DLISC1 - week 2

Question 1

what are the 4 main componenets in plasma membrane?

Answer 1

1. cholestrol
2. phospholipid bilayer
3. proteins
4. carbohydrates

Question 2

function of cell/plasma membrane

Answer 2

controls the movement of substacnes in and out of the cell
semipermeable membrane that surrounds the cytoplasm
protects the integrity of the cell by allowing certain substances into the cell whilst keeping others out
support the cell by maintaining shape

Question 3

explain glycoproteins (type of carbohydrate)

Answer 3

Glycoproteins are membrane carbohydrates linked to proteins. These protein chains account for the majority of protein chains found on the cell membrane. These compounds also help with cell-to-cell recognition.

Question 4

explain glycolipids (type of carbohydrate)

Answer 4

Glycolipids are membrane carbohydrates linked to lipids. They account for 5% of the lipids in the cell membrane. These carbohydrate chains help in cell-to-cell recognition.

Question 5

What is osmosis?

Answer 5

It is a type of diffusion in which water moves across a plasma membrane or any other selectively permeable membrane from a region of higher water concentration to a region of lower water concentration.

Question 6

osmosis - hypertonic

Answer 6

concentration of solutes is higher on the outside relative to the inside. if a cell is in a hypertonic environment, water will move out of the cell

Question 7

osmosis - isotonic

Answer 7

inside and outside have the same concentration so there is no water flow

Question 8

osmosis - hypotonic

Answer 8

concentration of solutes is lower outside than inside the cell, so water will move into the cell

Question 9

what is solute?

Answer 9

a substance dissolved in another substance, usually the component of a solution present in the lesser amount

Question 10

what is solvent?

Answer 10

a usually liquid substance capable of dissolving or dispersing one or more other substances

Question 11

explain passive transport

Answer 11

Does not require energy, and uses a concentration gradient (moves from higher to lower concentration)
there is a simple diffusion and facilitated diffusion which occurs until the concentration is equal on both sides

Question 12

what is simple diffusion

Answer 12

molecules that can freely pass through the membrane are controlled by the concentration gradient

Question 13

what is facilitated diffusion

Answer 13

aided by a carrier protein and controlled by a concentration gradient

Question 14

what is active transport

Answer 14

Does require energy
Goes against a concentration gradient (can move things from a lower concentration to a higher concentration)

Question 15

explain one type of active transport

Answer 15

coupled trasnport
some molecules move agaisnt their concentration gradient by using the energy stored in a gradient of a different molecule (indirect use of ATP)

Question 16

trasnport using a vesicle

Answer 16

When the cell needs to transport larger things they can use vesicles to transport things in and out of the cell
- Exocytosis: moving things out of the cell using a vesicle
- Endocytosis: moving things into the cell using vesicles