Biochemistry Ch3: Non enzyme protein function

Question 1

Define Collagen 
(3) characteristics

Answer 1

Trihelical
makes up most of the extracellular matrix of connective tissue
provides strength and flexibility

Question 2

Define Elastin

Answer 2

primary focus is to stretch and recoil like a spring, restoring original shape

Question 3

Define Keratins

Answer 3

intermediate filament proteins
mechanical integrity of cell
found primarily in nails and hair

Question 4

Define actin

Answer 4

makes up microfilaments
most abundant in eukaryotic cells
contain positive and negative side
allows motor proteins to move unidirectionally

Question 5

define Tubulin

Answer 5

Makes up micro tubules
chromosome separation in mitosis 
intracellular transport inside of cell using kinesin and dynein 
(-) end usually near the nucleus 
(+) end usually near plasma membrane

Question 6

define Myosin

Answer 6

motor protein that interacts with actin
cellular transport
they have a head and a neck
involved with sarcomere contraction

Question 7

Kinesins

Answer 7

play a role in aligning chromosomes during metaphase and deploymeration during anaphase
vesicles transport
takes molecules from the negative to the positive end

Question 8

Dyneins

Answer 8

movement of flagella and cillia
sliding movement
vesicles transport
takes molecules from the positive to the negative end

Question 9

Cell adhesion molecules (CAMs)

Answer 9

proteins found on the cell surface of cells, integral membrane proteins, they are split into three families cadherins, integrins and selectins

Question 10

Cadherins

Answer 10

glycoproteins that mediate calcium- dependent cell adhesion
they hold similar cells types together (epithelial and epithelial)
cell types have specific cadherins

Question 11

Integrins

Answer 11

they have alpha and beta sections, they bind and communicate with the extracellular matrix, play a role in cell signaling
(cell migration, cell division)

Question 12

Selectins

Answer 12

they bind to carbohydrate molecules that project from other cell surfaces (expressed on white blood cells)

Question 13

Immunoglobulins

Answer 13

Antibodies 
y shape
two regions antigen variable region and constant region
neutralize antigen 
mark pathogens
agglutinating pathogens

Question 14

Opsoinization

Answer 14

marking pathogen for destruction

Question 15

define biosignaling

Answer 15

cells receive and act on signaling

Question 16

Ion Channels

Answer 16

proteins that create a pathway for charged molecules to pass through the plasma membrane 
three kinds of Ion channels 
ungated 
voltage gated 
ligand gated

Question 17

ungated ion channel

Answer 17

they have no gates, unregulated, depends on equilibrium of the ion i question (example K+)

Question 18

Voltage gated channels

Answer 18

regulated by membrane potentials near the channel gate
closed in resting positions
they quickly open and close

Question 19

Ligand gated channels

Answer 19

they need to be opened and closed using the binding of a ligand to the channel

Question 20

Enzyme linked receptors

Answer 20

they can also display catalytic activity 
they have three domains 
membrane spanning domain 
ligand binding domain 
catalytic domain

Question 21

membrane spanning domain

Answer 21

anchors the receptor to the cell membrane

Question 22

ligand binding domain

Answer 22

stimulated by the appropriate ligand and induces a conformational change in the receptor to activate the catalytic domain

Question 23

catalytic domain

Answer 23

when this is activated it activates a secondary messenger cascade

Question 24

G - Protein - Coupled- Receptors

Answer 24

large family of signaling proteins and they are involved in signaling tranduction

ligand binds and ups the chances of a g protein to be attached to the protein
once a gprotien is added the receport is activated

Question 25

G- protein

Answer 25

they link to guanine nucleotides (GTP and GDP)

three main types of g proteins

Question 26

G(s)

Answer 26

stimulates adenylate cyclase, increases the levels of cAMP in the cell

Question 27

G(i)

Answer 27

inhibits adenylate cyclase, decreases the levels of cAMP in the cell

Question 28

G(q)

Answer 28

activates phospholipase C
cleaves phosphate from the membrane to form PIP1 and PIP2

this can lead to the cleavage of DAG and IP3

this then opens calcium channels in the endoplasmic reticulum

Question 29

what are the three subunits that make up the Gprotien

Answer 29

alpha beta and gamma

Question 30

what is the inactive form of gprotien

Answer 30

beta gamma and alpha GDP

Question 31

what is the active form of the gprotien

Answer 31

beta gamma and alpha GTP

Question 32

explain active g protein to inactive g protein

Answer 32

beta and gamma stick together

alpha subunit GTP seperates and enzyme adenylate cyclase removes a phosphate group turning the alpha GTP into alpha GDP

creating a inactive g protien
beta and gamma and alpha GDP

Question 33

electrophoresis

Answer 33

separate molecules using electric charge by their electric charge and their size
their migration depends on their migration velocity

Question 34

Native Page

Answer 34

analyze proteins in their native states

it is used mostly to determine the charge of the protien in question

Question 35

SDS Page

Answer 35

SDS (Sodium Dodecyl Sulfate)
separates proteins on the bases of mass alone
SDS makes all the proteins negative and it denatures the proteins (its a detergent)
therefore allowing the only variable present to be mass of the protien

Question 36

Isoelectric Focusing

Answer 36

protiens seperated based on their pI (isoelectric point) the pI is the pH at which the protien or amino acid is electrically neutral (zwittron) in the amino acid

when the protien stops moving pH=pI

anode - acidic (+) charge

Question 37

Chromatography

Answer 37

require homogenized protien mixture to be fractured through a porous matrix

preferred when using large amounts of protien

purpose is to use the similarity in characteristics (charge size ect) to see how far the protien migrates