a hypothesis with a large body of evidence to support it
a well-tested theory that has become an immutable fact
What are experiments designed to do?
to determine if the null hypothesis can be refuted
a condition that exists in more than one possible state, e.g. temperature,pH, exposure to sunlight etc.
variables that must be held constant in an experiment
variables that are allowed to fluctuate, the independent variable is the subject of the experiment only one thing.
a portion of the experiment that does not receive a treatment, this shows a baseline for comparison with the portion of the group that receives the treatment
a sugar pill used in drug treals, an individual in the trial will be unaware if they are receiving the treatment or a placebo to eliminate psychosomatic vareables
some test subjects will respond to a placebo because they are told it is an actual treatment
the experimenter(s) do not know whether an individual subject is getting the treatment ora placebo unti9l the study is complete, this eliminates experimenter bieas as a variable.
8 characteristics of life on earth
5. Metabolism=use of energy
6.Homeostasis=maintaining a steady state
7. Evolution=adapt to environment
8. Carbom/water based=organic molecules
the number of protons
the number of protoms and neutrons
atoms with the same number of protons but different numbers of neutrons
one atom takes an electron from another atom to create an elctrical attraction
two atoms share electrons to create a bond
water molecules "stick" to each other
water molecules form hydrogen bonds with other molecules
chemicals that cause the pH of water to decrease
chemicals that cause the pH of water to increase
solutions that have chemicals in them that resist changes in pH
examples of oganic elements
C H N O P & S
Carbohydrates, proteins, Nucleic acids,Lipids
single sugar molecule
two linked sugar molecules
a small chain (3-100) of sugar molecules
a long chain of sugar molecules, e.g. starch,glycogen,cellulose
energy storage, structural, in plant and bacteria cell walls
two linked amino acids
proteins are polymers of amino acids
a chain of amino acids
the sequence of amino acids
localized structure comsisting elements such as the alpha- helix and beta-pleated sheet
the three dimensional structure of a single polypeptide
the total proteirn shape that inludes multiple polypeptides
the capacity o do work
energy of position
energy of motion
Thermodynamics Law 1
energy can neither be created nor destoryed it can only change forms
thermodynamics law 2
anytime energy changes form some energy is lost as heat
the sum total of all chmial reaction in a cell or organism
the reaction requires an input of energy
the reaction releases energy
some chemical reations move in both the forward and reverse directions
this is the part of the encyme where the chemical reaction occurs.
are proteins that have large complicated structuresEncymes grab the reactants and position them so that they will react to form products. After the product are formed the enzyme releases them the suffix- ase
reactants in the enzyme ataized reaction
energy that must be added to a reation to get it started this applies to exergonic reactions as well as endergonic
enzymes work by lowering the activation energy of a reaction, this makes the reaction go faster however it does not effect the equilibrium
non-protein chmicas found in the active site that faciitate function
the end product of a series of reactions inhibits the first enzyme in the series
the end product of a series of reactions activates an enzyme in the series
new chapter 8 & 9
cell cycle phases
Phases a cell undergoes cell division and replication of DNA
G1 first phase
The first growth phase is when the cell carries on anabolism to prepare the cell for synthesis and subsequesnt division.
if a cell does not need to divide it stops early in the G1 phase to enter G0 where it will not divide.
the synthesis phase is when the cell replicates in DNA
G2 second growth phase of cell
during the second growth phases the cell prepares for division by condensing the DNA and assembling the proteirns need for diviosn.
the separating of the two identical copies of DNA
the physical separation of a single parent cell into two daughter cells.
In order for the cell to divide it must duplicate in DNA in a process called replication,it is important to know that double stranded DNAe is anti-parallel
How do enzymes help in the Replication of DNA?
Denzymes carry our replication of DNA in a specific sequences.
Mitosis is a four step process
opens up the double helix by breaking the hydogen bonds
single stranded binding proteins
bind to the single stranded DNA to prevent it from reforming the double helix
adds a short sequence of RNA to begin the duplication process
synthesis the DNA polymer from free nucleotides, the nucleotides that are added must pair with the existing strand according to chargraff's rule. DNA can only wrk in 3 to 5 direction
seals breaks in the sugar phoshate back bone
The strand of DNA that is synthezied continually
the other strand which is synthesized in fragments called Okazaki
1. DNA condenses in prep of cell division
DNA wrapped around proteins called histones.
is the genetic term for all of the cells DNA and associated proteins.
before cell division each of the individual segments of DNA condenses into these.
After DNA duplicates there are now two identical segments chomatids "sister".
The identical chromatids are attached to each other by a DNA protein complex.
a specialized cytoskeleton structure that separates the chromatids begins to form(during prohase.
the membrane around the nucleus breaks down.
the miotic spindle fibers attach to the chromosomes at proteins on the centromeres called kinetochores.
themiotic spindle pulls apart the chromatids, this breaks the centromeres
the chromatids move to opposite poles of the cell .
The nuclear membrane reforms
the chromosomes decondense
the miotic spindle breaks down
Mitosis is followed by what?
Cytokinesis the physical separation of the parent cell into two daughter cells This occurs because the cell membrane contracts at the equator until the two new cells are formed.