lecture 3b&4 Flashcards
what is the t test used for*
to test for the significant difference between the means of two groups
when do you use the unpaired t test*
when comparing independent samples (from different individuals)
when do you not use the unpaired t test*
data comes from the same individual before and after
less or more than two groups
no averages
11 steps for t test*
- state the null and alternate hypotheses
- list the data of the control and experimental groups
- record the number of replicates for each group
- calculate the mean of each group
- calculate the variance of each group
- calculate the standard deviation
- calculate the t value
- choose a significant value (0.05)
- figure out if you should do a one tailed or two tailed test
- find the critical t value using the table
- compare both t values
what are degrees of freedom*
number of categories or classes minus 1
opportunity for change
what is the formula for df*
df = (n1 - 1) + (n2 - 1)
what type of hypothesis is one tailed*
directional
what type of hypothesis is a two tailed hypothesis*
non directional
all living things contain
carbohydrates, lipids, proteins and nucleic acids
organic compounds contain
carbon (carbon backbone)
properties of an organic molecule depend on
arrangement of the carbon skeleton (straight, branched, rings with long or short bonds)
functional groups (give molecule distinct chemical properties)
single unit of molecules
monomer
chain of monomers
polymer
how do you build polymers
dehydration synthesis where water is released which forms a new bond
what is hydrolysis
when water is added and a bond is broken in the polymer chain
what is a carbohydrate
sugar
how are carbohydrates stored in humans
glycogen
how are carbohydrates stored in plants
starch
what are carbohydrates used for
broken down for cellular respiration
short term energy reserves in muscles
structure (cellulose)
carbs are found in which ratio
CH^2O= 1:2:1
monomers are which type of carbs
simple sugar
polymers are which type of carb
complex sugars
what is a monosaccharide
monomer of carbohydrates
types of monosaccharides
glucose, galactose, fructose
what are disaccharides
two linked monosaccharides
what is sucrose
glucose plus fructose
glucose plus galactose
lactose
glucose plus glucose
maltose
what are polysaccharides
polymers of monosaccharides
types of polysaccharides
storage and structural carbohydrates (starch, glycogen & cellulose, chitin)
what is the main feature of lipids
they are hydrophobic
function of neutral fats
long term energy reserve in fat tissue
maintain body temperature through insulation
protect vital organs
buoyancy
structure of neutral fats
1 molecule of glycerol
1-3 molecules of fatty acids
3 molecules of fatty acids is called
triglyceride
what is the difference between saturated and unsaturated fatty acids
saturated fatty acids have no double bonds between the carbon atoms while unsaturated fatty acids do have double bonds
saturated fatty acids are then easier to stack since there is no bend in the chain
differences between cis unsaturated and trans unsaturated fatty acids
more bend for cis
function of phospholipids
major constituent of cell membranes
structure of phospholipids
2 molecules of fatty acids
1 glycerol molecule
1 phosphate molecule
what is an amphipathic molecule
a molecule that has a side which is hydrophilic and a side that is hydrophobic (phospholipid)
which part of the phospholipid is attracted/repelled by water
the head is attracted to water (hydrophilic)
the tail is repelled by water (hydrophobic)
how does the phospholipid assemble
into a double layer that has the hydrophobic portions facing each other
what are the functions of steroids
cell membrane (cholesterol)
vitamins
hormones
structure of steroids
made from sterol (multiple rings of carbon)
what do proteins do
pretty much everything (transport, enzymes, antibodies,storage, etc)
proteins are made from
amino acids
what is a polypeptide
a polymer of amino acids
structure of amino acid
2 functional groups (amino and carboxyl)
1 variable group (R)
a hydrogen
all around a carbon
how do you link amino acids to make a polypeptide and where
dehydration synthesis/condensation reaction
link at the n-terminus and the c-terminus (amino and carboxyl ends)
is the polypeptide polar
yes
why is the shape of a protein important
the shape of the protein determines its function
how many levels of structure are there in proteins
- primary
- secondary
- tertiary
- quaternary
what is the primary structure of proteins
the specific and unique sequence of amino acids that make up a polypeptide
how is the unique sequence of a.a. determined in the primary structure
by the nucleotide sequence of the gene that encodes the protein (genetically determined)
what happens to the protein if an amino acid get switched
it will change the form of the protein which will affect how it performs its function
what is the secondary structure of proteins
the folding and coiling of a sequence of amino acids within a polypeptide
what causes the folding/coiling of proteins
hydrogen bonds between the amino and carboxyl groups in the polypeptide’s backbone
what is an alpha helix and where do the h-bonds occur
coil
bond occurs every fourth amino acid
alpha helix characteristics
common in fibrous proteins (hair, skin, nails)
h-bonds are strong when there are many bonds (weak individually)
able to stretch
what is a beta pleaded sheet and where do h-bonds occur
pleated sheet of polypeptide lying parallel
h-bonds between amino and carboxyl group
beta pleaded sheet characteristics
make up core of globular proteins and some fibrous proteins like fibroin (spider silk)
strong and flexible but not elastic
can twist
how is the distance between pleats decided in beta p.s.
the strong covalent bonds of the polypeptide backbone
what is the tertiary structure of a protein
the forces holding a singular polypeptide together
what determines the the 3D structure of a single polypeptide
- hydrogen bonds
- ionic bonds
- hydrophobic interactions
- covalent/disulphide bonds
what are ionic bonds
results from ions/ plus minus charged particles
what are hydrophobic interactions
hydrophobic molecules interacting with each other
what is a disulphide bond
bond between sulphide groups on amino acids (covalent bond)
what is the quaternary structure
the fusion of two or more polypeptide
how is the quaternary structure formed
by the interactions among polypeptide chains
has the same types of bonds as the tertiary structure
what is a monomeric protein
protein made of a singular polypeptide chain (no quaternary structure)
what is an oligomeric protein
protein made of two or more polypeptide chains
what is denaturation
when a protein breaks down by unravelling or changing shape (permanent or temporary)
what happens during denaturation
disruption or destruction of secondary and tertiary structures
disrupts alpha h. and beta p.s so becomes a random shape
primary sequence remains due to the reaction not being strong enough to break the peptide bonds (except at very high temp.)
what can cause denaturation
heat and alcohol
ribosomes characteristics (3)
displays quaternary structure
uses RNA to make other proteins
made in nucleolus
