yr 12 sac 1
what are rhe different types of scientific methodology
case study
controlled experiment
correlation study
fieldwork
modelling
product/process or system development
literature review
simulation
What is a case study
an investigation of particular activity, behaviour, event, problem
includes eal or hypothetical situation
what is classfication/identification
allows to classify typically living things through grouping, thus naming them
what is a controlled experiment
all factors that could affetc the DV are kept constant except for IV
includes extraneous/controlled variables
what is a control group
the group that is compared to the results
thus smae conditions without the IV
provides baseline to assist in detecting if IV is having effect
what is a correlation study
when study detects if one factor influences the other
positively correlated if both increase/decrease together
if does have an effect, this is causation, or cause and effect
imp as can have correlaton but not causation
what is fieldwork
research undertaken outisde of the labrotory
direct observation and recording sightings (time consuming)
instead, sampling techniques often used
what are some sampling techniques
quadrant sampling, transect and capture-work-recapture
What is modelling
visualisation models used to test/explain theories and to desribe the function/structure of an object/concept or system
to predict any additional outcomes
What is a product, process or system development
objects/processes/systems used to assist in organisms meeting their biological demands/requirements
this includes hearing aids and aritifical limbs
what is literature review
collation/analysis of secondary data related to other peoples findings and/or viewpoints
to question/provide background info
what is a simulation
the use of a odel to simulate whole of part of a system
to gain knowledge of its functioning
can alter variables to predict its response
What is a protein
one or more polypeptides
many control metabolic proceses
What are catalysts
enzymes (biological catalysts)
which are proteins made up of amino acid chains
what do catalysts do
increase rate of reaction without being used up
What is a proteome
all proteins in a single cell or organism
what is proteomics
the study of the proteome
What are amino acids
the variable group R
a subunit of polypeptide bonds (via condensation polymerisation)
what is condensation polymerisation
to join and dispell water
what makes up proteins/enzymes
amino acids
what do amino acids contain
essential carbon molecule
with amino group and caboxyl group (and hydrogen)
what is the primary structure
the nonfunctional sequence of amino acids determines by dna sequence
all proteins have this
how is the primary structure formed
translation as the DNA codes for the structure
what is the secondary structure
the primary but with folds as protein coils due to R group interactions held together by hydrogen bonds
all proteins have this
what types of coiling are there for seconday structures
alpha helix (coil/spiral)
beta pleated sheet (folding/fan)
random coilling
What is the tertiary structure
further folding/coiling/twisting
held together by H/ionic bonds and hydrophobic contact and disulphide bridges
these are critical for protein structure
all proteins have this
what happens to the structures when protein denatures
shape is lost and thus secondary and tertiary structures are lost, meaning it cannot function
what are quaternary structures
two or more polypeptides joining to form a mature protein
eg. haemoglobin or collagen
created by H, ionic anc covalent bonds
how do structures work
they are needed for the protein to function, as the interactions and bonding allow function
if it has one a more intense structure, it also has the less intense ones (if secondary, has primary etc)
What are pathways for biochemical reactions
chemical bonds forming/breaking
atoms rearranging
molecules gained/splitting
what is enzymes relevance within activation energy
all chem reactions require input of energy to start (activation)
enzymes lower this activation energy
thus change rate of biochemical reactions
what happens when enzymes lower activation energy
