Lecture exam 1

Emergent property

novel properties that appear at each level that are absent from the preceding level.

a. due to the arrangement and interaction of parts as complexity increases

b. not unique to life

population

A group of individuals of the same species that live in the same area and interbreed, producing fertile offspring.

community

All the organisms that inhabit a particular area; an assemblage of populations of different species living close enough together for potential interaction.

ecosystem

All the organisms in a given area as well as the abiotic factors with which they interact; one or more communities and the physical environment around them.

biome biogenesis

holism

reductionism

Reduces complex systems to simpler components that are easier to study

prokaryotic

• bacteria

• no membrane-bound organelles

• no nucleus

• single, circular chromosome

eukaryotic

- A cell with a membrane enclosed nucleus and membrane enclosed organelles

- plants & animals, protists, fungi

- membrane-bound nucleus

- distinct, membrane-bound nucleus

- multiple, distinct chromosome

taxonomy

A scientific discipline concerned with naming and classifying the diverse forms of life.

evolution

The process by which species accumulate differences from their ancestors as they adapt to different environments

- the change in an organism over time

natural selection

A process in which individuals have certain inherited traits tend to survive and reproduce at higher rates than other individuals due to the traits

- Charles Darwin & the theory of natural selection

- 1859 - published “on the origin of species”

- survival of the fittest

- Darwin’s 3 Essential Observations:

a. Individuals of a population vary in their traits, many of which seem to be heritable.

b. A population can produce far more offspring than can survive to reproduce.

c. Species are generally suited to their environment (they have adapted)

scientific method

hypothesis

a logical explanation; also often called an educated guess

inductive reasoning

deriving generalizations from a large number of specific observations

control group

A set of subjects that lacks / does not receive the specific factor being tested

variable

• a feature or quantity that varies in an experiment.

a. independent variable – the factor that is manipulated by the scientist

b. dependent variable – the factor being measured that is predicted to be affected by the independent variable.

c. control – the factor that is not changed; provides a baseline for comparison of the results

experimental group

deductive reasoning

1. involves logic that flows from general to specific

2. often seen in an “if-then” format

3. a hypothesis can never be proved beyond the shadow of a doubt

4. scientific consensus – the shared conclusion of many scientists that a hypothesis supports the particular data.

scientific theory

• much broader and more general than a hypothesis

a. general enough to generate many new testable hypotheses

b. generally supported by a much greater body of evidence

• theories are sometimes modified or rejected by new research results

matter

anything that takes up space and has mass

element

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

trace element

needed in minute (small) quantities

a. iron (Fe) – needed by all forms of life

b. others vary by species

c. iodine (I) – needed by vertebrates for a hormone produced by the thyroid gland. Lack of iodine = goiter

atom

the smallest particle having all the properties of the element

neutron

• non-charged particles (neutral).

• found in nucleus of an atom

proton

positively charged particles

electron

negatively charged particles found in a “cloud” around the nucleus

atomic nucleus

An atom's dense central core, containing protons and neutrons.

dalton

• unit of measurement for subatomic particles. Also called the “atomic mass unit”, or “amu”.

• protons & neutrons have masses close to 1 amu

atomic number

• the number of protons of an element

• an element’s number of protons equals its number of electrons

mass number

– the total number of protons & neutrons in the nucleus of an atom

- subtract the element’s number pf protons to get its number of neutrons

atomic weight

isotope

- different forms of the same element

a. have differing number of neutrons

b. have different masses

c. have different properties

d. example: carbon (C) has 3 isotopes

- same number of proton

radioactive isotope

- nucleus decays spontaneously, giving off particles and energy

- this changes the isotope to a different element

energy

the capacity to cause change

potential energy

- energy of position or structure

c. the further an electron is from the nucleus, the more potential energy it has

energy level

electron shell

- areas around the nucleus where electrons are found.

a. each shell has an average distance and energy level

b. the further out the shell, the more energy an electron has

c. electrons can move to different shells, but must gain or lose energy in the process

orbital

valence electron

electrons located in the valence shell

valence shell

the outermost shell

chemical bond

An attraction between two atoms resulting from a sharing of outer-shell electrons or the presence of opposite charges on the atoms.

