semester 1 Flashcards
define population
all the individual items that can be studied
define sample
a selection from a population
define individuals
in a sample are sample units, subjects or cases
define the variable type: continuous
have an infinite number of values eg. length, weight, height
define the variable type: discrete (discontinuous)
have limited number of values + can be subdivided
define the variable distribution type: parametric
these can be plotted to follow a distribution model these can be discrete (poisson, binomial, neg binom, hypergeometric) or continuous (rectangular, uniform, chi^2, exponential, normal)
define the variable distribution type: non-parametric
can’t be assigned to any distribution + so can be less ‘powerful’
define the variable distribution variation: modality
a distribution can be uni or multi-modal
define the variable distribution variation: skewness
a distribution have symmetry, positive or negative skew
define the variable distribution variation: kurtosis
a distribution can be neutral, platy or lepto-kurtic
what’s the basic 3 of central tendency?
mean- sum all + divide by number of individuals
median-put in order + find one in middle
mode-most common one
what’s the basic 3 of variation?
- variance= s^2
- standard deviation= S
- standard error of mean
variance, SD + SEM step by step
-calculate mean
-write table that subtracts the mean from each observed value
-square each of differences
-sum all
-divide by n-1 where n is number of individuals. this is s^2
-square route to get S
-to get SEM divide S by square root of n
-
define variation
how far individuals are spread out in relation to each other
define standard deviation
how far observations are comparatively from a mean
what is required when using T test?
paired or unpaired data
what is a t-test?
tests whether there’s significant difference in means of 2 data sets. value obtained is compared to a critical value which helps determine how likely results were due to chance
what is the p value in a t-test?
gives the probability of any observed difference in measurement between the 2 groups having happened by chance
when is the null hypothesis rejected?
if there’s a difference between 2 groups (p<0.05)
what needs to be reported when doing a t-test?
- 1 vs 2 tailed test?
- p value + significance + level
- degrees of freedom
- t-value
- test of variance
what is linear regression?
- used to quantify how one set of variables relates to another
- used if relationship is linear between the variables
- 2 variables: dependent (response) y-axis vs independent (explanatory) x-axis
- dependent variable value dependent on independent value
- y=mx+c
- R^2 (goodness of fit)
how do you calculate C1?
C1=(C2V2)/V1
- C1, initial concentration
- V1, initial volume
- C2, diluted concentration
- V2, diluted volume
what are the beer-lambert equations?
A= ε x C x l
- A, absorbance (unitless)
- ε, absorption coefficient
- c, concentration of solution
- l, pathlength, ie width of curvette
when do you round using decimal places?
when using addition or subtraction
when do you round using significant figures?
when using multiplication or division
The subatomic particles found in atoms consist of which fundamental particles?
quarks and leptons
what is the atomic number equal to?
number of protons
what is the mass number equal to?
sum of protons and neutrons
what are isotopes?
2 of the same element differ in number of neutrons but have the same number of protons
what are electrons?
sub-atomic particles having almost negligible mass. electrons move around nucleus of atom with speeds close to that of speed of light
what are atomic orbitals?
regions in space where there’s high probability of finding electrons
define the 1s orbital
a spherical region of space close to and surrounding the nucleus where there’s high probability of finding electron
why is water important?
- most abundant substance in living systems, 75% human brain is water, 75% of tree is water
- normal metabolic cellular activity can only occur when cells are at least 65% water
- water + its ionisation products are critical determinants biomolecule structure and function, proteins, lipids, carbohydrates
what are some properties of water?
- melting point 0°C
- boiling point 100°C
- heat of vaporization 2,260J/g
- water in aqueous form still has high number of hydrogen bonds however, lifetime of each bond is very brief + then it’ll form a bond with different or same water molecule. known as flickering clusters
why is waters melting point high?
due to hydrogen bonding that can occur between these molecules. when water is in its ice structure + forming a crystal lattice it means each water molecule is making 4 hydrogen bonds
are hydrogen bonds unique to water?
no
describe hydrogen bonds
- special dipole, dipole bond between an electronegative atom + a hydrogen atom bonded to another electronegative atom
- relatively weak bonds, bond dissociation energy ~23KJ/mol
- always involves hydrogen atom
what are biologically important hydrogen bonds?
- between hydroxyl group of an alcohol + water
- between carbonyl group of a ketone + water
- between peptide groups in polypeptides
- between complimentary bases of DNA
what are amphipathic compounds?
- contain regions that are polar + regions that aren’t
- non-polar parts interact leaving polar parts on outside
- when mixed with water, hydrophilic regions interact with water + dissolve, whilst hydrophobic regions cluster together to form von der waals
- able to minimise hydrophobic interaction with water but maximise hydrophilic interaction with water to form stable micspelles
what are examples of amphipathic compounds in biology?
- phospholipid bilayer of cell membrane
- proteins + their 3D folding
- proteins interaction with phospholipid bilayer of cell membrane
what’s hydrolysis?
chemical reaction/ process in which chemical compound is broken down by reaction with water
what’s condensation?
reaction in which 2 molecular fragments are joined + a water molecule is produced
describe the dissociation of water
hydrogen atom of hydrogen bond may find itself closer to the oxygen atom of a neighbouring water molecule than to the oxygen atom of its own molecule. the covalent O-H bond in H2O molecule stretches + hydrogen bond between molecules shortens. eventually covalent O-H bond stretches so far it breaks + new O-H bond forms with neighbouring molecule. process creates 2 new species each of which has full electric charge
how many water molecules dissociate in pure water at room temperature?
1 in a billion