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First Quarter > Cell Biology Exam 1 > Flashcards

Cell Biology Exam 1 Flashcards

1
Q

Cell Membrane Components

A

Phospholipids, proteins, cholesterol

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2
Q

Phospholipids

A

membranes are variously composed of these special lipids, they are amphipathic molecules with a hydrophobic and phillic end can assemble as micelle, bi-layer and liposome
hydrophobic effect determines the organization of phospholipids

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3
Q

glycolipids

A

carbohydrate branches attached to exterior end of lipid replacing the polar head

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4
Q

glycoprotein

A

carbohydrate attached to the exterior end of a protein in the cell membrane
nearly all membrane proteins are glycoproteins at somelevel

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5
Q

Proteins

A

functional part of the membrane, the ratio of proteins/lipid ratio depends on complexity of membrane functionality, sequence of amino acids assembled in such a way to be folded or wound up,
there are 2 kinds of membrane proteins: Integral Membrane proteins and Peripheral membrane proteins

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6
Q

Integral membrane proteins

A

regions of lipid sea, held in position

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7
Q

Peripheral membrane proteins

A

located on the surfaces of the lipid sea usually on the cytoplasm side

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8
Q

Kinds of membrane proteins

A

structural - give cell structural integrity, ECM
channels - allow for passive transport of molecule through membrane
transporters - active transport of molecule along natural conc gradient
pumps - active transport of molecule against concentration gradient
transducers - couple a membrane receptor to cytoplasmic enzyme
enzymes - perform cellular work by catalyzing rxn

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9
Q

Cholesterol

A

added agent involved in cell fluidity, amphipathic steroid, enhances cell membrane stability decreases permeability, helps with packing the phospholipids.

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10
Q

Fluid Mosaic Model

A

protein and lipid distribution is asymmetrical, in addition of the obvious barrier function a membrane must be able to engage in recognition, transportation and communication.

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11
Q

Membrane recognition

A

cellular adhesion, cellular interactions with prokaryotic organisms, cellular/tissue identity, cellular immunity

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12
Q

cellular adhesion during growth and development

A

by cellular density/contact with cell beside it, the part that is recognizable is the stage-specific embryonic antigens (SSEA’s)

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13
Q

cellular adhesion in mature tissues

A

cell adhesion molecules (CAM’s) are what join the cells together

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14
Q

cadherin

A

link cells to identical cells

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15
Q

integrin

A

links cells to the ECM

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16
Q

Cellular binding during diaphysis

A

The ability of a white blood cell to bond to and exit capillary lining linked to the display of interaction of special surface recognition molecules

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16
Q

cell junctions

A

adhering or tight junctions by ways of proteins

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16
Q

cellular interactions with prokaryotic cells

A

certain bacteria have tiny protein threads, fimbriae, to attack the host cell on the glycolipids

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17
Q

cellular binding during diapedesis

A

ability of WBC to bond to, and exit capillary lining linked to the display and interaction of special surface recognition molecules

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18
Q

cellular/tissue identity

A

by what carbohydrates are attached can define the type of cells they are “blood typing”

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19
Q

cellular immunity

A

cells immune systems express certain proteins on plasma membrane call human leukocyte antigens (HLA), these are used to present foreign material to other defender cells

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20
Q

antigen presenting cells

A

HLA cell that put foreign material on outside of membrane for other defender cells to see and attack

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21
Q

Cell membrane Transportation ways

A

passive transport, facilitated transport, active transport, vesicular transport

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22
Q

Passive transport

A

free passage - completely unaided movement governed by diffusion, unfit for nearly all significant biological molecules, movement through phospholipid sea
openings - various types of channels and pours and is selective, any type of unaided passage governed by diffusion, may be close able - added or subtracted from plasma membrane
commons eg: aquaporins, ion channels and gap junctions

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23
Q

Aquaporin

A

a pore for water, more than 10 different forms found where the proteins fold up in lipid by-layer to combin two hemi-phores

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24
Q

Ion channels

A

the channels are important for electrically excitable cells such as neurons and muscles, they change membrane potentials
voltage-gated channel - opened by applying voltage
ligand-gated channels - opening by docking a ligand
mechanically-gated channels - opened by physically stressing the cell
chemically-gated channel - opened by the pressence of Ca2+ or phosphorylation of the gate

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25
Q

Gap junction

A

special case used to direct cell-to-cell transmission, allows for electrical and metabolic coupling of cells, consists of 6 IMP’s termed connexons creating the channel

