BISC306 Lecture Notes - Lecture 2: Osmotic Concentration, Glycerophospholipid, Choline

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amberhippopotamus851

1 Oct 2017

School

University of Delaware

Department

Biological Sciences

Course

BISC306

Professor

Cain William

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Document Summary

Ex. cholesterol - maintains fluidity without being too rigid. Notes: when molecules increase in size the rate of diffusion slows. This is not a direct application of previous equation but it follows from that equation. Movement of uncharged solutes by simple diffusion across a membrane. Molar amount = generally used in the equations. Very limited permeability to ions and large polar molecules. Bilayer is permeable to water and small uncharged solutes. Diffusion of water across a membrane - osmosis. 1 molar solution of sucrose is ~ 1 osmoles/liter: 1 molar solution of nacl is ~ 2 osmoles/liter* Isosmotic - solutions that have the same osmolarity. A solution with the higher osmolarity is considered to be hyperosmotic to a solution with low the lower osmolarity would be considered hypoosmotic to the solution with higher osmolarity. *actually it is less then 2 osmoles/liter as the dissociation is not complete. Osmosis and osmotic pressure lower osmolarity, while the solution with larity.

Related Questions

3. In an aqueous environment, the phospholipids of a membrane____.

a) are arranged in a single layer

b) are arranged in a bilayer with the polar heads of each layerlocated at the surface

c) are arranged in a bilayer with the fatty acid tails locatedat the surface

d) are arranged in a bilayer but the phospholipids have nospecific orientation

e) dissolve

4. which of the following molecules demonstrate dual solubilitycharacteristics

a) sterols only

b) proteins only

c) phospholipids only

d) sterols and phospholipids

e) sterols, phospholipids, and proteins

5. The "mosaic" part of the fluid mosaic model refers to themembrane ____.

a) proteins

b) phospholipids

c) cholesterol

d) functions

e) layers

9. Transport of a molecule across a cell membrane by facilitateddiffusion ____.

a) does not exhibit specificity for a particular type ofmolecule

b) requires the input of energy

c) depends on a concentration gradient

d) goes against the concentration gradient

e) allows non-polar uncharged molecules to diffuse across amembrane

13. A transport system in which transport of an ion in onedirection provides the energy for active transport in the oppositedirection is known as ____.

a) primary active transport

b) active diffusion

c) secondary active transport

d) cotransport

e) osmosis

14. Cells undergo exocytosis ____.

a) to pump protons down a concentration gradient

b) when replicating

c) to secrete protein and wastes from the cell

d) to ingest nutrients

e) as a means of cellular protection

15. What is the molecular basis of familialhypercholestremia?

a) HDL enters cells using a specific receptor on the cellsurface

b) LDL enters cells using a specific receptor on the cellsurface

c) HDL exits cells using a specific receptor on the cellsurface

d) LDL exits cells using a specific receptor on the cellsurface

e) receptor-mediated exocytosis

16. Carrier molecules are utilized for ____.

a) active transport only

b) passive transport only

c) both active and passive transport

d) osmosis

e) transport of all types of molecules

17. All of the following are functions of integral membraneproteins EXCEPT ____.

a) transport of polar molecules

b) reception of chemical signals form other cells

c) cell division

d) recognition of other cells as being "like"

e) cell-cell binding

olivecod348

Cholesterol is transported in the bloodstream in lipoproteinparticles. There are several classes of lipoprotein particles, butone of the most important classes is called Low-densitylipoproteins (LDL). LDL particles are composed of a single moleculeof a large protein called apolipoprotein, as well as thousands ofcholesterols molecules and phospholipids. Part of theapolipoprotein forms the surface of the particles and faces theaqueous phase, while other parts face the hydrophobic interior ofthe particle where they interact with cholesterol and thehydrophobic tails of the phospholipids. When cells need additionalcholesterol, they produce a receptor protein on the surface oftheir plasma membrane that binds to the apolipoprotein andinitiates the uptake of LDL particles into the cell via a processcalled endocytosis.

1. What is the likely reason that LDL particles are used totransport cholesterol in the blood stream?

a. Cholesterol in LDL particles easily inserts into lipidbilayers

b. Cholesterol id largely insoluble in aqueous solutions

c. Cholesterol is synthesized within LDL particles

d. LDL particles can form lipid rafts in the lipid bilayer

2. What is the most likely location of phospholipids in LDLparticles?

a. Bound to the hydrophilic domain of apolipoprotein

b. In the lipid bilayer that surrounds LDL particles

c. On the surface interacting with the aqueous environment aswell as interacting with the hydrophobic core of the particle

d. Within the hydrophobic core of the particle

3. What best describes the class of protein that apolipoproteinbelongs to?

a. Amphipathic proteins

b. Cell surface proteins

c. Membrane associated protein

d. Multipass membrane proteins

4. What kind of molecule on the surface of the cell would bemost likely to serve as a receptor for LDL particles?

a. a cholesterol binding protein

b. a glycolipid

c. a phospholipid

d. trans membrane protein

5. What conditions would be most likely to trigger increaseduptake of LDL particles by cells?

a. increased glycolipid synthesis

b. increased plasma membrane growth

c. increased protein secretion

d. increase protein synthesis

Cells from which domain(s) of life are separated from theirenvironment by a plasma membrane? Select all correct choices.bacteria archaea eukarya 2. The active maintenance of a constantenvironment is referred to as: stability. homeostasis. symmetry.equilibrium. balance. 3. The electrical component of anelectrochemical gradient is due to: the use of ATP as an energysource to drive primary transport. a greater concentration ofpositive charges on the side of the membrane with the highestconcentration of protons. a greater concentration of positivecharges on the side of the membrane with the lowest concentrationof protons. a higher pH on the side of the membrane with the lowestconcentration of protons. a higher pH on the side of the membranewith the highest concentration of protons. 4. Which one of thefollowing would be found in the cells of a blade of grass but notin the cells of an insect feeding on that grass? Select all correctchoices. chloroplasts cytoskeletal elements mitochondriaendoplasmic reticulum nuclei 5. With which of the following is asignal-recognition particle (SRP) capable of interacting? Selectall correct choices. a signal sequence in a protein destined forthe ER a ribosome an SRP receptor 6. Which one of the followingcellular compartments does not have a double membrane structureseparating it from the rest of the cell? Select all correctchoices. mitochondria chloroplasts lysosomes the nucleus 7. True orFalse: purified phospholipids will gather together and formmembranes only if the appropriate enzyme is present. false true 8.Which component(s) of a phospholipid would most likely be found inthe interior of a lipid bilayer? Select all correct choices.glycerol fatty acids phosphate 9. Some drugs are now beingdelivered into cells through liposomes, where the drug issurrounded by a phospholipid bilayer. How do the drugs enter intothe cell? The liposome fuses with the phospholipid bilayer of thecell. The drug destroys the liposome and is transported viadiffusion into the cell. Protein channels on the cell surfacetransport the liposomes into the cell. The liposome cuts a hole inthe cell and injects the drug into the cell. 10. Some diseases canresult from defective transport across the membrane. For example,cystic fibrosis results from a chloride ion transporter that doesnot function. Which of the following would be affected when thistransporter does not function? the electrical gradient of the cellthe chloride concentration gradient Neither the chlorideconcentration gradient nor the electrical gradient of the cell Boththe chloride concentration gradient and the electrical gradient ofthe cell

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BISC306 Lecture Notes - Lecture 2: Osmotic Concentration, Glycerophospholipid, Choline

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