Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physiology > Cell physiology > Flashcards

Cell physiology Flashcards

1
Q

Cell

A

basic unit of life
structural and functional unit
smallest unit that can carry on all of life’s processes independently; ex. obtaining nutrients, converting to ATP, signalling molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Cell physiology

A

structure of cells, how they interact with one another and with the larger organism to which they belong

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Plasma membrane

A

surrounds cell surface
functions:
1. physical barrier (maintains difference in fluid composition between extra and intracellular fluid [ex. >Na+ outside cell at rest]; maintains homeostasis)
2. Cell-to-cell communication [contains receptors that bind specific signalling molecules like hormones]
3. structural support [specialized connections -proteins- between membranes and extracellular materials]
4. transport [selectively permeable]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

cell organelles

A

discrete structures that perform specific functions needed for the cell to survive; compartmentalize
most are membrane bound but some aren’t

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

cytoplasm

A

region inside the cell, outside of the nucleus
holds organelles
made of cytosol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

biological membranes

A

surround cell and most intracellular organelles
double layer of lipid molecules with embedded proteins
have different ratios of lipids and proteins that reflect different functions of cells/organelles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

mitochondria membrane

A

higher ratio of proteins (~70%) - crucial for making ATP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

lipids

A

made of hydrogens and carbons
some contain oxygen and phosphates
membrane lipids are amphipathic
phospholipids, cholesterol, glycolipids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

amphipathic

A

contain both polar (hydrophilic) and non-polar (hydrophobic) regions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

phospholipids

A

polar head group - phosphate, nitrogen containing chemical group (R), glycerol backbone
nonpolar tail - 2 fatty acid chains (carbon and hydrogen), both saturated and unsaturated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

saturated fatty acid

A

no double bonds in the hydrocarbon chain; all carbons are bonded to the maximum number of hydrogens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

unsaturated fatty acid

A

double bonds in the hydrocarbon chain, causes a kink/bend; not all carbons are bonded to the maximum number of hydrogens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

phospholipid bilayer

A

amphipathic → forms spontaneously; orients to form an energy favourable structure:
polar heads face aqueous environment; nonpolar tails form hydrophobic core (not in contact with water)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

steroids

A

ex. cholesterol
amphipathic - has OH group at end, the only polar region
maintains proper membrane fluidity
organelles do not have cholesterol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

glycolipids

A

lipids with CHO chain attached
outside of plasma membrane
amphipathic
form glycocalyx

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

glycocalyx

A

layer of carbohydrates linked to lipids; role in identification of pathogens and interaction between cells
pericellular matrix - surrounds the cell membranes
made of glycolipids and glycoproteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

membrane proteins

A

integral (intrinsic)
peripheral (extrinsic)
glycoproteins
all membrane proteins have selective permeability and are distributed unequally

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

integral membrane proteins

A

partially span membrane or transmembrane proteins
amphipathic (part that lies in membrane is non polar, outside of membrane is polar)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

peripheral membrane proteins

A

found in the inner or outer surface of membrane
are not amphipathic (polar)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

glycoproteins

A

sits outside of membrane on extracellular surface
protein with attached carbohydrates
form glycocalyx

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

cell junctions

A

stabilize interactions between cells and promote communication
desmosomes - anchor
tight junctions - barrier to movement
gap junctions - communication

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

desmosomes

A

adhering junctions
anchor cells together in tissues subject to considerable stretching ex. skin, uterus, heart
contain plaques, cadherins, and intermediate filaments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

plaques

A

cytoplasmic proteins
attach to cadherins and act as their anchoring point

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

cadherins

A

span the junction and link the cells together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

intermediate filaments

A

part of cytoskeleton, provide structure and support
anchor the cytoplasmic surface of desmosomes to cell components

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

tight junctions

A

found in epithelial tissue specialized for molecular transport
includes occludins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

epithelial tissue

A

lines hollow tubes and organs ex. GI tract
epithelial cells regulate what crosses from lumen to blood by forming a barrier