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26
Q

Facilitated Transport

A

facilitated diffusion, various types of IMPs that physically carry a solute across the plasma membrane, selective, non-energy dependant - aided by concentration gradient, uses a translocation mechanism to make a conformational change to IMP to create access, they are simple automatic and efficient.
eg. uniporter, symporter, multiporter

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27
Q

Glucose Tansporter

A

part of family of similar proteins GLUT 1 thru 5, stimulated by insulin and inhibited by ATP,

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28
Q

Bi-Chloride Antiporter

A

this anion transporter exchanges a HCO3 for a Cl- in RBCs

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29
Q

Active Transport

A

a carrier mediated transport system requiring ATP, works against the concentration gradient, selective
two broad types are primary and secondary where sec. does not use ATP directly often called co-transporter

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30
Q

Sodium Potassium pump

A

the main pump, hydrolysis of ATP is used to run the pump, an antiporter IMP the moves 3 Na out for 2 K in, is electrogenic b/c it moves ionic species, high level of Na is used for secondary co-transports systems

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31
Q

Calcium Pump

A

a uniporter IMP that moves Ca2+ out per ATP, in all cells, primary active transporter

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32
Q

Hydrogen Potassium Pump

A

an antiporter IMP that moves H+ out and K in per ATP, primary active transport

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33
Q

Sodium-Glucose Symporter

A

an IMP that moves 2 Na+ in with 1 Glucose in, glucose levels usually higher in cells so to move in against its gradient sodium is used, since it is then dependant on the sodium pump it is a secondary active transport

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34
Q

Sodium-Hydrogen Antiporter

A

an IMP that moves H+ out and Na+ in, secondary active transport, relies on sodium gradient by the Na/K pump, common in kidney tubule cells

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35
Q

Sodium-Calcium Antiporter

A

an IMP that moves Ca2+ out and Na+ in, actually faster than the Calcium pump, econdary active transport, relies on sodium gradient created by Na/K pump

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36
Q

Vesicular Transport

A

utilizing membrane sphere (vesicles) to shuttle material to and from the cell membrane, technically requires energy, broken down into endocytosis and exocytosis

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37
Q

Exocytosis

A

vesicles originate at the golgi apparatus and shuttles along the cytoskeleton to the plama membrane so it is moving things out also known as secretion.

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38
Q

Endocytosis

A

vesicles bud off of plasma membrane towards the interior as form of bulk transport, moving things IN using an endosome, there is 3 types; phagosytosis, pinocytosis and receptor-mediated endocytosis

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39
Q

phagosytosis

A

involves the engulfment of particulate, gobling of stray material, formation of pseudopodia that envaginate and fuse to form a phagocytic vesicle termed a phagosome

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40
Q

pinocytosis

A

a fluid phase endocytosis, non-specific internalization common in all cells, involves invagination of membrane to create pinocytotic vesicles

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41
Q

transcytosis

A

termed used to describe the shuttling of a endocyte across the cell to another surface

42
Q

receptor-mediated endocytosis

A

highyl specific internalization, receptor IMP are required, that must bind to a ligand before internalization
multistep process: receptor binding, clathrin pulls membrane down, pulls to create a cage called coated pit, endosome is formed and fuses with CURL vesicle

43
Q

CURL

A

Compartment the Uncouples Receptor and Ligand

44
Q

LDL receptor- LDL endocytosis

A

receptor that takes in cholesterol to the cell which is synthesized to be used by golgi apparatus and put back into the cell membrane

45
Q

Cell Membrane Communication 5 categories

A

endocrine secretion, neuro-endocrine secretion, paracrin secretion, autocrine secretion, synaptice transmission (neuronal secretion)

46
Q

Endocrine Secretion

A

the process involves the synthesis and exocytosis of a hormone from a source cell->released hormone enters ECM then into bloodstream where it circulates throughout the body -> then exits blood capillaries and in EC to land on or enter target cells
receptors at target cells determine sensitivity

47
Q

peptide hormone

A

water soluble, receptor located on the cell surface, typically transemembrane IMPs

48
Q

steroid hormone

A

lipid soluble and can easily cross the plasma membrane, receptors located in either cytoplsm or nucleus inside cell, protein with ligand or DNA binding site, directly turn gene expression on

49
Q

Autocrine Secretion

A

synthesis and exocytois of a chemical signal from a cell-> released chemical enters ECM where it stays locally -> then lands on the same cell as a target

50
Q

Paracrine Secretion

A

involves the synthesis and exocytosis of a chemical signal loosely called a hormone from a source cell -> released chemical enters ECM where it stays locally -> then lands on nearby target cells
receptors on target cells determine sensitivity
eg. Endothelial cells lining blood vessels can secrete stimulants to the underlying smooth muscle cells to induce vasoconstriction
During fetal development target tissues secrete nuerotrophic factor which serves as a chemo-attractent molecule. Nerve Growth Factor

