CELLULAR TRANSPORT MECHANISMS AND CELLULAR ABNORMALITIES

Cellular transport

The movement of substances into and out of the cell.

Homeostasis

The maintenance of stable internal conditions.

Types of cellular transport

Passive transport and active transport.

Passive transport

Movement of substances without using ATP.

Direction of passive transport

High concentration to low concentration.

Active transport

Movement of substances that requires cellular energy.

Direction of active transport

Low concentration to high concentration.

Does passive transport require ATP?

No.

Does active transport require ATP?

Yes.

Diffusion

Movement of molecules from high concentration to low concentration.

Factors that affect diffusion

Concentration gradient, molecular mass, temperature, solvent density, and solubility.

Osmosis

Diffusion of free water across a selectively permeable membrane.

Substance moving during osmosis

Water.

Facilitated diffusion

Movement of substances with the help of transport proteins.

Does facilitated diffusion require ATP?

No.

What helps substances move during facilitated diffusion?

Transport proteins.

Protein pumps

Membrane proteins that use ATP to move substances.

Does a protein pump require ATP?

Yes.

Example of a protein pump

Sodium-potassium pump.

Endocytosis

The process of bringing substances into the cell.

Does endocytosis require energy?

Yes.

Types of endocytosis

Phagocytosis, pinocytosis, and receptor-mediated endocytosis.

Phagocytosis

Taking in solid particles.

Pinocytosis

Taking in liquids.

Receptor-mediated endocytosis

Endocytosis that uses specific receptors to take in substances.

Exocytosis

The process of releasing substances outside the cell.

Does exocytosis require energy?

Yes.

Example of exocytosis

Release of neurotransmitters.

Easiest way to remember endocytosis

Endo = in.

Easiest way to remember exocytosis

Exo = out.

Easiest way to remember phagocytosis

Phago = solid particles.

Easiest way to remember pinocytosis

Pino = liquids.

Cellular abnormalities

Changes or problems in cells that affect normal cellular function.

Factors triggering cellular abnormalities

Viral infections, aging, oxidative stress, radiation, harmful chemicals, and environmental toxins.

Cancer

Abnormal and uncontrolled cell growth and division.

Apoptosis

Programmed cell death.

Consequence of failed apoptosis

Abnormal cells may survive and continue dividing.

Metastasis

The spread of cancer cells from the original tumor to other parts of the body.

Diabetes

A condition involving problems with blood glucose regulation and insulin function.

Insulin

A hormone that helps glucose enter cells and promotes glucose storage.

Consequence of improper insulin function

Glucose builds up in the bloodstream.

Function of insulin

Helps lower blood glucose.

Function of glucagon

Helps raise blood glucose.

What happens when blood glucose is high?

Insulin promotes glucose uptake and storage.

What happens when blood glucose is low?

Glucagon stimulates the liver to release glucose.

Cause of type 1 diabetes

Autoimmune destruction of pancreatic beta cells.

Insulin production in type 1 diabetes

Little or no insulin is produced.

Required treatment for type 1 diabetes

Insulin injections.

Main problem in type 2 diabetes

Cells become less responsive or resistant to insulin.

Can the body still produce insulin in type 2 diabetes?

Yes.