Chap 2 Chemistry of Life Flashcards
What is matter?
any material that takes up space
What is an element?
a substance that cannot be broken down by chemical means into other substances
What does the atomic number represent?
number of protons
What does the atomic weight (mass) represent?
number of protons and neutrons (avg)
What is an atom?
the smallest piece of an element that retains the characteristics of the element
List the three subatomic particles
Protons
Neutrons
Electrons
Where are the subatomic particles found?
Electrons - surrounding the nucleus
Protons and Neutrons - close together in the nucleus
What are the charges on the subatomic particles?
Electron - negative (-)
Neutron - none
Proton - Positive (+)
What are Ions?
When an atom either gains or loses electrons
What are Isotopes?
the number of neutrons vary among atoms of the same element
What are molecules?
two or more chemically joined atoms
What are compounds?
molecules of two or more elements
What determines chemical bonding?
electrons
In what way do electrons exist?
in energy shells/orbitals
When are atoms stablest?
when their outer shell has no vacancies
How do atoms fill vacancies in their outer shells?
bonding with other atoms
What is a Covalent bond?
electrons are shared
What is Electronegativity?
measure of an atom’s ability to attract electrons
Valency when looking at periodic table
Rows - number of energy shells
Columns - number of electrons
What determines the type of chemical bond formed?
electronegativity differences
Atoms with similar electronegativity form what kind of bonds?
nonpolar covalent
Atoms with some different electronegativity form what kind of bonds?
polar covalent
Atoms with very different electronegativity form what kind of bonds?
ionic
What is an Ionic bond?
a transfer of electrons
What creates an ionic bond?
the attraction between oppositely charged ions
Can some atoms be partially charged?
yes
What is a Hydrogen bond?
when an atom has a partial charge
What gives water its emergent properties?
hydrogen bonds
What is essential to life?
water
Unique properties of water
cohesive adhesive excellent solvent dissolves salt regulates temperature expands when frozen participates in chem rxns
What is cohesion?
tendency of water molecules to stick to one another
What creates surface tension on water?
cohesion
What is adhesion?
water molecules form hydrogen bonds with other molecules.
What can water dissolve?
Hydrophilic substances - Polar solutes, ions
What helps water dissolve most biologically important molecules?
its polarity
How does salt dissolve in water?
Neg charge (O) attracts positive (Na)
Pos charge (H) attracts negative (Cl)
Hydrogen bonds in water make it resist what?
temperature changes (cools and heats very slowly)
What happens when water freezes?
it expands and becomes less dense
What is a chemical reaction?
when two or more molecules (reactants) exchange their atoms resulting in different molecules (products)
What are life’s chemical reactions?
Photosynthesis
Respiration
What is the pH scale based on?
the amount of H+ in a solution
What pH do most chem rxns in a cell occur?
pH = 7
pH and H+ of acidic solution
pH = low
H+ - high
pH and H+ of basic solution
pH = high H+ = low OH- = higher than H+
What happens if an organism strays too far from its optimal pH?
it could die
What is the homeostasis pH of many organisms?
pH = 7
What does a Buffer Solution?
when pH is too high releasees H+ ion to lower pH
when pH is too low absorbs H+ ions to raise the pH
What is an organic molecule?
a molecule containing both carbon and hydrogen
What are the four categorized organic molecules needed for life’s processes?
Carbohydrates
Proteins
Nucleic acids
Lipids
What are organic molecules made up of?
functional groups
monomers
List the four functional groups
Hydroxyl -OH
Carboxyl -COOH
Amino -NH(2)
Phosphate -PO(4)^-2
What are monomers?
a single unit of a carbohydrate, protein, or nucleic acid
Monomers join to form what?
polymers
What joins monomers together
dehydration synthesis
During dehydration synthesis what happens with water?
a water molecule is released
What happens in dehydration synthesis?
enzymes form bonds between two monomers
What breaks polymers apart?
