Biology Lecture Exam 1 Flashcards
Define the scientific method?
The process that scientists use to investigate the natural world
Define Data?
information that they can analyze, often using computers and statistical methods.
Define Fact?
something KNOWN to be true
What is a Hypothesis?
testable explanation for observations or phenomena
What is an Independent Variable?
What you change in the experiment
What is a Dependent Variable?
What you are measuring
Predictions
What might be expected from experimental results.
Frame as specific if….then statements
What is an Experimental Group?
In a scientific experiment, a group in which the experimental variable is manipulated.
Control Group
In a scientific experiment, a group in which the experimental variable is kept constant.
Placebo
Used as an control in science.
Scientific Theory
an explanation supported by observations and experiments.
What are electrons?
A particle with one unit of negative charge and negligible mass, located outside the atomic nucleus.
What is a proton?
A particle present in the nuclei of all atoms that has one unit of positive charge and a mass of 1 atomic mass unit (amu).
Define an Atom
as the smallest portion of an element that retains its chemical properties
Define Neutrons
An electrically neutral particle with a mass of 1 atomic mass unit (amu) found in the atomic nucleus.
Valence electrons
The electrons in the outer electron shell, known as the valence shell, of an atom
Valence shell
The outermost shell of an atom containing the valence electrons
Compound
A substance made of two or more chemically bonded elements.
Molecule
The smallest particle of a covalently bonded element
Covalent bond
Involved the sharing of valence electrons between two elements.
Electronegativity
The Ability of an atom to attract shared electrons.
Polar covalent bond
A covalent bond between atoms that differ in electronegativity
Non polar covalent bond
When covalently bonded atoms have similar electronegativities the electrons are shared equally
Cation
Positive charge
A particle with one or more units of positive charge
Anion
Negative charge
A particle with one or more units of negative charge
Iconic bond
The chemical attraction between a cation and an anion.
Hydrogen bond
A weak attractive force existing between a hydrogen atom with a partial positive charge and an electronegative atom (usually oxygen or nitrogen) with a partial negative charge.
Cohesion
The property of sticking together.
Adhesion
The property of sticking to some other substance.
Capillary action
the tendency of water to move in narrow tubes, even against the force of gravity
Surface tension
The attraction that the molecules at the surface of a liquid may have for one another. (I.e bug standing on water)
Hydrophillic
Interact readily with water; having a greater affinity for water molecules than they have for each other. (“Water loving”, table salt , sugar)
- occur between a group of polar molecules.
Hydrophobic
Not readily interacting with water; having less affinity for water molecules than they have for each other (“water fearing, oil, gasoline)
- Occur between groups of nonpolar molecules.
Hydrophobic interaction
The tendency of hydrophobic substances to cluster together due to strong cohesive interactions among surrounding water molecules.
Heat of vaporization
The amount of heat energy that must be supplied to change one gram of a substance from the liquid phase to the vapor phase.
Specific heat
The amount of heat energy that must be supplied to raise the temperature of 1 g of a substance
Acid
A substance that is a hydrogen ion proton donor; acids unite with bases to form salts.
Base
Known as a proton accepter.
a substance or combination of substances that resists changes in pH when an acid or base is added.
pH
The negative logarithm of the hydrogen ion concentration of a solution (expressed as moles per liter). Neutral pH is 7, values less than 7 are acidic, and those greater than 7 are basic.
Salt
a compound in which the hydrogen ion of an acid is replaced by some other cation
amphipathic
A molecule that has both hydrophobic and hydrophilic
Lipids
Any of a group of organic compounds that are insoluble in water but soluble in nonpolar solvents; lipids serve as energy storage and are important components of cell membranes.
Nucleic acis
A class of biomolecules that are found in all living organisms
Protein
Long chain molecules made of strings of amino acids
Carbohydrates
Compound containing carbon, hydrogen, and oxygen, in the approximate ratio of C:2H:O (e.g., sugars, starch, and cellulose).
