Cellular and Molecular Biology - Exam 1

Life

• exists almost everywhere on earth

• it is diverse and ranges from microscopic bacteria to giant whales

• over 1,750,000 species have been classified

Hierarchy

1. atoms

2. molecule

3. macromolecule

4. cell

5. tissue

6. organ

7. organ system

8. organism

systematics

the discipline of identifying and classifying organisms

• domain = most broad (3 different domains)

• species = most specific

Archaea

• unicellular prokaryotes

• found in hostile environments like aquatic areas that lack O2, too salty, and hot or acidic

Bacteria

• unicellular prokaryotes

• found everywhere on earth

• can be beneficial and detrimental

• similar to archaea but biochemically very different

eukarya

• unicellular or multicellular

• have membrane bound nucleus and organelles

4 different kingdoms

• protists

• fungi

• plants

• animals

biosphere

region of land, air, and water

population

group of individuals of one species in one geographical location

• deer pop. in NU

community

• formed by many populations in a location

ecosystem

a biological community in which organisms intereact with each other and the environment

chemical cycling

chemicals moving from one species to another in the food

energy flow

flow of solar energy through plants and other organims as one species feds another

humans

depend on healthy ecosystems with chemical cycling and energy flow

the scientific method

• used by scientists/individuals interested in studying the world

• make observations with their senses

inductive reasoning

uses reason and logic to combine observed, isolated facts into a cohesive whole/hypotheses

deductive reasoning

determines how to test a hypothesis using ‘if… then” statements

prediction

final statement suggesting that the final statement will work

experimental design

• good set up = good results

• control group = everything is the same but w/o factor being tested

• independent variable= I do it - manipulated or changes

• dependent variable = affected by independent varibale

matter

anything that takes up space and has mass

• solid, liquid, gas

elements

substance that can’t be broken into substances with different properties

• composed of one type of atom

atom

smallest unit of matter that displays all properties of the element

protons

positively charged ; in nucleus

nuetrons

no charge ; in nucleus

electron

negatively charged ; in orbitals

electron shells

• first shell has lowest energy (2e-)

• second shell has higher (8e-)

• third shell highest (8e-)

• etc.

levels farthest away have more energy then closest to nucleus

mass number

number of protons and number of nuetrons

atomic number

number of protons

• defines what element it is

• this never changes per element

isotope

atoms of the same element that differ in number of neutrons

• radioactive isotopes emit energy over time in the form of rays and subatomic particles

• isotopes always have the same number of protons

cons of radioactive isotopes

radioactivity can damage DNA

• marie curie conducted research on radium and contracted cancer

• chernobyl - nuclear power plant explosion released radioactive particles into the atmosphere

pros of radioactive isotopes

medical uses

• imaging of the body (PET)

• sterilize medical products and instruments

• kill cancer cells

• x-rays

• kill bacteria/pathogens and fungi

periods on table

horizontal

• in order from lowest proton number to highest proton number

• period number is the number of orbital around that element

groups on table

vertical

• valance electrons are the group number of that element

election shells

• 1st shell = 2 es

• all the other shells = 8 es

• es fill lowest shells first and work up to the higher shells

octet rule

atoms are most stable when the outer shell has 8 electrons

molecule

formed when two or more atoms bound together by chemical bonds

ex) O2

compound

formed when two or more different atoms bound together by chemical bonds

ex) H2O

ion

a charged atom due to different numbers of protons and electrons

ionic bond

attraction between ions of opposite charges

• electrons want to fill outermost shell because then they are stable!!

cation

a positively charged ion that has more protons than electrons

anion

an atom or molecule that has a negative electrical charge because it has more electrons than protons

nonpolar covalent bond

• two atoms share electrons in order for each to have a complete outer electron shell

• single bond is sharing one pair of es

• double bond is sharing two pairs of es