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Biology > Unit 2 part 3 > Flashcards

Unit 2 part 3 Flashcards

Cell Membrane

1
Q

What is the fluid mosaic model?

A

The currently accepted model of the cell membrane

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2
Q

What is the “backbone” of the membrane

A

A bi layer produced from huge numbers of molecules called phospholipids

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3
Q

What happens when the fatty tails aren’t very attracted to each other

A

membrane tends to be fluid or flexible allowing animal cells to have variable shapes and allows the process of endocytosis

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4
Q

Phospholipid

A

2 fatty acid chains and a phosphate are bonded to a glycerol molecule

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5
Q

lipid bilayer

A

phospholipid bilayer of plasma membrane separates cytoplasm and cell contents from environment

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6
Q

What can pass through a bilayer?

A

Only hydrophobic (uncharged) particles through the centre

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7
Q

Kinetic theory

A

States that particles are in constant motion

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8
Q

What results in diffusion and osmosis

A

When particles in gasses, liquids, and solutes move at random in aquas solutions

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9
Q

What is diffusion and osmosis?

A

Passive process in cells as cells do not provide any energy to make particles

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10
Q

What are integral proteins

A

permanently attached to plasma membrane and penetrate into centre of phospholipid bilayer

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10
Q

What is simple diffusion?

A

Passive transport of particles from region of high concentration to a region of low concentration

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11
Q

CO2 and O2 in diffusion

A

Both are small uncharged molecules and can move between phospholipid molecules of the membrane which makes their diffusion easier

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11
Q

Integral proteins

A

Permanently attached to plasma membrane + penetrate into centre of phospholipid bilayer

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12
Q

Integral protein features

A
  • Can be trans-membrane or only partially penetrate the bilayer
  • Can be glycoprotiens, channels, or protein pumos
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12
Q

Integral protein traits

A
  • 2 hydrophobic sections
  • Can be trans-membrane or only partially penetrate the bilayer
  • Can be glycoproteins, channels, or protein pumps
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13
Q

Peripheral protein traits

A
  • Charged peripheral protein attached to charged sections of integral proteins + phosphate heads
  • Hydrophillic and do not penetrate phospholipid bilayer
  • Can be receptors or enzymes
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14
Q

Passive transport?

A

When a substance goes from an area of high concentration to low along concentration gradient
- Transport that does not require ATP

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15
Q

Active transport?

A

Substance usually moved against a concentration gradient

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16
Q

Types of passive transports?

A
  • Osmosis
  • Diffusion
  • Facilitated diffusion
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17
Q

Osmosis?

A

Water moving from a hypotonic (Lower concentration of solutes, high concentration of water) to hypertonic ( higher concentration of solutes, lower concentration of water) solution

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18
Q

Facilitated diffusion?

A

Passive transport of molecules from region of high concentration to low thought channel proteins

Requires two types of proteins:
- Channel = Most have gates that open and close in response to chemical signals, don’t change shape, and have pores
- Carrier = Change shape to carry a specific substance, usually ions, from one side of membrane to other and if carrier protein is not working no transport will occur

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19
Q

Types of proteins

A
  • Hormone binding
  • Enzymatic
  • Cell adhesion
  • Cell-to-cell communication
  • Channel forming
  • Pumps for active transport
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20
Q

aquaporins?

A

Integral channel proteins that selectively transport water rapidly through membranes
- its presence in plasma increases membrane permeability

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21
Q

Example of facilated diffusion

A

Osmosis through aquaporins

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22
Q

Channel proteins

A

Have central pores that allow particles to go though
- Pores are lined w/hydrophilic R groups from amino acids
- Some are gated and only open to let facilated fusion happen
- Cell membrane selectively permeable

23
Q

Five steps of active transport

A
  1. Specific practice binding to a site on a specific protein pump
  2. ATP bonds to protein pump * hydrolyzes to become ADP
  3. A phosphate stays attached to protein pump + causes protein pump to change shape
  4. Particle is moved against concentration gradient and released
  5. Phosphate is released causing protein pump to return to original shape
24
Q

Transports and their selectivity

A

Facilated diffusion
- Selective process b/c only specific particles can pass through protein channel
Active transport
- Selective b/c protein pumps ate specific to particles they can transport
Simple diffusion
- Not selective process because any small or hydrophobic molecule can pass through phospholipid bilayer

25
Q

Glycosylation

A

Process that attaches phospholipids and membrane with carbohydrate chains

26
Q

Glycoproteins?

A

membrane proteins with carbohydrate chain attached to

27
Q

Glycolipids?

A

Phospholipids with carbohydrate chain attached to

28
Q

Functions of glycolipids and proteins?

