Bio Exam 1

How is life recognized?

order, reproduction, growth and development, response to the environment, energy processing, regulation, evolutionary adaptation

The core theme

Evolution accounts for the unity and diversity of life

Charles Darwin

-published On the Origin of Species by Means of Natural Selection in 1859

Charles Darwin's 2 main points

-Species showed evidence of "descent with modification" from common ancestors
-"Natural selection" is the mechanism behind descent with modification

Tree of Life

A diagram depicting the genealogical relationships of all living organisms on Earth, with a single ancestral species at the base.

Levels of Biological Organization

biosphere, ecosystems, communities, populations, organisms, organs and organ systems, tissues, cells, organelles, molecules

Reductionism

the reduction of complex systems to simpler components that are more manageable to study

systems biology

An approach to studying biology that aims to model the dynamic behavior of whole biological systems based on a study of the interactions among the system's parts.

inductive reasoning

A type of logic in which generalizations are based on a large number of specific observations.

deductive reasoning

reasoning in which a conclusion is reached by stating a general principle and then applying that principle to a specific case (The sun rises every morning; therefore, the sun will rise on Tuesday morning.)

Hypothesis

an explanation, based on observations & assumptions, that leads to a testable prediction

experiment

a scientific test, carried out under controlled conditions to test a hypothesis (Data generation)

scientific theory

a well-tested concept that explains a wide range of observations

scientific law

A statement that describes what scientists expect to happen every time under a particular set of conditions

controlled experiment

An experiment in which only one variable is manipulated at a time.

independent variable

The experimental factor that is manipulated; the variable whose effect is being studied.

dependent variable

The measurable effect, outcome, or response in which the research is interested.

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
A compound has characteristics (emergent properties) different from those of its elements

Energy

the capacity to cause change

potential energy

the energy that matter possesses because of its location or structure

valence electrons

Electrons on the outermost energy level of an atom

covalent bond

A chemical bond that involves sharing a pair of electrons between atoms in a molecule

ionic bonds

Formed when one or more electrons are transferred from one atom to another

Cation

A positively charged ion

Anion

A negatively charged ion

hydrogen bond

A type of weak chemical bond formed when the slightly positive hydrogen atom of a polar covalent bond in one molecule is attracted to the slightly negative atom of a polar covalent bond in another molecule.

Electronegativity

A measure of the ability of an atom in a chemical compound to attract electrons

nonpolar covalent bond

equal sharing of electrons

polar covalent bond

A covalent bond in which electrons are not shared equally

van der Waals forces

the two weakest intermolecular attractions- dispersion interactions and dipole forces

Molecule

consists of two or more atoms held together by covalent bonds

single bond

the sharing of one pair of valence electrons

double bond

A chemical bond formed when atoms share two pairs of electrons

chemical equilibrium

a state of balance in which the rate of a forward reaction equals the rate of the reverse reaction and the concentrations of products and reactants remain unchanged

Four emergent properties of water

cohesive behavior, ability to moderate temperature, expansion upon freezing, versatility as a solvent

Cohesion

Collectively, hydrogen bonds hold water molecules together, a phenomenon

surface tension

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

Adhesion

attraction between molecules of different substances

specific heat

The amount of energy required to raise the temperature of 1 gram of a substance by 1 degree celcius

Why does water have a high specific heat?

Much of the added energy is required to break hydrogen bonds.

heat of vaporization

the heat a liquid must absorb for 1 g to be converted to gas

evaporative cooling

As a liquid evaporates, its remaining surface cools

Expansion upon freezing

hydrogen bonds in ice are more "ordered and spaced out" making ice larger and LESS DENSE

Solution

A homogeneous mixture of two or more substances

Solvent

the dissolving agent of a solution

Solute

the substance that is dissolved

aqueous solution

a solution in which water is the solvent

hydration shell

the sphere of water molecules around each dissolved ion

Hydrophilic

Having an affinity for water.

