Plasma Membrane And Organelles Flashcards
What do cells do
- Make things, make things to be alive, this is called to manufacture cellular materials
- obtain materials
- by making stud and being alive, the cells will make a lot of waste products and we don’t want the waste products so we need to get rid of them and this requires a lot of
- energy , we need energy to also make sure that everything is controlled all the time.
What is the plasma membrane and explain what the semi permeable barrier does in the plasma membrane
The cell has a plasma membrane, this is at the boundary of each cell and it provides special conditions within the cell, the plasma membrane is very important for the cell just to exists, it allows things to move across if we wanted to, and we call this the SEMI PERMEABLE BARRIER.
The semi permeable barrier controls movement of substance in and out of a cell, it also controls how big a cell can get. The more smaller a cell is, the easier it is for things to pass across the membrane / easier to get rid of. And so the more larger the cell is the harder it is for the cell to get nutrients in and get waste out and then we reach a point where the cell is unable to get any nutrients to survive as it is too big
What are some things that we want to pass across the plasma membrane
Nutrients, oxygen, waste - as we don’t want waste to be just sitting inside the cell.
What is the plasma membrane made out of
Phospholipid bilayer
What is the phospholipid bilayer
It is 2 layers of phospholipid, it has a hydrophilic head and a hydrophilic tail and it arranges itself with fat acids in the middle. These fat acids effect the membrane fluidity and stuck inside is a whole bunch of protons
Is the plasma membrane static and no and explain why
The plasma membrane is NOT static, so therefore it is always moving, they are always swapping places with each other or protons are coming in and out. Fusion of vessical are going to attach to it and because of this we want the consistency of the phospholipid bilayer to be just right. For example we don’t want to to be to liquid or too solid
What are the things that keep the phospholipid bilayer at the right consistency
- saturation, is its saturated it will be hard to move around, it will be packed ticketless together and have less fluids and more viscus. if it’s unsaturated, the tails will prevent the tight packing and there will be more fluid and less viscus
-Temperature - high temperature means that it’s more fluid and low temperature means that it’s less fluid
-cholesterol- thus helps stabilise fluidity
What is cholesterol
Helps stabilise fluidity
What are the plasma membrane proteins
- the proteins determine the function of the membrane as different proteins have different jobs and the proteins are specific to the cell
-each cell has many types of proteins and can be there at any time depending on what the cell needs - and as said before proteins have multiple functions
What are the five functions of the membrane protein
- signal transduction
- cell recognition
- intracellular joining
- linking cytoskeleton and ejxtracelleur matrix
- membrane transport
What is signal transduction
- taking information in one form from one location to another form in another location, its job is to relay messages from the body ( or environment ) into the cell and as a result the cell might grow, divide, move or make something. How this works is that is binds onto the receptor and when the receptor gets the information it passes it onto another protein and another and another so that the cell can grow, divide, more or make something
What is cell recognition in function of a membrane protein
Another important function of membrane proteins is in identification and recognition between cells. This particular function is useful in the immune system, as it helps the body to recognize foreign cells that may be causing infection. His often includes glycoprotein ( this is proteins with added sugars )
What is intracellular joining in membrane function
Some cells will float around and do there own stuff while other cells will work together
For example the skin is made up of sheets of cells that work together and the proteins often form long lasting connections
What js linking cytoskeleton and extra cellular matrix
On the inner side of the membrane, the integrins are linked to the cytoskeleton. Integrins anchor the cell to the extracellular matrix, with also of fibres and proteins and sugars In addition, they help it sense its environment and connect physically with something outside the cell They can detect both chemical and mechanical cues from the extracellular matrix and trigger signaling pathways in response .
What is membrane transport
This allows small amounts of molecules to move across the membrane
How do substances move across the membrane
This really depends on how small the molecule is,
- so will smal, molecules that have small volumes, membrane transport is perfect for it
- moving large substances that has large volumes will require something called, bulk transport
What are the ways to do membrane transport
- diffusion ( no energy, passive , moving down a concentration gradient, high to low concentration )
- facilitated diffusion ( no energy, passive, moving down a concentration gradient, high to low concentration)
- active transport ( needs ATP, moving across a low to high concentration gradient )
- co transport ( NEEDS ATP moving across a low to high concentration gradient )
What us passive transport
This requires no energy and you can do this in 2 types of ways,
- Diffusion, this only works for lipid soluble molecules, so glucose and ions can’t make there way across
- facilitated diffusion - this requires no energy and is the passive movement of molecules along the concentration gradient. This requires a membrane protein called channels and carriers, this is for like the glucose, sugars, the carrier proteins can change shape regarding on what they are trying to move, an example of facilitated diffusion is water as it is important that we can move water in and out of the cell as it is an essential to its survival.
Moving water across the cell what does it require
It requires channels called, Aquaporins, Aquaporins are channel proteins that allow water to cross the membrane very quickly, and they play important roles in plant cells, red blood cells, and certain parts of the kidney (where they minimize the amount of water lost as urine).
A process called Osmosis is also required, this is movement from a high water concentration to a low water concentration gradient
If you have a high water concentration in osmosis what is the solute
LOW
What js active transport
the movement (as across a cell membrane) of substances from regions of lower concentration to regions of higher concentration by the use of energy. This requires ATP, making the concentration inside the cell high
What is CO transport
the transport of one solute across a membrane from a region of low concentration of another solute to a region of high concentration of that solute
This is indirect active transport, it is one substance that is pumped across the membrane and that concentration gradient that that membrane went through js use to power the movement of a second substance against its concentration gradient
How do different parts of the cells do different things
Organelles
What are organelles
These are separate compartments inside the cell. Organelles provide special conditions for special processes
- allows specific substances to be concentrated and this allows us to form concentration gradients, moving things from one place to another
- most organelles are membrane bounded, this is because each organelles provide special conditions and that’s why they all need a phosphate bylayer
Definition- An organelle is a subcellular structure that has one or more specific jobs to perform in the cell,
