Cell Surface Memebrane Flashcards
Why don’t molecules freely diffuse across cell surface membrane
Not soluble in lipids therefore cannot pass through the bilateral
Too large to pass through channels in the membrane
Of the same charge as protein channel and so even if they are small enough they are repealed
ElectricLly charged therefore difficulty passing through non polar sections such as hydrophobic tails
Why is membrane called fluid
Because individual molecules can move relative to one another this gives membrane the flexible structure so constantly changing shape
Why is membrane mosaic
Protiens embededd in the phospholipid bilateral vary in shape size and pattern in the same way as a mosaic
What is diffusion
The net movement of molecules or ions from region where they are more highly concentrated to one where concentration is lower until evenly spread out
Where does energy come from in diffusion
From natural inbuilt motion of the particle
What are the three things to understand how atp doesn’t provide energy
All particles are constantly moving in motion due to kinetic energy that the possess
The motion is random and in all directions no set pattern
Particles are constantly bouncing off each other as well as other objects
What is facilitated diffusion
It’s a passive process relies on only the inbuilt motion of the diffusing molecules it occurs down a concentration gradient but with the use of protein channels or carrier protiens
What are protein channels
Water filled hydrophilic tubes which allow water soluble substances to pass through
They are selective and open in prescribed of particular ion which binds to the protein causin f it to change shape and release the ion to other side
What is a carrier protein
Protiens which span across the membrane
When molecule specific to the protein is present it binds to the protein causing it to change shape so molecules is released inside of the membrane
What is osomosis
The passage of water from a region of high water potential to low water potential through selectively permeable mebrane
What is selectively permeable
They are permeable to water molecules and other small molecules but not large molecules
What is waterpotential
Measured in units of pressure the water potential is the pressure created by the water molecules 25.c is 100kpa
What are some of the principle of water potential
The addition of dilute to pure water will lower its water potential
Water potential of a solution must always be less than zero
More solute addedthe more concentrated so more negative
Water will move by osomsois from an area of high concentration to low concentration
What will happen to animal cells in high water potential and why
It will absorb water by osomosis as it has lower water potential cell surface membrane are very thin and cannot stretch a lot so cell membrane will therefore break lysis
What is the protoplasm
The outer surface membrane the nucleas the cytoplasm and the inner vacuole mebrane
What is active transport
The movement of molecules from an area of low concentration to high concentration against concentration gradient and using atp and carrier protein
What is atp used directly for
Directly move molecules
Individually move molecules using a concentration that has already been set up co transport
How is at different to diffusion’s
Metabolic energy in form of atp is needed
Substances moved against a concentration
Carrier protiens act as a pump
Process is very selective
Describe active transport
Carrier protein span the plasma membrane and bind to molecule or ion being transported
The molecules bind to the carrier protien
Once inside the atp binds to protien and it’s hydrolysed to form adp and phosphate as a result the carrier protien changes shape in presence of phosphate molecule and release the ion
The phosphate molecule is then released which Male protien revert to original shape and recombine with adp to form atp during respiration
How is Vikki adapted
Has microcilli which increase surface area which allows more carrier protiens so diffusion and active transport can take place
How are things absorbed in the ileum
Carbs are being digested there are higher levels of glucose and amino acid in ileum than the blood
So glucos then moves by facilitated diffusion into the blood
The blood is continuously moving so helps maintain concentration gradient
How does co transport word
Sodium ions are actively transported out of epithelial cells into the blood using a carrier protien
This increase the concentration gradient between the cavity and the epithelial cells as there is less sodium in the epithelium cells so sodium ions diffuse down this gradient through carrier protien carrying an amino acid or glucose with them
The glucos then pass into the blood through facilitated diffusion
What is special about the corralspott
Sodium moves into the cell through diffusion whereas glucose and amino acid move into the cell against concentration gradient using active transport the movement of ions is powered by the movement of sodium ions tea their than atp it powers the molecules to move
