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Science Membrane Qz.

VWA science membrane quiz....7th grade

The cell membrane protects what? The cell
Certain materials need to enter the cell. Some important materials a cell needs come through the membrane. Some are: water, food, oxygen
The mebrane helps cells get rid of waste and collect important materials(move in and out)
The membrane can be like a gatekeeper-lets certain things in and out.
Between the lipids there may be protein and carbohydrate molecules attached.
Carbs and proteins help by: helping materials move through the membrane.
A membrane is selectively permeable. What does this mean? certain substances are allowed to enter the cell while others cannot enter.
The structure of a cell membrane reflects its: function.
Fats do not mix with what? water
the fat molecules on the membrane loves or does not love water? loves water.
There are two types of transport: Passive and active
Through passive transport what happens materials like water, gases, or dissolved solutions, cross the membrane without using energy.
What are the 2 types of passive transport? diffusion and osmosis.
What is diffusion? The movement of materials from areas of high concentration to low concentration.
What types of molecules travel through diffusion? Small and gas molecules.
Diffusion occurs until: Both concentrations are equal.
How do molecules move: molecules gather in an area, collide, and then push away.
Molecules that are too big to get across use: facilitated diffusion.
What is facilitated diffusion: The process in which proteins create a channel for the other molecules to pass through.
The molecules need "assistance" because they are too fat.
What is an example of a molecule that uses facilitated diffusion? Glucose.
It is a carrier protein:True or False True
What is osmosis: The diffusion of water molecules across a cell membrane(selectively permeable)
Osmosis is a form of: Passive transport
Does osmosis use energy No.
Under certain conditions, osmosis can cause water to move more quickly out than in. This results in: the cytoplasm shrinking and the organelles in it pulling away from the membrane. If conditions don't change, the cells can die.
Sometimes when they have too much water they use what: a pump-contractile vacuole.
An example is a paramecium-constantly having water come in.
Is this passive transport no
The paramecium's solution using the pump: it pumps the water out using energy.
When substances move in and out of the membrane using energy it is active transport.
In Active transport molecules move from areas of lower concentration to higher concentration.-involves energy.
They move the opposite way due to diffusion
What helps the substances move? proteins
Substances that are "picked up" and carried are Calcium, Potassium, and sodium.
Active transport includes: Ion pumps, endocytosis, and exocytosis.
An ion pump is: A pump that transports proteins and molecules from areas of lower concentration to higher concentration using energy.
When materials are too large too move through pumps.. they use endo/exocytosis.
The process of endocytosis is: a particle gets engulfed by the cell. The membrane then fuses and creates a vacuole(vessel or bubble) that is taken across the membrane into the cell where it spreads.
Does endocytosis use energy: No
What are 2 things engulfed? Bacteria and food
The opposite process is: exocytosis
The cells use energy to; get big molecules out of the cell.
Describe the procedure of exocytosis: a vacuole fuses with the membrane and the membrane opens and spills out the contents. The membrane then fuses.
Does exocytosis require energy: yes.
Created by: giugiu427