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Biology
science of life
Deductive reasoning
applies general principles to predict specific results
takes big ideas and deducts it to get results
ex. all mammals have hair, ants don’t have hair, so ants aren’t mammals
Inductive reasoning
specific observations are used to construct general principles
small evidence that infers a principle
ex. terrier, poodle, lab has hair so conclude all dogs have hair
Scientific Method Steps
observation
question
hypothesis
experiment
conclusion
Experimental group
group that differs by 1 key factor
Control group
group compared to the experimental group
Independent variables
factor that differs or is changed in the experimental group
Dependent variables
factor that will change because of the independent variable
Controlled variable
factors that remain the same with both groups
Atomic number
number of protons in a nucleus
Atomic mass
protons and neutrons combined measured in amu which is the weighted average of isotopes
Isotopes
atoms of the same element but different masses
Radioactive isotopes
unstable nuclei of isotope because of an incorrect balance of protons and neutrons
Half-life
rate of decay or release of neutron
used to identify age of objects
Electrons
give elements their chemical properties
can be shared, lost, or gained
usually the number of electrons = protons
Ions
electrically charged atom
Cation
positive charged ion
more protons than electrons
caused by loss of electron
Anion
negatively charged ion
more electrons than protons
caused by a gain of electrons
Oxidation reaction
loss of electrons
Reduction reaction
gain of electrons
Ionic Bond
ionizes elements where charges are opposite and the same magnitude
force of attraction between 2 opposite charges
elements on opposite sides of table
NaF, NaCl, KCl
Covalent Bond
strong, sharing of electrons
O=O, H-H, N-=N
Nonpolar Covalent Bond
electrons are shared equally
C-H or anything bound to itself
Polar Covalent
electrons are shared unequally
O-H, N-H, S-H
Hydrogen Bond
weak force of attraction between 2 opposite partial charges of oxygen on one molecule to hydrogen on another
Adhesion
water adheres to items, climb up items
binding of unlike molecule
capillary action of water transport in plants
transport H2O against force of gravity
Cohesion
water binds to water itself
creates water tension
why water is liquid at moderate temps
Specific heat
water has a high specific heat
how much energy is needed to raise 1g of substance 1 degree C
more polar = higher specific heat
need to break H-bonds to raise temp
helps organisms maintain constant temp
High heat of vaporization
heat of vaporization - energy needed to change substance from liquid to gas
H bonds need to broken
Cools surrounding surface - sweating cools the body
Density of solid water
ice is less dense than liquid water
ice floats - water reaches maximum density at 4 degrees Celsius, H bonds space water molecules farther apart
Solvent
substances that dissolve another (H2O)
Solute
substance that gets dissolved (Kool-Aid)
Solubility
polar and ionic compounds dissolve easily in water
like dissolves like - substance with similar properties will dissolve well with like substances (polar with polar)
Hydrophobic
water fearing
nonpolar molecules
fats and oils
clump together to get away from water
Hydrophilic
water loving
polar molecules
H-bonds form between substance and water
Acid
higher concentration of H+ ions (lower pH)
Basic
lower concentration of H+ ions (higher pH)
Buffers
help resist the changes in pH
contains pairs of substances - one acid, one basic
ex. carbonic acid/bicarbonate
Ecosystems
all organisms that live in a particular place plus the abiotic environment in which they live/interact
Biogeochemical cycles
chemicals moving through ecosystems
biotic and abiotic processes
Carbon cycle
major constituent of the bodies of organisms
aerobic cellular respiration releases CO2
Carbon Fixation (photosynthesis)
metabolic reactions that make nongaseous compounds from gaseous ones
Methanogens
produce methane by anaerobic cellular respiration
Greenhouse gasses
CO2, H2O, CH4
absorb infrared radiation emitted by Earth
re-emit radiation in all directions (back to Earth)
Earth temp rises
Earth would be cold at night without it
Water cycle
all life depends on the presence of water
60% of adult human weight is water
amount of water available determines the nature/abundance of organisms present
can be synthesized and broken down
synthesized during cellular respiration
broken down during photosynthesis
Ocean Acidification
bridge of water and carbon cycle
carbonic acid/bicarbonate get into water
lowers pH of ocean systems making them acidic
shelled organisms breakdown shells
Basic water cycle
liquid water evaporates from surface into atmosphere
also evaporated by plants
water in atmosphere is a gas and cools and falls to surface as precipitation
Transpiration
water loss through plant’s stomata
Percolation
water goes through rocks/ground and creates groundwater
Aquifers
permeable, underground layers of rocks, sand, and gravel saturated with water
95% of fresh water in US
two subparts:
upper layers constitute water table
lower layer can be tapped by wells
Nitrogen cycle
nitrogen is a component of all proteins and nucleic acids
uses the element in shortest supply
nitrogen in atmosphere cannot be uses
can use NH3 and NO-3
nitrogenous wastes and fertilizer us radically alters global nitrogen cycle
humans have doubled rate of transfer of N2 in usable forms into soil and H2O
Phosphorus Cycle
required by all organisms
occurs in nucleic acids, membranes, ATP
exists as inorganic phosphate
plants and algae use free inorganic phosphorus, animals eat plants to obtain their phosphorus
Weathering
phosphates stuck in rock become soluble by rain and goes into river, soil, lakes, ponds
Carboxyl
acid functional group
Amino
base functional group
Polymer Macromolecules
made of repeating units called monomers
Dehydration Synthesis (condensation)
building of polymer from monomer subunits
done by removing H2O molecule
forming polymer requires release of water
Hydrolysis
breaking polymer into monomer
done by inserting water molecule
Carbohydrates
monosaccharides are monomer subunits
all have a C:H:O ratio of 1:2:1
Disaccharides
2 monosaccharides
Ex. sucrose, maltose
Oligosaccharides
few monosaccharides (less than 20)
Polysaccharides
many monosaccharides
ex. starches, cellulose, chitin
Nucleic acids
monomer subunits are nucleotides
Nucleotide
consists of 5 carbon sugar, phosphate, nitrogenous base and carbohydrate inside the structure
Proteins
amino acids are monomer subunits
Amino acids
will ionize in water, backbone has nothing to do with properties
polar group in amino acid is dominant
Peptide bonds
joined through condensation reaction
bond between 2 or more amino acids
Intramolecular bond
within 1 protein structure
Primary protein structure
number and sequence of amino acids in a chain
Secondary protein structure
alpha-helix and beta plated sheets
Tertiary protein structure
primary and secondary structures put into a 3D showing
Quaternary protein structure
protein forms bond with other proteins
2 or more tertiary proteins bonded together
Intermolecular bonds
bonds that are between proteins
Protein function
determined by it’s structure and if misshaped it will not function correctly
incorrect amino acid sequence
wrong environmental conditions
Denatured
protein that has been damaged, unfolded, and doesn’t work
could be due to an H+ ion bonding to protein or raise in temperature
Functions of proteins
enzyme catalyst, defense, transport, support, motion, regulation, and storage
Saturated fatty acids
organized and can be solid at room temperature
all single bonds
animal fats and considered bad
Unsaturated fatty acid
liquid at room temperature
have one or more double bonds
plant fat like oil or fish and considered good
Amphipathic
2 sides; one nonpolar hydrophobic (tail) and one polar hydrophilic (head)
Lipids in water
micelle (come together to form a ball like shape)
form phospholipid bilayer
Phospholipid bilayer
2 layers
main separating layer from inside and outside the cell
nonpolar
fluid-mosaic
selectively permeable
Transmembrane protein
transport across membrane
cell communication
enzymes
Interior protein network (peripheral protein)
provide shape
works with cytoskeleton to move cell
Polysaccharides in phospholipid bilayer
help cells stick together
Oligosaccharides in phospholipid bilayer
act as cell identity markers
Cholesterol in phospholipid bilayer
help support and give structure to bilayer
hydrophobic
make cell membrane more flexible when cold and more rigid when warm
Simple Diffusion
passive transport - stuff easily passes through membrane
high to low concentration
small, non polar molecules
ex. oxygen, CO2, and steroids
Facilitated Diffusion
passive transport - transport things that cannot go easily through membrane
high to low concentration
larger items and ions
need use of proteins - channels and transport proteins
Osmosis
movement of water through a semipermeable membrane
passive transport
facilitated transport
protein is called aquaporin
some of the membrane is “leaky”
Hypotonic
lower solute concentration as the cell
i.e. higher water amount
Hypertonic
higher solute concentration as the cell
i.e. lower water amount
Isotonic
same solute concentration as the cell
Active Transport
low to high concentration
requires energy
requires protein
ex. Na+/K+ pump
Coupled transport (secondary active transport)
use stored energy in concentration to move other molecules against their concentration
Endocytosis
bring something into the cell
cell eating (taking in big substance) = phagocytosis
form of active transport
Exocytosis
release something from the cell
Why are cells so small
cells need to interact with their environment
surface area to volume ratio
if too small cell cannot interact with environment
the bigger the cell, the smaller the ratio
All Cells contain
genetic material, plasma membrane, and cytoplasm
Nucleoid
not membrane-bound, circular chromosomes, usually 1
prokaryotic (mostly bacteria)
Nucleus
membrane-bound, linear chromosomes, multiple chromosomes
eukaryotic (everything but bacteria)