Hydrophobic

Having an aversion to water; tending to coalesce and form droplets in water.

Molarity

the number of moles of solute per liter of solution

molecular mass

The sum of the masses of all the atoms in a molecule

Acids

compounds that form hydrogen ions when dissolved in water

Bases

Compounds that reduce the concentration of hydrogen ions in a solution.

pH

pH \= -log [H+]

Buffers

weak acids or bases that can react with strong acids or bases to prevent sharp, sudden changes in pH

Carbohydrates

the starches and sugars present in foods

Lipids

Energy-rich organic compounds, such as fats, oils, and waxes, that are made of carbon, hydrogen, and oxygen.

Protein

A three dimensional polymer made of monomers of amino acids.

nucleic acids

DNA and RNA

Polymer

A long molecule consisting of many similar or identical monomers linked together.

Macromolecules

A very large organic molecule composed of many smaller molecules

enzyme

specialized macromolecules that speed up chemical reactions such as those that make or break down polymers

dehydration reaction

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

Hydrolysis

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

types of protein function

enzymatic, defensive, transport, hormonal, receptor, structural, contractile and motor, and storage,

enzymatic proteins

selective acceleration of chemical reactions

defensive proteins

protection against disease

storage proteins

storage of amino acids

transport proteins

transport of substances

hormonal proteins

coordination of an organism's activities

receptor proteins

response of cell to chemical stimuli

contractile and motor proteins

movement

structural proteins

to support

amino acids

-monomers of proteins
-To determine whether it is hydrophobic/hydrophilic/nonpolar/polar look at charges and functional groups

peptide bond

The chemical bond that forms between the carboxyl group of one amino acid and the amino group of another amino acid

Polypeptide

A polymer (chain) of many amino acids linked together by peptide bonds.

Protein structure

primary, secondary, tertiary, quaternary

primary structure

The first level of protein structure; the specific sequence of amino acids making up a polypeptide chain.

secondary structure

The second level of protein structure; the regular local patterns of coils or folds ( called an α helix and a β pleated sheet) of a polypeptide chain.

tertiary structure

The third level of protein structure; the overall, three-dimensional shape of a polypeptide due to interactions of the R groups of the amino acids making up the chain.

quaternary structure

The fourth level of protein structure; the shape resulting from the association of two or more polypeptide subunits.

disulfide bridges

A strong covalent bond formed when the sulfur of one cysteine monomer bonds to the sulfur of another cysteine monomer.

Collagen

a fibrous protein consisting of three polypeptides coiled like a rope

Denaturation

In proteins, a process in which a protein unravels and loses its native conformation, thereby becoming biologically inactive. In DNA, the separation of the two strands of the double helix.

gene expression

The process by which information encoded in DNA directs the synthesis of proteins or, in some cases, RNAs that are not translated into proteins and instead function as RNAs.

Gene

A segment of DNA on a chromosome that codes for a specific trait

Nucleotide

monomer of nucleic acids made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base

Pyrimidines

cytosine, thymine, uracil (1 SIX MEMBERED RING)

Purines

Adenine and Guanine (1 SIX MEMBERED RING + 5 MEMBERED RING)

phosphodiester linkage

covalent bonds that join adjacent nucleotides between the -OH group of the 3' carbon of one nucleotide and the phosphate on the 5' carbon of the next

antiparallel

The opposite arrangement of the sugar-phosphate backbones in a DNA double helix.

Monosaccharides

Single sugar molecules, simple sugars

Disaccharide

A double sugar, consisting of two monosaccharides joined by dehydration synthesis.

glycosidic linkage

A covalent bond formed between two monosaccharides by a dehydration reaction.

Polysaccharides

large macromolecules formed from monosaccharides

storage polysaccharides

starch and glycogen

Starch

A storage polysaccharide in plants consisting entirely of glucose. (simplest form is amylose)

Glycogen

storage form of glucose in animals