Biology - Lecture 5 (Neurons)
- Created by: Former Member
- Created on: 07-04-16 18:22
View mindmap
- Lecture 5 - Neurons
- The brain contains neurons, and neurons are like eukaryots...
- they have a nucleus that contains DNA, they have mitochondria,a cytoplasm and a cell membrane
- The cell membrane (any cell in the body)
- Phospholipid (onion sprout) made up of the phosphate head, and two fatty acid tails (legs)
- The phospholipids form a bi-layer. Anything that wants to get into the cell has to get past the phospholipid bi-layer.
-
This membrane is
called selectively permeable, it will let some things through and other
things have to go through extreme lengths to go through.
- Anything electrically charged cannot go through this bi-layer. The molecules that can go through are things like water, oxygen, glucose, and amino acids.
-
This membrane is
called selectively permeable, it will let some things through and other
things have to go through extreme lengths to go through.
- The phospholipids form a bi-layer. Anything that wants to get into the cell has to get past the phospholipid bi-layer.
- The fatty acid tails are hydrophobic.Phosphate head is hydrophilic.
-
Some molecules can
diffuse through the membrane = anything
that moves from an area of high concentration to an area of low concentration
down the concentration gradient.
- If there are less particles or molecules on one side of them membrane, then molecules will randomly move to make it even (all about equilibrium).
- Phospholipid (onion sprout) made up of the phosphate head, and two fatty acid tails (legs)
- A protein is a chain of amino acids
- A transmembrane protein is one that has a channel all the way through. These channels only
allow certain molecules to pass through (e.g. sodium, potassium).
- Other little things that hold membrane together: cholesterol molecules, glycolipids and glycoproteins (which look like trees) that are receptors and are specialised to only receive messages from certain molecules.
- A transmembrane protein is one that has a channel all the way through. These channels only
allow certain molecules to pass through (e.g. sodium, potassium).
- Three important proteins in the membrane
-
Pumps use ATP for energy, and can push things out of the cell.
-
What do pumps do for the cell?
- The sodium-potassium pump pumps three Na out for every two K in. To change the shape in order to allow for that requires ATP (energy).
- The calcium pumps take calcium out of the cytoplasm (Ca2+).
-
Pumps make the concentration of the ions different, relative to inside
and outside of the cell.
- Osmosis: the movement of water molecules from an area of high concentration to an area of low concentration down the concentration gradient.
-
What do pumps do for the cell?
-
Ion channels = sodium, potassium, chlorine or calcium. Don’t
use energy, pass through by diffusion; channels open and close by changing
shape.
-
What do channels do for the cell?
- They allow ions across the brain, such as sodium, potassium and calcium.
- Most channels are made from four proteins that have a central pore (channel).
- They have a selectivity filter, only allow certain ions of a specific charge, size and shape through the membrane.
-
Cell membranes have potassium
leak channels which are always open and let potassium out but not
sodium.
-
The
channels are really important because they allow for more potassium to leave
the cell
- Which means that the outside is more positive than the inside of the cell and so electrostatic forces start out pull the potassium back into the inside.
-
The
channels are really important because they allow for more potassium to leave
the cell
-
What do channels do for the cell?
- Receptors = can bind to specific molecules, and once they’ve bound they transmit information across the membrane.
-
Pumps use ATP for energy, and can push things out of the cell.
- Periodic table
- Groups 1&2 lose
electrons easily. Group 17 all gain electrons easily
- When you have an atom or a molecule, you have balanced protons and electrons.
-
A positive ion (Na+
(sodium), K+(potassium)) is a cat ion, they have more protons than electrons,
which makes them more positive.
- A negative ion (Cl- (chlorine)) have more electrons than protons, and are anions.
- Groups 1&2 lose
electrons easily. Group 17 all gain electrons easily
- The brain contains neurons, and neurons are like eukaryots...
Comments
No comments have yet been made