Endobrane System And Bulk Transport

Question 1

What is the endomembrane system made up of

Answer 1

Endomembranes are made up of a lot of organelles, what the endomembrane include is that it starts off with the nuclear envelope
- endoplasmic reliclum ( it’s either smooth or rough ) and this is where things are made
- Golgi apparatus, this is the package place
- vesicles, this is bubbles surrounded by membrane , and this is the directions, it tells us where to go
- lysosomes
- vacuoles
- plasma membrane

Question 2

How do you move proteins out of the cell

Answer 2

1) synthesise proteins -this happens in the endoplasmic reticulum ( making the proteins )
2) tag and package - once we have made the protein, we can package them up, modify them and label them to where they need to go , in this case it is the Golgi apparatus
3) deliver -use vesicles, the vesicles will transport the proteins from one place to place, in this case it is the plasma membrane and also the vesicles are made up of the same thing as the plasma membrane and so it can fuse with membrane of organelles

Question 3

What is the endoplasmic retidum ( ER )

Answer 3

There are 2 types ( rough and smooth )

Question 4

What is the smooth ER ( SER ) function and give an example

Answer 4

• metabolism of carbohydrates
• making lipids that form the membrane
• detoxifying anything that can harm the cell , for example drugs and toxins
• it stores calcium ions, we are able to release the calcium to make something fantastic in the cell.

EXAMPLE, the liver will need a lot of SER as it detoxifies the blood, for example if you think about alcohol or do drugs, they could go through your blood and harm your body, the ,over will break these things down and to do this we need SER and so the liver needs a lot of SER,.

• SER is only there if you need it or not, so if at times you need a lot of SER then a lot of SER will be active but if you don’t need it as much it will not be as active.

Definition of the function ! Smooth ER is responsible for the synthesis of essential lipids such as phospholipids and cholesterol. Smooth ER is also responsible for the production and secretion of steroid hormones. It is also responsible for the metabolism of carbohydrates.

Question 5

Rough ER function

Answer 5

How we identify the RER is that is has dots that make it look rough
Its main job is involved in protein synthesis. We have a lot of proteins in our cells all of the time, the proteins are either going to be realised ( secreted ) leaving the cell or are going to become MEMBRANE BOUND PROTONS ). These enter the lumen ( interior ) of the RER

Question 6

What is the Lumen

Answer 6

This is in the RER, amd this is a when the proteins in RER become membrane proteins and these membranes proteins enter the lumen. When they enter they get processed, and they get changed and get modified in different ways to give a new structure to help with their function and then they are passed on along through rest of the endomembrane system where they can be released when they reach the plasma membrane

Question 7

What is free ribosomes

Answer 7

These are oritems that float around the cytoplasm, these are ribosomes that are not attached to the RER And this is where cytoplasm proteins are made

Question 8

What are the 2 things that can happen to the proteins in RER

Answer 8

• secreted, leaving the cell
• become membrane bound proteins, enter the lumen

Question 9

What js the Golgi complex

Answer 9

These are membrane bound flattened layer / structure

Question 10

What is the function of the Golgi

Answer 10

• they receive the proteins, Golgi is a cell organelle that helps process and package proteins and lipid molecules
• how this happens is that the vestals are going to carry the proteins that were made in the endoplasmic retcium. Carry it over to the Golgi, to the CIS face and it’s going to fuse with the Golgi and after the proteins inside the lumen of the Golgi and in there we can modify the proteins some more and we can sort them and then ship them off using the Trans face

Question 11

What is the cis and trans face.

Answer 11

Proteins from the ER enter the CIS face and go out through TRANS face in three GOLGI

Question 12

How do the modifications happen in the Golgi

Answer 12

They mostly happen in sacks and once the modification is finished and ready to go , there is going to be more vesicals that are butting away from the trans face ( the trans face faces towards the plasma membrane) and they leave the trans face and is ready to be delivered

Question 13

How do we modify the proteins

Answer 13

1) glycosylation - this is the process in which we are adding carbon hydrates to proteins and if they don’t need the carbohydrates we can just adjust them to whenever they need to be. This helps determine the function of the protein.
2) polysaccharides- Golgi also makes polysaccharides, these are chains of sugars that can be secreted from the cell

Question 14

How do we sort proteins, modifying the proteins

Answer 14

To make sure that the Golgi is in the correct vesacal, and in order to do this, we add molecular markers. These are little tabes that tell the protein what visical it needs to be in. This is to make sure the proteins are properly tagged and this is called “sorting” so it goes in the right place.

