BIOL 1010 Lecture Notes - Lecture 1: Unsaturated Hydrocarbon, Lipid Bilayer, Alkane

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

Which of the following Scientist(s) described the contemporary“fluid- mosiac”model of the plasma Membrane
Davson and Nicholson
Nicholson and Danielle
Singer and Davson
Nicholson and Singer
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The “fluid-mosaic” model of the PM differ from the first proposedmodel in that:
The first model did not have cholesterol
The first model was devoid of some lipids
The first model was devoid of some proteins
The first mode was devoid of some carbohydrates
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Which is most likely to be a membrane receptor protein?
A glycosylated protein containing three hydrophobic regions
A glycosylated protein devoid of hydrophobic regions
A protein containing hydrophobic regions but devoid of sugars
A glycosylated protein devoid of hydrophilic regions
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Which secondary structures of proteins are formed within thePM?
Alpha-pleated sheets
Beta-pleated sheets
Alpha-helicies
Beta-helicies
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Intergal proteins project
entirely outside of the bilayer on the extracellular surface
entirely through the membrane having N- and C- terminusexposed.
entirely outside of the bilayer on the cytoplasmic surface
outside bilayer but covalently linked to lipids withinmembrane
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Which is the driving force which maintains the lipid bilayer?
Van der waals forces
Hydrophobic interactions
Hydrophilic interactions
Ionic interactions
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What affect do lipids with double bonds in their nonpolar tailshave on the integrity of the PM?
They increase the fluidity of the PM
They decrease the fluidity of the PM
They allow more lipids to pack tighter in the membrane
They cause the membrane to become less stable
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As the fluidity of the PM increases, what happens to theentropy?
increases
decreases
stays the same
none of the above
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The consistency of membranes at various temperatures can beunderstood using the Margarine and Butter analogy. Butter containslonger saturated chains of fat derived from animals while Margarinecontains short polyunsaturated fats derived from corn oil. Whentaken directly from the refrigerator, Margarine can be spread withease while the Butter does not. What conclusion should you drawregarding how the composition of membrane lipid regulate thefluidity of the PM?
Longer chains exhibit more double bonds and increases contact oflipids
Longer chain exhibit fewer double bonds and increases contact oflipids
Shorter chains exhibit more double bonds and increases contact oflipids
Shorter chains exhibit more double bonds and increases contact oflipids
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Which PM lipid covalently anchors proteins?
Phosphoglycerides
Sphingolipids
Cholesterol
Triglycerides
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Which PM lipid is the least amphipathic?
Phosphoglycerides
Sphingolipids
Cholesterol
Triglycerides
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Which of the following is not a function of the PM?
Signal Transduction
Energy Transduction
Regulates which molecules enters and exits cell
Site of Biochemical events such as production ofmacromolecules
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Which two PM phospholipids have negative charges?
Phosphatidylcholine and Phosphatidylethanolamine
Phosphatidylethanolamine and Phosphatidylserine
Phosphatidylinositol and Phosphatidylserine
Phosphatidylserine and Phosphatidylcholine
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Which PM lipid is the only true glycolipid?
Phosphatidylcholine
Phosphatidylethanolamine
Sphingolipid
d. Cholesterol
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Which is NOT a function of the Plasma Membrane
It serves as a barrier allowing all molecules to enter cell
It serves as a site for energy and signal transductions
It is composed of lipids, proteins, and carbohydrates
It compartmentalizes the cells
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Cholesterol, which is not present in bacteria, controls the PMfluidity of animal cells. Which is the CORRECT orientation of thehydroxyl group of the four-member ring of cholesterol in thePM.
The hydroxyl group is oriented inside the membrane
The hydroxyl group is oriented toward the cytoplasm
The hydroxyl group is oriented toward other cholesterolmolecules
The hydroxyl group is oriented toward the membrane surface
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PM carbohydrates are oriented:
Inside the membrane
Toward the cytoplasm
Toward other carbohydrate molecules
Away from the cytoplasm and inside organelles
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Sugars constituents various on red blood cells depending on bloodtype, why would giving someone the wrong blood type be fatal?
Blood groups differ in the levels of hemoglobin they carry
The body would view the sugars as antigens and form antibodiesagainst them.
Because of the incompatible sugar arrangement, the blood would notflow to the heart properly.
The foreign sugar sequences will attack to the sugar sequences onnormal cells.
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NaCl most likely get into cells by which of the followingmethods?
Diffusion
Facilitated Transport
Osmosis
Active Transport
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Sufferers of type II diabetes (adult onset) have normal insulinlevels but no target cell response due to deficiency in receptorsfor insulin. Which type of transport is missing?
Diffusion
Facilitated Transport
Osmosis
Active Transport
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The movement of molecules against a gradient refers to which typeof transport?
Diffusion
Facilitated Transport
Osmosis
Active Transport
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Which is the correct exchange of sodium and potassium in the Na/Kpump of cells?
three sodium for three potassium
two sodium for three potassium
three sodium for two potassium
two sodium for one potassium
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This type of transport is important to cells because they receivetheir oxygen and rid themselves of carbon dioxide by thismethod:
Diffusion
Facilitated Transport
Osmosis
Active Transport
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Maintaining membrane fluidity is important to cells because?
Cells are able to maintain proper function at differenttemperatures
Cells can break down membranes lipids very quickly when energy isneeded
Larger molecules can pass through the membrane when fluidity isincreased
The membrane fluidity helps to maintain the positions ofglycoproteins and glycolipids
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Scientists agreed that the plasma membrane was the site ofbiochemical events when peroxide was broken to produce bubblescontaining?
water
hydrogen
oxygen
carbon dioxide

