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Lipids - Cell Membranes [I] In your Lipid post: (A) Describe a phospholipid in terms of polarity.

(B) Describe phospholipid alignment in cell membranes.

(C) Based on "Like Dissolves Like" explain why cell membranes have double layers of phospholipids.

[II] Also: (D) Describe the structure and function of HDLs and LDLs and

(E) Explain how the HDL/LDL membrane differs from cell membranes.

(F) Why are HDL/LDL membranes single layered whereas cell membranes are double layered?

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Patrina Schowalter
Patrina SchowalterLv2
28 Sep 2019
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Related questions

Cell Membranes Lab Report

  1. Diffusion

  1. Compare the following terms: solvent, solute, andsolution.

  1. Go to Lab, Section I, Exercise 1 to explore the factorsinfluencing the rate of diffusion and complete the following:

  1. Predict how molecular mass and temperature may affect theoutcome of this experiment.

  1. Record the data from information in the Lab in the tablebelow.

Time

(min)

Diameter (mm)

5°C MB

5°C PP

23°CMB

23°C PP

0

15

30

45
  1. Construct a line graph of the data from the table above. Yourgraph should include labeled axes, units, and a legend indicatingwhich treatment is presented. Sign, date and prepare an image ofyour graph and include it with this lab report.
  1. Osmosis

  1. Go to Lab, Section II, Exercise 2 to view a demonstration ofosmosis and answer the following questions:

  1. Describe the net movement of water in osmometer 1.
  1. How is the movement of water molecules related to theconcentration gradient of the solution?

  1. Go to Lab, Section II, Exercise 3 to observe the effect ofsolute concentration on the rate of osmosis. Answer the followingquestions:

  1. Was the net movement of water in bags 1 to 4 into or out of thebags?
  1. Explain the results from bags 4 and 5.
  1. Selective Permeability of Membranes

  1. Go to Lab, Section III, Exercise 4 to learn about theimportance of selectively permeable membranes, then complete thetable and answer the following questions:

Contents of Beaker

0 Min

30 Min

Starch

Chloride ion
  1. Which substances diffused through the dialysis membrane?

  1. How does dialysis tubing model the selective permeability of aplasma membrane?
  1. Tonicity

  1. Go to Lab, Section IV, Exercise 5 and 6 to observe plasmolysisin Elodea cells and tonicity in red blood cells. Summarizethe concept of tonicity using blood and Elodea cells asexamples. Your description should incorporate these terms: turgid,plasmolysis, hemolysis, and crenation.

Cells

Isotonic Solution

Hypertonic Solution

Hypotonic Solution

Elodea

RBC

  1. Based on your previous work, reproduce the table below and drawan illustration of a single cell in each box. Include arrows toshow the direction of water flow relative to each cell and dots tosymbolize solutes. Sign, date and prepare an image of your drawingand include it with this lab report.

Cells

Isotonic Solution

Hypertonic Solution

Hypotonic Solution

Elodea

RBC

Summary Questions

  1. Compare diffusion and osmosis. Give an example of each.

2. In which direction will osmosisoccur if a 15% sugar solution is separated from a 25% sugarsolution by a selectively permeable membrane?

3. Why did osmosis, but not diffusionof sucrose molecules, occur across the dialysis membrane containing20% sucrose solution?

4. You are having a party and thecelery is limp. What might you do to make the celery crisp (turgid)again? What will occur in the cells?

5. A small amount of fertilizer(mineral salts) will stimulate plant growth, but over fertilizationcan kill plants? Why?

6. Michael adds sugar to his coffee.Explain what in this drink is the solvent, solute, and solution.

7. You add a cube of sugar to yourdrink. How could you speed up the diffusion of sugar moleculeswithout stirring?

8. How is dynamic equilibriumestablished within a solution?

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.

Question 1


Which of the following provides the best description of adifference between prokaryotic and eukaryotic cells?.l.14.3>

The cell membrane of prokaryotic cells contains proteins, whilethe cell membrane of eukaryotic cells contains only lipids andcarbohydrates.

The DNA in eukaryotic cells is enclosed in the nucleus, whilethe DNA in prokaryotic cells is not separated from the rest of thecell’s contents.

Eukaryotic cells have cell walls that consist mainly of sugars,while prokaryotic cells do not.

