Biology 3.4-3.6

When was the Fluid Mosaic Model established?

1972

What is Active Transport?

A cell uses energy to move materials across the concentration gradient, as oppose to between the concentration gradient.

What is an electrochemical gradient?

A gradient of electrochemical potential, usually for an ion that can move across a membrane.

Phospholipid molecules have what?

A hydrophilic head and a hydrophobic tail

Hypertonic

A lot more concentrated fluid solution that the cells are sitting in.... The water flows out of the cell.

Hypotonic

A lot more water that the cells are sitting in, extracellular fluid. (Dilute Water Solution) ... The water flows into the cell.

Is endocytosis passive or active transport?

Active Transport

What are passive and active transport?

Active and passive transport are biological processes that move oxygen, water and nutrients into cells and remove waste products

Isotonic

An even amount of concentrated and diluted extracellular fluid... Water flows both in and out of the cell.

Warning signs for Passive Transport:

Carrier Proteins, Hydrogen or Oxygen, Water

What does Active Transport need?

Energy (In the form of ATP)

What is an equal distribution of substances called?

Equilibrium

Examples of Passive Transport:

Facilitated Diffusion, Simple Diffusion, Osmosis

Phagocytosis

Form of endocytosis which food is engulfed.

Pinocytosis

Form of endocytosis which liquids are engulfed.

What are the three types of osmosis?

Hypertonic Solutions, Hypotonice Solutions, and Isotonic Solutions.

What if the cell membrane is not big enough to let the substance pass?

It engulfs it and the substance becomes a part of the cell.

Concentrated:

More of the substance than water.(Example: Dilute Sugar)

Dilute:

More water than the substance. (Example: Dilute Sugar)

Osmosis

Net movement of water from hypotonic to hypertonic solutions.

Does passive transport need energy?

No.

Forms of Passive Transport?

Osmosis and Diffusion

Differences between passive and active transport?

P: Equilibrium, Does not need energy, Molecules are moved down the concentration gradient A: No Equilibrium, Needs energy in the form of ATP, Molecules are moved against the concentration gradient

Does passive or active transport move hydrogen and oxygen molecules?

Passive Transport

Is osmosis passive or active transport?

Passive Transport

Describe passive transport.

Passive transport is a naturally occurring phenomenon and does not require the cells to expend energy to accomplish the movement. Substances are able to move from an area of higher concentration to an area of lower concentration in a process called diffusion.

Examples of Active Transport:

Phagocytosis, Pinocytosis (Both types of Endocytosis), Sodium/Potassium Pump

What is the cell membrane made of?

Phospholipids (A phospholipid bilayer)

What doesn't pass through easily?

Polar substances do not pass through the cell membrane easily.

Warning signs for Active Transport:

Protein Pumps, "Engulfs"

Characteristics of the cell membrane:

Semipermeable, It is particular about what enters, Liquid-like, Porous, Contains certain molecules

Types of diffusion?

Simple diffusion and Facilitated diffusion

What passes through the cell membrane easily?

The cell membrane easily passes lipid-soluble materials, small ions, and fat-soluble drugs and vitamins through, along with oxygen.

Endocytosis

The cell membrane engulfs the material into the cell.

What is a concentration gradient?

The difference between concentrations.

The Fluid-Mosaic Model: For Dummies Website

The fluid-mosaic model describes the plasma membrane of animal cells. The plasma membrane that surrounds these cells has two layers (a bilayer) of phospholipids (fats with phosphorous attached), which at body temperature are like vegetable oil (fluid). And the structure of the plasma membrane supports the old saying, "Oil and water don't mix." Each phospholipid molecule has a head that is attracted to water (hydrophilic: hydro = water; philic = loving) and a tail that repels water (hydrophobic: hydro = water; phobic = fearing). Both layers of the plasma membrane have the hydrophilic heads pointing toward the outside; the hydrophobic tails form the inside of the bilayer. Because cells reside in a watery solution (extracellular fluid), and they contain a watery solution inside of them (cytoplasm), the plasma membrane forms a circle around each cell so that the water-loving heads are in contact with the fluid, and the water-fearing tails are protected on the inside.

Who are S.J. Singer and Garth Nicolson?

The men that came up with the Fluid Mosaic Model Theory.

Why is the plasma membrane called a fluid mosaic model?

The plasma membrane is called a fluid mosaic model, because some parts of the membrane can move around freely and change positions, since they aren't attached to other parts of the cell. Another reason is because it is composed of phospholipids, cholesterol, proteins, and carbohydrates. Last but not least, the cholesterol acts as in anti-freeze.

Describe the plasma membrane.

The plasma membrane is made up of primarily a bilayer of phospholipids with embedded proteins carbohydrates, glycolipids, and glycoproteins. It is flexible, has markers on the surface for recognition, and the surface also has receptors. In animal cells, it also has cholesterol, but not in plant cells.

What factors affect the rate of diffusion?

The rate of diffusion can be affected by extent of the concentration gradient, the mass of molecules diffusing, the temperature, and the solvent density.

Which way do the substances move?

The substances move from a higher concentration to a lower concentration.

How do viruses gain entry into a cell?

Viruses gain entry into a cell by exploiting cellular processes to gain entry into the cell, than deliver their genetic cargo.