Question 15

Direct visical trafficking

Answer 15

This is after we add the “molecular tags, so it can know where to go and is transported to the right place to pass on the contents to its DOCKING SITE, the docking site is basically the proteins binding to visical and they fuse and realise the content, either outside the plasma membrane or release protein to the plasma membrane so it can become a membrane protein

Question 16

What are vesicals

Answer 16

-These are little membrane bonded lipid bylayers
- inside there is some fluid / cytoplasm and also inside is whatever we are trying to transport

Question 17

What are ways that we can classify vesicals

Answer 17

• transport vesicals , this is moving from one place to another in the cell
• secretory vesicles , these head to the plasma membrane, fuse with it and then release the content

Question 18

liposomes

Answer 18

Liposomes are small artificial vesicles of spherical shape that can be created from cholesterol and natural non-toxic phospholipids, there main function is to deliver drugs and vacuoles into our cell, this is because they are made up of the same stuff as the plasma membrane

Question 19

What is Bulk transport across the plasma membrane

Answer 19

This is how we Get lots of something across a membrane

Question 20

How can we get something across the membrane using bulk transport if it’s a solid

Answer 20

1) exocytosis - this is the process of moving things out of the cell like waste, it transports materials out of the cell, like glycoprotein or delivers it to the cell surface, and there are 2 types of exocytosis, the first one is cordite, this releases extraceller matrix proteins and the second one is REGULATED exocytosis-this is controlled, it’s told what to do and when to do it and a signal is needed to tell the cell to release something, for example hormones, hormones don’t just get released at random, they travel through the blood to somewhere else.

2) endocytosis , this is bringing things in the cell.if we are moving something big and solid we call this PHAGOCYTOSIS, this is the uptake of food particles, it forms a phagocytic vacuole, these reach out and fuse into a bubble and bring the food particles inside the lysosome which is digested by the lysosomes, the lysosome has enzymes that will then digest and break down the food particle into something a cell can use.

Question 21

Bulk transport across plasma membrane if it is something fluid the function

Answer 21

This is called PINOCYTOSIS, these can rake up extracelleir fluids containing various solutes, for example sugars and proteins.
- the process is that it will form a little vesicle and to do that we get proteins called coat proteins from inside of the membrane and it starts shaping the vesicle
- the fluids from outside them float in and then we close it and move it away from the plasma membrane and we are left with a vesicle with random assortment and this is called non selective uptake and this is random so if the cell does not need these random stuff and wants particular stuff then we can do something called,
RECEPTOR - medicated endocytosis, this is the process in which we use receptors, these are just membrane proteins that combine with different things and allows us to rake up bulk quantities of specific substances even if outside of the cell is at low concentration and the receptors will only bind to specific substances that they want

Question 22

What are lysosomes

Answer 22

This has enzymes that will break up big particles, how it does this is that the enzymes will get into the food particle and break up it into little tiny blocks. However enzymes requires very specific environments, for example only some work in acidity and the environment is probably different from the rest of the cell. Lysosomes main function is to break down things and they can digest many other things for example if we don’t need something in our body anymore the lysosome will break it down and can use it for something more useful in the cell. This is called autophagy, this is breaking down things in the cell that we no longer need in order to keep the cell healthy

Lysosomes are membrane-enclosed organelles that contain an array of enzymes capable of breaking down all types of biological polymers—proteins, nucleic acids, carbohydrates, and lipids.

Question 23

What is autophagy

Answer 23

This is breaking down things using lysosomes, to break down things in the cell in order to keep the cell healthy