The plasma membrane and cell transport

Why is the plasma membrane often referred to as "Fluid Mosaic"?

Fluid = because individual phospholipids and proteins can move around freely within the layer, like liquid Mosaic = because of the pattern produced by scattered proteins when the membrane is viewed from above

If a material is too large, polar, or carries a charge then it must pass through a...

Protein channel or pump to enter and exit the cell.

What types of molecules are able to pass through the membrane via simple diffusion?

Small molecules/Nonpolar molecules

Active transport definition two

The movement of ions or molecules across a cell membrane into a region of higher concentration, assisted by enzymes and requires energy.

What is the job of the plasma membrane?

The plasma membrane acts as a gatekeeper It's jobs are to... 1. regulate what enters and leaves the cell 2. provide protection and support to the cell

Endocytosis

The process of engulfing materials into cell Or is the process of taking material into the cell by means of infoldings, or pockets, of the cell membrane. The pocket that results breaks loose from the outer portion of the cell membrane and forms a vacuole within the cytoplasm. Large molecules, clumps of food, and even whole cells can be taken up in this way. Two examples of endocytosis are phagocytosis

A plant with a full central vacuole is otherwise named

Turgid

Lipid bilayer

Two layers of phospholipid molecules that create a flexible barrier

Active transport

Uses energy to move molecules "uphill" from areas of lower concentration into areas of higher concentration. Since active transport goes against the concentration, it uses ATP energy for help to "climb upwards"

What does facilitated diffusion do?

1. Molecules move along (down) a concentration gradient 2. Always involves channel (membrane - spanning ) proteins 3. Moves ions like Na+ and K+ 4. Moves large molecules.

What does diffusion do?

1. Molecules move along (down) a concentration gradient 2. Molecules pass between the phospholipids. 3. Moves polar and nonpolar molecules

What does active transport do/need?

1. Requires energy input by the cell 2. Moves molecules up along concentration gradient 3. Involves channel (membrane - spanning) proteins 4. Moves ions like Na+ and K+ 5. Moves large molecules

What is a plasma membrane made of?

1. lipid bilayer. 2. proteins 3. carbohydrate chains

What do animal and plant cells have in common?

A cell membrane.

What does a plant cell have that an animal cell does not?

A cell wall

Passive transport

A. Does not use energy to move molecules "downhill" from areas of higher concentration into areas of lower concentration.

Water can either slowly diffuse across the lipid bilayer by itself or use a special protein channel called an....

Aquaporin

Carbohydrate chains

Attached to some of the proteins, these act as chemical name tags allowing cells to identify each other.

Isotonic

Concentration is equal on both sides and cell has reached a state of equilibrium. Net is zero.

In a rate of transport vs constant concentration difference graph why is diffusion represented in a steady increasing line?

Diffusion does not require any help, therefore it is a steady line and does not level off at any point.

Proteins

Embedded in the lipid bilayer, these act as channels and pumps to move materials across the membrane (doorway for things to pass in and out)

Where do we find a plasma membrane?

Every cell has an outer layer holding the cell together called the plasma membrane or cell membrane.

In a rate of transport vs concentration difference graph, why does facilitated diffusion level off at a certain point?

Facilitated diffusion has only a certain amount of help available so it stops rising at some point.

Hypotonic

High concentration transports into cell. Low concentration transports out of cell. Too much concentration in cell makes cell burst (process of lysis)

Hypertonic

High concentration transports out of cell. Low concentration transports into cell.

Pinocytosis

In a process similar to endocytosis, many cells take up liquid from the surrounding environment. Tiny pockets form along the cell membrane, fill with liquid, and pinch off to form vacuoles within the cell

What types of molecules can across the plasma membrane without any help?

Molecules that are both small and nonpolar.

What types of molecules must pass through the membrane via facilitated diffusion?

Moves large molecules and ions like Na+ and K+

Diffusion of water is known as...

Osmosis.

In a rate of transport vs. concentration difference graph, why is active transport represented as a consistent, straight line?

The concentration difference is the same on both sides therefore it is at a state of Equilibrium, leaving the line straight and consistent line.

What is a common type of passive transport?

The diffusion of water.

Exocytosis

Vesicles fusing with cell membrane to push materials out of cell. Or the membrane of the vacuole surrounding the material fuses with the cell membrane, forcing the contents out of the cell. The removal of water by means of a contractile vacuole is one example of this kind of active transport.

plasmalysis

a. Opposite of lysis process b. When the plant cell is placed in a hypertonic environment and all the water leaves the central vacuole so the cell membrane peels away for the for the cell wall collapsing inwards

Animal cells

a. Too much water pressure inside the cell makes it burst (lysis, hypotonic) b. Not enough water pressure inside the cell causes the cell to shrivel up. c. Normal animal cells keep their shape only an iso tonic environments.

What do plants consist of, in structure?

a.Plant cells have a strong, rigid outer cell wall and a large central vacuole to store water. b. They need lots of water pressure inside the vacuole in order to grow tall, strong, and straight towards sun. c. Water is needed for plants to carry out photosynthesis

Phagocytosis

extensions of cytoplasm surround a particle and package it within a food vacuole. The cell then engulfs it. Amoebas use this method of taking in food. Engulfing material in this way requires a considerable amount of energy and, therefore, is correctly considered a form of active transport.