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

occludins

A

form nearly impermeable junctions by linking adjacent cells together
attach together like snap buttons
limit movement of molecules between cells; pass through cells instead
limit movement of integral membrane proteins and lipids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

example of tight junction

A

glucose in food has to pass through junction by glucose transporters from lumen/apical side of cell to the basolateral side to reach blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

gap junctions

A

transmembrane channels linking cytoplasms of adjacent cells by connexons
electrically (ion movement) and metabolically (bone cells - passage of nutrients) couple cells
communicating junctions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

connexons

A

transmembrane channels
allow movement of molecules if they are small enough

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

nucleus

A

transmission of genetic material; contains information for protein synthesis (receptors, enzymes, transporters)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

chromatin

A

DNA associated with proteins (condenses to form chromosomes during cell division)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

nuclear envelope

A

double layered porous membrane (phospholipid)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

nuclear pores

A

allow selective movement of molecules in and out of nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

nucleolus

A

synthesis of ribosomal RNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

structure of nucleus

A

double phospholipid bilayer makes up the nuclear envelope
a protein complex makes up nuclear pores that allow molecules like RNA to pass from cytoplasm to nucleus and back (DNA cannot move through)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

cells without a nucleus

A

red blood cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

cells with more than one nucleus

A

(multinucleate)
skeletal muscle cells - formed by fusion of precursor cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

ribosomes

A

non membrane bound (no phospholipid bilayer)
responsible for protein synthesis
have two subunits - each is composed of proteins and ribosomal RNA; subunits join prior to protein synthesis to form functional ribosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

functional ribosomes

A

free ribosomes - found in cytoplasm
ribosomes bound to ER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

endoplasmic reticulum

A

fluid-filled membranous system just outside of nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

rough ER

A

made of flattened sacs and has a granular appearance - ribosomes bound to its cytosolic surface (the surface facing the cytoplasm)
synthesis of proteins with bound functional ribosomes - post-translational modification of proteins

44
Q

smooth ER

A

branched tubular structure with an agranular appearance - has no ribosomes
different functions depending on the cell + its function:
- synthesizes lipids (fatty acids, steroids)
- stores Ca2+ (muscle cells, sarcoplasmic reticulum)
- drug detoxification (liver cells)

45
Q

golgi apparatus

A

made of 3-8 cisternae
incoming and outgoing transport vesicles
functions:
- post-translational modification of proteins made in RER
- sorts and packages proteins

46
Q

cisternae

A

sets of flattened slightly curved membrane bound sacs stacked in layers

47
Q

path of proteins

A

protein is made and some modifications occur at RER; then packaged into vesicle and sent to golgi apparatus where further modifications occur; packaged into vesicles and can be: secreted from cell, become integral membrane proteins, or proteins of lysosomes, ER, or golgi

48
Q

lysosomes

A

~50 per cell
contain digestive enzymes - hydrolytic enzymes break down polymers into smaller subunits
function at acidic pH
degrade extracellular and intracellular debris - recycle cell organelles, destroy endocytosed bacteria and viruses

49
Q

peroxisomes

A

contain oxidative and antioxidant (catalase) enzymes
oxidative use oxygen to remove hydrogen from molecules to break down fatty acids, alcohol, drugs - are abundant in liver and kidneys; produces H2O2 (toxic)
catalase breaks down hydrogen peroxide into water and oxygen = no longer toxic

50
Q

mitochondria

A

has two phospholipid bilayers - inner membrane forms cristae that have lots of enzymes to make ATP
cellular respiration
have their own DNA (double stranded circular) - symbiotically evolved

51
Q

cells with lots of mitochondria

A

highly active
skeletal muscle, heart muscle, liver, sperm

52
Q

cells with no mitochondria

A

red blood cells (mitochondria are excreted before maturation)

53
Q

vesicular transport

A

endocytosis and exocytosis
using vesicles (parts of the bilayer) to move materials

54
Q

endocytosis

A

uptake of material into a cell via vesicles that pinch off from the plasma membrane
phagocytosis, pinocytosis, receptor-mediated endocytosis

55
Q

phagocytosis

A

“cell eating”
formation of pseudopodia (extensions of the plasma membrane) to take in something large like bacteria or cell debris
ex. white blood cells