51
Q

Synaptic Transmission (Neuronal Secretion)

A

transmitting end of neurone; small intercellular space or ECM; and a receiving cell
receptors postsynaptic side determine sensitivity, selectivity due to physical construction of synapse

52
Q

4 Basic Categories of chemical signalling (reception)

A

steroid hormone receptor mechanism, ligand-gated receptor mechanism, G-protein receptor mechanism, enzymatic receptor mechanism

53
Q

Steroid Hormone Receptor Mechanism

A

b/c steroids are lipid soluble they pass thru membrane, receptor is inside cell and has a steroid DNA and Gene-regulatory domain

54
Q

Ligand-gates Receptor Mechanism

A

involves a external receptor site as an IMP where ligand binds to the receptor to open the channel

55
Q

Nicotininc Acetylcholine Receptor

A

receptor has ligand attach and IMP undergoes a conformational change to allow for Na and K to pass, stimulates an action potential by secondarily activating voltage gated K channels nearby creating an Excitatory post synaptic potential, the Ach is broken down by acetylcholinesterase

56
Q

receptor

A

an IMP that receives a primary messenger and indigoes a conformational change which convey message further

57
Q

transducer

A

a PMP that relays/converts signal from receptor to amplifier

58
Q

amplifier

A

IMP that boost signal by activation many secondary messengers

59
Q

secondary messengers

A

cytosolic signalers formed by phosphorylated precursor that activate internal agent

60
Q

internal effector

A

cytosolic protein that activate other proteins by phosphorylating them

61
Q

cAMP

A

cyclic adenosine monophosphate system

62
Q

protein phosphorylation

A

when a protein is phosphorylated and it changes its conformation and is thereby activated

63
Q

protein kinase

A

enzyme that phosphorylate other proteins

64
Q

protein phosphotase

A

enzyme that de-phosphorylate other proteins

65
Q

The Mechanism of G-Protein-Linkes Receptor

A 
External signal (first messenger)
Receptor
Transducer
Amplifier
Phosphorylated precursor
Second Messenger
Internal Effector
Cellular Response
66
Q

3 major types of transducer G-proteins

A

Gs - stimulatory, and activates adenylate cyclase
Gi - inhibitory, and inhibits adenylate cyclase
Gp - stimulatory, and activates phospholipase C

67
Q

What are the G-Proteins subunits?

A

alpha subunit - the most variable and functionally important

beta and gamma - are similar, these bind the molecule together and hold it in the cell membrane

68
Q

Amplifiers relavent to this course

A

these PMPs produce many copies of the second messenger
adenylate cyclase - converts ATP into cAMP
phospholipase C - converts PIP2 into IP3 and DG,

69
Q

Second Messengers relevant to this course

A

cAMP - stimulates A-kinase

IP3, DG, and Ca2+- variously stimulates C-kinase and calcium/calmodulin kinase

70
Q

Internal effectors relevant to this course

A

A-kinase - activated by cAMP

C-kinase- activated by DG

Ca2+/calmodulin kinase - activated by Ca2-

71
Q

The Activation of the cAMP Signal Transduction

A

with the activation of adenylate cyclase by activated G-protein, cAMP made.
cAMP diffuse in cytosol and binds to A-kinase, this releases a catalytic component (c) from the regulatory cap (r)
A-kinase phosphorylates cellular proteins, thus activating them, conformational change allows this to happen

72
Q

In-Activation of the cAMP Signal Transduction

A

system shuts down by a number of mechanisms that relate to the continual recycling of molecules, done by phosphatase enzymes available in the cell

  • GTP -> GDP then causing G-protein to become quiet
  • protein-P _> protein then returning them to resting conformation
  • cAMP ->AMP thus eliminating the second messenger
73
Q

The Activation of the IP3, DG, Ca2+ Signal Transduction

A
  • with the activation of PL-C by activated G-protein IP3 and DG are made by cannibalizing the membrane phospholipid called PIP2.
  • IP3 enters cytosol, DG moves thru membrane, IP3 stimulate the release of ER stored Ca2+, DG binds to near C-kinase
  • Ca2+ binds to the Ca2+/calmodulin kinase, this phosphorylates the proteins, fairly fast acting but temporary
  • C-kinase phosphorylates cytosolic proteins, this is somewhat slow
74
Q

