biol+3+faq+(nsfaq)+aos1

If you have any any questions or are uncertain about anything to do with the course, then this is the place to get help. It will be up to you (as a class) then to answer the issues raised. You can keep your input anonymous or include your initials, it's up to you.

//A. Yep, you obviously need to know the four types but you should also be familiar with specific examples of each and their role in cells. The more you know the better but as we go through the course you will naturally become more familiar. Eg. an example of polysacharide is starch and it is a primary source of stored energy in plant cells.//
 * Q. Do we have to remember the names of different organic substances?**

//A. This may not be the full answer...But I know two differences between carbohydrates and lipids that would help to tell the difference between them: 1. It is true that both organic molecules are made up of carbon, hydrogen and oxygen, but lipids have a much smaller proportion of oxygen compared to the amount of oxygen present in carbohydrates. Also, lipids often contain other elements such as phosphorus and nitrogen. This would help if you were given a chemical formula, or even a structural diagram if the elements were included on it. 2. Lipids are built up from only a very small number of molecules, and therefore aren't classed as polymers, in comparison with some carbohydrates, such as cellulose, which is a polysaccharide polymer made up of a chain of monosaccharides. Therefore if you were given a structural diagram, you might be able to tell which organic molecule it is, depending on the examples shown.//
 * Q. How do I tell the difference between a carbohydrate and a lipid if I am given a structural diagram or chemical formula?**

The above response includes some insightful points. I will wait for some more posts to the question before making a final comment.-vm

//A. If you are given a structural image of the two organic molecules: -__Lipids__ usually appear to be in long 'rows' -C__arbohydrates__ generally appear to be ring-shaped structures. This can be seen especially when looking at carybohydrates monomer (that is, a monosaccharide).//
 * //xoxo gossip girl//**

Nice addition to the responses, what do the long rows represent though? VM

The long rows represent the fatty acid chains. These can help to identify within the chemical configuration as the fatty asid chains are made up of long rows of carbons with single of double bonded carbons (depending on whether it saturated or unsaturated fat). Carbohydrates have their carbons represented in a hexagon type shape generally.

//A. Im not sure if i am suppose to write this here but here is the website for all you enthusiastic biologists:// http://highered.mcgraw-hill.com/sites/dl/free/0072437316/120060/ravenanimation.html //xx Chicken//
 * Q. What is the website for the animations of endocytosis and exocytosis?**

//A. They're probably not the same thing as protein channels. I think they're types of proteins that carry specific substances across cell membranes or in the blood. Though I'm not sure, maybe I'm thinking of transport proteins.// AP
 * Q. I came across the term "carrier proteins". What are they and are they the same thing as protein channels?**

//A. Here are a few websites i found which help explain the difference between the two.// http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mboc4.figgrp.1993 http://au.answers.yahoo.com/answers2/frontend.php/question?qid=20080207214555AARM5G2 //So, my understanding is that they are two different types of protein that are involved in different processes. The protein carriers are embedded into the cell membrane and have a very specific shape. They carry molecules that have a complementary shape across the membrane and require energy in the form of ATP to do so. Thus, are involved in active trasnport. Whereas protein channels are used in the process of faciliated diffusion and therefore do not requite the input of energy.//

Well done on coming here an immediately editing your answer to this AP! The answer is not quite there yet, hopefully someone else can add to this, although you can modify it further if you wish. VM

//A. The first thing that I think of would be to look at the chemicals of the structure, and focus particularly on the sugar. DNA nucleotides consist of deoxyribose (missing one oxygen) sugar (OH-H) and RNA nucleotides a ribose sugar (OH-OH). The link below is to a picture that will show you what I've just written. The OH-OH of the ribose sugar is highlighted in green and the OH-H of the deoxyribose sugar is highlighted in red. Hope that helps!// [|http://fig.cox.miami.edu/~cmallery/150/chemistry/sf3x6.jpg] AH :-)
 * Q. If I am given a structural diagram of a nucleotide, what are all the ways that I can tell with it is an RNA or DNA nucleotide?**

Fantastic response AH. I wonder what the others think? VM

//A. Look at the nitrogenous base. If its a DNA nucleotide is will be either Guanine, Adenine, Thymine or Cytisine. If its a RNA monomer it will be the same except, a uracil instead of a thymine. LM//


 * Q. Has anyone completed the biological molecules worksheet? If so, in the table we had to fill in, what figures did you get in the molecule column? I got figure C, A, H, D, K, E, B, J, F, I, G.**

//A. Yeah, that's exactly what I got.//


 * Q. In regards to the same worksheet, does anyone know what the general function of a disaccharide is?** **I know what they are, just not what they're mainly used for.**


 * Q. Receptor mediated endocytosis--> are the molecules that are being ingested just let free when enetreing the cell or are they enclosed in vesicles or can it be both (i'v got two diffreent diagrams)?**

//A. All endocytosis processes require the formation of vesicles as part of the formation of a membrane that eventually pinches off the cell membrane. This would be appropriate so that the cytosol/cytoplasm of the cell isn't affected by the uptake of contents, especially if they are potentially harmful (like in phagocytosis). After the formation of a vesicle, the contents may then be released into the cytoplasm or they may make their way to a particular organelle within the cell. Or the vesicle amy fuse with a lysosome as is the case for pahgocytosis. If possible bring the two different diagrams you have to class or email them to me. VM//

