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BISC 1111 Lecture Notes - Lecture 5: Pinocytosis, Hydrolysis, Exocytosis

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turquoiseseal559
19 May 2016
School
GWU
Department
Biological Sciences
Course
BISC 1111
Professor
Doebel Hartmut

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Document Summary

Plasma membrane exhibits selective permeability: allows some substances to cross more easily than other. Phospholipid: amphipathic molecule: hydrophilic region and hydrophobic region. Membrane held together by hydrophobic interactions: weaker than covalent bonds. Peripheral proteins: appendages loosely bound to the surface of the membrane. Glycolipids: membrane carbohydrates covalently bonded to lipids. Function by having a hydrophilic channel that molecules use as a tunnel. Aquaporins: passage of water molecules through the membrane in certain cells is greatly facilitated by channel proteins. Diffusion: movement of particles of any substance so that they spread out. Concentration gradient: region along which the density of a chemical substance increases or decreases. Osmosis: diffusion of free water across a selectively permeable membrane. Tonicity: ability of surrounding solution to cause a cell to gain/lose water. Isotonic: no net movement of water across plasma membrane. Hypotonic: less water will enter faster than leaves. Hypertonic: cell will lose water, shrivel and die. Osmoregulation: control of solute concentrations and water balance.

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Related Questions

True or False? True False
1. Proteins rapidly pass artificial membrane (liposome).--------------------------------------------------------------------------------------( ) ( )
2. Amphiphatic detergent such as SDS spontaneously forms bilayer inwater. ------------------------------------------------------------( ) ( )
3. Cholesterol does have a hydrophilic head and hydrophobic tail.-------------------------------------------------------------------------( ) ( )
4. Fat molecules are one of the major components of the plasmamembrane.------------------------------------------------------------- ( ) ()
5. Phospholipid molecules such as phosphatidylcholine spontaneouslyform bilayer. ----------------------------------------------------( ) ( )
6. Flippase facilitates lateral movement of phospholipids withinthe plane of the membrane.----------------------------------------- ( ) ( )
7. Glycolipids make bilayer less permeable to small water solublemolecules.----------------------------------------------------------- ( ) ()
8. Membrane inner leaflet is enriched with phosphatidylcholine,Sphingomyelin, and Glycolipid. -----------------------------------( ) ( )
9. Plasma membrane proteins can have an enzyme activity.--------------------------------------------------------------------------------( ) ( )
10. A single pass membrane protein must have an amphiphatic alphahelix.-------------------------------------------------------------- ( )( )
11. Plasma membrane proteins can be linked to a lipid molecule atthe outer leaflet of the plasma membrane. --------------------- ( )( )
12. The lateral motility of membrane proteins can be restricted bytight junctions.------------------------------------------------------ ( ) ()
13. Channel proteins have specific binding sites for ions and thusslower than carrier proteins.--------------------------------------- ( ) ( )
14. An antiport would function as a symport if its orientation inthe membrane were reversed. ---------------------------------------( ) ( )
15. A transmembrane pore can be formed by multiple amphipathicalpha helices. ----------------------------------------- ( ) ()
16. Porin proteins form water-filled channels in the outer membraneof a bacterium and are mostly composed of beta sheets. ---- ( ) ()
17. Glucose uniporters localize at the apical side of theintestinal epithelium.------------------------------------------------------------ ( ) ()
18. GAP junction is a selective pore for anions.-----------------------------------------------------------------------------------------------( ) ( )
19. A voltage-gated Na+ channel adopts only two conformationstates: open and closed.----------------------------------------------- ( ) ( )
20. Voltage gated K+ channel opens faster than the Voltage gatedNa+ channels.-------------------------------------------------------- ( ) ()
21. Opening of chloride channel at the synapse will help to fire anaction potential.------------------------------------------------------ ( ) ()
22. The nuclear pore complex forms a gate through which moleculespass the nucleus uni-directionally. -------------------- ( ) ()
23. A completely folded protein is imported into a mitochondrionthrough a large non-selective pore.--------------------------------- ( ) ( )
24. ER signal sequence contains multiple lysine and arginineresidues.----------------------------------------------------------------------( ) ( )