In-Activation of the IP3, DG, Ca2+ Signal Transduction

A

this system is shut down by a number of mechanisms that relate to the continual recycling of molecules, done by various phosphotase enzymes
GTP->GDP, thus causing it to become quiet
IP3->IP2 thus eliminating this second messenger
Ca2+ re-pumped back into ECM and into ER
Protein-P->Protein thus returning them to resting conformation

75
Q

Enzyme Receptor Mechanism

A

this process involves an external receptor that spans the membrane and can directly phophorylate cytosolic proteins
-external, ligand binding domain
-membrane-spanning domain
-internal, catalytic domain
most of these are tyrosine kinases because they add phosphates to tyrosine residues on proteins of the cell interior by using ATP

76
Q

Nucleoplasm

A

the contents of the nucleus

77
Q

Cytoplasm

A

the bulk of the cell including the cell organelles and fluid

78
Q

Cytosol

A

fluid inside cell mostly water, amino acids, proteins, fatty acids, lipids, nucleotides, simple sugars and complex carbohydrates

79
Q

Sytoskeleton

A

an array of proteins that can criss cross the interior

80
Q

Organelles

A

ER, Golgi Apparatus, lysosomes, mitochondria

81
Q

Functions of the Endoplasmic Reticulum (Smooth and Rough)

A 
Protein synthesis
Hydroxylation (Smooth but some Rough)
Glycosylation (Rough but some smooth)
Glycogenolysis (Smooth)
Sterol Metabolism (Smooth)
Lipid Synthesis (Both)
Calcium Storage (Smooth)
82
Q

Hydroxylation

A

addition od hydfroxyl group to lipid-soluble toxins, converting them to water-soluble molecules that can be easily disposed of
can be done to complete the synthesis of certain molecules

83
Q

Glycosylation

A

addition of sugar residue (to specific amino acids) in peptide chains, usually done on rough endoplasmic reticulum bound ribosomes

84
Q

Glycogenolysis

A

breakdown of glycogen to glucose

85
Q

Sterol Metabolism

A

steroid hormone synthesis in endocrine glands

cholesterol synthesis and availability for membrane stability

86
Q

Lipid Synthesis

A

new phospholipids added to cytoplasmic side of ER bilayer
the special enzyme used to flip the new lipid to the cisternal side to prevent mono-lipid layer formation is the flippase

87
Q

Calcium Storage

A

common muscle cells as a way to sequester Ca2+ during the resting state

88
Q

alpha helices

A

amino acid chain that has commonly spiraled into large sections

89
Q

globular

A

when the alpha helices fold up further this is what they form

90
Q

5 kinds of proteins based on their structure

A

tripartite (transmembrane) single pass, hydrophilic region extends from both sides, single hydrophobic region spanning the membrane, hydrophobic regions as an alphas helix
multipass (transmember) IMP -multiple helices spanning over lipid by-layer, may contain polar or charged amino acids that contribute to formation of an aqueous pore
non-spanning IMP - embedded in one side
PMP ionically bonded to another IMP or PMP
PMP ionically bonded to an phospholipid

91
Q

Extra-Cellular Matrix

A

structural proteins in between cell that connect them and hold them together

92
Q

Stage-specific embryonic antigens

A

family of glycolipids expressed in embryogenesis
linked to specific stages of development
affect the further growth of the embryo

93
Q

cell adhesion molecules

A

family of glycoproteins involved in maintaining tissue integrity

94
Q

diffusion

A

the net movement of molecules from an area of high concentration to an area of low concentration

95
Q

osmosis

A

thee diffusion of water across a semi-permeable membrane

96
Q

transport maximum

A

the maximum rate of penetration allowed through a cell

97
Q

Donnan Effect

A

imbalance in distribution of mobile ions and causing water to achieve its own equilibrium by moving

98
Q

Donnan Swelling

A

it the cell is unable to move molecules out it this is what happens

99
Q

Polarized cells

A

since the cell is then constantly moving Na+ out of the cell and the Proteins -ve and Cl- inside create differences in charges from the inside to the outside.

100
Q

Electrical potential across cell

A

the net potential across the plasma membrane is about 60-mV

101
Q

Action Potential

A

There is a voltage at which enough gates open to briefly overwhelm the pumps, and cause very serious membrane action to occur
this is a self-propagating wave of depolarization due to sequential ionic gating

102
Q

Digoxin

A

poison found in Digitalis Foxglove plant. The toxin binds top the sodium pump in cardiac muscle cells and inhibits it. Therefore a higher level of Ca is in the heart causing strong heart beat, can be used for congestive heart failure

103
Q

Residual Bodies

A

any indigestible materials persist as permanent phagosomes

First Quarter (26 decks)

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