//A. Here is a great diagram of all the three types of endocytosis. It clearly shows that all three processes require the formation of vesicles (im just repeating voijy.) but yeh i hope this helps. You should defiantly print this off and stick in on your wall :) Lozzzaaaa// http://upload.wikimedia.org/wikipedia/commons/thumb/1/1a/Endocytosis_types.svg/672px-Endocytosis_types.svg.png


 * Q. There is a section of the activities page that is to do with making class summary notes. So when shall we receive the first secret question hmm? That is if everyone else wants to do it of course! I think it's a really good idea :-)**

//A. Yes, well, I have them and I was going to give them today but I forgot about them as I ended up in a hmmm... bad mood! I wonder why! Anyway they are coming but I will wait til after your membrane SAC. VM//

//A. Well as you can see I didn't totally wait til the end of the membrane SAC, perhaps there is a reason, which I assume you can all work out. VM//

//An R-Group itself has no distinct chemical structure. It is simply a generic label representing the side chain of an amino acid. It is a// //variable and the determines physical and chemical characteristics of a particular amino acid. An R-Group can be nonpolar, polar, or electrically charged (ionic). Here's a link to the 20 standard amino acids - the red box holds the variable R-Group in each amino acid shown.// http://trc.ucdavis.edu/biosci10v/bis10v/week2/2webimages/ch5-amino-acids.jpg
 * Q. How do i explainn what a R group is in terms of chemical structure....?**

//A. I think your safest by saying membrane proteins but VM told me that: -Protein channels are primarily for ions -Glucose and amino acids usually involve carrier proteins (this distincition is probably more detailed than required of us at this level) -Thus, i think it depends on the substance that is passing through the membrane as opposed to the type of transport (active or facilitated diffusion) Lozz//
 * Q. I know this has been discussed like 20 times, but does active transport only involve carrier proteins? Or does it also involve protein channels? Various sources just keep saying different things and I'm not sure who's right (or more right than the others).**

//A. One of the difficulties in biology is the differences in interpetations and meanings of terminology etc. Hence, what Lozz has said is good advice. Active transport only involves carrier proteins but there are carrier proteins that transport ions across the membrane, for example Na+ and K+ ions are transported through protein channels separately but also through a carrier protein called Na+/K+ ATPase (yes carrier proteins sometimes are really acting as enzymes but this is way too much detail). This carrier protein requires ATP for it to function in active transport. VM//

I think a protein channel combines with the substance entering into the cell during transportation??

Diffusion: Small/tiny, uncharged, lipid soluble (therefore water insoluble) molecules. Eg. Carbon Dioxide, oxygen etc. (but are these polar or nonpolar??) Osmosis: Same as diffusion but only includes water molecules. These would be polar then? Facilitated diffusion and active transport: Large, charged, lipid insoluble (therefore water soluble, polar molecules. Eg. Ions, amino acid**
 * Q. Im really struggling to understand what kinds of substances pass directly through the membrane vs. through proteins. Is this right:

//A. I think you need to look at it like this. The phospholipid bilayer involves diffusion and osmosis only. Osmosis is for water molecules (although polar they are small enough), end of story. Diffusion through the bilayer requires substances to be either lipid soluble (generally this means they a non-polar substances) or if water soluble they need to be small and uncharged. All other substances must go through protein membranes, whether by facilitated diffusion or active transport. So what you have said above is correct. For reference, oxygen and carbon dioxide are both non-polar (I don't think you really need to know this level of chemistry). VM//


 * Q. how do you tell the difference of a cofactor and a coenzyme?? sar :)**

//A. good question. But i have put this question and the answer in the enzyme SAC page. But hopefully others can contribute their thoughts here as well. VM//


 * Q. Can someone please put the lyrics of our fabulous #1 hit CELLULAR RESPIRATION on this wiki. just for the record.. i cant get it out of my head. xoxo gossip girl.**

//A. Hey gossip girl, I did write on the lesson page for you guys to save it on the classroom stuff page. And that is where you will find it. Go you singing star girl! VM//


 * Q. I've looked everywhere and i can't find the exam question on designer drugs. Could you please attach a link to it? Or even send it to my hotmail - Ta, lozz**

//A. That's because you see but do not observe my budding biologist! check out the march 11th lesson down the bottom VM//


 * Q. Ok, this is still AOS 1, so i'll post it here. In the textbook it talks about how in the Krebs Cycle pyruvate molecules are oxidised to yield acetyl molecules. Yet later (following the production of CO2 and 2 ATP) it goes on to say that no oxygen has been used yet. But if the pyruvate was oxidised, doesn't that mean oxygen was used?**

//A. Oxidation is a chemistry term and refers to a chemical substance that has lost (or given off) electrons. Hence when pyruvate is oxidised it means it is releasing electrons which then go on to be used in the ETC part of respiration thanks to the carrier molecules. So, the term is not based on oxygen. Do you need to know this? Well, not really. It's never been examined, as it is chemistry. VM//