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105 Cards in this Set

  • Front
  • Back
living things. organisms are composed of chemicals
the chemistry of living organsims
smallest units into which something can be subdivided and still have the essential chemical properties of that substance.
substances that cannot be broken down chemically into simpler substances
discovered by dalton. they are the smallest unit of an element that still has the chemical properties of that element
atomic theory
most important of all chemical theories. Dalton;s principles for the basis of theory.
shows the number of atoms of each element in a molecule
makes it easier to understand how something is built and how it operates, but not the real thing
conclusions that follow logically from laboratory data
what are molecules made of?
atoms that have chemically combined
about 97% of the compounds present in organisms contain only what six elements?
carbon, hydrogen, oxygen, phosphorous, nitrogen, and sulfur.
subatomic particles
these particles are smaller than, or "below" the level of atoms
carries a negative charge in atom
carries a postive charge in the atom
has a neutral charge in the atom
elecron shells
energy levels or attraction surrounding nucleus
atoms of the same element that differ in their number of neutrons
protons and neutrons are in the nucleus of the atom aile electrons are where?
around the nucleus and are attracted to the positive nucleus.
electrons in shells near the nucleus are held more tightly than?
those in shells farther from the nucleus.
chemical bonds
the attraction, sharing, or transfer of outer shell electrons from one atom to another.
chemical reactions
involves the making and breaking of chemical bonds
basic units of life
conservation of matter
states that matter is neither created nor destroyed in chemical reactions
activation energy
energy needed to get a chemical reaction started
chemical equations
a representation of chemical reactions as short statements
cell membrane
in an animal cell it encloses the cell
chemical reactions are important to the cell for what two reasons?
1. they are the only way to form new molecules that the cell requires for such things as growth and maintenance.
2. the making and breaking of bonds involves changes in energy. as a result energy may be stored, used to do work, or released.
is an atom or a molecule that has acquired a positive or negative charge as a result of gaining or losing electrons
ionic bonds
the attracion between oppositely charged ions.
covalent bonds
two atoms share one or more pairs of electrons
polar covalent bond
if the electrons of a bond are not shared equally
electrons in a molecule are shared equally
hydrogen bond
a weak attraction between hydrogen atoms and oxygen, nitrogen, or flourine aroms; hold together the strands of DNA in their double helix.
pH scale
the level of Hydrogen and hydroxide ions in soution is described by this range of numbers
has more hydrogen than hydroxide ions and has a low pH.
has a high pH and has more hydroxide ions
when a nonionic compound, such as water, is converted to ions.
mixture in water
logarithmic scale
change of one pH unit is equal to a tenfold change in the level of H+ ions
structural formula
models that show both the number and arrangement of atoms in molecules.
Why is pH important to biology?
because the pH of a cell's interior helps regulare the cell's chemical reactions
refers to compounds that are made up of carbon atoms and other elements; origainlly thought to be associated only with living things.
a large complex molecule
carbon atoms can combine in large chains that form what
carbon skeleton of macromolecules
other atoms and molecules can attach to the carbon skeleton which give what to each macromolecule?
a particular structure and therefore a particular function
what are the four most important classes of molecules in living things?
carbohydrates, lipids, proteins, and nucleic acids
an orgain compound made of carbon, hydrogen, and oxygen with the hydrogen and oxygen atoms in a 2:1 ratio; examples are sugars, starches, and cellulose.
a simple sugar with three to seven carbon atoms in its carbon skeleton
a double sugar composed of two chemically bonded simple sugars
a complex carbohydrate composed of many simple sugars chemically bonded in a chain; for example starch and cellulose
long chains of monomers
sub-units that make up polymers
most organisms use what as a source of energy?
the energy in molecules is contained where?
in the bonds of the molecules itself.
sugar phosphate
biologically important sugars often have a phosphate group attached to the carbon skeleton
a fat, an oil, a wax, or a fatlike compound that usually ahs fatty acids in its molecular structure; an important component of the plasma membrane
saturated fatty acids
fatty acids with single bonds
unsaturated fatty acids
fatty acids with double bonds
what are the two functions of lipids?
