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Biology 121 > Study Questions #4 > Flashcards

Study Questions #4 Flashcards

Septemer 17-21

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1
Q

What is the difference between cilia and flagella?

A

Cilia - usually has many, but shorter and they beat like oars. Can also be used for sensing what’s going on outside cell
Flagella, one or a few, longer, undulating motion that generates movement

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2
Q

What functions are performed by cilia and flagella?

A

movement

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3
Q

what makes cilia and flagella move

A

cilia beat perpendicular to the membrane and flagella use breast strokes. Both have a rigid stroke and limp recovery

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4
Q

What is the extracellular matrix and what sorts of cells have it?

A

mix of different proteins made in Golgi that occupies space between animal cells
cell wall in plants

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5
Q

What are the two classes of molecules used to express cell identity?

A

Glycolipids and glycoproteins

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6
Q

What are major histocompatibility complex proteins?

A

glycoproteins used by cells to identify themselves to their own immune system

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7
Q

why are heart transplant patients treated with drugs which suppress the immune system

A

so the body doesn’t reject the foreign organ

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8
Q

What are the three types of cellular junctions found in animal tissues?

A

Tight, Anchoring, and communicating

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9
Q

What are desmosomes and what do they do?

A

type of anchoring junction-cadherin that joins the cytoskeleton to that of the next cell

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10
Q

What is cadherin and what does it do?

A

connects cytoskeletons of adjacent cells

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11
Q

What are adherens junctions?

A

integrins that join cells to extracellular matrix

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12
Q

What are integrins and why is it important for the to be attached to the extracellular matrix?

A

…

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13
Q

What is a connexon?

A

sodium channel embedded in the plasma membrane that allows sodium to move from one cell to its neighbor

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14
Q

What are plasmodesmata?

A

Gap junctions in plants where the ER extends between cells.

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15
Q

Why must all cells have a plasma membrane?

A

keeps what you want in, in and what you want out, out

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16
Q

Why do we say that membranes are semipermeable and why is this important?

A

They regulate what goes in and out of the cell to make sure it’s appropriate. Cells need to be semipermeable to allow the transfer of nutrients, waste, and information.

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17
Q

Why do phospholipids form bilayers in water?

A

The hydrophilic head is attracted to water while the hydrophobic tail repels water.

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18
Q

Why must membranes be fluid to function?

A

allows for semi-permeability
turn corners
seal proteins
fuse and form vesicles

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19
Q

What are 3 methods cells use to adjust membrane fluidity?

A

Changing fatty acids
changing the head group
adding cholesterol

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20
Q

What sorts of molecules can pass through lipid bilayer membranes?

A

gasses
small uncharged particles
some water

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21
Q

Why do cells need integral membrane proteins?

A

to allow polar molecules to come in

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22
Q

What is the general model for the structure of biological membranes?

A

fluid mosaic model

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23
Q

what keeps integral membrane proteins from leaving the membrane

A

the part inside the membrane has to be hydrophobic and the parts exposed to the surface have to be hydrophilic

24
Q

how do we know that proteins can diffuse within membranes

A

they are evenly dispersed within the membrane

25
Q

how can proteins form holes through membranes?

A

hydrophilic amino acids line the channel and hydrophobic aminos face the bilayer

26
Q

What is special about the structure of the plasma membrane and what sorts of proteins do you find in it?

A

sugar coating on the outside
physically attached to cytoskeleton
transmembrane proteins, peripheral proteins

27
Q

What are the functions of the plasma membrane

A

physical isolation, regulation of exchange with the environment, sensitivity to the environment, structural support

28
Q

What is osmosis and why does it occur

A

movement of water across membrane

goes from higher concentration to lower concentration

29
Q

what kinds of cells want to be isosmotic and what kinds want to be hyper osmotic

A

animal cells want to be isosmotic and plants want to be hyper osmotic

30
Q

why do cells shrink when placed in a hyper osmotic solution?

A

the water all rushes out of the cell to be at the lower concentration

31
Q

Why do red blood cells explode when you place them in distilled water?

A

the water rushes in and the cells swell and burst

32
Q

What is turgor pressure and what is it used for

A

osmosis pushes the membrane against the cell wall to make the structure rigid

33
Q

How is bulk transport accomplished?

A

via vesicles

34
Q

What is the difference between endocytosis and exocytosis

A

endocytosis brings things in and exocytosis brings things out

35
Q

what is the difference between phagocytosis and pinocytosis?

A

phagocytosis is large objects and pinocytosis is several small objects

36
Q

What is receptor-mediated endocytosis?

A

plasma membrane proteins bind to specific objects and when enough bind, pits become vesicles

37
Q

What are the differences between bulk transport and selective transport?

A

Bulk transport - Vesicles move large objects across the Plasma membrane by endocytosis and exocytosis. Requires some energy
Selective transport - The plasma membrane proteins move specific items across but saves energy in the process. However they are specific (1 Item / carrier)

38
Q

What is selective transport and what substances do cells move by selective transport?

A

Proteins embedded in the membrane whose job is to bring in ONE type of molecule across the membrane
polar molecules and positively charged molecules are brought in by selective transport.

39
Q

How do aquaporins prevent the passage of molecules other than water?

A

They are a tight channel. Only few objects can fit through it.
It has 2 positive charges on one side, so anything with a charge will not go through. (+ charges are repelled, - charges get stuck. Water doesn’t have a charge and it’s
relatively small so it fits though fine.

40
Q

how can ion channels tell the difference between one type of ion and another

A

by size and charge

41
Q

How are ion channels regulated?

A

open and closed like a gate

42
Q

what are the differences between ion channels and facilitated diffusion?

A

ion channels are like a gate whereas facilitated diffusion binds with certain things and changes shape to help get them across the membrane

43
Q

why is facilitated diffusion saturable whereas channels are not?

A

Channels - are somewhat specific but not completely. It depends on the size and the charge of the substance, but can anything that matches. They are controlled by “opening and closing” so a whole lot of material can pass through at one time when it opens
Facilitated diffusion - Is specific to a certain molecule.
the plasma membrane has to bind it, carry it through the dump it out. This is a longer slower process therefore not saturated

44
Q

what are the differences between facilitated diffusion and active transport?

A

facilitated doesn’t require energy and active does

45
Q

how can you tell if a substance is moved by active transport?

A

ATP was used

46
Q

How can cells have 35 fold higher concentrations of K+ inside than in the surrounding blood?

A

the plasma membrane has a pump that exchanges sodium and potassium

47
Q

how do cells remove sodium

A

thought the na/k pump

48
Q

why does the toxin from poison arrow frogs kill you slowly and painfully

A

it freezes the Na/K pump and cells burst because there’s too much sodium

49
Q

why are cardiac glycosides useful for treating heart patients

A

at the right dosage, it stimulates the heart

50
Q

what is the difference between active transport and coupled channels?

A

active transport only brings in one chemical whereas coupled channels bring in more by piggy backing

51
Q

why are coupled channels often called secondary active transport

A

it brings in a secondary particle

52
Q

what is the difference between symport and antiport

A

a symport imports things and anti ports export them

53
Q

Why do cells lining the small intestine have two different kinds of glucose transport proteins?

A

there’s proteins that require energy and some that don’t

54
Q

What are ionophores and why are they so deadly?

A

they dissipate the concentration gradient so all the work was done for nothing and things can move freely

55
Q

What are contractile vacuoles and what is their function

A

Contractile vacuoles are membrane-bound organelles that pump water out of the cell. They work to maintain a solvent/solute balance in the cell through a process called osmoregulation.

56
Q

why did you get a larger diameter circle with lugol’s than with Brilliant Blue G?

A

it had smaller molecules that were able to diffuse earlier

Biology 121 (9 decks)

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