lysosomal and membrane protein assimilation on surface

More highly developed in secretory cells such as the lacrimal gland acinar cell

Synthesised proteins from ribosome enter ER and translationally folded for secretion via golgi apparatusW

Question 13

What happens at the smooth ER

Answer 13

Site of synthesis for lipids, triglycerides, steroids

Highly developed in RPE and meibomian gland cells

Question 14

What is the function of the golgi apparatus?

Answer 14

Falttened smooth membrane sacs and vesicles

Translational modifcation of secretory and membrane proteins by sequential glycosylation reactions

Question 15

How many functional regions of golgi

Answer 15

5

Cis golgi network - connection with ER entry point
Cis golgi
Medial golgi
Trans golgi
Transgolgi network - exit point for vesicles

Question 16

What are peroxisomes?

Answer 16

Contain enzuymes that funciton in oxidatie reactions which produce hydrogen peroxide and other organic peroxides e.g catalase

Question 17

What are the structures of the cytoskeleton?

Answer 17

Microfilaments
Made of actin
Dynamic and contractile
7nm

Microtubules
Made of tubulis
Mobile, dynamix
24nm diameter

Intermediate filaments
Robust durable
10nm diameter

Question 18

What are the three cell junctions

Answer 18

Tight (occluding junctions) zonula occludens

Anchoring junction

Communicating (gap) junctions

Question 19

What are tight (occluding) junctions composed of

Answer 19

Occludin and claudin

Question 20

What is the funciton of tight junctions

Answer 20

Seal neighbouring cells together so that water soluble molcules cannot pass between cells

Between epithelial

Question 21

What are the funciton of anchoring junctions?

Answer 21

Maintaining tissue integrity

Link cellular cytoskeleton with that of neighbouring cell or the extracellular matrix

Consist of intracellular attachment protein
Transmembrane linked glucoprotein on anoterh cell

Question 22

What do adherens junctions do?

Answer 22

Join actin cytoskeletons together

Question 23

What do desmosomes do?

Answer 23

Anchoring sites for intermediate filaments in cell to cell adhesion and provide tensile strength

Question 24

What are the cell adhesion proteins of the desmosomes?

Answer 24

Desmoglein and desmocollin

MEmbers ot he cadherin cell adhesion moelcule family

Bridge the space between adjacent epithelial cells by homophilic binding of extracellular domains to other desmosomal cadherins on adjcent cells

Calcium dependent

Question 25

What are hemidsmosomes?

Answer 25

Attach to the extracellular matrix Use integrin cell adhesion protins Connect the basal aspect of cells to the basement membrane

Question 26

What are gap junctions? Function?

Answer 26

Do not seal membranes together or restrict the passage of material between membranes Allow inorganic ions carrying current and water soluble molecules to pass from one cell to another Electrical and metabolic cell coupling

Question 27

What is a gap junction composed of

Answer 27

2 connexons - hemi-channels Cross intercellular space Molecules of up to 1000Da can pass through a pore

Question 28

What are cadherins?

Answer 28

Glycoproteins that form part of a desmosome and invovled in cell adhesion Calcium dependent

Question 29

What are integrins? Functions?

Answer 29

Receptors that mediate attachment between a cell and tissue surrounding it Attachment of cell from ECM and signal transduction from ECM to cell Invovled in immune response, cell migration and viral cell binding

Question 30

Where are L-selectins?

Answer 30

Leukocytes

Question 31

Where aer E electives

Answer 31

Activated endothelial celss

Question 32

Where are P-selectins

Answer 32

Activated platelets and endothelial cells

Question 33

What are selectins? Functions

Answer 33

Calcium dependent cell adhesion molecules Heterophilic bidning to carbohydrate ligands Leukocyte endothelial interactions Local chemical mediators such as histamine, thrombin, cytokines, TNF-a Results in trolling of cells across endothelial cells until integris are activated