Heads - form surfaces and are hydrophilic

Tails - form the interior and are hydrophobic

It is permeable to lipid-soluble substances

water-soluble

(attracts moisture)

not water-soluble

(fear of water)

Receptors

Pores, channels and carriers

Enzymes

CAMs (cellular adhesion molecules)

Self-markers

What is the role of CAMs

(cellular adhesion molecules)

They guide cells on the move

Important for growth of embryonic tissue

Important for growth of nerve cells

Rough ER

(Studded with ribosomes)

Smooth ER

(Lipid synthesis-added to proteins arriving from rough ER, and Break down of drugs)

membranous sacs that store and transport substances

(vesicle trafficking - transporting substances into and out of cells by a fleet of vesicles.)

Two membrane layers - inner and outer.

The inner membrane folds in forming shelflike partitions called Cristae

Adenosine Triphosphate

The mitochondrian captures and transfers newly release energy (from cellular respiration) into special chemical bonds of the molecule ATP that cells can readily use.

Thin rods and tubules

Support cytoplasm

Allows for movement of organelles

Nuclear envelope

Nucleolus

Chromatin

Dense collection of RNA and proteins,

Site of ribosome production

Consists of all the cells chromosomes, each containing DNA wound around proteins.  Fibers of DNA and proteins.

Stores information for synthesis of proteins.

Physical (Passive) Process

Physiological (Active) Process

Requires no cellular energy and include:

Simple diffusion

Facilitated diffusion

Osmosis

Filtration

Require cellular energy and include:

Active transport

Endocytosis

Exocytosis

Transcytosis

Movement of substances from regions of higher concentrations to regions of lower concentration.

Oxygen, carbon dioxide and lipid-soluble substances.

Diffusion across a membrane with the help of a channel or carrier molecule.

Glucose and amino acids.

Describe Osmosis:

Movement of water through a selectively permeable membrane from regions of higher concentration to regions of lower concentration.

Water moves toward a higher concentration of solutes.

Same osmotic pressure.

Cells placed in isotonic have no net gain or loss of water

Higher osmotic pressure (water loss).

Cells placed in hypertonic solution lose water.

Lower osmostic pressure (water gain).

Cells placed in hypotonic solution gain water.

When smaller molecules are forced through porous membranes.

(i.e. small molecules leaving blood capillaries.)

Requires hydrostatic pressure.

Carrier molecules transport substances across a membrane from regions of lower concentration to regions of higher concentrations.

Requires energy.

Sugars, amino acids, sodium ions, potassium ions, etc.

An Active transport mechanism.

Creates balance by pumping 3 sodium (Na+) out and 2 potassium (K+) into the cell.

(3:2 ratio)

Pinocytosis - substance is mostly water

Phagocytosis - substance is solid

Receptor-mediated endocytosis - requires the substances to bind to a membrane-bound receptor

Reverse of endocytosis.

Substances in a vesicle fuse with cell membrane and the contents are released outside the cell.  Release of neurotransmitters from nerve cells.

Endocytosis followed by exocytosis.

Transports a substance rapidly through a cell.

Interphase

Mitosis

Cytokinesis

The cytoplasm is apportioned into the two daughter cells.

Cytoplasm division (in anaphase of mitosis)

The nuclear contents divide.

Meaning: Nucleus movement

Benign - usually remains localized

Malignant - invasive and can metastasize, cancerous

Oncogenes

Tumor suppressor genes

They normally regulate mitosis.

If inactivated they are unable to regulate mitosis and cells are known as "immortal".

Can divide to form two new stem cells (self renewal)

Can divide to form a stem call and a progenitor cell.

Can give rise to a restricted number of cell types.

(can follow several pathways, but not all of them).

Programmed cell death

Acts as protective mechanism

Is a continuous process