Lipid (Biology)

Lipid is chemically defined as a substance that is insoluble in water and soluble in alcohol, ether, and chloroform. Lipids are an important component of living cells. Lipids are the main constituents of plant and animal cells. Cholesterol and triglycerides are lipids.

Fatty Acids

The common feature of these lipids is that they are all esters of moderate to long chain fatty acids. Acid or base-catalyzed hydrolysis yields the component fatty acid, some examples of which are given in the following table, together with the alcohol component of the lipid. These long-chain carboxylic acids are generally referred to by their common names, which in most cases reflect their sources. Natural fatty acids may be saturated or unsaturated, and as the following data indicate, the saturated acids have higher melting points than unsaturated acids of corresponding size.

Protein (Biology)

Proteins

Proteins are macromolecules. They are constructed from one or more unbranched chains of amino acids, which is polymers. Proteins are the most diverse group of biologically important substances and are often considered to be the central compound necessary for life. In fact, the translation from the Greek root word means “first place.”

Amino Acids

Amino acids bonded together by the dehydration synthesis. By continually adding amino acids, called peptides, two amino acids join together to form dipeptides; as more peptides join together, they form polypeptides. Proteins vary in length and complexity based on the number and type of amino acids that compose the chain. There are about 20 different amino acids, each with a different chemical structure and characteristics. For instance, some are polar, others are non-polar.

Protein Structure

The first level, or primary structure, is the linear sequence of amino acids that creates the peptide chain. In the secondary structure, hydrogen bonding between different amino acids creates a three-dimensional geometry like an alpha helix or pleated sheet. An alpha helix is simply a spiral or coiled molecule, whereas a pleated sheet looks like a ribbon with regular peaks and valleys as part of the fabric. The tertiary structure describes the overall shape of the protein. Most tertiary structures are either globular or fibrous. Generally, nonstructural proteins such as enzymes are globular, which means they look spherical. The enzyme amylase is a good example of a globular protein. Structural proteins are typically long and thin, and hence the name, fibrous.

Enzyme (Biology)

Enzymes are biological molecules (proteins) that act as catalysts and to help complex reactions to occur everywhere in life. Proteases would go to work and help break down the peptide bonds between the amino acids. Enzymes take part in the reaction - that is how they provide an alternative reaction pathway. But they do not undergo permanent changes and so remain unchanged at the end of the reaction. They can only alter the rate of reaction, not the position of the equilibrium.

Lock and key hypothesis

This is the simplest model to represent how an enzyme works. The substrate simply fits into the active site to form a reaction intermediate.

Redox and Electrolysis (Chemistry)

Oxidation and reduction in terms of oxygen transfer

Definitions:

Oxidation is gain of oxygen

Reduction is loss of oxygen

Redox is a contraction of the name for chemical reduction-oxidation reaction. A reduction reaction always occurs with an oxidation reaction. Redox reactions include all chemical reactions in which atoms have their oxidation state changed; in general, redox reactions involve the transfer of electrons between chemical species. The chemical species from which the electron is stripped is said to have been oxidized, while the chemical species to which the electron is added is said to have been reduced. Oxygen is not necessarily included in such reactions as other chemical species can serve the same function.

Electrolysis is the process by which ionic substances are decomposed (broken down) into simpler substances when an electric current is passed through them. For electrolysis to work, the ions must be free to move. Ions are free to move when an ionic substance is dissolved in water or when melted.

Here is what happens during electrolysis:

- Positively charged ions move to the negative electrode during electrolysis. They receive electrons and are reduced.

- Negatively charged ions move to the positive electrode during electrolysis. They lose electrons and are oxidized.

The substance that is broken down is called the electrolyte.

Chemical Bonding (Chemistry)

Chemical compounds are formed by the joining of two or more atoms. A stable compound occurs when the total energy of the combination has lower energy than the separated atoms.

Since opposite charges attract via a simple electromagnetic force, the negatively charged electrons that are orbiting the nucleus and the positively charged protons in the nucleus attract each other. An electron positioned between two nuclei will be attracted to both of them, and the nuclei will be attracted toward electrons in this position. This attraction constitutes the chemical bond.

