Sat Bio Organic and Bio chem Flashcards
All matter is made from
different combinations of 92 naturally occurring substances known as elements.
Element
a naturally occurring substance. Ex: hydrogen, oxygen, helium
Atom
The smallest quantity of an element that still exhibits the characteristics of that element
Isotope
An atom that contains a larger or smaller number of neutrons than usual
Ion
An atom that either lacks or has extra electrons and so is a charged particle and is chemically interactive with other atoms
Molecules
Atoms combined which create a unique substance with physical and chemical properties distinct from their combined elements. Combining two hydrogen atoms with one oxygen atom creates water - very different from hydrogen or oxygen alone. Molecules such as water containing more than one type of element can also be called compounds. A water molecule made up of oxygen and hydrogen can be called a compound; a hydrogen molecule, which contains only two hydrogen atoms, cannot be called a compound.
Chemical Bonds
The connections between the atoms in a compound.
Covalent bond
Bond formed through the (more or less equal) sharing of electrons between atoms. aka molecule. A single covalent bond results when two atoms share one pair of electrons. A double covalent bond results when two atoms share two pairs and triple covalent bond results when they share three.
Nonpolar Covalent Bond
electrons in a covalent bond shared equally. Examples: H2, O2
Polar Covalent Bond
Any bond between two non-identical atoms is polar. Polar means they are not sharing electrons equally. Example: H2O - Hydrogen needs one electron. Oxygen needs two
Ionic Bonds
One atom pulls the shared electrons away from another other atom entirely. Ionic bonds are stronger than polar bonds. Example: the reaction between sodium (Na) and chlorine (Cl) to form table salt (NaCl). The chlorine atom steals an electron from the sodium atom. Because it loses an electron, the sodium atom develops a charge of +1. The chlorine atom has a charge of -1, since it gained an electron.
Dipole-Dipole Bonds
Dipole means two magnetic poles. Most important dipole-dipole bond in SAT II Biology is the dipole-dipole interaction between positively charged hydrogen molecules and negatively charged oxygen molecules. This reaction is so important, it gets its own special name: hydrogen bond. These bonds account for many of the exceptional properties of water and have important effects on the structure of proteins and DNA.
Radioisotopes
radioactive isotopes. They emit particles and decay at a known rate called a half-life. Useful in measuring the age of fossils, medical diagnosis, treatment, research. Radioactive iodine can be used to diagnose and treat thyroid diseases. Also used on PET scans.
cation
an ion with a positive charge produced by the loss of one or more electrons
anion
an ion with a negative charge produced by the addition of one or more electrons
Rule For Solutions
All polar molecules will mix to form solutions. Al non polar molecules will mix to form solutions. But polar and non polar molecules will not mix to form solutions
isomer
compounds with the same molecular formula but different structures. Ex: glucose, galactose, fructose
The internal pH of most living cells is
7
Buffers
regulate pH bu removing excess or adding needed hydrogen ions
Name the four classes of organic compounds
Carbohydrates, lipids, proteins, nucleic acids
All organic compounds contain ________
Carbon
Carbohydrates consist of ________
carbon, hydrogen, oxygen
The three classes of carbohydrates are
monosaccharides, disaccharides, polysaccharides
Monosaccharides
All have chemical formula of C6 H12 O6 They are single sugar molecules - glucose, fructose, galactose;
Disaccharides
All have chemical formula of C12 H22 O11 A double sugar, consisting of two monosaccharides joined by dehydration synthesis. Sucrose, Lactose, Maltose
Polysaccharides
polymers of carbohydrates - many monosaccharides join together by dehydration synthesis. 4 important are cellulose, starch, chitin, and glycogen
Cellulose
Polysaccharide that makes up plant cell walls
Starch
Polysaccharide - the way plants store carbohydrates
Chitin
Polysaccharide - makes up the exoskeleton in arthropods and cell walls in mushrooms
Glycogen
Polysaccharide - “Animal starch”; in humans this is stored in the liver and skeletal system
polymer
a large molecule formed when many smaller molecules bond together
Lipids
Fats, phopholipids, steroids - Made of glycerol and three fatty acids.
Saturated Fats
Contain only single bonds in the chain
Unsaturated Fats
Have at least one double bond between carbon atoms in their hydrocarbon chain so they will have fewer (missing in the chain at the point of the carbon bond) hydrogen atoms
Lipid Functions
- Energy storage: 1 gram releases 9 calories
Proteins
Polymers or polypeptides consist of repeating amino acids joined by peptidebonds. Consist of elements S,P,C,O,H and N.
Amino Acid
Know there are 20, know basic structure so you can tell if it is an amino acid or if it is something else
Protein Structures
Act as enzymes, membrane channels, hormones…
Primary structure of protein
the sequence of amino acids that make the protein chain
Secondary structure of protein
hydrogen bonding within the molecule
Tertiary structure of protein
responsible for protein’s shape and how it functions
Quaternary structure of the protein
proteins that consist of more than one polypeptide chain. hemoglobin, is quaternary because it has four polypeptide chains
Nucleic Acids
DNA and RNA; carry hereditary information. Are polymers of nucleotides.
Nucleotide
The base units of nucleic acids, each containing a sugar, a phosphate group, and one of four nitrogenous bases.
Two important hydrogen bonding functions
- Keeps the two strands of DNA bonded together, forming a double helix
van der Waals
very weak attraction between nonpolar molecules. Example is CO? which is very linear and balanced