Hydrolysis
What happens in hydrolysis?
enzymes break bonds between monomers
During hydrolysis what happens with water?
a water molecule is needed for the rxn to occur
What do carbohydrates include?
simple sugars
polysaccharides
What are monosaccharides?
simple sugars; they are the monomers that make up carbohydrates
Examples of monosaccharides?
ribose, glucose, fructose
How are carbohydrates synthesized?
Dehydration synthesis (bonds two monosaccharides together forming a disaccharide) e.g. sucrose
How are carbohydrates broken down?
Hydrolysis (separates disaccharides into monosaccharides)
What are polysaccharides?
long chains of carbohydrates
Examples of polysaccharides
cellulose: structure
starch: energy
glycogen: energy
Proteins have many different what?
structures and functions
What are proteins?
the workers of the cells; they do almost everything
What are proteins made of?
amino acids
What are the monomers of protein?
amino acids
What is the general animo acid structure?
look up slide 32 of lecture 4
How many different amino acids are there in nature?
20
What determines the properties of a protein?
the properties of the amino acids (each has its own R-group)
How are Proteins synthesized?
dehydration synthesis (binds two amino acids together forming a dipeptide)
What is a long chain of amino acids called?
polypeptide
What breaks down proteins?
hydrolysis (separates dipeptides and polypeptides into individual amino acids)
How do polypeptides form proteins?
they fold up
Denatured proteins lose what?
their shape
The function of a protein depends on what?
shape or tertiary structure
Primary structure of proteins
amino acid sequence of polypeptides
Secondary structure of proteins
localized areas of coils, sheets, and loops within a polypeptide
Tertiary structure of proteins
overall shape of one protein
Quaternary structure of proteins
overall protein shape; arises from the interaction b/w the multiple polypeptides that make up the functional protein
What do nucleic acids do?
carry genetic information
Give examples of nucleic acids
DNA
RNA
The primary structure of each protein in a cell is determined by?
the nucleic acids
What are the monomers of nucleic acids?
nucleotides
What are the three parts of a nucleotide?
phosphate group
five-carbon sugar
nitrogenous base
How many different possible nitrogenous bases are there?
5
List the 5 nucleotides
Adenine (A) Cytosine (C) Guanine (G) Thymine (T) Uracil (U)
Which nitrogenous base does only DNA use?
Thymine (T)
Which nitrogenous base does only RNA use?
Uracil (U)
Which nitrogenous bases does both DNA and RNA use?
Adenine (A)
Cytosine (C)
Guanine (G)
How are nucleic acids synthesized?
dehydration synthesis (binds two nucleotides together forming a dipeptide)
How are nucleic acids broken down?
hydrolysis
Characteristics of DNA
double helix
Nitrogenous baes held together by hydrogen bonds (A to T, G to C)
Function: store genetic info
Characteristics of RNA
single stranded
nitrogenous bases: A to U, G to C
Function: caries DNA information to protein-synthesizing organelles
Are lipids built from chains of monomers?
No
Are lipids hydrophobic or hydrophilic?
hydrophobic
Classes of lipid
Triglycerides
Steroids
What are triglycerides?
fats and oils
energy rich
for long term energy storage
What are steroids?
have four ring structure
How are Triglycerides formed?
by covalently attaching three fatty acid molecules to a glycerol molecule
What links fatty acids to the glycerol?
dehydration synthesis
How are triglycerides broken down?
hydrolysis
What are saturated fatty acids?
all carbons are bonded to four other atoms. gives it a straight shape
What are unsaturated fatty acids?
contains at least one double bond. gives it a bent shape (prevents them from packing close together)
At room temp what are saturated fatty acids?
solid
At room temp what are unsaturated fatty acids
liquid
At room temp what are trans fats?
solid
Cholesterol is what?
a lipid in the steroid class
What does cholesterol do?
regulates the fluidity of animal cell membranes
also used to synthesize many sex hormones