Strong chemical bonding is associated with the sharing or transfer of electrons between the participating atoms. The atoms in molecules, crystals, metals and diatomic gases—indeed most of the physical environment around us—are held together by chemical bonds, which dictate the structure and the bulk properties of matter.

The two extreme cases of chemical bonds are:

-         Covalent bond: bond in which one or more pairs of electrons are shared by two atoms.

   Ionic bond: bond in which one or more electrons from one atom are removed and attached to another atom, resulting in positive and negative ions which attract each other.

Force (Physics)

Force is a push or pull upon an object resulting from the object's interaction with another object. Whenever there is an interaction between two objects, there is a force upon each of the objects. When the interaction ceases, the two objects no longer experience the force. Forces only exist as a result of an interaction. 

Forces (interactions) between objects can be placed into two broad categories:

- Contact forces: are those types of forces that result when the two interacting objects are perceived to be physically contacting each other. Examples of contact forces include frictional forces, tension forces, normal forces, air resistance forces, and applied forces.

     - Forces resulting from action-at-a-distance: are those types of forces that result even when the two interacting objects are not in physical contact with each other, yet are able to exert a push or pull despite their physical separation. Examples of action-at-a-distance forces include gravitational forces. For example, the sun and planets exert a gravitational pull on each other despite their large spatial separation.

Dynamics (Physics)

Dynamics:

Dynamics is the name given to the rules of motion. It’s something that you would think would be one of the first things to be figured out, but wasn’t fully locked down until fairly recently. That being said the rules haven’t changed much and are fairly predictable, at least on large scales.

Scalar quantities:

·         - Have a magnitude only.

·         - Energy, Length, Mass, Speed, Temperature and Time are all scalar quantities.

Vector quantities:

·        -  Have both a magnitude and a direction

·         - Displacement, Force, Velocity, Acceleration and Momentum are all vector quantities.

How Kinematics is used in daily life? (Physics)

 One dimensional kinematics:

Example is train on a straight railroad. Piston in a cylinder. Climbing up the rope.

2-d vectors and projectiles:

Example is cannonball, or any other ball flying through the air. Every motion on a flat surface.

Centripetal motion:

The Moon and the Earth, satellites

Torque:

Wrench, screwdriver, gears, bicycle chain and sprocket, all kinds of rotating levers.

Sound and light:

There's so many examples that it's hard to pick one :)

Moving membrane of a loudspeaker can be example of sound-generating device, and mirrors and lenses are related to light phenomena.

And where would hitting a golf ball be in physics?

It depends. It can be in kinematics or in dynamics (which are both parts of mechanics). If only motion of a golf ball is discussed, with terms like velocity, acceleration, displacement etc. then it's in kinematics. Kinematics doesn't deal with mass, force and impulse. If mass, force, and impulse are also mentioned, than its dynamics.

For cool experiment, go check: https://www.youtube.com/watch?v=Q3oItpVa9fs 

How Atom Worked? (Chemistry)

Atoms themselves are made up of three kinds of smaller particles, called protons (which are positively charged), neutrons (which have no charge) and electrons (which are negatively charged). The protons and neutrons are in the middle of the atom. They are called the nucleus. 

Go check: https://www.youtube.com/watch?v=EMDrb2LqL7E for further information

Olestra Case Study (Biology)

Olestra

Olestra is a fat substitute that has the properties of a fat in flavor and texture, but is indigestible-hence a fake fat. It does not add any calories as a normal fat would. Olestra is part fatty acids from cottonseed or soybean oils and part sucrose rather than glycerol in triglycerides. The six to eight fatty acids are bonded to the hydroxyl or alcohol groups on the sucrose using an ester synthesis reaction. This makes for a rather large molecule that looks like an octopus with many arms. Olestra cannot be digested by enzymes which hydrolysis the sucrose or the triglycerides. Since the enzymes cannot break down the olestra, it travels through the intestines undigested and unabsorbed. In 1996, the FDA approved the use of olestra in potato chips, tortilla chips, crackers and fried snacks, as it is the only heat stable fat substitute for fried foods. There have been some reports of adverse reactions in the intestines including diarrhea and cramps, indicating that it may act as a laxative in some people. Since olestra is such a large nonpolar molecule, it may dissolve or combine with some of the fat soluble vitamins such as A, D, E, and K, and carotenoids. As a result, the FDA now these vitamins must be added to any products containing olestra.