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1. What is an organic molecule?

2.Name three hydrocarbons and be able to draw their structural formulas.

3. What is an isomer? List and describe the three types (structural, geometric, and enantiomers).

4. Be able to recognize and describe the properties of these functional groups: aldehyde, ketone, hydroxyl, sulfhydryl, carboxyl, amino, and phosphate groups.

5. What is a monosaccharide? Give two examples of these molecules and their functions.

6. Describe these chemical reactions: dehydration synthesis (condensation reaction) and hydrolysis (rehydration).

7. What is a disaccharide? List two and give their functions.

8. What is a polysaccharide? List two storage forms and two structural forms. How are they formed and what is their specific function?

9. How do the pancreatic hormones insulin and glucagon regulate blood sugar levels?

10. What is molting and why is it necessary in certain animals?

11. What four molecules are bonded together to form a triglyceride or fat? Why are fats nonpolar? What are some functions of fats as well as other lipids such as oils and waxes?

12. How do saturated and unsaturated fats differ? Discuss bonding patterns and possible sources of these fats. Which type is healthier for you? Why?

13. Why do animals store most of their excess glucose as fats or oils rather than as glycogen or protein? Give two reasons.

14. What are phospholipids? Identify parts of the phospholipid bilayer that are hydrophobic or hydrophilic? What important cell structure do these molecules help create?

15. Describe the structure of a steroid. How is cholesterol used in beneficial ways in your body?

16. What are LDLs and HDLs? Which is considered good or bad cholesterol? What condition could result from high blood pressure?

17. What are four ways to either reduce high blood cholesterol or maintain a safe level?

18. What is the composition of an amino acid? Why would they be considered nonpolar, polar, acidic, or basic?

19. Define dipeptides and polypeptides.

20. Describe the primary structure of a protein. What type of bonding creates it?

21. What is the secondary structure of a protein? Name two types of secondary structure and indicate what type of bonding holds them together. List three fibrous proteins.

22. What is the tertiary structure of a protein? What types of bonds or chemical interactions allow a protein to maintain this structure? List three globular proteins.

23. What is the quaternary structure of a protein? Describe a hemoglobin molecule.

24. What are the subunits of nucleic acids and what is their composition? How are these subunits bonded together? What is DNS's basic shape?

25. List three differences between DNA and RNA.