Prokaryotic cells contain chloroplasts and mitochondria, whileeukaryotic cells do not contain specialized organelles.

Question 2

Cellular respiration is a process involving the breakdown ofglucose molecules in order to generate energy for cellularactivities. Given the general reaction below, which of thefollowing best describes the products labeled x andy?

C6H12O6 + O2 → _x___+ __y___ + energy.l.18.8>

The products are CO (carbon monoxide) andH2O2 (hydrogen peroxide), which thendecompose into carbon dioxide (CO2) and water(H2O).

The products are H2O (water) and CO2 (carbondioxide), which then undergo anaerobic respiration.

The products are CO2 (carbon dioxide) andH2O (water), which then become the reactants forphotosynthesis.

The products are O2 (oxygen) and H2O(water), which are then used for growth and to keep the organismhydrated.

Question 3

If a researcher added a quantity of phospholipid molecules to abeaker of water, what would be most likely to happen to theorientation of the phospholipid molecules?.l.14.2>

They would break apart, and the remaining lipid tails wouldfloat up and form a layer on the surface of the water.

Their lipid tails would align within a spherical double layerwith their phosphate heads in the water inside and outside thesphere.

They would form a single-layered sphere with the phosphate headspointing outward and the lipid tails pointing inward.

Their lipid tails would adhere to the glass of the beaker andtheir phosphate heads would float in the water.

Question 4

While looking at a cell under a microscope, a scientist is ableto see a biological molecule. This molecule is a nucleic acid witha ladder structure and contains the nitrogenous bases adenine,thymine, cytosine, and guanine. Based on this information, whatconclusion can the scientist draw regarding this nucleicacid?.l.18.1>

The nucleic acid is RNA and would be found in the cell’snucleus.

The nucleic acid is RNA and would be found in the cytoplasm.

The nucleic acid is DNA and would be found in the cytoplasm.

The nucleic acid is DNA and would be found in the cell’snucleus.

Question 5


Which of the following is needed for cellular respiration tooccur?.l.18.8>

Sodium

Oxygen

Water

Nitrogen

Question 6


What would be the most likely effect if the side chain of an aminoacid group was unable to vary its structure?.l.18.4>

The organism would not be able to make and store starches.

The organism would not be able to process glucose moleculeseffectively.

The organism would not be able to regulate the creation ofspecialized cells.

The organism would not be able to make more than one type ofprotein.

Question 7


During photosynthesis, unused oxygen atoms form oxygen gas(O2) which is released as a waste product. How did theseoxygen atoms originally enter the plant?.l.18.7>

They were part of the ATP molecules gathered by thechloroplasts.

They were part of the sugar molecules(C6H12O6) the plant brought in forfood.

They were part of the carbon dioxide (CO2) moleculesthat entered through the leaves.

They were part of the water molecules (H2O) pulled inthrough the roots.

Question 8


Which of the following organelles houses DNA in eukaryoticcells?.l.14.3>

Endoplasmic reticulum

Golgi apparatus

Nucleus

Mitochondrium

Question 9


M. J. Schleiden shifted the scientific community's attention tocellular processes with his.l.14.1>

attention to disproving spontaneous generation

publication of ideas on cell generation

theories on the division of cells

claim that cells were the basic unit of all plant matter

Question 10


While the average human is able to hold his or her breath forapproximately one minute, a whale can dive for over 30 minuteswithout returning to the surface. Which of the following correctlydescribes this difference?.l.18.10>

Whales need less energy than humans.

Whales gather energy from their environment better thanhumans.

Whales are able to tolerate the products of cellular respirationbetter than humans.

Whales have a slower cellular respiration metabolism rate thanhumans.

Question 11


What can you conclude about the advantage of the cell membranehaving hydrophobic ends in the phospholipid bilayer?.l.18.3>

The cell requires the ability to digest and eliminateenzymes.

The cell requires a barrier between itself and itsenvironment.

The cell requires a means to store starches and glucose.

The cell requires a structure for eliminating waste.

Question 12


What would be the most likely outcome if the ribosomes of a cellwere damaged and stopped functioning?.l.14.3>

The cell would lose structure and shape.

Cell growth and repair would slow or stop.

Cell waste would no longer be processed.

The cell would produce more mitochondria.


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