25. The plasma membrane is a sorting station of inward endocyticpathway.---------------------------------------------------------------- () ( )
26. The trans Golgi functions as a sorting station of outwardsecretory pathway.----------------------------------------------------------- ( ) ()
27. Vesicles budding from ER are coated with Clathrin.----------------------------------------------------------------------------------------( ) ( )
28. RabGTPases and tethering proteins are the major specificitydeterminant of vesicle transport system. --------------------------( ) ( )
29. v-SNARE proteins are one of the tethering proteins.------------------------------------------------------------------------------------( ) ( )
30. In secretory cells, the constitutive and regulatory pathways ofexocytosis diverge at the cis Golgi network. ------------------ ( )( )
31. Many proteins are posttranslationally glycosylated at tyrosineresidues in the ER.------------------------------------------------- ( ) ( )
32. Cells import LDL molecules exclusively through pinocytosis.-------------------------------------------------------------------------( ) ( )
33. Cells recycle LDL receptors from lysosome to the plasmamembrane.----------------------------------------------------------------- () ( )
34. Phagosomes fuse with late endosome.------------------------------------------------------------------------------------------------------( ) ( )
35. Small vesicles from ER near the plasma membrane can fuse withthe plasma membrane upon bypassing Golgi apparatus. -- ( ) ()
36. If a Sec mutant showed an accumulation of newly synthesizedproteins at ER,
then the Sec gene is likely a component of vesicle-buddingmachinery of trans-Golgi network.------------------------------------ ( ) ( )
37. A signal recognition particle is a single pass trans-membraneprotein of the ER membrane.---------------------------------------- ( ) ( )
38. Typical animals cells display higher levels of intracellularsodium than extracellular compartments.------------------------------ ( ) ( )
39. Typical animals cells display higher levels of intracellularchloride than extracellular compartments.----------------------------- ( ) ( )
40. The Na-K Pump is a GTPase that can adopt active and inactiveconformational states.----------------------------------------------- ( ) ( )
1. Phospholipase
C-­-ß
produces
phosphatidylinositol
3,4,5-­-trisphosphate
and
diacylglycerol.
(
)
(
)
2. PDGF
activates
GPCR.
-­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­----­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­-
(
)
(
)
3. Rho
is
an
example
of
heterotrimeric
G
proteins.
-­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­----­--­--­--­--­--­-
(
)
(
)
4. All
members
of
the
G
protein
coupled
receptors
interact
with
small
GTPase
Ras.
-­--­--­--­--­--­--­--­--­--­-
(
)
(
)
5. Adrenaline
is
an
example
of
the
ligands
for
the
RPTK
family.
-­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­-
(
)
(
)
6. Ras
GEF
activates
RPTK.
-­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­----­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­-
(
)
(
)
7. PH
domain
containing
proteins
bind
to
activated
EGFR.
-­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­-
(
)
(
)
8. Ligands
for
GPCR
proteins
induce
dimerization
of
the
receptor.
-­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­-
(
)
(
)
9. Grb2
is
an
adaptor
protein
that
binds
to
a
phospho-­-tyrosine
residue
of
activated
RPTK
through
a
PH
domain.
-­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­----­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­-
(
)
(
)
10. When
a
cell
is
expressing
a
large
number
of
dominant
negative
EGFR
proteins,
an
introduction
of
a
constitutively
active
Ras
mutant
will
allow
EGF
signaling.
-­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­-
(
)
(
)
11. PI3K
generates
phosphatidylinositol
3,4,5-­-trisphosphate
from
IP3.
-­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­-
(
)
(
)
12. Calcium
inhibits
PKC.
-­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­----­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­-
(
)
(
)
13. cAMP
activates
PKA.
-­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­----­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­-
(
)
(
)
14. The
MAP
kinase
ERK
inhibits
MAP
kinase
kinases.
-­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­----­--­-
(
)
(
)
15. cAMP
is
an
example
of
a
first
messenger.
-­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­----­--­--­--­--­--­--­--­--­--­--­--­--­--­--­-
(
)
(
)
16. All
7-­-Transmembrane
receptors
are
G
Protein
Coupled
Receptors.
-­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­--­-
(
)
(
)
17. Both
Ga
and
Gß
subunits
of
the
heterotrimeric
G
protein
can
mediate
GPCR
signaling.
-­--­--­-
(
)
(
)
18. Both
Ga
and
Gß
subunits
of
the
heterotrimeric
G
protein
have
GTPase
activity.
-­--­--­--­--­--­--­--­--­--­--­--­-
(
)
(
)
19. The
Gas
subunit
of
the
heterotrimeric
G
protein
suppresses
the
function
of
Adenylyl
cylase.
(
)
(

