molecules of life
mass:
a measure of the amount of material in an object
what are the 3 forms of mass?
solid
liquid
gas
element:
a substance that cannot be broken down into other substances by chemical reactions
all atoms with the same number of ____ in the nucleus are all of the same _____
protons
element
atomic number:
the number of PROTONS in the nucleus
top number
mass number:
the TOTAL number of PROTONS and NEUTRONS present in the nucleus of an element
bottom number
what are the 4 most abundant and important elements that make up about 96% of the weight?
oxygen (O)
carbon (C)
hydrogen (H)
nitrogen (N)
compounds:
elements combined together
atom:
smallest unit of matter
what 3 subatomic particles make up an atom?
proton
neutron
electron
proton:
positively charged (+)
electron:
negatively charged (-)
neutron:
neutral/no charge
what determines the element?
protons
what participates in chemical reactions?
electrons
what determines isotopes?
neutrons
what is an atom when the protons and electrons are equal?
it is neutral
what moves around the nucleus?
electrons
nucleus:
the center core of an atom that contains neutrons and protons
isotope:
atoms of the same element that have different number of neutrons
chemical bonds:
atoms transferring or sharing electrons
what are the three types of chemical bonds:
ionic bonds
covalent bonds
hydrogen bonds
ionic bonds:
when an atom gains or loses and electron
always polar; electrically charged
distinct positive and negative ions that attract each other
table salt
covalent bonds:
when 2 atoms share electrons
hold atoms together in a molecule
formaldehyde
hydrogen bonds:
polar molecules with an uneven distribution of charge
attraction between a covalently bonded hydrogen atom and another atom taking part in a separate covalent bond.
chemical reactions:
process of breaking down or forming new chemical bonds
reactant:
the starting material
product:
the end material
matter cannot be ____ or ____
created
destroyed
what are water’s 4 life-supporting properties
cohesion
ability to moderate temperature
ice floats
being the universal solvent
cohesion:
the tendency of molecules of the same kind to stick together
what makes water cohesive?
hydrogen bonding
surface tension:
measure of how difficult it is to stretch or break the surface of a liquid
evaporated cooling:
when a substance evaporates and the surface of the liquid remaining behind cools down
solution:
a liquid consisting of a homogenous mixture of 2 or more substances
solvent:
the dissolving agent
solute:
the dissolved substance
water does not mix with ______/_____
oil/fat
acid:
chemical compound that releases H+ to a solution
pH level BELOW 7
water in solid form is _____, ______, and ______
less dense
further away
moves slower
base:
a compound that accepts H+ and removes them from a solution
pH level ABOVE 7
pH scale:
measures the acidity of a solution
each pH unit represents a ______ change in the concentration of H+
tenfold
what is pH 7
neutral
lactose:
the main sugar found in milk
lactose intolerance:
the inability to properly digest lactose
organic compounds:
carbon-based molecules
carbon mostly bonds with what other elements
hydrogen
oxygen
nitrogen
polymer:
made by stringing together many smaller monomers
monomer:
subunit of a polymer
dehydration reaction:
removes a molecule of water to line 2 monomers together
hydrolysis:
adds water to breaks down molecules
digestion is an example of what kind of chemical reaction?
hydrolysis
4 types of macromolecules:
carbohydrates
lipids
proteins
nucleic acids
carbohydrates:
sugars and polymers of sugars
primary source of dietary energy
hydrophilic
hydrophilic:
water-loving
monosaccharides:
the simplest carb molecule
glucose:
the universal food
disaccharide:
double sugar from two monosaccharides by dehydration reaction
sucrose:
when glucose and fructose are combined
ex > table sugar
lactose:
combination of galactose and glucose
ex > milk sugar
maltose:
2 glucose linked together
polysaccharides:
3 or more monosaccharides
glycogen:
animal starch
glycose is ______ to _____ when u need energy
broken down
release glucose
cellulose:
the most abundant organic on Earch
ex > grass , wood
lipids:
fats
hydrophobic: water-resisting
saturated fats:
do not have a double bond
maximum number of hydrogens
ex > butter
unsaturated fats:
have double bond
has fewer than the maximum number of hydrogens
ex > oils
steroids:
lipid with 4 carbon rings and no fatty acid tails
polarity:
Separation of charge into positive and negative regions.
fat:
a triglyceride
cholesterol:
key compenent of a cell membrane
functions of fat:
energy storage
cushioning
insulation
proteins:
polymers of amino acid monomers
account for 50% of the dry weight of most cells
instrumental in almost everything you do
5 function of protein:
structural proteins > provide support
storage protein > provide amino acids for growth
contractile proteins > helps movement
transport proteins > help transport substances
enzymes > help chemical reactions
how many amino acids make up proteins?
20
what enables the molecule to carry out its specific functions?
the proteins 3D structure
what can a change in the sequence do to a protein:
affect the proteins ability to function
3 attachment groups for amino acids:
carbon group
amino group
hydrogen atom
how do cells link amino acids together?
dehydration reactions
nucleic acids:
macromolecules that store information
polymers made from monomers called nucleotides
polypeptide chains:
long chains of amino acids linked by dehydration reactions
2 types of nucleic acids:
RNA
DNA
DNA:
genetic material inherited from parents
gene:
discrete unit of inheritance encoded in a specific stretch of DNA that programs the amino acid sequence of a polypeptide
4 nitrogenous bases used to make up DNA
adenine(A)
thymine (T)
guanine (G)
cytosine (C)
which nitrogenous bases pair together every time?
A with T
G with C
3 parts that make up each nucleotide:
five-carbon sugar
phosphate group
nitrogen-containing base