more substrate molecules (reactants)/ enzymes have enough energy to react
thus enzymes=efficient
what are the features of an enzyme
most consist of 2 or more polypeptide chain subunits
thus quaternary structure
the enzymes active site
all enzymes have this
small area w/3d shape
completemnary to its substrate molecules
sire where substrate binds to enzyme at the binding site
what is the relevance of the active site
it forces temporary enzyme substrate complex
this can be shown in fructose biphosphate aldolase (refer to book)
what is catabolic
to break down
How can the reaction rate for chemical reactions be increased
raise temp
increase conc of reactant
increase SA:V
add catalyst
How can the reaction rate for BIOchemical reactions be increased
raise temp
change pH
increase substrate conc
effect of low temp on enzyme activity (look up graph right now)
all have optimum range
reduced reaction rate
less kinetic energy (which means less colliding which means less reaction occuring)
effect of high temp on enzyme activity (look up graph right now)
reduced reaction rate
denaturisation occurs, losses secondary and tertiary structure thus cannot react
How is the substrate concentration relevant
increase means increase rate of reaction
until a plateau as all enzyme active sites are occupied
enzyme to substrate complxes must dissociate before another reaction can occur
thus limiting rate
relevance of enzyme conc
directly increase rate of reaction until a plateau once all substrates are being interacted with
they do have a higher affinity for theyr substrate to reach max rate faster
What is the relevance of pH in enzymes
enzymes have limited pH range
most have optimal range of 7.0-7.4
moving away from this alters bonds in enzymes (denaturation)
as change shape = prevent functionality
complete inhibitors
compete with substrate
have similar shape as substrate
bind to active site, preventing substrate
thus rate of reaction decreases
concentration affects this
can be reversed
non-competetic inhibitors
binds with enzyme at allosteric (behind) site
thus causes conformational change in active site
thus substrate cannot bond
not competing for active site, thus conc does not affect as fixed percent always inactivated
can be reversesd
irreversible inhibition
substrate is permanently blocked from active site
theoretcal experiment design results (based on the 5 marks)
IV
DV
2 controlled variabls
control group
repeat trial 10 or more times
what is condensation polymerisation (look up an image of this now)
when monomers join together and release a small molecule, very likely water, as a byproduct
What is a nucleic acid
a polymer of nucleotides (DNA/RNA)
encode instructions for protein synthesis
What is a nucleotide
a monomer
includes a phosphate group, deoxyribose sugar (ribose in RNA) and a nitrogenous base
Comparison meaning in bio questions
give similarities and diff
contrast questions in bio meaning
give differences
similarities between DNA and RNA
both have a sugar, phosphate and base
both store, transmit and express genetic info
differences between DNA and RNA
DNA has less oxygen, a deoxyribose sugar, and has Thymine
RNA has more oxygen, a ribose sugar, and has Uracil
Structure of DNA
look up an image please
two chains of nucleotides running antiparallel
5' end (phosphate end) attacted to sugar
3' end is end of sugar
hydrogen bonds form between complementary bases
when DNA combined with histones/other proteins what occurs
condenses to form chromosomes
Structure of RNA
single stranded chain of nucleotides
same as DNA in that it is built off of sugar phosphate backbone but only one set of this
What is mRNA
messenger RNA
carries genetic msgs from nucleus to ribosomes
msgs translated into proteins
what is rRNA
ribosomal RNA
joins with proteins to make ribosomes in cytosol
What is tRNA
transfer RNA
carries amino acids to ribosomes
then used to construct proteins
anticodon binds to complimentary codon on the mRNA
What is a codon
a group of three nucleotides
what is an anticodon
complimentary nucleotides to the codon given
What is genetic code
a triplet code of nucleotides that elicits a specific amino acid
is genetic code universal?
