Topic 3 Flashcards Preview

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Flashcards in Topic 3 Deck (48):
1

Glycoproteins

Proteins with attached carbohydrate chains/sugars
cellular recognition and the immune response
Surface receptors to hormones and neurotransmitters
Stabilise the membrane

2

Cholesterol

membrane fluidity and stability

3

Aquaporins

Some water moves across the membrane through special protein channels called aquaporins

4

Glycolipids

Sugars/carbohydrate chains attached to lipids
cellular recognition and immune response
Surface receptors to hormones and neurotransmitters
Stabilise the membrane

5

Phospholipid

Two hydrophobic fatty acid chains joined to a hydrophilic phosphate containing group

6

Fluid mosaic model

Double layer of lipids is quite fluid, within which proteins move quite freely

7

Integral proteins

Embedded in the phospholipid bilayer and described as transmembrane proteins

8

Peripheral proteins

either anchored to the exterior of the plasma membrane by bonding with the lipids or are indirectly associated with the plasma membrane through interaction with integral proteins within the membrane

9

Diffusion requiring proteins

Water
Water-soluble substances
amino acids
glucose
charged ions

10

Diffusion that does not require proteins

Water
oxygen
carbon dioxide
alcohol
lipid soluble substances

11

Water can move through phospholipid bilayer

Even though it is not soluble in phospholipids, it can still move through the layer because this layer is constantly moving, so it is able to pass in between the phospholipid molecules

12

Solute

Substance that can be dissolved in another substance

13

Solvent

Substance in which other substances can be dissolved

14

Solution

Solute dissolved in a solvent

15

Concentration gradient

The difference in solute concentration between two regions

16

Water

Although overall charge of water is neutral, oxygen end is slightly negative and hydrogen end is slightly positive
Polar- molecules that have a positive and negative end

17

Cohesion

Water molecules stick to each other and are held in place by weak hydrogen bonds

18

Adhesion

Water molecules stick to other polar molecules

19

Water as a versatile solvent

Water's versatility as a solvent is due to its polar nature

20

Hydrophobic

Substances that are insoluble in water
water fearing

21

Hydrophilic

Substances that are soluble in water
Water loving

22

Simple diffusion

The net passive movement of molecules from an area of high concentration to low concentration, down the concentration gradient

23

Osmosis

The net passive movement of water across a semi-permeable membrane from a solution of low solute concentration to one of high solute concentration

24

Equilibrium

ratio of solute: water is equal
number of molecules is equal on both sides of the membrane

25

Haemolysis in animal cells

Water will diffuse into the cell when water concentration is higher outside the cell
This causes the cell to swell and burst
Haemolysis- death

26

Crenation in animal cells

When the water concentration is higher in the cell than outside the cell, water moves out of the cell and the cell dehydrates
Cell shrinks and crinkles
Crenation

27

Turgidity in plant cells

When a plant cell is placed in water, water enters via osmosis and the cell swells up but it does not burst
cellulose cell wall is tough and elastic, it stretches but does not break
Eventually the cellulose cannot stretch and so the cell stops swelling
Cell becomes turgid
Turgidity or turgor helps make cells firm and provides support for plant parts

28

Plasmolysis in plant cells

Water moves out of the cell via osmosis and the cell shrinks
Becomes flaccid
Cytoplasm and membrane eventually pull away from the cellulose cell wall
Plasmolysis

29

Hypotonic

Solution with a lower concentration of solutes compared to the solute concentration inside a cell
Water moves into cell

30

Hypertonic

Solution with a higher concentration of solutes compared to the solute concentration inside a cell
Water moves out of the cell

31

Isotonic

Surrounding fluid is of equal concentration to the solution inside the cell
No net movement of water- water will diffuse equally in both directions

32

Solute concentration of cells is determined by...

All of the dissolved substances in the cell

33

Contractile vacuole

In single celled organisms such as Paramecium which live in freshwater environments
Do not have a cell wall and instead have a contractile vacuole
Actively expels water from the cell absorbed by osmosis from their surroundings

34

Facilitated diffusion

Water-soluble molecules (amino acids, ions, glucose) can't cross through bilayer and require channel proteins
Net passive movement of molecules from an area of high to low concentration through the use of protein channels and carrier proteins

35

Factors affecting rates of diffusion

Concentration gradient
Distance
Area
Barriers to diffusion
Temperature
Size of molecules

36

Factors for diffusion- concentration gradient

Diffusion rate is higher when there is a greater difference in concentration between two regions

37

Factors for diffusion- the distance involved

Diffusion over shorter distances occurs at a greater rate than diffusion over larger distances

38

Factors for diffusion- The area involved

The larger the area across which diffusion occurs, the greater the rate of diffusion

39

Factors for diffusion- barriers to diffusion

Thicker barriers slow diffusion rate
pores in a barrier enhance diffusion

40

Factors for diffusion- Temperature

The higher the temperature, the quicker the rate of diffusion, because molecules move faster at higher temperatures

41

Size of molecules

At a given temperature, a smaller particle will move faster than a larger one and so a smaller particle will diffuse faster than a larger one

42

Active transport

The process of moving substances across the plasma membrane from a region of low concentration to a region of high concentration of those substances. This requires an input of energy in the form of ATP
Enables cells to maintain stable internal conditions in spite of extreme variation in the external surroundings

43

Endocytosis

Transports bulk material into the cell
Phagocytosis and Pinocytosis

44

Phagocytosis

Solid particles can be taken into a cell

45

Pinocytosis

Material that is in solution can be transported into cells

46

Exocytosis

Transports bulk materials out of the cell
Vesicles formed within a cell fuse with the plasma membrane before the contents of the vesicles are released from the cell

47

Transmembrane proteins

receptors to hormones and neurotransmitters

48

Channel and carrier proteins

assists substances to be transported in and out of cells