Exam 1 Concepts Flashcards
What is science?
The use of objective, verifiable evidence to answer questions about the natural world.
Scientific Method
Process by which scientists formulate a hypothesis, gather data by observation and experimentation, and come to a conclusion.
Characteristics of Life
Organization, acquiring materials and energy, reproducing, growing and developing, being homeostatic, responding to stimuli, adaptation
Element
Substance that cannot be broken down into substances with different properties; composed of only one type of atom.
Atom
Smallest particle of an element that displays the properties of the element
Isotopes
Atoms with the same atomic number but a different atomic mass due to a different number of neutrons.
Compound
Substance having two or more different elements united chemically in a fixed ratio.
Ions
Charged particle that carries a negative or positive charge.
Ionic bonds
Chemical bond in which ions are attracted to one another by opposite charges.
Covalent bonds
Chemical bond in which atoms share one pair of electrons.
Polar
Combination of atoms in which the electrical charge is not distributed symmetrically.
Hydrogen bond
Weak bond that arises between a slightly positive hydrogen atom of one molecule and a slightly negative atom of another, or between parts of the same molecule.
pH Scale
Measurement scale for hydrogen ion concentration; logarithmic scale. 0 = most acidic and 14 = most basic.
Acid
Substances that dissociate in water, releasing hydrogen ions (H+); they raise the hydrogen ion concentration in a solution and lower its pH numerically.
Bases
Substances that take up H+ or release hydroxide ions (OH-); they lower the hydrogen ion concentration in a solution and raise the pH numerically.
Functions of each organic molecule
Carb: quick and short-term energy storage
Lipids: energy storage
Protein: support, enzymes, transport, defense, hormones, motion
Nucleic acids: store genetic information
Dehyration and Hydrolysis Reaction
Dehyrdration: Chemical reaction resulting in a covalent bond with the accompanying loss of a water molecule.
Hydrolysis: Splitting of a compound by the addition of water, with the H+ being incorporated in one fragment and the OH– in the other.
Mono, Di, and Polysaccharides
Mono: Simple sugar; a carbohydrate that cannot be decomposed by hydrolysis (e.g., glucose).
Di: Two monosaccharides combined by dehydration reaction (e.g., maltose).
Poly: long chain of monosaccharides (glycogen, cellulose/fiber)
Function of triglycerides
As fats and oils, they are used for energy storage, heat insulation, protective cushion around organs, and synthesize phospholipids and steriods
Uses of phospholipids and steriods
Phospholipids: cellular membranes
Steriods: sex hormones, membrane components
Why not all lipids should be avoided in diet?
Lipids are essential for functions in organisms (energy storage, protection, membranes), so they should still be consumed in a certain amount
Functions of proteins
Support, enzymes, transport, defense, hormones, motion
Structure of an amino acid
Central carbon bonded to a hydrogen, an amino group, and acid group, and an R group
Four levels of protein structure
Primary: sequence of amino acids
Secondary: alpha helix/pleated sheet
Tertiary: final shape of polypeptide
Quaternary: two or more associated polypeptides
