unit 6 and 7

Cell junction types

Tight junction, desmosome junction, and gap junction

Tight junction

Inpermeable junction that encircles, the cell seals cells together

Desmosomes

Anchor cells together for strength

Gap junction

Allow communication and exchange of small molecules between cells and allows chemical substances to pass

Cell adhesion molecules (CAMs)

They are proteins on the cell surface that helps cells stick to each other or on the extracellular matrix

Anchor cells to the extra cellular matrix

Assist in movement of cells past one another

Rally protective white blood cells to injured areas

There are cadherins, integrins, selectins, and immunoglobulins

Cytoskeleton

Skeleton of the cell

Dynamic series of rods running through cytosol

Consist of microtubules, microfilament and intermediate filaments

Microtubules

Made from protein tubulin

Come from the microtubule organizing centre in the centrosome

cell shape, cell movement, vesicle transport

Motor molecules

Protein complexes that function in motility

Myosin protein converts chemical energy to mechanical energy

Powered by ATP

Attached to receptors on organelles walk up microtubules and microfilaments

Transport organelles

Microfilaments

Dynamic strands of the protein actin

Attached to the cytoplasmic side of the plasma membrane

Cell structure, cell movement and cell cortex

Attaches to cams and function in endocytosis and exocytosis

Intermediate filaments

Tough in soluble fibres with high tensile strength

Resist pulling forces on cell and help form demo results

Uses keratin

Extra cellular matrix

Long collagen fibres in a elastic bed

Anchor cells within and between tissues

Endo membrane system

System of organelles that function to produce store and export biological molecules

Degrade potentially harmful substances

The system includes

Nuclear envelope smooth and rough endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles, transport vesicles, and plasma membrane

Endoplasmic reticulum

interconnected tubes and parallel membranes enclosing cisternae

Continuous with the nuclear membrane

Rough and smooth

Rough ER

External surface is studied with ribosomes

Makes all secreted proteins

Responsible for the synthesis of integral membrane proteins

Ribosome

Contain protein, and r RNA

Site of protein synthesis

Signal mechanism of protein synthesis

mRNA - ribosome complex is directed to rough ER

SRP - is released and polypeptide grows into cisternae

At the er, the Protein folds into three-dimensional

Protein is enclosed in a transport bicycle and moved towards Golgi apparatus

Smooth ER

Tubules arranged in a looping network

Catalyzes the following reactions in various organs of the body

Liver- lipid and cholesterol metabolism

Testees- synthesis of steroid based hormones

Intestinal cells - absorb synthesis and transport of fats

Skeletal and cardiac muscle - storage and release of calcium

Golgi apparatus

Stacked and flattened

Functions in modification, construction and packIng of protein

Transport vessels from ER fuse to Golgi

lysosomes

Circle membranous bags containing digestive enzymes

Digest, ingested, bacteria, viruses, and toxins

Degrade non-functional organelles

Breakdown, glycogen, and release thyroid hormone

Breakdown non-useful tissue

Secretory lysosomes are found in white blood cells, immune cells, and melanocytes

Synthesized by Golgi apparatus

Peroxisomes

Membrane is sacks containing oxidases and catalases

Detoxify harmful or toxic substances

Neutralize dangerous free radicals ( highly reactive chemicals with unpaired electron)