Organelles are

structures within the cell. Eukaryotic cells

membrane bound organelles.

The nucleolus is the part of the nucleus where

are synthesised. It is the region where

is transcribed into ribosomal

The rER is arranged in stacks known as

The sER have a more tubular structure with two faces known as

faces towards the plasma membrane and

faces towards the nucleus

Tight junctions are called

These are points on adjacent lateral membranes that form close contacts at

membranes.

They form a network of contacts and the more elaborate the network, the

seal. They act to seal paracellular pathways.

Adhesion belts are called

Usually formed just basal to the

Transmembrane adhesion molecule is

Desmosomes are known as

Gap junctions are known as

made up of pores from

identical subunits in the membrane. These pores are continuous with the adjacent cell membrane

This allows the passage of

between cells.

Secretion, transport and absorption are usually

The key to epithelia function is membrane

Cell-cell junctions separate membranes into two domains, the

and

Tight junctions

paracellular permeability.

The apical and basolateral domains

separated from the outside.

For molecules to cross the epithelia, they need to go

the cell.

Ion channels are placed on

of the epithelial cell membrane to ensure directional flow

Secretory tissues can be

or

ECM surrounds connective tissue and is a complex network of

It has both fibrillar and non-fibrillar components, it has multiple functions:

Provides support, determines mechanical properties,

influences growth and is essential for development

All connective tissues contain

in the ECM. Collagen type 1-3 are

type 4 is in the

Glycoproteins include: Fibronectin, fibrinogen and

Proteoglycans include: Aggrecan, Versican, Decoran and

Collagens are major proteins in bone, tendons and

The number of collagen types is

Each collagen is made up of

forming a triple helix

Every third amino acid in the chain is a

It faces the interior of the helix as it is

All newly synthesised chains have non-collagenous domains at the N- and C- terminals, these are removed

secretion of the collagen.

Hydroxylation of lysine and proline causes

between adjacent collagen molecules.

These are done by prolyl and lysyl hydroxylases which require vitamin c and

Collagen and elastic fibres are

which limits the stretching.

Elastic fibres are made up of a core of

Elastin is an unusual protein as it consists of two types of segments that alternate along the chain:

hydrophobic regions and alpha helical regions

Laminins are

They have

chains, alpha, beta and gamma, they form a cross shaped molecule.

They are very large and can interact with cell surface receptors

They can self associate but also interact with other components of the

Specific chain mutations are associated with muscular dystrophy and epidermolysis

Globular domains are used to interact with

and help in self assembly

Absence of alpha-2 chain causes

muscular dystrophy

These are found in the

They're glycoproteins present as an insoluble fibrillar network or

They are multi-adhesive and form dimers

They are derived from

gene(s). Variation is achieved by alternate

No known mutations as fibronectins are vital.

They form a mechanical continuum with the actin cytoskeleton in cells by binding with

on the cell surfaces.

Proteoglycans are heavily

Consist of a core protein with one or more

chains covalently attached. They're long unbranched sugars consisting of repeating disaccharides.

They occupy a

volume relative to their mass and are hydrated gels that are very resistant to compression.

There are several proteoglycan groups: Basement membrane e.g.

Aggregating e.g

Small leucine-rich e.g.

Cell surface e.g

In GAG chains, one of the two repeating sugars is always an

Many are carboxylated or sulphated and are charge is