BIOL 110 Principles of Biology

1.Describe the structure of a plasma membrane.

2.Define an amphipathic molecule and give an example.

3.Explain the difference between integral and peripheral proteins.

4.Describe the fluid-mosaic model of a membrane.

5.Identify and discuss the function of proteins located in the plasma membrane.

6.Explain the difference between glycoproteins and glycolipids.

7.Why can carbon form chemical bonds with so many elements?

8.Explain the meaning of concentration gradient as it pertains to movement of substances into and out of cells.

9.Explain diffusion and osmosis.

10.What molecule is thought to facilitate the movement of water molecules through a plasma membrane?

11.Explain the difference between active and passive transport across the plasma membrane. Provide examples that occur in the human body.

12.Explain the impact to a cell if placed in a hypertonic solution; include a definition of hypertonic solution and why the change occurs.

13.Identify a similarity and difference between facilitated transport and active transport. Do not state that both move substances across the membrane.

14.Explain the sodium-potassium pump and identify the type of membrane protein involved.

15.Identify and explain the process used by cells to secrete substances.

16.Explain the composition of a plant cell wall and how it differs from the cell wall of a prokaryotic cell.

17.Explain the plasmodesmata and identify the kingdom in which they are found.

18.Define energy and identify the two basic forms of energy.

19.Define entropy.

20.Define metabolism.

21.Explain the difference between exergonic and endergonic reactions.

22.What are coupled reactions and what roles can ATP serve in these reactions?

23.Explain the difference between oxidation and reduction reactions.

24.What is energy of activation?

25.What factors affect the speed of enzymatic reactions?

26.What is an electron transport chain?

27.What occurs at the active site of an enzyme?

28.Define enzymatic inhibition.

29.Define chemiosmosis.

30.Define vitamins and identify their function.

Question 1

Plasma membranes are selectively permeable. This means that

A.

glucose cannot enter the cell.

B.

the plasma membrane allows some substances to enter or leave a cell more easily than others.

C.

plasma membranes must be very thick.

Question 2

Oxygen molecules O2 crosse a plasma membrane by

A.

passive transport

B.

osmosis

C.

active transport

Question 3

Facilitated diffusion across a biological membrane requires ________ and moves a substance ________ its concentration gradient.

A. energy and channel proteins; against (up)

B. transport proteins that make channels ; down

C. energy ; down

Question 4

When two aqueous solutions that differ in solute concentration are placed on either side of a semipermeable membrane and osmosis is allowed to take place, the water will

A. move to the side with lower water concentration

B.

move to the side with higher water concentration

C.

move to the side with lower solute concentration

Question 5

Kinetic energy differs from chemical energy in that

A.

chemical energy is a particular form of kinetic energy.

B.

kinetic energy is the energy of a moving object, whereas chemical energy is the potential energy of molecules.

C.

kinetic energy is stored energy that has the potential to do work, and chemical energy is the energy of movement.

Question 6

When a cell uses chemical energy to perform work, it uses the energy released from a(n) ________ reaction to drive a(n) ________ reaction.

A.

exergonic; endergonic

B.

endergonic; exergonic

C.

spontaneous; exergonic

Question 7

When an enzyme catalyzes a reaction

A. it raises the activation energy of the reaction.

B. it lowers the activation energy of the reaction.

C. it is used once and discarded.

Question 8

Which of the following statements regarding enzyme function is false?

A. An enzyme's function depends on its three-dimensional shape.

B. Enzymes are very specific for their substrates.

C. Enzymes are used up when they catalyze a chemical reaction so must be synthesized for each new chemical reaction