Biology Test 1

Biology

The study of life

Variation

Differences in traits amond members of a group or population; variety

Artifical selection

selection by humans that produces changes in organisms over generations; dog breed

Heritable variation

a trait that can be inherited and therefore can be selected

Natural Selection

The cause of change in a population’s traits when teh environment favrors some heritable variations over others

Evolution

Change in frequency of traits in a population over generations; survival of the fittest

Adaption

Increase in the fitness of a population to its environment

Environment

The surroundings or conditions that interact with variation and influence whih traits are favored

Biome

A community of species that lives in a particular place or type of habitat on Eath; Habitat for groups of species

Diversity

The variety or richness of life, including the many different types of species on Earth

Matter

Anything that occupies space and has mass

Mass

Measure of amt of material in an object

Element

A substance that cannot be broken down into other substances by chemical reactions; Pure substance

Trace element

An element required for life in only very small amounts

Compound

A substance containing two or more elements in a fixed ratio

Molecule

A group of atoms joined together molecules make up compounds

Organic Molecule

A molecule that contains carbon

Atom

The smallest unit of matter that still retains the properties of an element

Subatomic particle

A particle smaller than an atom; protons, neutrons, and electrons are the main examples discussed

Nucleus

Central part of an atom that contains protons and neutrons

Proton

Positively charged subatomic particle found in the nucleus

Neutron

Neutrally charged subatomic particle found in the nucleus

Electron

Negatively charged subatomic particle that occupies orbitals around the nucleus and is directly involved in chemical reactions

Orbital

A region or path around the nucleus associated with an electron

Atomic Number

Unique number of protons in atoms of a particular element; Number of protons

Mass number

Total number of protons and neutrons in an atom’s nucleus; Protons + Neutrons

Isotope

An atom of the same element with the same number of protons but a different number of neurons

Radioactive Isotope

Isotope whose nucleus decays spontaneously

Chemical Reaction

Process in which atoms rearrange as chemical bonds break or form; matter is not created or destroyed

Chemical Bond

Attraction that holds atoms close together after electrons are transfered or shared

Covalent Bond

Strong bond formed when two atoms share one or more pairs of electrons

Nonpolar covalent bond

A covalent bond in whihc electrons are distributed equally; Equal distribution of electrons

Polar covalent bond

A covalent bond in which electrons are distributed unequally; unequal distribution of electrons

Hydrogen bond

A weak electrically attraction between partial charges, such as the attraction between neighboring water molecules; Weakest bond type

Ion

An atom or nmolecule with a net electrical charge because it gained or lost electrons

Ionic Bond

A bond formed between oppositely charged ions after electrons are transferred

Ionic compound

A compound such as table salt, held together by ionic bonds

Hydrophillic

Able to interact with and dissolve readily in water; Water-loving, dissolves easily

Hydrophobic

Unable to mix or dissolve readily in water; Doesn’t dissolve in water

Observation

something notices or recorded during scientific exploration

Data

recorded observations; the evidence on which scientific inquiry is based

Hypothesis

A proposed explanation for a set of observations that must be testable and falsifiable

Testable

Able to be evaluated by an experiemnt or by further observations

Falsifiable

Able to be shown wrong if evidence does not support it

Predicition

A ststement of what should happen if a hypothesis is correct

Experiment

scientific test used to evaluate a hypothesis

Theory

A comprehensive, well-substantiated explanation supported by a large, varied, and growing body of evidence

Fact

Piece of information considered objectively true based on current evidence and that can be verified

Variable

A factor that changes in an experiment

Controlled experiment

experiment comparing groups that differ in only the variable being tested

Control group

group that lacks or does no recieve the specific factor being tested

Experimental group

group that has or recieves the specific factor being tested

peer review

Evaluation of scientific work by qualified but uninvolved experts to determine whether it meets scientific standards

Pseudoscience

field of study falsely presented as having a scientific basis

Anecdotal evidence

assertion based on a single or a few examples that do not support a generalized conclusion

biosphere

all life on Earth and all the places where life exists

ecosystem

All living organisms in an area plus the nonliving component of the environment with which they interact

Community

all organisms living together in an ecosystem

Population

a group of interacting individuals of one species

organism

individual living thing

organ system

group containing two or more organs that work together in an organism

organ

a body structure made of several different tissues

tissue

group of similar cells performing a specific function

cell

the smallest unit that can display all the characteristics of life

organelle

a functional component inside a cell, such as the nucleus

cohesion

tendency of molecules of the same kind to stick together; water has strong cohesion becuase of hydrogen bonding

surface tension

measure of how difficult it is to stretch or break the surface of a liquid

evaporative cooling

cooling that occurs when a substance evaporates and the liquid left behind becomes cooler

solution

homogeneous liquid mixture of two or more substances

solvent

dissolving agent in a solution

solute

substance dissolved in a solution

aqueous solution

solution in which water is the solvent

acid

a chemical compound that releases hydrogen ions into a solution

base

compound that accepts hydrogen ions and remoces them from solution

pH

a scale used to describe acidity by measureing hydrogen ion concentration in a solution

buffer

substance or system that minimized changes in pH

radiometric dating

method of estimating age by measuring radioactive isotopes and the number of half-life reductions that have occurred

Half-life

time associated with a radioactive isotope decreasing ot half of its previous amount of radioactivity

Fossil record

Ordered sequence of fossils used to document the history of life

Macromolecule

very large biological molecule; many macromolecules are built from smaller molecular building blocks; big molecule

monomer

small molecular builiding bliock that can be joined to other similar units building block

polymer

a large molecule made by strining together many monomers; chain of monomers

dehydration reaction

reaction that links monomers together while removing a molecule of water; dehydration

hydrolysis

the breakdown of a polymer by adding water; essentially the reverse of a dehydration reaction

carbohydrate

sugar, saccharide; a class of organic molecules that includes sugars and plymers of sugars and is used for energy and structure

monosaccharide

simple carbohydrate; a carbohydrate monomer that cannot be broken down into smaller sugars

polysaccharide

complex carbohydrate; a carbohydrate polymer made from many monosaccharides

glucose

monosaccharide that is a major fuel for cellular work and a monomer of several important polysaccharides

fructose

monosaccharide found in fruit; same molecular formula as glucose but a different structure

isomer

molecule that has the same molecular formula as another molecule but a different strcutre

starch

polysaccharide made from glucose that can be stored in the liver and muscles

glycogen

polysaccharide made from glucose that can be stored in the liver and muscles

celluose

a glucose-based polysaccharide that humans cannot digest

lipid

fat; a diverse group of hydrophobic molecules that do not mix with water

fatty acid

a molecular building block used in fats and phospholipids

glycerol

the molecule joined to three fatty acids to form a typical triglyceride

triglyceride

fat; a typical fat consisting of one glycerol molecule joined to three fatty acid molecules

saturated fatty acid

a fatty acid with the max number o fhydrogens and no carbon-carbon double-bond kink

unsaturated fatty acid

a fatty acid with fewer than the max number of hydrogens beceuase it contains one or more double bonds

saturated fat

solid fat;

a fat whose three fatty acids are saturated; these fats can stack and tend to be solid at room tempurature