56
Q

steps of phagocytosis

A
  1. recognition of bacteria by receptors in membrane
  2. attachment of bacteria to phagocyte
  3. pseudopodia ingest bacteria into a phagosome (vesicle)
  4. phagosome and lysosome fuse to form phagolysosome
  5. destruction of bacteria and digestion
  6. release of end products into or out of cell
    (recognition, attachment, ingestion, fusion, digestion, elimination)
57
Q

pinocytosis

A

“cell drinking”
plasma membrane indents to form an endocytic vesicle
nonspecific process: extracellular fluid + dissolved substances
small molecules

58
Q

receptor mediated endocytosis

A

receptors in membrane of cell bind specific ligands; clathrin forms a coated pit around inside of membrane and the ligand is concentrated inside the forming vesicle
the vesicle may deposit contents into lumen of organelle, travel across cell and fuse with plasma membrane to release contents, or fuse with endosomes which then sort contents to Golgi or lysosomes

59
Q

clathrin

A

protein that accumulates around membrane in endocytosis to coat vesicle
afterwards, it is released to be used again

60
Q

exocytosis

A

vesicles fuse with plasma membrane and release contents into ECF
used to secrete specific substances, release waste products, and replace components to plasma membrane removed by endocytosis

61
Q

driving forces for non-vesicular transport

A

chemical
electrical
electrochemical

62
Q

chemical driving force

A

molecules move passively down the concentration gradient, from an area of high concentration to low
as size of gradient increases, the rate of transport of substance increases

63
Q

electrical driving force

A

ion experiences attractive and repulsive forces due to membrane potential

64
Q

membrane potential

A

difference in electrical potential or voltage across cell membrane
separation of charge

65
Q

electrochemical driving force

A

sum of electrical and chemical driving forces acting on ion
direction depends on the net direction of electrical and chemical driving forces

66
Q

simple diffusion

A

passive movement of molecules through a biological membrane’s lipid bilayer without use of proteins from high to low concentration
molecules that are soluble in lipid (non polar/hydrophobic) and smaller in size diffuse more readily ex. fatty acids; ethanol

67
Q

factors influencing the rate of simple diffusion

A
  1. magnitude of driving force
  2. membrane surface area ex. villi in intestines
  3. membrane permeability
68
Q

membrane permeability

A
  • lipid solubility of diffusing substance is the most important factor in deciding if a molecule can pass by simple diffusion (nonpolar)
  • size and shape of diffusing substance - smaller and more regularly shaped
  • temperature = higher temp, higher energy, higher rate
  • diffusing distance - rate inversely proportional to distance
69
Q

mediated transport

A

transport of molecule is mediated by proteins
facilitated diffusion and active transport

70
Q

facilitated diffusion

A

passive transport, moving down concentration gradient by carriers or channels
specific binding sites for substrate

71
Q

carrier-mediated facilitated diffusion

A

transported solute binds to the binding site of the transporter protein and causes a conformational change - solute is release inside the cell
does not require energy
ex. glucose transporters (GLUT family of proteins) move glucose down concentration gradient

72
Q

channel-mediated facilitated diffusion

A

electrochemical gradient determines ion flux - affected by the potential in the cell
channels are selective - for ions or for water (aquaporins)

73
Q

voltage-gated channel

A

changes in voltage cause the channel to open

74
Q

ligand-gated channel

A

binding of signaling molecules opens channel

75
Q

mechanically-gated channel

A

mechanical stimuli such as stretching of the cell causes channel to open

76
Q

active transport

A

‘uphill’ transport - against the gradient
concentrates substrate
requires energy to move from low to high concentration
protein has specific binding sites for substrate

77
Q

primary active transport

A

hydrolysis of ATP releases energy

78
Q

ex. Na+/K+ pump

A

at rest, the concentration of Na+ is high outside of the cell and the concentration of K+ is high inside the cell
the binding of 3Na+ to the pump (intracellular side) causes the hydrolysis of ATP - release of energy and conformational change to pump - releases Na+ outside of cell
2K+ bind to the pump from the outside and cause the release of a phosphate molecule (negatively charged) - re-orient the protein and release K+ inside cell
electrogenic
creates and maintains Na+ and K+ concentration gradients

