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Altius Full Length Questions
#1 Posted : Sunday, June 20, 2021 10:21:03 PM
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I had some questions from the Altius 1 full length C/P:

8) For q8, they mention that anaerobic respiration also produces CO2, but in the cc it mentions that CO2 is also produced by yeast when produce alcohol. Can you please confirm where we produce CO2 for anerobic for humans?

11) Can you please explain how a hydrophobic interaction column works - specifically the role of salt? Also, does a hydrophilic interaction column exist?

18) What is resolution for gas chromatography and how does that relate to speed of elution?

40) Can you please explain this question and how to answer it?

49) I understand how to do this question, but I was curious how do you know if the rotating/static diffuser is the object or is it the sensor?

52) What is complexed iodine?
#2 Posted : Tuesday, June 22, 2021 8:26:16 PM
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1. CO2 is produced in the body through cellular respiration. We breathe in oxygen and breathe out CO2. This is analogous to how fuels produce water and CO2 during combustion in the presence of oxygen. Carbon dioxide is a waste product.
Biochemical reactions produce carbon dioxide (waste product) on a CELLULAR level through aerobic respiration when sufficient oxygen has been provided. "Fuels" like sugars, long-chain carbohydrates, fats, and proteins, can be "burned" for energy. In the absence of sufficient oxygen (during short bursts of high-intensity exercise), anaerobic respiration can occur in muscle cells. However, this doesn't last for very long and can fatigue the cells rapidly.

You can read more about the mechanisms here:


2. "Hydrophobic interactions" describes how hydrophobic molecules (i.e. non-polar molecules) and water interact with each other. Hydrophobic molecules tend to form droplets (and not a big slick) in aqueous solutions. You can see this when you add a tablespoon of oil to a glass of water. The oil will form droplets in the glass of water, and not a single layer on top of it.

A hydrophobic interaction column (HIC) is used to SEPARATE hydrophobic molecules (like proteins!) by taking advantage of the relative hydrophobicity of their amino acid side chains.

How does it work?

A column is filled with beads (stationary phase) that have different ligands attached to them. These ligands are like velcro and help selectively bind different proteins (mobile phase) to them.

What's the point of the salt?

The beads are designed to grab onto the hydrophobic molecules, but these interactions don't work very well in water. So we add salt, which makes the mobile phase MORE POLAR, and "salts out" the hydrophobic molecules. The more hydrophobic a molecule is, the less it wants to be in the salty (i.e. polar) phase, and the more it will be want to be grabbed by the stationary phase.

Yes, there is also such a thing as hydrophilic interaction chromatography. It works on the opposite premise, and uses ligands that grab onto polar molecules.

3. In general, resolution refers to how well you can distinguish two different peaks or signals. When you have two peaks that are too close together, the resolution is poor, and vice versa:


If you elute too quickly, or change the characteristics of the eluent too rapidly, then you may end up with signals that are too close together (i.e. poor resolution). This becomes the "fun part" of chromatography -- figuring out the perfect elution strategy!

4. You may or may not have come across these terms (Table 2) in biochem before. If not, you are supposed to glean the basic meaning of the terms from the Stokes radius (basically just means "radius") from the values in Table 2.

Here is a great image that summarizes what the terms mean:


Take your favourite arm (I like my left arm!) and hold it out straight in front of you.

This is an unfolded protein. (Arms are protein, too!)

Bend it slightly. This is a premolten globule.

Bend it more. This is a molten globule.

BEND IT IN HALF. This is a natively folded protein.

The questions asks us about "the structural state wherein a globural protein is PARTIALLY EXTENDED". Sounds like PREMOLTEN to me!

B is the best answer to this question.

5. The sensor is the thing that is detecting the possible presence of an image. It's acting as the "eye" of the instrument, so it must be the image forms.

6. The passage describes the formation of complexed iodine and starch a few sentences earlier: a mixture of iodine ion and starch. Complexed iodine and starch are really cool! The starch forms a "cage" or "coil" around the iodine, and it's blue. It can be used as a test for the presence of starch (specifically amylose) in mixtures. When starch is present, you get a blue colour. No starch? The colour stays orangey-yellow.

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