Tutor profile: Lewam M.

Electronic transitions occur when which kind of electromagnetic radiation is absorbed? a. x-ray b. microwaves c. infrared waves d. radio waves e. ultraviolet light

answer is E (ultraviolet light). When a molecule contains non-bonding electrons (pi-electrons), energy in the form of UV light can be absorbed which causes the pi-electrons to be excited and move up into higher anti-bonding molecular orbitals.

Which of the following does salivary amylase chemically digest? (biology question) a. triglycerides b. amyloids c. starches d. amino acids e. vitamines

The answer to this question is C (starches). As it's name suggest, salivary amylase is an enzyme that is found in our saliva. Salivary amylase is able to digest carbohydrates. The only carbohydrate in the list is starch. E. Vitamines such as vit B and K are produced by bacteria in the large intestine. D. Proteins are broken down into amino acids in the stomach and small intestine (never in the mouth). Pepsin breaks protein down in the stomach, and the small intestine enzymes trypsin and chymotripsin break proteins down. B. amyloids are not directly involved in the digestive system. Amyloids refers to an aggregation of abnormally folded proteins that are involved in plaque formations that can be seen in individuals with alzheimer's for example. A. Fats are broken down into smaller droplets by bile (which isn't an enzyme). Pancreatic lipase breaks down emulsified fats into glycerol and fatty acids.

How does the Citric Acid Cycle (TCA) work? What are the major products and why are these products important?

The citric acid cycle is series of chemical reactions used by aerobic organisms in order to facilitate energy production in cells. In eukaryotic cells, the TCA cycle takes place in the matrix of the mitochondria whereas in prokaryotic cells, the TCA cycle simply takes place in the cytoplasm of the cell. Interestingly, the TCA cycle is a closed loop processes that involves 8 steps. The first step of the TCA cycle involves the molecule Acetyl-COA, a 2 carbon molecule that is gets combined with oxaloacetate (which is a 4 carbon molecule formed in step 8 of the cycle). This combination forms a 6 carbon molecule called citrate which is processed through the TCA cycle in order to produce 3 NADH, 1 FADH2, 1 ATP, 1 GTP and 2 CO2 molecules. The NADH and FADH2 molecules then enter the Electron Transport Chain where a system of proton pumping fuels an ATP Synthase that produces ATP. And ATP is the all so important energy currency!