79
Q

secondary active transport

A

couples movement of an ion down its electrochemical gradient with another substance moving against its concentration gradient
cotransport and countertransport

80
Q

cotransport

A

two substances transported in same direction
symport

81
Q

ex. Na+/glucose

A

cotransporter
influx of Na+ into the cell provides the energy to drive movement of glucose into the cell
the charge on Na+ causes a conformational change to the protein when Na+ binds, moving both Na+ and glucose into the cell
electrogenic

82
Q

countertransport

A

two substances transported in opposite directions
antiport

83
Q

ex. Na+/H+ exchanger

A

countertransport
movement of Na+ into the cell drives H+ out of the cell
electroneutral (equal charges moving in opposite directions)

84
Q

electrogenic

A

net movement of charge

85
Q

saturated transport

A

an increased number of binding sites are occupied as the solute concentration increases - reaches maximum rate when all binding sites are occupied
mediated transport

86
Q

non-saturated transport

A

linear increase in rate according to the concentration; does not reach a maximum
simple diffusion (does not involve binding sites)

87
Q

chemical messengers

A

bind to receptor to produce response
can be lipid soluble or water soluble

88
Q

signal transduction

A

sequence of events between binding of messenger to receptor and the production of a cellular response

89
Q

properties of receptors

A

specificity for the ligand they bind
saturation (amount of ligand they can bind)
affinity

90
Q

intracellular receptors

A

found inside the cell either in the cytoplasm or nucleus, are bound to by lipid-soluble chemical messengers
together, the messenger and the receptor bind to response element on DNA

91
Q

transcription factors

A

alters transcription of mRNA by binding to response element
alters rate of protein synthesis

92
Q

response element

A

specific sequence of DNA near the beginning of a gene

93
Q

membrane-bound receptors

A

channel, enzyme, or G-protein linked receptors

94
Q

first messenger

A

hydrophilic extracellular chemical messenger that binds to a specific membrane receptor

95
Q

second messenger

A

substances that enter or are generated in the cytoplasm in response to the binding of the first messenger to a receptor

96
Q

protein kinase

A

an enzyme that phosphorylates another proteins and changes the response of something in the cell

97
Q

G-proteins

A

cytosolic surface of membrane; bind guanosine nucleotides link between GPCR and effector protein
3 types:
affect ion channels
stimulatory G proteins (Gs)
inhibitory G proteins (Gi)

98
Q

G-protein linked receptors

A

when bound by first messenger, causes conformational change that releases GDP from the G protein (inactive) and causes GTP to bind to the G protein (active)

99
Q

Action of G-proteins on Ion Channels

A
  1. binding of first messenger to receptor causes conformational change in receptor
  2. affinity of a-subunit for GTP increases; GDP dissociates, GTP binds
  3. GTP-bound a-subunit dissociates from B and y, moves to ion channel
  4. ion channel opens or closes to alter flow of ions across membrane
100
Q

Gs proteins

A

stimulatory; activate enzymes

101
Q

Gi proteins

A

inhibitory; inhibit enzymes

102
Q

Action of G-proteins on enzymes

A
  1. binding of first messenger to receptor causes conformational change in receptor
  2. affinity of a-subunit for GTP increases; GDP dissociates, GTP binds
  3. GTP-bound a-subunit dissociates from B and y, moves to enzyme
  4. Gs or Gi protein - stimulates or inhibits enzyme
  5. alters production of second messenger in cytosol
103
Q

cAMP second messenger system

A

epinephrine is the first messenger - binds to receptor; a subunit binds to GTP and activates adenylyl cyclase. an enzyme that converts ATP to cAMP - the second messenger
cAMP activates cAMP-dependent protein kinase that phosphorylates the protein and causes the cell’s response

104
Q

inactivation of cAMP

A

cAMP is converted to noncyclic AMP by phosphodiesterase

105
Q

calcium as a second messenger

A

1st messenger binds to receptor (ligand gated ion channel or GPCR)
causes increase in cytosolic Ca2+ (influx through calcium channel) → induces Ca2+ release from ER
Ca2+ is a second messenger - activates calmodulin → activates calmodulin-dependent protein kinase
kinase phosphorylates a protein and causes a cell response

106
Q
A

Physiology (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions