AP Biology Unit 1 (mods 1-3)

Biology

Study of all living things

organism

living beings that display the properties of life

gene

the unit of heredity

(smaller than genome)

genome

all of the genetic information that an organism contains

cell

simplest self-reproducing unit that can exist independently

Species

a group of interbreeding organism that produce fertile offspring

ex. ligers can’t produce offspring because two different species produced it

evolution

change over time

natural selection

some individuals survive and reproduce more than others as a result of a variation among them which is passed down to the next generation

Big Idea 1: Evolution

Terms: species, evolution, natural selection

ex. Hares who got away from the Lynx because they were fast, reproduced and passed that trait down

Energy

the ability to do work

energetics

examines the properties of energy

• how it is distributed in biological, chemical and physical processes

Big Idea 2: Energetics

Terms: energy, energetics

ex. The Lynx had to attain energy through other organisms in order for it to be able to chase the Hare

Big Idea 3: Information storage and transmission

Term: DNA

ex. Lynx and Hare are able to run fast because of a genetic variation that was passed down through DNA (transmitted that genetic information)

biotic

living organisms

abiotic

non-living components

biological system

made of biotic and abiotic entities that interact

emergent property

a property of a system that the individual parts do not have on their own

Big Idea 4: System Interactions

Terms: biotic, abiotic, biological systems, emergent properties

ex. tendons, muscles, and bones interact in the hare to allow it to run

All organism obtain energy from which two sources?

sun and chemical compounds

What makes a good investigative question?

• observable and testable

• data can be collected to support or refute null hypothesis

Why can you not prove a hypothesis?

• a confounding variable or a possible different explanation can be the real reason for the evidence

• a single experiment cannot provide enough strong evidence to prove a hypothesis

What is the reason for a control group?

allows the scientist to compare results with the variables and without

• ensures that the results are due to the independent variable not a different one

experimental group

the group that experiences the variable

control group

is not exposed to the variable

positive control

this group gets a treatment with a known result

ex. a medicine that is known to increase heart rate to ensure that it works

negative control

the group where no affect is expected to be observed

• control

qualitative vs. quantitative

descriptive qualities

numerical numbers

null hypothesis

predicts that the treatment has no effect at all

alternative hypothesis

predicts that the treatment has an effect

(difference between test and control is real)

Equation for percent change

final-initial/initial x 100

error bars

• represents a range of values that could possibly be included in the data due to miscalculations, etc.

• found through the standard error of the mean (st. dev. first)

• 1 SEM is around 68%, multiply by 2 to get around 95% confidence

How does a scientist turn an observation into a hypothesis?

• make observations that prose a possible explanation

• investigated through experiments, research, and data interpretation

matter

anything that has mass and takes up space

molecule

chemicals made up of 2 or more atoms

organic molecule

molecules that contain carbon and hydrogen (both)

How does matter flow through ecosystems?

it cycles and can be reused

• exchanged with other organisms/ environment

How does energy flow through ecosystems?

flows in one direction

• harnessed from environment and transformed by organisms

How does the flow of matter depend on the flow of energy?

energy is converted into carbon rich molecules that are eaten by organisms

• these molecules are a source of energy and matter (shows relation)

atomic number

the amount of protons in an element

• the second number/ subscript

atomic mass

the number of protons and neutrons

• superscript

isotope

Atoms of the same element that have a different amount of neutrons

ion

an electrically charged atom

What are the maximum number of valence electrons shells in the first and second shells?

first - 2 max

second - 8 max

• amount of electrons in valence shell usually determine the average amount of bonds an atom makes (ex. 4 valence electrons for carbon —> max bonds = 4)

• closer to nucleus —> less energy

• farther from nucleus —> more energy

What are the four most common elements?

carbon, hydrogen, oxygen, nitrogen

• phosphorus and sulfur

How are the rows and columns of the periodic table organized?

