CONTRACEPTIVES: The use of a device or procedure to prevent conception (pregnancy) as a result of sexual activity Sexual Abstinence Voluntary restraint from sexual intercourse Advantages NO risk of pregnancy NO risk of STIs Appeals to certain religions/beliefs Disadvantages May not experience pleasure Calendar/Rhythm Method No sexual intercourse during ovulation Advantages NO side…
Endosymbiotic Theory: Mitochondria & Chloroplast are descendants of prokaryotic cells; they share clear structural/ biochemical features with modern prokaryotes. Cyanobacteria: blue-green algae; obtain their energy through photosynthesis Lateral gene Transfer: Gene from Mitochondria & Chloroplast MOVE from Mitochondria & Chloroplast to the nucleus Evidence of Endosymbiosis (Happened after evolution of aerobic prokaryotes) Morphology: Form of…
A Catalyst increases the rate of reaction by providing alternative energy pathway ; usually increasing the rate of by 1012-1020. However it does not affect free energy ∆G (can’t make endergonic reaction go). Instead an enzyme can couple an exergonic reaction with an endergonic reaction via ATP breakdown. It will decrease EA for a spontaneous…
Drake’s Equation is an equation used to estimate the number of detectable extraterrestrial civilizations in the Milky Way galaxy. Invented by Frank Drake, the founder of SETI. Ns 1011 Stars discovered so far Fp (0.5) Half the planets in the Milky Way galaxy have stars around them Ways to detect planets Transit Method: Diming of…
Summary Carbon Monoxide Detectors is a device that detects the presence of Carbon Monoxide (CO) Excess Carbon Monoxide(CO) = Carbon Monoxide Poisoning Silent Killer Incomplete Combustion History of Dalton’s Law John Dalton (6 September 1766 – 27 July 1844) was an English Chemist, Meteorologist and physicist He investigated and published the atomic theory which states…
HISTORY Over 100 years ago it was found that nitroglycerin can treat the pain of heart disease and heart attacks In 1987 it was discovered that nitric oxide was naturally produced in the body Nitrogen monoxide (NO) was the 1992 Molecule of the Year The work of the biochemical role of nitrogen monoxide by Robert…
Two Types of Impact Craters Impact craters can be categorized in one of two ways: simple or complex. A simple crater has a smooth bowl shape small with a small depth to diameter ratio. This ratio is typically 1:6 which means that if the crater is 1 m deep, it is 6 m wide. A…
What Darwin Observed Darwin sent specimens collected on his voyage back to England to be examined by experts Fossils collected were confirmed to be large versions of the present-day sloth and armadillo The Galapagos Island’s bird specimens were in fact many different species of birds Darwin originally thought they were just variations of the same…
What Really Happened with the Apple? There is a popular story that Newton was sitting under an apple tree, an apple fell on his head, and he suddenly thought of the Universal Law of Gravitation. As in all such legends, this is almost certainly not true in its details, but the story contains elements of…
Capillary action, or capillarity, is a phenomenon where liquid spontaneously rises in a narrow space such as a thin tube, or in porous materials such as paper or in some non-porous materials such as liquefied carbon fibre. This effect can cause liquids to flow against the force of gravity or the magnetic field induction. It…
Surface Tension (N/m² = J/m³) Fluid property associated with the presence of a surface toward air Interfacial tension- is used to describe analogous phenomena for fluid having interfaces with solids or other liquids (can be +/-) Water molecules are forced toward the surface of a fluid due to placement on other molecules and attractive forces.…
Fluid: system that yield to any force that attempts to alter their shape, causing system to flow until it reaches mechanical equilibrium; fluid conforms to shape of container Molecules of liquid in condense state; maintain CONSTANT intermolecular distance. Liquid will form SURFACE. Gas will not form surface; adjust intermolecular distance to fill space provided (compression/…
Intrinsic property of particles that comprise matter Point charge: charged particle with negligible size Mass and charge are independent from each other Positive Charge (q+) and Negative Charge (q-) Coulomb’s Law Magnitude of electric force between two charged spheres is proportional to the absolute amount of charge on each sphere, and is proportional 1/r2 where…
Capacitor: two conducting plates charged with equal amount of charge of opposite signs, with insulator in between (we assume a vacuum unless said otherwise) Three quantities characterize a capacitor: 1) surface charge density 2) capacitance 3) dielectric constant Capacitance (q= C x ∆V) Unit: Farad (F) The potential difference across a parallel plate capacitor is…
Stress: force exerted per unit area of surface on an extended object. STRESS LEAD TO STRAIN Three types of deformation due to strain: Stretching (change in length) Twisting (change in angle) Compression or Expansion (change in volume) ***Each of these strains is caused by a different form of stress Tensile stress= Stretching Shearing stress= Twisting…
There are critics who disagree with the expenditure on space exploration, which they claim can better be used to solve earthly problems. However, they seem to forget that this is one of the fields which tests a man’s intellect. But, how does a common man draw benefits of space exploration? The advances made in the…
A lunar eclipse is an event during which Earth’s shadow prevents the sunlight from reaching the moon. When an eclipse occurs, the moon usually remains visible, but has a dusky red or coppery color, which results when Earth’s atmosphere bends some sunlight-mostly longer red wavelengths-into the umbra. A total lunar eclipse occurs when the moon…
Lunar craters are basically circular hollows on the surface of the moon. They are formed because of the impact of the meteoroids strikes. The smallest craters are microscopic pits, but the largest, the Aitken Basin, is nearly 21000 kilometres wide. Just an interesting fact, one of the most interesting craters on the moon is Copernicus.…
From Earth, one can look towards the night sky and observe that the moon appears to have areas that are lighter, and areas that are considerably darker. These dark areas are referred to as lunar maria, which are basically land basins on the moon in varying sizes. These basins were formed when hot, molten lava…