bio test 1-4

science definition

the systematic study of the natural world through observation and experimentation to gain knowledge

sciences limitations

can only investigate things that can be observed, measured, and tested

• cannot test supernatural or spiritual claims

scientific method

• not necessarily linear: steps are fluid

• common procedure: observation-question-hypothesis-experiment-evaluate

hypothesis

a testable explanation for a set of observations

• cannot be proven- just fail to reject or reject

independent/experimental variable

the factor that a scientist intentionally changes in an experiment

experimental treatment

the condition or factor being tested on the experimental group

Type 1 error

you incorrectly find support for your hypothesis

Type 2 error

you incorrectly reject your hypothesis

correlation vs causation

correlation: two things are associated or related but they do NOT cause each other

causation: one thing directly produces a change in another

scientific theory

a well supported explanation for observations—explains WHY

scientific law

a statement that describes an observation or pattern under conditions— describes WHAT is happening

biology definition

the study of life and living organisms

5 basic characteristics of life

1. living things require materials and energy (metabolism)

2. living things maintain homeostasis (body temp, blood sugar—through feedback systems)

3. living things respond to their environment (behaviors)

4. living things reproduce and develop

5. living things adapt and evolve

metabolism definition

the total sum of all chemical reactions that happen inside the cells of a living organism to sustain life

behaviors defintion

an activity or response conducted by an organism in response to its environment

matter definition

anything that has mass and takes up space

atom

the smallest unit of an element that retains the properties of that element

element

an substance that is made up of only one type of atom (carbon, oxygen)

proton

positive part of the atom, in the nucleus, determines the type of element (atomic number)

neutron

neutral part of an atom, in the nucleus, determines the isotope (mass different than normal version of that element)

electron

negative apart of an atom, in the electron shells, help to create bonds, find mass from it (p + e= atomic mass)

electron shells

• first shell has 2 electrons

• every shell after has 8 electrons

• outermost shell= valence shell (where valence electrons are for bonding)

molecule

a group of 2 or more atoms chemically bonded (element or compound)

compound

a substance/molecule made up of two or more different elements chemically bonded together (ex. H2O)

electronegativity

the ability of an atom to attract electrons towards itself in a chemical bond

• electronegative increases left to right

ionic bonds

a chemical link formed when one atom completely transfers one or more electrons to another atom

• typically happens between nonmetals and metals

• atom loses an electron= becomes positive

• atom gains an electron= becomes negative

cation

a positively charged ion—usually formed when an atom loses an electron

anion

a negatively charged ion—forms when an atom gains electrons

covalent bonds

a bond where the atoms share electrons back and fourth

• nonpolar and polar

nonpolar covalent bonds

electrons are shared approximately equally between atoms

polar covalent bond

electrons are shared unequally because one atom is more electronegative

• more electronegative one will become slightly more negative since they hold the electron longer

hydrogen bonds

a weak attraction between a slightly positive hydrogen atom and a slightly negative atom in another molecule

Van der Waals interactions

weak attractions caused by the temporary uneven distribution of electrons in polar bonds

water polarity

water has polar covalent bonds and hydrogen bonds

• polar covalent bonds help O and H bond

• hydrogen helps H2O bond to other H2O molecules

4 important properties of water

1. cohesion

2. moderation of temperature

3. ice floats

4. water as a solvent

cohesion property of water

attraction between molecules of the same substance

• water molecules stick to other water molecules because of the hydrogen bonding

• also has adhesion: attraction to different substances— water can stick to other surfaces and molecules

moderation of temperature property of water

• the amount of heat required for water to change by 1 degree C is high (specific heat) because of the releasing and absorbing of hydrogen bonds

• breaking H bonds= absorbs heat

• forming H bonds= releases heat

• ex: oceans moderate coastal temperatures, sweating (breaking bonds absorbs the heat)

heat vs temperature definition

heat= the thermal energy that is transferred between objects/matter because of a temperature difference (boiling water)

temperature= the average kinetic energy of particles in a substance

ice floats property of water

water is unusual since its solid form is less dense than its liquid form

• important= forms an insulating layer that helps keep the water underneath from freezing solid, helping marine life

water as a solvent property of water

• water is a universal solvent because it helps dissolve a lot of things

• it dissolves things that are hydrophilic (water loving), not things that are hydrophobic (water fearing)

dissociation

the separation of a compound into its ions when it is dissolved in water

acids and bases

acid= a substance that increases H+ concentration in a solution

more H+= a lower pH

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less H+= higher pH

base= a substance that decreases H+ concentration in solution

pH scale

0-14

• 0-6= acidic

• 7= neutral

• 8-14= basic/alkaline

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more H+= a lower pH= more acidic

less H+= a higher pH= less acidic

buffer

a solution that resists/minimizes changes in Ph when acids or bases are added

• important to living organisms because cells need the pH to stay in a certain range

carbonic acid-bicarbonate buffer system

in the body when CO2 is produced, it can help create carbonic acid and or bicarbonate

if the H+ increases= blood is more acidic/pH decreases so bicarbonate helps make it normal

if the H+ decreases= blood is less acidic/pH increases so carbonic acid helps make it normal