Yes, it is degenerate, meaning multiple codons can be for the same amino acid and
the same amino acids are present in all life
What is gene expression
when DNA is converted into proteins (protein synthesis)
What are the steps of gene expression
transcription of DNA to pre-mRNA
RNA processing of pre-mRNA to mRNA
translation of mRNA to proteins
what is the template strand
the strand of DNA that is used in protein synthesis
the other is the coding strand
What is transcription
when the genetic instructions from DNA are copied into mRNA
so that it can leave the nucleus
What are the steps of transcription
1. RNA polymerase protein attaches to sequence of DNA upstream
DNA unqinds, exposed base of template strands
2. RNA polymerase moves along DNA from 3' to 5'
bringing complementary nucleotides into place
3.at end of coding region, pre-mRNA released (A pairs w/ U etc)
What are the steps of transcription
1. RNA polymerase protein attaches to sequence of DNA upstream
DNA unqinds, exposed base of template strands
2. RNA polymerase moves along DNA from 3' to 5'
bringing complementary nucleotides into place
3.at end of coding region, pre-mRNA released (A pairs w/ U etc)
What is RNA processing
post-transcriptional modification
introns are spliced out
exons are spliced together
methylated guanine cap added to 5' end
poly A-trail added to 3' end
thus mature mRNA moves to cytosol
What are introns
pieces of pre-mRNA removed and arent translated
this is due to their function being elsewhere
what are exons
the pre-mRNA that remains after the introns are spliced out
what does the methylated guanine cap do
increases stability
protexts from enzyme attacks
helps attach to ribosome
what does poly A-tail do
helps mRNA leave the DNA
increases stability
what does post-transcriptional modification look like
look up image now please
What is alternative splicing
exons may be removed by spliceosomes
resulting in proteins with different size, sequence and function
What is translation
mRNA decoded and translated into amino acids
which form polypeptide chains
What are the steps of translation
1. mRNA strand read codon by codon
2.amino acids brought to ribosome by tRNA
each tRNA having an anticodon
3. ribosom moves along mRNA
tRNA brings amino acids and these amino acids join via condensation polymerisation
4. stop codon is reached
thus polypeptide chain is released
What is the coding region
part of the gene that contains instructions for making
What are promoter regions
where RNA polymerase binds to begin transcription
eg TATA box, CAAT box
What happes when the upstream region (promoter region) is altered
mutation occurs
coding regions may no longer work
causes some inherited disease
what is the terminator region
marks the end of the gene sequence (a series of nucleotides)
What are operator genes
only in prokaryotes
located between promoter and gene trascribed
act as switches to control transcription of adjacent structural genes
What is gene regulation
refers to genes being turned on (transcription) or off (no transcription)
some genes always on, some change
function of structural genes
produce proteins that become part of structure and functionality
eg gene encoding an enzyme
function of regulatory genes
produces proteins that are involved in altering expression of other genes
eg gene encoding for suppressor protein
What are operons
regulatory systems found in BACTERIAL cells
sets of glues are transcribed under control of regulatory genes
What is tryptophan
trp is an amino acid that E.coli takes in or it can be synthesized in the body
controled by the trp operon
What does the structure of the trp operon look like
look up now please
What occurs when trp levels low in terms of repression
operon switched on
repressor remains inactive (cannot bind to operator)
RNA polymerase can bind to promoter
thus transcription can occur from beginning
what occurs when trp levels present/high in terms of repression
operon is switched off
2 tryptophan molecules bind to repressor (activate by changing shape)
activated repressor can bind to operator (conplementary)
RNA polymerase now blocked off from promoter
no transcription occurs from beginning
blocks initiation
please look up image of this
what does the body prevent over creation of trp
trp production uses a large amount of energy, thus it is more efficient to not produce it when it is not needed
What occurs when trp low supply in attenuation
ribosome stalling (slows down at two trp codons in leader sequence)
allows for antiterminator loop to form on mRNA (it was terminator, but bc slowed down, has time to form antiterminator)
transcription continues
What occurs when trp levels high in attenuation
ribosome doesnt pause at two trp codons in leader sequence
thus terminator hairpin loop stays as such (formed)
creates pulling action and reparates bonds at alternator region
ripping mRNA from RNA polymerase
blocks completion of transcription
How does the ribosome know to pause at the two trp codons on the leader sequence (attenuation)
if the ribosome is moving quick, then the trp is being pulled in quickly for the interaction
thus there must be lots of trp
thus terminator hairpin loop formed
however if it is slow, then low supply, then operation continues as terminator has time to become antiterminator
What is in the operon for a prokaryotic cell
regulatory gene is present but before the operon
promoter
operon
structural genes
terminator
also leader/attenuation sequences
lacks non coding introns (only has presumed exons)
What is in the operon for a eukaryotic cell
structural genes
promoter
regulatory sequences/genes
perhaps terminator
contains introns and exons
What is the protein secretory pathway
the pathway, using the rough ER, then ribosomes, then golgi apparatus then vescicles, which allows for proteins to be exported out of the cell (exocytosis)
What is the ribosomes role in the protein secretory pathway
in both eu and pro
location of transport (as it is where polypeptide transformation occurs)