Human Anatomy & Physiology: Ch.3 PART 2: Ch.3.4- end lecture (Ch.3 cells: the living units) Flashcards


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1

active membrane transport process=

characteristic=

types of solutes/conditions it is used=

2 types=

ALL require ATP

-against [] gradient

-too large for channels

-not lipid-soluble

vesicular transport

active transport

2

active transport

desc. structure and how it works (what is required?)

_ transports more than 1 substance

req. carrier proteins.

substance binds specifically to carrier protein= conf. change= solutes move

symporters, antiporters

3

symporters=

transport type=

carrier protein for secondary active transport

2 diff solutes move in same direction

4

antiporters=

transport type=

type of transporter carrier protein

secondary active transport

2 diff solutes move in opp direction: one in one out

5

primary active transport

active transport (move against electrochemical gradient) that DIRECTLY requires/uses ATP hydrolysis

6

secondary active transport=

EX:

common solutes=

active transport that uses energy from [] gradient of a different solute that was directly created by ATP hydrolysis (primary active transport)

sodium/glucose transporter: sodium is pumped against [] by a Na/K pump. as sodium DIFFUSES across membrane, brings glucose with it

sugars, ions, a.a. (per TA, technically can be transported via facilitated, but most usually through secondary active transport)

7

how does ATP hydrolysis allow solute to move against gradient?

energy released from ATP hydrolysis

= conf. change

=solutes pumped across :)

8

sodium pot. pump

desc=

location=

desc= enzyme Na+/K+ ATPase pumps 3 Na+ out, 2K+ in

location= ALL plasma membranes, but especially active in excitable cells (ex: nerves and muscles)

9

leakage channels=

affect on membrane potential=

channels that allow mvmnt of substances. *ions move according to electricalchemical gradient (based on concentration and charge of ions)

cause Na+ leak into cell, K+ leak out of cell

maintains electrochemical gradient

10

expl. GENERAL steps of Na/K pump

- ATP and Na+ binds

-ATP hydrolysis= Conf change

-Na+ released

-K+ bind

-P released

-K+ released

11

Does vesicular transport req ATP

YESSSSSS

12

types of vesicular transport (4)=

endocytosis

exocytosis

transcytosis

vesicular trafficking

13

types of endocytosis (3)

phagocytosis

pinocytosis

receptor-mediated endocytosis

transcytosis

14

endocytosis

(desc. vesicle's characteristics; what happens to the vesicle?)

PROTEIN coated vesicles form

vesicles become uncoated

usually involves receptors

they either:

fuse with lysosome

undergo transcytosis

15

phagocytosis

desc. vesicle formation and migration

solutes

EX of phagocytic cells

pseudopods (membrane projections) surround particle

vesicle= phagosome

phagosome combines with lysozome

may/may not be protein coated

large or solid particles

EX: WBC, macrophages

16

pinocytosis

desc. vesicle formation and migration

EX of pinocytosis cells

membrane infolds

fluid/dissolved particles

EX: located in cells that line small intestine (absorption)

17

Specificity of phagocytosis vs pinocytosis

phagocytosis: more specific. usually contain receptors

pinocytosis: nonspecific. NO receptors

18

transcytosis

via vesicular transport: moves substances into, across, and then out of cell

19

receptor mediated endocytosis

solutes (NOT SURE HAVE TO KNOW FOR TEST)

fates:

MAIN MECHANISM for specific endocytosis and transcytosis

large proteins (enzymes, insulin, hormones), LDL, iron, viruses, cholera, etc

fates

released inside cell

digested by lysosomes

moved across the cell and then out of cell

20

Desc. docking process in exocytosis

V-Snare on vesicle

T-Snare on plasma membrane

V-Snare and T-Snare hook together= exyocytosis

21

substances exocytosed

hormones, neurotransmitters, cellular waste, mucus

22

polarized cells

applies to which cells?

cells that have a charge (there is a difference in electrical charge across membrane)

ALL cells (all cells have RMP<0)

23

resting membrane potential occurs at

ONLY membrane surface.

fluid or the rest of the cell= electrically neutral

24

desc "key player(s)" (solutes) that lead to RMP.

which is more important? why?

-KEY PLAYER: K+

K+ driven out of cell by leaky channel diffusion

BUT K+ driven into cell by electrical gradient (neg)

-other player: Na+

driven to diffuse into cell b/c concentration AND electrical gradient

-K+ more imp b/c membrane more permeable to K+ than Na+

25

when is RMP established?

when flow of K+ into cell= flow of K+ out of cell

26

Why does Cl- NOT contribute to RMP

electrochemical gradient is EXACTLY balanced

27

through what process/function is RMP maintained?

Na/K pump pumps 3 Na+ out, 2 K+ in

28

Why does steady state able to be maintained if there is an unequal [Na+] across the membrane?

active pumping of Na+ out of cell= rate of Na+ diff into cell

29

how is RMP disrupted

opening of GATED ion channels (Na+ and K+)

30

how do cells interact with env (directly, indirectly)

directly to cells

or indirectly to env

31

role of glycocalyx in cells=

main types=

REQUIRED for ALL interactions of cell with other cells and cell with environment

CAMs (cell adhesion molecule)

Plasma membrane receptors

32

CAM

cell type=

func=

glycoprotein

"velcro"- anchors cells to each other and to ECM

"arms"- help cells move past each other

"SOS!!!"- attract WBC to injured/infected area

"sensor"- detect and respond to changes in local tension/ fluid mvmnt at cell suface THEREFORE stimulates synthesis/degradation of adhesive junctions (ex: tight junctions)

"signal"- transmit intracellular signals that direct cell migration, proliferation, and specialization

STORY: "CAM!! SOS! come here! Being a mother I sensed something was wrong with my cell phone signal so had to use this dumb velcro arm to get your attention.

33

plasma membrane receptors=

cell type=

func=

membrane receptors that serve as binding site for signals

glycocalyx (Text desc. it as glycoproteins)

contact signaling

chemical signaling

34

desc. contact signaling of plasma membrane receptors

func=

important in=

cells tough each other through the receptors

cell recognition

normal development and immunity

35

desc. chemical signaling of plasma membrane receptors

func=

important in=

receptor-ligand (chemical messenger) interaction

cause changes in cell activities (through enzyme activation, open ion channels, etc...)

binding of neurotransmitters, hormones, paracrines (chemicals that act locally and are rapidly destroyed)

36

GPCR

func=

MAIN steps=

acts as "middleman" btwn extracell. 1st messenger and intracell 2nd messenger

1. ligand-receptor binding= G-protein activation

2. G-protein activates protein= 2nd messenger produced

  • Ex: cAMP, calcium

3. 2nd messenger activates enzyme (usually protein kinase, which phosphorylates using P of ATP)

37

HW: True of False: In their resting state, all body cells exhibit a resting membrane potential; therefore, all cells are polarized. EXPL

True. All cells have RMP<0, therefore is polarized (polarized is then there is a difference in charge across the membrane)

38

HW: Which transport process is the most common way of intaking macromolecules into the cell

receptor- mediated endocytosis

39

HW: True or False:

A resting membrane potential is a sign of a depolarized membrane.

False.

at RMP: cell is polarized.