1. long term storage of energy
2. carbon building of structural parts of cell membranes
biologically important properties of simple fats depend on what?
their fatty acids and properties of fatty acids depend on the length of the carbon chains and the type of bonds between the carbons
when do phospholipids form?
when a molecule of glycerol combines with two fatty acids and a phsophate group. for celluar membranes with proteins which are critical to cell survival because they separate a cell's internal chemical reactions from the outside environment.
an organic compound composed of one or more poplypeptide chanis of amino acids; most structural materials and enzymes in a cell are proteins
amino acids
an organic compound composed of central carbon atom to which are bonded a hydrogen atom. an amino acid group, an acid group, and one variety of other atoms or groups of atoms; the building blocks of polypeptides and protiens
peptide bonds
a covalent chemical bond formed between two amino acids; bonds the amino group of each amino acid to the carboxyl group of the next.
a long chain of chemically bonded amino acids
primary structure
the first level of organization of a protein or nucleic acid; refers to the specific sequence of amino acids or nucleotides.
secondary structures
in proteins, the shape of a folded polypeptide chain; results from hydrogen bond between adjacent parts of the molecule
tertiary structure
the three dimensional folded structure of a polypeptide or protein molecule
the tendency to repel water; substances that are hydrophobic are non-polar and cannot hydrogen bond to water
quaternary structure
the shape of a complex protien defined by the three-dimensional arrangement of its polypeptide sub-units.
what is the protiens most essential role?
what determines the three dimensional shape in a protein
the sequence of amino acids
nucleic acids
DNA or RNA; a polymer of nucleotides important in encoding instuctions for cell processes.
a subunit of DNA or RNA composed o a 5-carbon sugar, a nitrogen-containg base, and a phosphate group
ribonucleic acid; a nucleic acid similar to DNA but hagin the sugar ribose rather than deoxyribose and uracil rather than thymine as one of the bases
deoxyribonucleic acid; the hereditary material of most organisms; a nuclic acid composed of deoxyrobose sugar, phospate groups, and four nitrogen containg bases
what is the source of genetic information in chromosomes?
nucleic acids
What are the four different bases of DNA
adenine, thymine, guanine, or cytosine
What is different about RNA as far as bases?
has uracil rather than thymine
What is the difference in shape for DNA and RNA?
DNA always occurs in double helic. RNA is single stranded.
James Watson and Francis Crick proposed what?
a model for the structure of DNA molecules that is still accepted todaay.
Who found the DNA was a double helix?
Rosalind Frankilin and Maurice Wilins.
What is a double helix composed of?
two long chains of nucleotides which are connected between their DR sugars.
the fundamental physical unit of heredity, which transmits a set of specifications from one gereration to the next; a segment of DNA that codes for a specific product.
DNA stores informationin a code consisting of uits that are three nucleotides called?
triplet codons
The sequence of amino acids determines its shape which then determines the function. What is the function?
1. perform most of the chemical reactions that keep cells alive.
2. can be copied and passed through inheritance from one generation to the next.
How do monomers connect?
dehydration synthesis.
what is dehydration synthesis?
bringing out hydrogen and HO out which forms H2O. which makes an available bond and polymer gets bigger.
covalent bonds connecting monomers are disconnected how?
using hydrolysis
what are carbs made of?
sugars and polysaccharides
what is the monosaccharide formula?
what is the formula for glucose?
how are sugars clasified?
by the number of carbons in the backbone.
what is an isomer?
same molecular and empirical formula but different structural formulas.
what makes something rich in energy?
carbon and hydrogen
what is another name for starch?
made only by plants. energy storage.
made by plants. complex polysaccharide. structural thing in plant's cell walls. commenly called fiber.
how animals store glucose. Eventually stores as body fat.
Why are lipids an exception to macromolecules?
because they dont form polymers
3 fatty acids + 1 glycerol =
Who proposed a model for the structure of the DNA molecule that is still accepted today?
James Watson and Francis Crick
Who found that DNA was a double helix?
Rosalind Franklin and Maurice Wilkins.
What is a double helix composed of?
two long chaings of nucleotides which are connected between their sugars.
the fundamental physical unit of heredity which transmits a set of specifications from one generation to the next; a segment of DNA that codes for a specific product.