Rows: each element has one more proton and electron than the last

column- same number of valence shell electrons

covalent bond

when a pair of electrons are shared equally between two atoms

• 2 electrons in one bond

• 4 in two bonds

electronegativity

the ability of atoms to attract electrons

polar vs. non polar covalent bonds

polar- unequal sharing of electrons due to a higher electronegativity in one atom vs the other

non polar - equal sharing of electrons due to similar electronegativity

How are the charges distributed in a water molecule?

polar

• oxygen is partially negative (higher electronegativity)

• hydrogen is partially positive

ionic bond

a bond in which 2 ions with opposite charges bond due to their differences in charge

How does water dissolve molecules?

anything polar will be dissolved well by water (polar) - like dissolves like

• the partial negative and positive charges will be attracted to water and start to pull apart the molecule and be surrounded by water molecules

Why is carbon a key element in organisms?

• very abundant

• occurs as a solid, liquid, and gas (carbon cycle —> can be reused)

• forms many varied structures and performs many functions

• breaking carbon bonds release lots of energy

• only 4 valence electrons

monomer

a single molecule that can bond chemically with similar molecules in a polymer

(single bead in a necklace)

polymer

a larger molecule composed of many smaller subunits

(necklace)

Hydrophobic

• nonpolar

• water hating

• does not dissolve in water

hydrophilic

• polar

• water loving

• dissolves in water

Why is carbon’s number of valence electron shells important?

• can form multiple covalent bonds

• single bonds can allow carbon compounds to rotate freely and form a variety of shapes

hydrogen bond

a weak bond formed when a partially positive hydrogen interacts with a partial negative charge of another molecule

• o and h are interacting with other o and h molecules

Are hydrogen bonds weaker or stronger than ionic or covalent bonds

hydrogen bonds are weaker

• when there are many they can stabilize a molecule

which two electronegative atoms frequently involved in hydrogen bonding?

oxygen and nitrogen

cohesion

water molecules stick to one another

adhesion

water molecules stick to other materials

• allows water to move through channels in plants

high surface tension

water molecules on the surface only have molecules surrounding them on one side —> forms hydrogen bonds with other molecules

• measure of the difficulty of breaking the surface of a liquid

water density as a solid

water is less dense as a solid

• water molecules in liquid are able to move close together than in ice (liquid = more dense)

high specific heat

amount of heat required per unit mass of a substance to raise the temperature of it by one degree

• the large number of hydrogen bonds give water stability and requires more energy to break apart bonds

• additional energy needed causes temperature to heat up less fast

What do these unique properties of water cause?

hydrogen bonds formed between water molecules

How does the density of water as a solid affect organisms living in a lake during winter?

lakes freeze from the top down allowing organisms underneath to survive

• ice acts as an insulator to prevent water from becoming too cold

Why is water’s high specific heat important?

water can resist temperature variations

• provides a stable living environment for organisms

How does the polarity of water enable hydrogen bonding?

• the oxygen and hydrogen are partially positive and negative (same in all other water molecules)

• difference in charge allows oxygen to form hydrogen bonds with hydrogen (opposite charges)

What are three properties that result from hydrogen bonding?

cohesion, high specific heat, and surface tension, adhesion

sig figs

• all non zero numbers are significant

• zeros to the left are never significant

• zeros to the right with no decimal = no sig

• zeros to the right with decimal = sig

scientific notation in math problems

• exponent indicates how far left or right to move the decimal place until you get this- #.# or #.##

• exponent of 10 needs to be the same to add and subtract

• just add or subtract the main number without touching the exp or base of 10

• final answer should be rounded to the fewest amount of sig figs in a term

solvent

capable of dissolving many substances

What type of molecules can water dissolve?

polar and hydrophilic (two go hand in hand)

• nonpolar/ hydrophobic and arrange themselves to minimize contact with the partially charged regions of water

Water dissociation equation

H2O —> OH- + H+

• oxygen takes electron from hydrogen

Characteristics of acids

• donates H+ ions to solutions

• less than 7

• ex. lemon juice and vinegar

• have a higher concentration of H+ ions

characteristics of bases

• accepts H+ (removes them from solutions making them less acidic)

• greater than 7

• ex. antacids and baking soda

• greater concentration of OH- ions

How can you find the difference of on PH unit?

PH measures concentration of H+ ions

• as PH decreases, concentration of H+ increases tenfold

• ex. PH = 5 (2 below neutral) —> 2×10= 100 times more ions

dehydration synthesis

Water is removed to create larger molecules from smaller ones (removes water to join monomers through covalent bonds)

hydrolysis

water is added across a covalent bond —> breaks down the molecule