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BIOL > Ch 5 > Flashcards

Ch 5 Flashcards

1
Q

What does it mean to be amphipathic and give an example

A

Both hydrophobic and hydrophilic regions
Ex: phospholipids + membrane proteins

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2
Q

What are lipid rafts

A

Proteins associated in specialized patches of lipids

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3
Q

Membranes are held together mainly by __

A

Hydrophobic interactions

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4
Q

Fluid mosaic model function

A

Acts for passage of things into and out of cell and communication between cells

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5
Q

Some proteins are immobile; what does immobile mean?

A

Attached top cytoskeleton or extracellular matrix

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6
Q

Membrane fluidity depends on __

A

Temp and saturation of fatty acid chains

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7
Q

Difference between unsaturated tails and saturated in membrane fluidity

A

Unsaturated = prevent packing
Saturated = tails pack together

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8
Q

Function of cholesterol in fluidity

A

Reduces fluidity at high temperature
Decreases temp for solidification

Fluidity Modulation: At lower temperatures, cholesterol prevents the fatty acid chains of phospholipids from packing too closely together, thus maintaining fluidity. At higher temperatures, it can help to restrain excessive movement, preventing the m

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9
Q

How do lipid composition vary with colder and higher temp

A

Colder = more unsaturated phopholipids
Higher = unique lipids which decrease fluidity

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10
Q

Embedded at least partially in hydrophobic region ___

A

Integral proteins

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11
Q

Bound to the surface of the membrane

A

Peripheral proteins

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12
Q

Membrane protein functions (6)

A
  1. Intercellular joining
  2. Attach to cytoskeleton and extracellular matrix
  3. Enzymatic activity
  4. Signal transduction
  5. Cell-cell recognition
  6. Transport
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13
Q

Short branched carbohydrate chains used to create

A

Glycoplipids and glycoproteins

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14
Q

Glycolipid and glycoproteins functions

A
  1. Sort cells into tissues and organs
  2. Recognition of self vs non-self: immune system
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15
Q

Membrane layers differ in (2 things)

A
  1. Lipid composition
  2. Direction of inserted proteins
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16
Q

Where and when is the arrangement of membrane lipids and proteins determined

A

During synthesis in the ER and GA

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17
Q

Selective permeability meaning

A

Allow passage of some substance, but not others

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18
Q

Is it easy for nonpolar molecules to dissolve in lipid bilayer and why

A

Yes
Nonpolar molecules share similar chemical properties with the lipid tails of the phospholipids, allowing them to integrate seamlessly into the bilayer. T

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19
Q

How are ions and polar dissolve in lipid bilayer

A

Water crosses slowly and larger molecules even more slowly

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20
Q

Meaning of passive transport

A

DOES not use energy

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21
Q

How does substance concentration move in passive transport

A

High concentration to low

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22
Q

What is the difference between diffusion and osmosis

A

Diffusion = movement of particles
Osmosis = movement of water

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23
Q

Dynamic equilibrium meaning

A

Equal movement in either direction across membrane

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24
Q

How does the movement of diffusion differ from osmosis in regards to concentration gradient

A

Diffusion = move from high to low region
Osmosis = move from high (low solute) water to low (high solute) water concentration

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25
Q

Tonicity meaning

A

Ability of soln to cause cells to gain or lose water
Tells us what happens to cell when they are put in different solution

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26
Q

3 diff solution in tonicity

A
  1. Isotonic
  2. Hypertonic
  3. Hypotonic
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27
Q

This solution means the outside solution has the same amount of stuff (like salt) as the inside of the cell. Water moves in and out equally, so the cell stays the same.

A

Isotonic solution

28
Q

outside solution has less stuff than the inside of the cell. Water moves into the cell, making it swell like a balloon, and it might even burst!

A

Hypotonic solution

29
Q

When water moves out of the cell, cell volume decreases (shriveling, what is this process called

A

Crenation in RBCs

30
Q

solution has more stuff than the inside of the cell. Water moves out of the cell, causing it to shrink like a raisin.