A
  • Reception
  • Cell to cell communication
  • Immune response
  • Cell to cell adhesion
29
Q

Reception

A

Glycoproteins are receptors for hormones b/c when a hormone bonds to a specific protein receptor it changes metabolism within cell

30
Q

Cell to cell communication

A

Neurotransmitters bind to glycoproteins letting cells communicate

31
Q

Immune response

A

Glycoproteins act as makers on cell letting immune system distinguish between self and not self cells

32
Q

Cell to cell adhesion

A

Glycoproteins interact with each other on neighbouring cells which formulates tissue

33
Q

Cell recognition

A

Carbohydrates in glycoproteins and lipids have specific shapes letting immune system recognize cells as self
- If carbohydrate chains are not recognized as self by immune system, glycoproteins and lipids act as antigens

34
Q

Antigens

A

Substances that stimulate immune response + production of antibodies

35
Q

Saturated fatty acids

A

Single bonds between carbons on hydrocarbon chain
- Linear
- Triglycerides with saturated fatty acids have higher melting point

36
Q

Unsaturated fatty acids

A

Have at least one double bond between carbon as hydrocarbon chain
- Bent at position of double bond
- Triglycerides w- unsaturated fatty acids have lower melting point

37
Q

Fluid phospholipid

A

Phospholipids in membrane are fluids b/c they are not in a fixed position and move around
- Fluidity is affected by type of fatty acid in phospholipid

38
Q

Saturated fatty acids + fluidity of membrane

A

No double carbon bond, straight fatty acid tails that allow close packaging of phospholipids
- Results in phospholipids having higher melting point which increases viscosity
- Saturated fatty acids make membrane stronger at higher temps

39
Q

Unsaturated Fatty Acids + fluidity of membrane

A

Have double carbon bond = kinks in fatty acid tails preventing close packaging of phospholipids
- Results in phospholipids having lower temps
- Unsaturated fatty acids make membranes have lower melting points and viscosity

40
Q

Cholesterol?

A

A lipid that can be made in the liver and found in blood
- Most are non polar ( hydrophobic)

41
Q

Where is the cholesterol located?

A

Between fatty acid tails in membranes of animal cells + helps regulate fluidity of membrane

42
Q

What forms a hydrogen bond a/ phosphate of phospholipids

A

Hydroxyl group (-OH) on cholesterol
- Hydrophilic ( non polar)

43
Q

Cholesterol + membrane fluidity

A

At higher temps cholesterol reduces fluidity + increases melting point of phospholipid resulting in stable membranes

44
Q

Cholesterol + membrane fluidity

A

At higher temps cholesterol reduces fluidity + increases melting point of phospholipid resulting in stable membranes

45
Q

Vesicles

A

Small membrane bound structures involved in transporting material w/in cells
- Fluid nature of membranes allows formation of vesicles

46
Q

Bulk transport ( endo and exocytosis)

A

Is possible due to fluid nature of plasma membrane allowing formation of vesicles + fusion of beagles w/ the membrane

47
Q

Steps of protein transport w/in cell

A
  1. Proteins are to be secreted from cells are synthesized by ribosomes attached to rough endoplasmic reticulum
  2. Rough ER forms a vesicle containing protein which is sent to golgi apparatus
  3. Vesicles fuse w/ golgi apparatus which modifies to protein
  4. Golgi apparatus packages proteins in secretory vesicles
  5. Secretory vesicles move towards plasma membrane
  6. secretory vesicles fuse w/ plasma membrane (exocytosis) releasing protein outside of cell
48
Q

Exocytosis?

A

Release of large particles from a cell
- Involves 6
- Active process

49
Q

Endocytosis?

A

Process by which large particles enter cell
- Large particles are surrounded by a plasma membrane which buds off inside the cell to form vesicles
- Active process

50
Q

Gated ion channel

A

Integral proteins that allow specific ions to pass through by facilitated diffusion
- Pore ion channel = hydrophobic, allowing specific ions to enter
- Play a number of roles in transmission of nerve impulses

51
Q

Examples of gated ions

A
  • Voltage gated channels –> respond to changes in membrane potential dif
  • Ligand gated channels –> respond to a Ligand attaching to channels
52
Q

Sodium potassium pump

A

Actively transports sodium ions out of cell and potassium ions into cells
- maintains resting potential in neurons

53
Q

Process of sodium potassium pump

A
  1. 3 Na+ attached to sodium ion binding site on sodium potassium pump protein
  2. ATP attaches sodium potassium pump
  3. ATP = hydrolyzed w/ a phosphate remaining attached to a protein pump, ADP is released
  4. Phosphate causes pump to change shape, moving sodium across axon membrane, releasing Na+ outside axon
  5. Two K+ attach to potassium ion binding site on sodium potassium pump protein
  6. Phosphate from the pump
  7. Pump returns to original shape moving K+ into axon
    - process can be repeated
54
Q

Indirect active transport?

A
  • Glucose transport
  • Facilitated diffusion
  • Sodium dependent glucose co transporters
55
Q

Glucose transport?

A

Transported by 2 mechanisms from small intestine to epithelial cells that line the intestine

56
Q

Facilitated diffusion?

A

Glucose is passivley transported through glucose channels from small intestine into epithelial cells

57
Q

Sodium dependant glucose co transporters

A

Co-transport links movement of an ion (Na+) down its concentration gradient w/movement of a solute (glucose) against its concentration gradient

58
Q

Process of indirect transport

A
  1. Na+ actively pumped out of epithelial cells by sodium potassium pump = low concentration of Na+ in epithelial
  2. Na+ and glucose bind to sodium dependent glucose co transporters protein
  3. Attachment of sodium + glucose causes protein to change shape, moving both glucose and sodium into epithelial cell

Biology (22 decks)

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