Olestra has an extraordinary avidity for certain fat-soluble substances, far exceeding what one would expect based on the fat substitute's proportion of the diet. Olestra's removal from the body of fat-soluble nutrients is linked directly to the additives being a non-absorbable lipid-like substance.

In Procter & Gamble's two eight-week clinical studies, the lowest level tested -- 8 gm/day (equivalent to 16 olestra-containing potato chips) — caused dramatic depletion of fat-soluble vitamins within two weeks. Procter & Gamble also measured total serum carotenoids, alpha-carotene, beta-carotene, lutein, and lycopene. Olestra caused significant declines in all carotenoids monitored. Total serum carotenoids declined sharply by the fourteenth day of olestra consumption and was down by 50% to 60% by the end of the studies. A dosage of 32 gm/day of olestra reduced total serum carotenoids by 70% over the eight weeks.

Feeding olestra with one or more meals, as was done in the several clinical studies, results in the greatest depletion of carotenoids. While that might seem to be a worst-case scenario, many people would, indeed, consume olestra-containing foods with meals. In fact, Procter & Gamble's petition states that mealtimes constitute the great majority (79%) of the occasions during which consumers eat "savory snacks." Also, since the frequency of consumption of snacks would likely increase if olestra snacks were available, interaction between nourishing foods and olestra at meals would be likely to increase, resulting in lower serum levels of fat-soluble carotenoids and other phytochemicals. There would also be more opportunities for olestra to reduce the absorption of beta-carotene and fat-soluble vitamins that people ingest in dietary supplements and fortified foods.

Olestra's depletion of carotenoids is of great concern, because a growing body of evidence indicates that they may confer important health benefits. The physiological activities of fat-soluble plant nutrients are just now being elucidated. For instance, in a recent case-control study, lutein (along with zeaxanthin) was strongly associated with a lower risk of macular degeneration, the most common cause of blindness in the elderly (J.A.M.A. 272: 1413 (1994)). That observation is buttressed by the fact that lutein and zeaxanthin form the yellow pigment in the macula (the central part of the retina). In three clinical studies, 3 gm/day of sucrose polyester or 8 gm/day of olestra reduced lutein levels by 20% to 40%.

Atom Case Study (Chemistry)

ATOM

Most of the Universe consists of matter and energy. Energy is the capacity to do work. Matter has mass and occupies space. All matter is composed of basic elements that cannot be broken down to substances with different chemical or physical properties. Elements are substances consisting of one type of atom, for example Carbon atoms make up diamond, and also graphite. Pure (24K) gold is composed of only one type of atom, gold atoms. Atoms are the smallest particle into which an element can be divided. The ancient Greek philosophers developed the concept of the atom, although they considered it the fundamental particle that could not be broken down. Since the work of Enrico Fermi and his colleagues, we now know that the atom is divisible, often releasing tremendous energies as in nuclear explosions or (in a controlled fashion in) thermonuclear power plants.

Subatomic particles were discovered during the 1800s.

 For our purposes we will concentrate only on three of them, summarized in Table 1. The proton is located in the center (or nucleus) of an atom, each atom has at least one proton. Protons have a charge of +1, and a mass of approximately 1 atomic mass unit (amu). Elements differ from each other in the number of protons they have, e.g. Hydrogen has 1 proton; Helium has 2.

The neutron also is located in the atomic nucleus (except in Hydrogen). The neutron has no charge, and a mass of slightly over 1 amu. Some scientists propose the neutron is made up of a proton and electron-like particle.

The electron is a very small particle located outside the nucleus. Because they move at speeds near the speed of light the precise location of electrons is hard to pin down. Electrons occupy orbitals, or areas where they have a high statistical probability of occurring. The charge on an electron is -1. Its mass is negligible (approximately 1800 electrons are needed to equal the mass of one proton). It's the electrons in orbit around the nucleus that allow one atom to interact with other atoms so they can be linked together.

