Biochemistry

The secondary structure of a protein, such as alpha helices and beta sheets, is mainly stabilized by hydrogen bonds between the backbone atoms of the protein. These hydrogen bonds form between the carbonyl oxygen of one amino acid and the amide hydrogen of another amino acid. These bonds help maintain the regular repeating structure of secondary protein elements.

Please refer to the official Fiitjee website or contact their admissions office for the most up-to-date information on upcoming entrance tests.

Some of the most important physical properties of crude oil include:

oAPI

oAPI = (141.5/SG 15oF) - 131.5 The purpose of this equation was to extend the range of the specific gravity scale. Crude oil SG changes, although small, may be important.

Crude Oils oAPI = 10 - 50

Higher oAPI, more paraffinic crude, higher yields of gasoline.

Lower oAPI, more aromatic crude, lower yields of gasoline.

Viscosity

Resistance to flow, usually measured @ 100oF in centistokes (kinimatic viscosity)

Pour Point

Measured by ASTM D-97 - temperature at which oil ceases to flow. Diesel may contain waxes, smaller than candle wax, which could solidify in cold weather.

Flash Point

Temperature above which the oil will spontaneously combust. Fractions in vacuum tower are the least combustible. They are the heaviest.

Vapor Pressure

Measured by ASTM D-323. Also know as Reid vapor pressure (RVP). True vapor pressure is usually 5-9% > RVP

Carbon Residue

The solid residue (%wt) remaining after heating to coking temperatures (700-800oC)

ASTM D-524 Ramsbottom Carbon

ASTM D-189 Conradson Carbon

CCR incr. then Asphaltene incr.

Salt Content

Measured by ASTM - 3230 (lb NaCl/1000 bbl)

Desalting is necessary because NaCl content > 10 lbs/1000 bbl leads to corrosion

Metals

Measured by EPA Method 3040 These include Ni, V, Ag, Hg, Na, and Ca. Metals can cause catalyst deactivation and corrosion.

Sediment and Water

Measured by ASTM D - 96 These inorganic particles can lead to operational problems.

Acidity

Measured by ASTM - 664

Sulfur

Measured by ASTM D - 129, 1552, 2622

Sour crudes > 0.5 wt% and sweet crudes < 0.5 wt%. Today it is difficult to find crudes below 1% sulfur.

Below is a "best guess". I'm not certain whether or not either of the two explanations are correct, but they're the most sensible explanations I can think of.

Lemon juice contains a weak organic acid.

The acid will react with the plastic polymers, which will undergo "acid hydrolysis". The acid acts as a catalyst, while the water in the lemon juice reacts with the polymer and breaks it down into its monomers.

For example, if a bottle were made out of PVC, it would be made of a long chain of lots of these:

H Cl

-C-C-

H H

The acid hydrolysis reaction breaks the long chain up into an alcohol (chloro-ethanol).

This reaction is very unlikely to occur with PVC due to its stability (it is used here for its simplicity), but other plastics may undergo acid hydrolysis quite easily (for example, polylactic acid, which is used as 'biodegradable' plastic).

Acid hydrolysis would only occur where the plastic meets the lemon juice, so only the inside surface would be hydrolysed. This would explain why your bottle feels thinner and weaker, since the hydrolysis has actually thinned the plastic.

Alternatively, any plastic left in strong sunlight may become weaker over time. This will be due to thermal decomposition in extreme cases, but mostly it will be because warming the plastic breaks the intermolecular forces that hold the long polymer chains together. This allows them to 'flow' more freely, which would explain why it feels thinner. In this case it wouldn't be thinner at all, but would give that impression as it would feel softer and bend more easily. Once cooled, the plastic may "set" again in its position, and stiffen, but some plastics will not set so easily, and may remain flimsy forever.

This effect is the same principal as ironing - the heat allows the structure to change easily, then sets in its new position once cooled. Ironing also relies on breaking intermolecular forces that hold individual molecules together.

It is possible, but I cannot confirm it, that the acid in the lemon juice will cause this effect to happen faster or more easily, but it should not occur at all (by this method) if the bottle is kept out of direct sunlight and away from radiators or other sources of heat.

GDP. Guanine diphosphate. Then the protein is phosphorylated and undergoes a conformational change in concert with its docking with the G protein linked receptor.

The trait could show up in two different forms.

