SAT Biology - Chapter 4 - Biochemistry - Barron's

celine's version from 2018-02-13 01:30

Section 1

Question Answer
Condition of an electron when it is not excited. It is in its lowest energy level.ground state
When an atom absorbs energy, its electrons move to a higher energy level.excited state
Atoms of one element that vary only in the number of neutrons in the nucleusisotopes
Radioactive isotopes. The nuclei emit particles and decay at a known rate called a half-life.radioisotopes
Amount of time it takes for a radioactive isotope to decay to half its mass.half-life
Radioactive substance that can be used to track a substance as it moves through an organism or through a metabolic pathway. They can be used in research or as a diagnostic tool in medicine.tracer
When two atomic nuclei attract the same electronsIonic bonds
When atoms share electrons to form a moleculecovalent bonds
When 2 atoms share one pair of electronssingle covalent bond
When 2 atoms share two pairs of electronsdouble covalent bond
When 2 atoms share three pairs of electronstriple covalent bond
2 Types of covalent bondsnonpolar and polar
Electrons shared equally & formed between any 2 atoms that are alikenonpolar covalent bond
Electrons shared unequally & formed between any 2 atoms that are unalikepolar covalent bond
Attractions between moleculesintermolecular attractions
3 Types of Intermolecular attractions1. polar-polar attraction 2. hydrogen bonding 3. nonpolar molecules
There are stronger attractions between polar molecules than between nonpolar molecules. The negative end of one polar molecule attracts the positive end of another polar molecule.polar-polar attraction
Keeps the two strands of DNA bonded together, forming a double helix & Causes water molecules to stick together and is responsible for many special characteristics about waterhydrogen bonding
Only the weakest attractions (van der Waals) exist between nonpolar molecules. It is llinear and balanced.nonpolar molecules
An example of nonpolar molecule CO2 O=C=O (It's linear & balanced)
"Water hating" or repelled by waterhydrophobic
"Water loving" or "attracted to water"hydrophillic
Characteristics of water1. Water has a high specific heat 2. Water has a high heat of vaporization 3. Water has high adhesion properties 4. Water is the universal solvent 5. Water exhibits strong cohesion tension 6. Ice floats because it is less dense than water
A measure of acidity and alkalinity of a solution. pH
Anything with a pH less than 7acidic
Anything with a pH value greater than 7 alkaline or basic.
A substance with a pH of 7neutral
A solution of pH 1 is x times more acidic than a solution with a pH of 210 times
A solution of pH 1 is x times more acidic than a solution with a pH of 3100 times
A solution of pH 1 is x times more acidic than a solution with a pH of 41000 times
As the concentration of H+ increases, the pHdecreases
pH value of stomach acid2
pH value of orange juice3.5
pH value of carbonated drinks3.0
pH value of acid rain<5.6
pH value of milk6.5
pH value of human blood7.4
pH value of seawater8.5
Substances that resist change in pH allowing for biological system to regulate their pH. It works by absorbing excess hydrogen ions or donating ions when there are too few.buffers
The most important buffer in human bloodbicarbonate Ion ( HCO3 - )
Compounds that contain carbon. organic Compounds
Four classes of organic compounds: carbohydrates, lipids, proteins, and nucleic acids
Consist of only three elements: carbon, hydrogen, and oxygen.carbohydrates
3 classes of Carbohydratesmonosaccharides, disaccarides, and polysaccharides
Have a chemical formula of C6H1206 and are isomers of each othermonosaccharides
Examples of monosaccharidesglucose, galactose, and fructose
Compounds with the same molecular formula, but with different structuresisomers
Have a chemical formula of C12H22O11 and consist of 2 monosaccharides joined by a process known as dehydration synthesis.disaccharides
Examples of disaccharidesmaltose, lactose, and sucrose
The opposite and reverse of dehydration synthesis,and it is the breakdown of a compound with the addition of water, and it is what occurs during digestion.hydrolysis
Polymers of carbohydrates and they form as many monosacharides are joined together by dehydration synthesis.polysaccharides
Examples of Polysaccharidescellulose, starch, chitin, and glycogen
A diverse class of organic compounds that include fats, oils, and waxes. lipids
Combines with fatty acids to make lipidsglycerol
Fats (with a few exceptions) come from animals and solid at room temperaturesaturated fat
Fatty acids which contain only single bonds between carbon atomssaturated fatty acids
Fats extracted from plants and liquid at room temperatureunsaturated fat
Fatty acids which contain at least one double bond between carbon atoms in the hydrocarbon chain and have fewer hydrogen atomsunsaturated fatty acids
Functions of lipids1. Energy storage: 1 gram of any lipid will release 9 calories of heat per gram when burned in a calorimeter. 2. Structural: Phospholipids are a major component of the cell membrane 3. Endocrine: Some lipids or hormones
Molecules that are chains of repeating unitspolymers/polypeptides
Polypeptides consisting of repeating units called amino acids joined by peptide bondsproteins
Bonds that join aminoacidspeptide bonds
A molecule consisting of two amino acids connected by one peptide bonddipeptide
Proteins have many functions and their function depends on their shape
The shape of a protein is the result of four levels of structure which are primary, secondary, tertiary, & quaternary
Results from the sequence of amino acids that make up the protein chainprimary structure
Results from the hydrogen bonding within the molecule. The helical nature of many proteins is the result of hydrogen bonding.secondary structure
The intricate, three-dimensional shape or conformation of a protein and most directly determines that way it functions and its specificitytertiary structure
Refers to proteins that consists of more than one polypeptide chain.quaternary structure
Large proteins that serve to speed up reactions by lowering the energy of activationenzymes
The amount of energy needed to begin a reactionenergy of activation
The chemical that an enzyme works on is calledsubstrate
Describes how enzyme work and as the substrate enters the active site, it induces the enzyme to alter its shape slightly so the substrate fits betterinduced-fit model
Minerals that assist in the normal functioning of enzymescofactors
Vitamins that assist in the normal functioning of enzymescoenzymes
Characteristics of enzymes1. large proteins 2. serve to speed up reactions by lowering the energy of activation 3. specific 4. not degraded during a reaction and are reused 5. named after their substrate and end in the suffix "ase" 6. efficiency affected by temp and pH
Infectious proteins that causes several brain disease, including mad cow diseaseprions
A misfolded version of a protein normally found in the brains of mammalsprions
Polymers of nucleotidesnucleic Acids
2 types of nucleic AcidsDNA & RNA
A single nucleotide consists ofa phosphate, a 5-carbon sugar, and a nitrogenous base
DNA basesadenine, cytosine, guanine, and thymine
RNA basesadenine, cytosine, guanine, and uracil
Bases which are purinesadenine & guanine (A & G)
Bases which are pyrimidinescytosine, thymine, and uracil (C, T, & U)