For example, H2O consists of an Oxygen atom linked to 2 Hydrogen atoms. The linkage or interaction between the electrons of the Hydrogen and Oxygen atoms is called a Chemical Bond. More on these later.

Some matter is either smaller or larger than an atom. Examples of chemical species that are not typically considered atoms includes particles that are components of atoms: protons, neutrons and electrons. Molecules and compounds consists of atoms but are not themselves atoms. Examples of molecules and compounds include salt (NaCl), water (H2O) and ethanol (CH2OH). Electrically charged atoms are called ions.

Sometimes atoms gain or lose electrons.  The atom then loses or gains a "negative" charge. These atoms are then called ions. Positive Ion - Occurs when an atom loses an electron (negative charge) it has more protons than electrons. Negative Ion - Occurs when an atom gains an electron (negative charge) it will have more electrons than protons.

Kinematics Case Study (Physics)

Kinematics

Kinematics is the branch of classical mechanics which describes the motion of points (alternatively "particles"), bodies (objects), and systems of bodies without consideration of the masses of those objects nor the forces that may have caused the motion. Kinematics is the geometry of pure motion – motion considered abstractly, without reference to force or mass. Engineers use kinematics in machine design. Although hidden in much of modern technology, kinematic mechanisms are important components of many technologies such as robots, automobiles, aircraft, satellites, and consumer electronics, as well as biomechanical prostheses. In physics, kinematics is part of the teaching of basic ideas of dynamics; in mathematics, it is a fundamental part of geometric thinking and concepts of motion. The development of high-speed computers and robotics, and the growth of design synthesis theory and mechatronics have recently revived interest in kinematics and early work in machine design.

Working in the decades following Ampere’s death, Franz Reuleaux (1829-1905) is considered the founder of modern kinematics. Reuleaux called it “the study of the motion of bodies of every kind…and the study of the geometric representation of motion” (Kinematics of Machinery 56).

Kinematics flourished in the 19th century as machine inventors learned to transmit information and forces (power) from one element in the machine to another. Steam- and water-based machines revolutionized the l9th century, but both of those energy sources generate circular motions, creating the need to convert these steady circular motions into non-steady linear and curvilinear motion for machine applications.

In real life, we can apply kinematics is that the importance of peak bar velocity and starting posture adopted by a novice weightlifter to the outcome of a Snatch lift. Multiple observations of both successful and unsuccessful attempts were captured using 3D motion analysis (VICON MX: 500 Hz). The following data analysis was then used to derive feedback. In total, 133 attempts of loads ranging from 75 to 100% of 1 repetition maximum (1RM) were performed by the subject (age = 25 years, stature = 171 cm, mass = 74.8 kg, Snatch 1RM = 80 kg).

Variables included peak bar velocity, pelvis, hip, knee and ankle joint angles at the starting position for the right side and the difference between (left minus right) sides. No main effects for load, success, or their interactions were found for peak bar velocity. Starting position kinematics were mostly non-significant between the outcomes of Snatch attempts. Right ankle joint angle was the only exception, where unsuccessful attempts displayed greater (p = 0.0228) dorsiflexion. A more comprehensive finding was achieved through the partition modeling; this analysis provided valuable insight and coaching feedback for the subject in relation to his lower body kinematics at the starting position. Furthermore, the accuracy of this feedback was verified using a holdback data set. Specifically, anterior pelvic tilt (>17.6°) and hip joint (<89.6°) angle were identified as the key features to increasing the likelihood of success. In conclusion, this case study outlines a method of data collection and analysis to assist coaching feedback for an individual.

Biology Topics for Semester 1

1. Biological Molecule
2. Lipid
3. Enzyme
4. Globular Protein

Chemistry Topics for Semester 1

1.  Moles and Equations
2. Atomic Structure
3. Electrons in Atoms
4. Chemical Bonding
5. States of Matter
6. Enthalpy Changes
7. Redox reactions and electrolysis

Physics Topics for Semester 1

1. Physical Quantities and units
2. Measurement Techniques
3. Kinematics
4. Dynamics
5. Force, Density and Pressure
6. Work, Energy and Power