Alleles are individual units that determine what trait will be expressed in an offspring. Alleles exist for most traits such as hair color or wing size. Having two alleles simply means that the trait can be expressed in different variation. One trait can have several different alleles.

because eating one apple isn't going to slim you down, and keep you healthy. That's just isn't how your body works. Your body uses up the nutrition from the apple and therefore needs more and more all throughout your life

Gertrude Elion is famous for her research in biochemistry. One of them had contributed to the development of AZT, a drug for AIDS.

Excreted through respiration, where it is expelled as waste from the body. Carbon dioxide is a byproduct of cellular metabolism and needs to be removed to maintain proper pH balance within the cell.

Octane and methane are both saturated hydrocarbons and follow the formula CnH2n+2. The only thing that's different is the number of carbons (and hence hydrogens) in the backbone. Octane has 8 carbons and has formula C8H18. Methane has 1 carbon and has formula C1H4.

tRNA is a type of RNA molecule that carries amino acids to the ribosome during protein synthesis. The tRNA has an anticodon sequence that is complementary to the mRNA codon, allowing it to base pair with the mRNA and ensure the correct amino acid is added to the growing polypeptide chain.

It's pretty simple if you think about it, viruses are really good at it. The sequences just overlap and have different points of transcription/translation. Being that viruses don't really need much stuff to begin with, their genomes aren't really all that big. It's probably one of the most compact and convenient ways to store your DNA. Think of it like a strange coincidental set of point mutations that suddenly shifted your gene sequence, but it just so happens that that works out for you and makes something else you may need...it's like knocking out many birds with one stone.

The top of the food chain.

As organisms consume other organisms, the toxins are all passed up in the food chain. Therefore, the top of the food chain will have the highest concentration of toxins.

Three types of technology in science include biotechnology, information technology, and nanotechnology. Biotechnology involves using biological systems to develop products and processes. Information technology involves the use of computers and software to manage and process data. Nanotechnology involves manipulating materials at the atomic and molecular scale to create new materials and devices.

An isotope is a form of an element. Isotopes (forms of an element) occur when an atom/s of a single chemical element gains or loses 1 or more neutrons.

Eg.. the first isotope "Hydrogen-1" or "Protium" hydrogen has 1 proton in the centre of the atom or nucleus, and 1 electron going around on the outside, isotope two "Hydrogen-2" or "Deuterium" Hydrogen, has 1 proton AND 1 neutron in the nucleus and 1 electron, and isotope three is "Tritium" Hydrogen that has 1 proton, 2 neutrons and 1 electron. The number of protons always stays the same, it's the number of neutrons that determines the form of an element or in other words the isotope.

Catabolism itself is not bad, as it is the process of breaking down molecules to release energy. It is a necessary part of metabolism that helps provide the body with energy and building blocks for new molecules. However, excessively high catabolic activity can lead to muscle wasting and other health issues.

1. its called a book

2. should of took notes

3. probably gonna fail your next test

4.Carbohydrates

The building blocks of the enzyme catalase are amino acids. These amino acids are arranged in a specific sequence to form the catalase protein, which catalyzes the breakdown of hydrogen peroxide into water and oxygen.

Cyclin-dependent kinases (CDKs) are a type of molecule that control the cell cycle by regulating the progression of cells through different phases. These enzymes work in conjunction with cyclins, which are regulatory proteins that bind to CDKs to activate their kinase function. The activity of CDK-cyclin complexes helps to coordinate the events of the cell cycle.

Bacteria can move using flagella, which are whip-like appendages that spin and propel the bacteria forward. Some bacteria can also move using pili or by secreting slime to glide along surfaces. Additionally, bacteria can move in response to stimuli such as light, temperature, or chemical signals.

The mosaic quality of the cell membrane is due to the presence of various components such as phospholipids, cholesterol, proteins, and glycolipids. These components are arranged in a dynamic and fluid manner, creating a mosaic pattern that allows for flexibility and functionality of the cell membrane. Additionally, the diverse composition of these components helps in maintaining the structural integrity of the membrane.

Foods that supply carbs, proteins and lipids include tofu. Tofu is an even better source of protein that is a good way for vegetarians to get what they need. It also is high in certain lipids, such as potassium. Salmon also gives proteins & lipids.

Glucose is the monosaccharide present in all three disaccharides: sucrose (glucose + fructose), lactose (glucose + galactose), and maltose (glucose + glucose).