A

Hypertonic soln

31
Q

What is this process called, when water enters cell and cell volumen increases = cell burts/lysess

A

Hemolysis

32
Q

Osmoregulation meaning and examples

A

Ability of cells to protect themselves from extreme water loss/gain

Paramecium
Contractile vacuoles

33
Q

What is turgor pressure

A

When cells with walls exert pressure back against water trying to move into a cell

34
Q

Facilitated diffusion is aided by )___ and what does it mean

A

Transport proteins
Span memb to allow passage of polar and charged molec and ions

S

35
Q

T or f, facilitated diffusion is not passive transport

A

False, it is bcs no energy input

36
Q

___ channel that allows passage of polar and charged molec

A

Hydrophilic channel

37
Q

__ channel that allow passage of specific ions

A

Ion channel,

38
Q

what are carrier proteins and give one example

A

Bind to specific molec, ion, change shape and release on other side of the membrane

Ex: glucose transporter

39
Q

What is membrane potential caused by and what is its function

A

By uneven distribution of anions (-) and cations (+)
This favours passive transport of cations into the cell and anions out

40
Q

Electrochemical gradient is determined by

A

Both chemical gradient (concentration) and membrane potential (electrical)

41
Q

Active transport meaning + characteristics

A

Moves substance against concentration gradient
1) involves carrier proteins
2) uses energy

42
Q

A type of transport protein that produces voltage across a membrane as it moves ions

A

Electrogenic pump

43
Q

Give 2 examples of electrogenic pump

A
  1. Sodium potassium pump in animals
  2. Proton pump in other organisms
44
Q

Proton pump movement

A

Moving against chemical and electrical gradient
Pumps hydrogen from internal to external
Creating higher positive charge outside the cell

45
Q

Cotransport meaning

A

Couples the transport one substance down its electrochemical gradient and one against

46
Q

why is it called cotransport

A

Gradient created by hydrogen pump is often coupled with a transported for larger biomolecules

47
Q

T OR F: bulk transport does not need active transport

A

False

48
Q

Meaning of bulk transport + give 2 examples

A

Movement of large quantities across the membrane in vesicles (rather membrane proteins0

1) endocytosis
2) exocytosis

49
Q

What is exocytosis and where is it formed

A

Contents released to external space
= vesicles move to cell membrane, merge with it and release contents outside the cell

Formed in golgi apparatus

50
Q

Endocytosis meaning and give 3 kinds

A

Formation of vesicles from cell membrane for extracellular substances (bring materials into the cell)
1. Phagocytosis
2. Pinocytosis
3. Receptor-mediated

51
Q

Phagocytosis function

A

Cell engulf (eat) external particle by extending pseudopodium around it

Pseudopodium wrap around entire particle creating a food vacuole

52
Q

In phagocytosis, where does food vacuole fuse to

A

Fuses to lysosome to digest contents

53
Q

Pinocytosis meaning

A

Form of internalization in which vesicles are filled with extracelullar fluid

Cell “gulps” up fluid

Coated with proteins

54
Q

Specialized form of pinocytosis which is specific to a certain substance is called

A

Receptor-mediated endocytosis

55
Q

How does receptor mediated endocytosis work

A

Protein receptors bind to substance and are then internalized into the vesicle

56
Q

Two major divisions of cell signalling

A

1) direct cell contact (local)
- inhibits growth of cells (contact inhibition)
- recognition of cell surface molecules (ex: immune system)

2) chemical signalling (local or long distance)

57
Q

Long distance signaling uses __

A

Hormones

58
Q

2 forms chemical signaling works

A

1) a chemical signal in extracellular fluid interacts w/ receptor of target cell

2) a chemical signal enters the cell and interacts w/ intracellular receptor

59
Q

3 stages of cell signalling and give its brief meaning

A

1) reception: binding of chemical signal to receptors
2) transduction: series of stacking of chemical rxn
3) response: action that happens in the target cell

60
Q

Molecule which binds to another molecule in reception

A

Ligand

61
Q

Ligand binding results in __

A

Receptor activation & induction of a cascade of cellular events

62
Q

Where is intracellular receptors located

A

In the cytoplasm or nucleus of the target cell

63
Q

How does intracellular receptors work

A

by receiving signals inside the cell, interacting with DNA, and regulating gene activity to produce a specific response.
= acts as transcription factors and carry out transduction part of the pathway

64
Q

How does signal transduction work and what step is this and what does it allow

A

2nd step

= this turns signal into a form that create specific cellular response

= allows
A) amplification
B) coordination
C) control of signal

65
Q

Signal transduction involves the work of __ (3)

A
  1. Protein kinases
  2. Protein phosphatases
  3. Secondary messengers
66
Q

What does cellular response cause

A
  1. Activation or deactivation of one or more cellular processes
67
Q

What does cellular response regulate

A

Regulate
1) protein synthesis ( growth factors)
2) protein activity (metabolic enzymes)

BIOL (31 decks)

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