covalent bond

the sharing of a pair of valence electrons by 2 atoms

molecule

2 or more atoms of the same element held together by covalent bonds

structural formula

molecular formula

double covalent bond

2 pairs of shared electrons

valence

the bonding capacity of the atom; usually, the number of e─ needed to complete the outer shell

electronegativity

the attraction of an atom for the electron of a covalent bond

nonpolar covalent bond

the electrons are shared equally between the 2 atoms of similar electronegativity

polar covalent bond

- the electrons are NOT shared equally between the 2 atoms, for example:

• a. water (H2O) is very strongly polar. The electrons spend more time near the oxygen atom.

  b. methane (CH4) is weakly polar

ion

oppositely charged atoms or molecules created when the more electronegative atom strips an electron from the other atom

cation

positive ion, formed by losing an electron

anion

negative ion, formed by gaining an electron

ionic bond

bond formed between an anion and a cation

hydrogen bond

weak chemical bonds

– the noncovalent attraction between a hydrogen and an electronegative atom

a. the electronegative atoms are usually either nitrogen (N) or oxygen (O)

b. found in:

1) water

2) DNA

- heat of vaporization

chemical reactions

changes in the composition of matter due to the making & breaking of chemical bonds

reactants

the starting materials

products

the resulting materials.

chemical equilibrium

– the point at which the reactions in each direction are happening at the same rate.

a. no net effect of reactions

b. reactants & products are not necessarily at equal concentrations

c. reactants & products concentrations are stable at a certain ratio

organic chemistry

the study of all chemicals containing carbon

hydrocarbon

- organic molecules containing only carbon & hydrogen.

1. major components of petroleum (fossil fuel)

2. not prevalent in most living organisms

3. can undergo reactions that release high levels of energy

isomer

compounds that have the same number of atoms of the same elements. Different structures yield different properties.

structural isomer

- differ in the covalent arrangements of their atoms

- differ in location of double bonds

geometric isomer

cis-trans isomers

a. atoms differ in spatial arrangement due to inflexibility of double bonds

b. compounds often change between the cis and trans forms

enantiomer

- one of two compounds that are mirror images of each other

- usually only one of the forms is biologically active

functional group

- A specific configuration of atoms commonly attached to the carbon skeletons of organic molecules and involved in chemical reactions.

1. hydroxyl – alcohols

2. carbonyl

a. ketone

b. aldehyde

3. carboxyl – carboxylic acid

4. amino

5. sulfhydryl – thiol

6. phosphate – organic phosphate

7. methyl – methylated compound

hydroxyl group

- A chemical group consisting of an oxygen atom bonded to a hydrogen atom.

- attached to the 3’ carbon

alcohol

carbonyl group

- A chemical group present in aldehydes and ketones and consisting of a carbon atom double-bonded to an oxygen atom.

- ketone, aldehyde

aldehyde

An organic compound that contains a carbonyl group with the central carbon bonded to a hydrogen and R group (R-CHO)

ketone

an organic compound containing a carbonyl group =C=O bonded to two hydrocarbon groups, made by oxidizing secondary alcohols. The simplest such compound is acetone.

carboxyl group

A chemical group present in organic acids and consisting of a single carbon atom double-bonded to an oxygen atom and also bonded to a hydroxyl group.

carboxylic acid

amino group

A chemical group consisting of a nitrogen atom bonded to two hydrogen atoms; can act as a base in solution, accepting a hydrogen ion and acquiring a charge of 1+.

amine

an organic compound derived from ammonia by replacement of one or more hydrogen atoms by organic groups.

sulfhydryl group

- A chemical group consisting of a sulfur atom bonded to a hydrogen atom.

- thiol

thiol

An organic compound which contains a sulfhydryl group.

phosphate group

- attached to the 5’ carbon

- A chemical group consisting of a phosphorus atom bonded to four oxygen atoms; important in energy transfer.

- phospholipids

- heads on the outside