Chapter 7 Flashcards

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1
Q

Ampiphatic

A

A molecule containing both hydrophilic and hydrophobic areas

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2
Q

What does the fluid mosaic model state?

A

That the membrane is a fluid structure with various proteins embedded into it

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3
Q

Why can phospholipids move within bilayer?

A

Hydrophobic interactions are weak

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4
Q

What are the two kinds of phospholipid movements?

A

Lateral (more often) and flip-flop

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5
Q

Why do phospholipids in membrane move around?

A

Create heat to prevent solidification

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6
Q

A membrane is fluid in ______ conditions

A

warmer

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7
Q

Cells in colder climates have more ______ to prevent ________

A

unsaturated hydrocarbon tails

solidificiation

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8
Q

How is cholesterol a buffer in both high and low temperatures?

A

High: cholesterol makes bilayer less fluid by restraining phospholipid movement
Low: cholesterol hinders close packing of proteins, lowering temperature required for solidification

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9
Q

What determines the function of the membrane?

A

Proteins

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10
Q

Integral proteins

A

Proteins that penetrate through whole bilayer

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11
Q

Peripheral proteins

A

Proteins loosely binded to membrane surface

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12
Q

Transmembrane proteins

A

Peripheral proteins that span membrane

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13
Q

What does the hydrophobic region of integral proteins consist of?

A

1 or more stretches of non polar amino acids coiled into alpha helices

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14
Q

Major functions of membrane proteins

A

Transport, enzymatic activity, signal transduction, cell-cell recognition, intercellular joining, attachment to cytoskeleton and extracellular matrix

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15
Q

How do cells recognize eachother?

A

By binding to surface molecules (often carbs) on membrane

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16
Q

Membrane carbs may be bonded to ______, creating _______, or more commonly bonded to _______, creating ____________

A
  • bonded to lipids, forming glycolipid

- bonded to proteins, forming glycoprotein

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17
Q

Exchange of material with surroundings is controlled by what?

A

Membrane

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18
Q

______ molecules can pass through membrane easily

A

Hydrophobic

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19
Q

List hydrophobic molecules that can pass through membrane

A

Carbon dioxide, oxygen, hydrocarbons

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20
Q

_____ molecules can not cross membrane easily

A

Polar

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21
Q

List some molecules that cannot pass membrane easily

A

Sugar, water

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22
Q

What allows passage of hydrophilic substances

A

Transport proteins

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23
Q

Transport proteins

A

Allows passage of hydrophilic substances

24
Q

Channel proteins

A

Transport protein with hydrophilic channel that certain molecules and ions can use as a tunnel

25
Q

Aquaporin

A

Channel protein that facilitates passage of water

26
Q

Carrier proteins

A

Transport proteins that bind to molecules and change shape to shuttle across membrane

27
Q

Transport protein is specific to _______

A

substance that it moves

28
Q

Diffusion

A

Tendency for molecules to spread out evenly into available space

29
Q

Rule of diffusion

A

Diffusion of population exhibits net movement in one direction

30
Q

Dynamic equilibrium

A

where as many molecules cross one way as the other way

31
Q

Concentration gradient

A

Difference in concentration of substance from one area to another

32
Q

Osmosis

A

Diffusion of water across selectively permeable membrane

33
Q

Tonicity

A

Ability of a solution to cause cell to gain/lose water

34
Q

What does tonicity depend on?

A

The concentration of solutes that cannot cross the membrane

35
Q

Osmoregulation

A

Control of water balance necessary for adaption to life in hypertonic/hypotonic conditions

36
Q

What’s special about the Paramecium?

A

Pond is hypotonic to cell (water moves into cell), so it has contractile vacuole that acts as a pump

37
Q

Plant cell in hypotonic solution is calledf

A

Turgid

38
Q

Plant cell in hypertonic solution causes lethal effect called….

A

Plasmolysis

39
Q

Facilitated diffusion

A

Passive transport quickened by aid of transport proteins

40
Q

Facilitated diffusion, what do channel proteins do?

A
  • Provide corridors for molecules/ions to move across

- Aquaporins and ion channels

41
Q

Active transport

A

Movement of substances against concentration gradient, requiring energy

42
Q

Active transport is performed by what?

A

Carrier proteins

43
Q

What does active transport allow for cell to do?

A

Maintain concentration gradient different from surroundings

44
Q

What does the sodium-potassium pump do?

A

Exchanges sodium for potassium across membrane to maintain steep concentration differences

45
Q

How do large molecules cross in bulk?

A

Packaging into vesicles, requiring energy

46
Q

Exocytosis

A

Transport vesicles migrate to membrane, fuse, and release contents

47
Q

In which cells is exocytosis useful?

A

Secretory cells (to export products)

48
Q

Endocytosis

A

Cells take in macromolecules by forming vesicles from plasma membrane

49
Q

Types of endocytosis

A

Phagocytosis, pinocytosis, receptor-mediated endocytosis

50
Q

Phagocytosis

A

Cell engulfs particle in a vacule

51
Q

How is the vacuole created in phagocytosis digested?

A

When fused with lysosomes

52
Q

Pinocytosis

A

Cell gulps droplets of extracellular fluid into tiny vesicles

53
Q

Receptor-mediated endocytosis allows…

A

Allows human cells to take cholesterol in for use in synthesis of membranes/steroids

54
Q

Ligands

A

Any molecule that binds specifically to receptor site of another molecule

55
Q

Receptor-mediated endocytosis

A

Binding of ligands to receptor, creating a vesicle

56
Q

Aquaporins speed up….

A

Rate at which water reaches water potential equilibrium