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Intro Biology - Unit II

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Matter
Defined as anything that has mass and occupies space.
Proton
This subunit of an atom is found within the nucleus of the atom - and possesses a positive charge.
Neutron
This subunit of an atom has no charge (electrically neutral) and is found within the nucleus of the atom.
Electron
This subunit of an atom possesses a negative charge - negligible mass - and is found orbiting the nucleus in shells (orbits).
Atomic Number
Defined as the number of protons found in the nucleus of a given atom.
Atomic Mass
This term is defined as the number of protons plus the number of neutrons found in the nucleus of an atom.
Cation
In an effort to become more stable - a sodium atom will lose an electron - and become one of these. (positive ion)
Anion
In an effort to become more stable - a chlorine atom will gain an electron - and thus become one of these. (negative ion)
Isotope
This term refers to a variation of an atom that either gains or loses neutrons - rather than electrons - they are often used in medicine and research.
Ionic Bond
This type of chemical bond is formed when one atom gains an electron and the other loses an electron - this resulting molecule has a neutral charge.
Polar Covalent Bond
This type of bond is created when atoms share electrons - but not equally - creating both negatively and positively charged regions within the molecule - an example of this bond is found in water.
Hydrogen Bond
This type of chemical bond - although relatively weak and easily broken - helps to maintain the complex shape of large macromolecules like proteins.
Acid
Defined as a substance that releases (generates) hydrogen ions when it is dissolved in water.
Base
Defined as a substance that releases (generates) hydroxide ions when it is dissolved in water.
Salt
If a substance is dissolved in water - and releases (generates) neither hydrogen nor hydroxide ions - it is one of these.
Solvent
In a solution - this substance actually does the dissolving - water is an excellent example of one of these.
Solute
In a solution - this is the substance that is actually dissolved.
Buffer
This term refers to a substance that works to keep our internal pH stable (within the homeostatic range) - it can either bond with hydrogen ions or release hydrogen ions to help prevent dramatic changes in pH.
Monosaccharides
A simple sugar (typically 6 carbons or less) - examples include glucose, fructose, and galactose.
Disaccharides
These organic molecules are defined as short chains of two or more monosaccharides - examples include sucrose, lactose, and maltose.
Polysaccharides
These organic molecules are complex chains of hundreds - or even thousands of monosaccharides linked together - examples include amylose, cellulose, glycogen, and chitin.
Triglycerides
This organic molecule - also referred to as a neutral fat - is comprised of one glycerol molecule and three fatty acids.
Saturated Fats
These lipids come from an animal source (butter, lard, bacon fat, etc.) - and exist as solids at room temperature.
Unsaturated Fats
These lipids are from plant sources (corn, peanut, safflower, oils, etc.) - and are liquids at room temperature.
Emulsification
In our bodies - bile is used to break large fats (lipids) into smaller pieces so that they can be digested - this is the term for that process.
Phospholipids
This organic molecule is the major structural component of our cell membranes - it is comprised of hydrophilic heads of glycerol and hydrophobic tails of fatty acids.
Steroids
Examples of this organic molecule are vitamin D, cholesterol, estrogen, and testosterone - complex lipids that have very important functions in our bodies.
Waxes
This type of organic molecule is defined as a highly insoluble lipid - and acts as water repellent/insulator on the fur and feathers of animals/birds, and outer protective covering of many leaves and stems, and used in the construction of beehives.
Amino Acids
These molecules are the "building blocks" of all proteins - held together by numerous peptide bonds.
Peptide Bonds
This type of bond holds amino acids together in our proteins.
Denaturation
This term describes a process where a complex protein loses its shape (and usually its function) due to the breaking of its hydrogen bonds.
Nucleotides
This term refers to the subunit (building block) of all nucleic acids - it is comprised of a five-carbon sugar, a phosphate group, and a nitrogen-containing base.
ATP
Adenosine Triphosphate - a very important nucleotide that is the main source of energy for our body's cells.
DNA
This type of nucleic acid - called Deoxyribonucleic Acid - is a double strand of nucleotides that forms the genetic material of our cells.
RNA
This type of nucleic acid - called Ribonucleic Acid - is comprised of a single strand and is responsible for directing the synthesis (production) of proteins in all of our cells.
Non-polar Covalent Bond
In this type of chemical bond - electrons are shared equally between two atoms - like in a molecule of oxygen gas - these are very strong bonds.
Properties of Water
■Highly polar molecule. ■Maintains body temperature. Absorbs and releases energy (heat) slowly. ■Has high surface tension (cohesion). ■Universal solvent. ■Involved in most reactions in the body - making it our most important inorganic molecule.
pH Scale
Ranges from 0 to 14. 0 most acidic. 14 most alkaline (basic). 7 is neutral. Human blood is between 7.35 - 7.45.
Glucose
Monosaccharide: blood sugar - the main source of energy for most organisms.
Fructose
Monosaccharide: fruit sugar.
Galactose
Monosaccharide: milk sugar.
Sucrose
Disaccharide: table sugar from sugar cane or sugar beets (glucose + fructose).
Lactose
Disaccharide: milk sugar (glucose + galactose).
Maltose
Disaccharide: malt or grain sugar (glucose + glucose).
Amylose
Polysaccharide: plant starch - stored energy source in plants.
Cellulose
Polysaccharide: indigestible fiber found commonly in plant cell walls - has a structural function.
Glycogen
Polysaccharide: animal starch (quick energy source stored in animal tissues) - most notably the liver and skeletal muscles.
Chitin
Polysaccharide: insoluble, structural substance found in the exoskeletons of certain insects (arthropods) - very strong.
Lipids (The Fats)
■Insoluble in water - they are "non-polar" molecules. ■Mostly hydrocarbons. ■Form basic structures of animal cell membranes. ■Storage of energy (on average more than twice the energy of carbohydrates gram for gram). ■Provide insulation/protective function.
Adipose Cells
Human fat cells. Unlimited capacity to store fat.
20 Different Amino Acids
"12 non-essential" (liver can synthesize). "8 essential" (need in diet).
Protein Functions
■Act as enzymes - catalyze reactions in all organisms. ■Structure. ■Regulatory - controls cell activities (hormones). ■Transport - hemoglobin transports oxygen and carbon dioxide.