Bio Exam 1

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lipids

large class of biological molecules that do not form polymers

Taxonomy

branch of biology that names and classifies species into groups

organize diversity of life

domain,kingdom,phylum, class, order, family, genus, species.

Domain Bacteria ( one of the three domain systems)

comprise prokaryotes

Domain Archaea (one of the three domain systems)

comprise the prokaryotes

Domain Eukarya ( one of the three domain systems )

includes all eukaryotic organisms

Protista

Other eukaryotic organisms were formerly grouped into a kingdom called Protista, though these are now often grouped into many separate kingdoms

Unity (common traits)

underlies the diversity of life

Charles Darwin

published On the Origin of Species by Means of Natural Selection

selection (natural)

the mechanism behind “ descent with modification”

population

Over time, more individuals in a population will have the advantageous traits

diversity

Darwin’s theory explained both unity and diversity (i.e. why organisms have common traits, yet are also distinct)

descendant species

Darwin proposed that natural selection could cause an ancestral species to give rise to two or more

dendrogram

Evolutionary relationships are often illustrated with tree-like diagrams (dendrograms) that show ancestors and their descendants

inquiry

is a search for information and explanation

data (plural)

are recorded observations or items of information

Qualitative

descriptions rather than measurements (seeing something)

Quantitative

recorded measurements, which are sometimes organized into tables and graphs

hypothesis

Hypothesis-based science centers around a hypothesis,

which is a tentative answer to a well-framed question that is

also falsifiable

falsifiable

can test the hypothesis

tested

A scientific hypothesis leads to a prediction that can be

tested by observation or experimentation

inductive

reasoning draws broad conclusions based on specific events/observation (general from specific)

Deductive

reasoning draws specific conclusions based on broad events/observations (specific from general)

theory

• Broader in scope than a hypothesis

• General, and can lead to new

testable hypotheses

• Supported by a large body of

evidence in comparison to a

hypothesis

examples

• Darwin’s theory of natural selection

• Einstein’s theory of relativity

matter

anything that takes up space and has mass

element

a substance that cannot be broken down to other substances by chemical reactions

compound

a substance consisting of two or more elements in a fixed ratio

96%

carbon, hydrogen, oxygen, and nitrogen make up —- of living matter

subatomic

Atoms are composed of three subatomic particles

Neutrons

one of the three subatomic particles and no charge

Protons

one of the three subatomic particles positive charge

electrons

one of the three subatomic particles negative charge

(atomic) number

is the number of protons in its nucleus

(atomic ) mass

the atoms total mass, can be approximated by the mass number (total of protons and neutrons in an atom)

Isotopes

two atoms of an element that differ in the number of neutrons

Radioactive

isotopes decay spontaneously, giving off particles and energy

Potential

is the energy that matter has because of its location or structure

level

An electron’s state of potential energy is called its energy level, which relates to its electron shell

Valence

electrons are those in the outermost shell, and they prefer to exist in pairs

Inert

Elements with a full valence shell are chemical example Argon

covalent

bond is the sharing of a pair of valence electrons by two atoms

molecule

consists of two or more atoms held together by covalent bonds

single (bond)

A single covalent bond, or single bond, is the sharing of one pair of valence electrons

double (bond)

A double covalent bond, or double bond, is the sharing of two pairs of valence electrons

nonpolar (bond)

the atoms share the elections equally example H2

polar (bond)

In a polar covalent bond, one atom is more electronegative, and the atoms do not share the electron equally example H2O

partial (positive/negative)

Unequal sharing of electrons causes a partial positive or negative charge for each atom or molecule (e.g. water )

ion

A charged atom (or molecule) is called an ion

cation

a positively charged ion

anion

a negatively charged ion

ionic (bond)

An ionic bond is an attraction between an anion and a cation

ionic (compound)

Compounds formed by ionic bonds are called ionic compounds, and are often found as crystals example salt

hydrogen (bonds)

Weak chemical bonds, such as ionic bonds and hydrogen bonds, are also important

Chemical (reactions)

are the making and breaking of chemical bonds

reactants

The starting molecules of a chemical reaction are called

products

The final molecules of a chemical reaction are called products

polar (properties of water)

The opposite ends have opposite charges

Polarity

allows water molecules to form hydrogen bonds with each other

cohesion

Collectively, hydrogen bonds hold water molecules together, a phenomenon called cohesion

adhesion

is an attraction between different substance ( a water droplet on glass)

tension

Surface tension (related to cohesion) is a measure of how hard it is to break the surface of a liquid (example running on water lizard)

specific (heat)

heat of a substance is the amount of heat that must be absorbed or lost

solution

A solution is a liquid that is a homogeneous mixture of substances

solvent

A —— is the dissolving agent

solute

The substance that is dissolved

hydration (shell)

When an ionic compound is dissolved in water, each ion is surrounded by a sphere of water molecules called a hydration shell

hydrophilic

A substance (e.g. ethanol) is one that has an affinity for water

hydrophobic

A hydrophobic substance is one that does not have an affinity for water

proton

A hydrogen atom leaves its electron behind and is transferred as a proton

pH

scale to describe whether a solution is acidic (scale rich in H+ ) or basic (rich in OH-to describe whether a solution is acidic

acid

is any substance that increases the H+ concentration of a solution

base

is any substance that reduces the H+ concentration of a solution

hydrocarbons

are organic molecules consisting of only carbon and hydrogen

Isomers

are compounds with the same molecular formula but different structures and properties:

• Structural isomers have different covalent

arrangements of their atoms

• Cis-trans isomers have the same covalent

arrangements but differ in spatial arrangements

• Enantiomers are isomers that are mirror images of

each other (non-superimposable)

functional groups

groups are the components of organic molecules that are most commonly involved in chemical reactions

dehydration

reaction occurs when two monomers bond together through the loss of a water molecule

Enzymes

are macromolecules that speed up the dehydration process

hydrolysis

Polymers are disassembled to monomers by hydrolysis, a reaction that is the reverse of the dehydration reaction

monosaccharides

The simplest carbohydrates are monosaccharides, or single sugars

• Monosaccharides have molecular

formulas that are usually multiples of

CH2 O (e.g. glucose, C6 H12 O 6 )

disaccharide

formed when a dehydration reaction joins two monosaccharides

Polysaccharides

the polymers of sugars, have storage and structural roles

Lipids

are the one class of large biological molecules that do not form polymers

Saturated (fat)

fatty acids have the maximum number of hydrogen atoms possible and no double bonds

Unsaturated (fats)

fatty acids have one or more double bonds

phospholipid

two fatty acids and a phosphate group are attached to glycerol

Steroids

are lipids characterized by a carbon skeleton consisting of four fused rings

Cholesterol

an important steroid, is a component in animal cell membranes

enzymes

are a type of protein that acts as a catalyst to speed up chemical reactions

polypeptides

small proteins are often called

peptide (bonds)

amino acids are linked by peptide bonds

primary

structure of a protein is its unique sequence of amino acids

Secondary

structure, found in most proteins, consists of coils and folds in the polypeptide chain

Tertiary

structure is determined by interactions among various side chains (R groups) that give a 3D shape

Quaternary

structure results when a protein consists of multiple polypeptide chains (more than one protein)

disulfide

Strong covalent bonds called disulfide bridges may reinforce the protein’s structure

polynucleotides

Nucleic acids are polymers called polynucleotides