Biochemistry

Glucokinase is the enzyme responsible for phosphorylation of glucose in the first step of glycolysis. The glucokinase complex is modified by two different molecules: citrate and ATP. Citrate and ATP are both products of the sequence of reactions in aerobic respiration and are consequently products of glycolysis. As these two molecules' concentrations in the cell build up, they bind to the allosteric site of glucokinase and shut it down.

Yes serine is a polar amino acid as it has an hydroxyl group (OH-) attached to the r group.

No. First of all, the name maltase indicates that the enzyme breaks down maltose. Maltose is a disaccharide composed of two glucose monomers. Cellulose is an entirely different polysaccharide, composed of many monomers of beta glucose. Second, very few organisms have the ability to hydrolyze cellulose. In most organisms including humans, cellulose passes through our digestive tract without changing chemically. This is what we call "fiber". Even though we can get no nutrients from it, cellulose is good for the muscles lining the small intestine.

The sodium-potassium pump is an active pump working against an electrochemical gradient, and cuts ATP to ADP with every transfer of sodium and potassium across acell membrane.

Most motor proteins are also ATPases, requiring the lysing of ATP with each "movement" of the motor protein in order to function. This is actually the cause ofrigor mortis; although ATP is not needed to cause the muscle's motor proteins to constrict, it is required to allow them to slide past one another into the resting state once more. As death halts respiration, and thus ATP creation, the muscles can become rigid, but cannot relax again (not until other decay processes simply cause these proteins to decay altogether).

The hydrogen-potassium pump that regulates acidity of the stomach contents is also an ATPase.

The adrenal medulla secretes adrenaline (epinephrine) and noradrenaline (norepinephrine), which are hormones involved in the body's response to stress and the "fight or flight" response. These hormones help regulate heart rate, blood pressure, and glucose metabolism.

Glucose and galactose react to form lactose, a disaccharide composed of one glucose molecule and one galactose molecule, along with a molecule of water. This reaction is a condensation reaction, where a water molecule is removed to form the new compound lactose.

No, a quadrillion transistors is not approximately the same as the number of neurons in the human brain, because the neurons can make multiple connections to other neurons. Also, it is more than just a "number of bits" in the brain - it is chemistry, meaning that it is more analog than digital - and it is (in some schools of thought) spiritual and/or quantum or sub atomic.

Orlistat is one chemical that can inhibit the activity of enzyme lipase. Higher version of orlistat which is only available through prescription is Xenicol. There are several enzymes that break down fat molecules in our food so it can be used/stored in our body. Certain drugs resist the activity of those enzymes and fat is passed through the system unabsorbed.

RNA polymerase.... What a wonderful, uplifting speech she gave at the convocation memorial service at Va Taech the day after the shootings there.

She raised the spirits of both the students and the staff along with those of the world.

She gave hope to the hopeless of the world and raised every single person involved with Va Tech to the highest of all highs.

Va Tech is indeed lucky to have her as one of their professors.

I hope and pray that they all recover from this horrible tragedy and with staff like her, the students will prevail!

Go Hokies! Go Hokies!

Carbon is used to make sugars in the "carbon fixation" step of the carbon cycle, which occurs during photosynthesis in plants. During this process, carbon dioxide from the atmosphere is converted into organic sugars, which are used for energy and growth by plants.

Soft gel vitamins are absorbed more easily by the body due to their liquid contents. They also have a longer shelf life compared to other types of supplements, as they are less prone to degradation from exposure to air and light. Additionally, soft gels are easier to swallow for some people who have difficulty with larger pills.

CH4, also known as methane, is a gas composed of one carbon atom and four hydrogen atoms. It is not a fat or oil; instead, it is a simple organic compound that is the primary component of natural gas and is commonly used as a fuel source.

The pentose phosphate pathway is mainly an anabolic pathway that generates NADPH and ribose-5-phosphate for nucleotide synthesis. It is essential for the production of nucleotides, which are building blocks for DNA and RNA.

a) Oxygen has 6 valence-shell electrons. c) Phosphorus has 5 valence-shell electrons. d) Nitrogen has 3 valence-shell electrons. e) Carbon has 4 valence-shell electrons.

The nucleotide is the building block for nucleic acids, such as DNA and RNA. It consists of a sugar molecule, a phosphate group, and a nitrogenous base, which combine to form the structure of nucleic acids.

Specifically peroxidase, the enzyme that resides in the peroxisomes.

Salt metabolism in humans involves the regulation of sodium and chloride ions in the body through processes like absorption in the intestine, reabsorption in the kidneys, and excretion through urine. The renin-angiotensin-aldosterone system plays a key role in regulating salt balance by controlling sodium reabsorption in the kidneys. Imbalances in salt metabolism can lead to conditions like hypertension or dehydration.

DNA Mutations can be positive in the fact that they can be beneficial to the host of the mutation. For example, if our DNA mutated so that we could have fins and gills, we could be better equipped for the ocean, which could be useful if the Earth's landmass was devastated or could no longer support all of us. Most of the time, DNA Mutations are useful adaptations to maintain homeostasis in the human body.

The diameter of the hydrogen atom nucleus is about 10^-15 m, so if you want to make it 5 mm in your scale model, you would need to scale up by a factor of about 10^13. Therefore, the diameter of the entire model would be 5 mm * 10^13, which is 5 x 10^10 m.

Yes, amino acids will contain oxygen in their carboxyl group and might in its variable R group.

The four types of amino acid side chains [R-groups] are i) non-polar (zero for 8) - no oxygen, ii) uncharged-polar - (5 out of 7 have oxygen), iii) charged-polar - both have oxygen, and iv) basic amino acids - zero for 3 have oxygen.