BIOLOGY

function of mRNA

single stranded RNA template that carries genetic information from the nucleus for translation

function of rRNA

structural component of ribosomes that synthesises proteins

tRNA

transfers amnio acids to ribomsomes for translation

step 1 of DNA transcription

Initiation: RNA polymerase binds to the promoter and unwinds the DNA double helix to separate the strands

step 2 of DNA transcript

Elongation: RNA polymerase ‘reads’ the template DNA strand to build mRNA

step 3 of DNA transcript

Termination: once it hits a terminator the mRNA is released from the polymerase

what is added and removed during RNA processing

added = 5 methyl cap and 3 poly-A tail. removed = introns

what is the difference between repression and attenuation in regulating the trp opern

repression = blocks transcripition initiation of the trp operon to reduce the tryptophan

attenuation = causes transcription to stop prematurely to reduce tryptophan

function of single guide RNA (sqRNA) in CRISPR - Cas 9 gene editing

attaches to the cas9 enzyme to bind to the desired strands of target DNA (complementary sequence)

How can CRISPR-Cas9 increase crop yields

can knock out genes that limit crop yield by introducing framshift mutations

step 1 of polymerase chain reaction (PCR)

Denaturation: break apart the two strands of DNA by heating to 94C

step 2 of polymerase chain reaction (PCR)

annealing: prepare and mix in DNA primers for binding at 52-58C

step 3 of polymerase chain reaction (PCR)

elongation: extend primers into full DNA strands at 70-80C

what are the differences between endonucleases and ligases in plasmids

endonucleases = cut DNA and create sticky ends

ligases = reattach DNA fragments by gluing together sticky ends through the formation of phosphodiester bonds

transgenic organism

an organism with a foreign gene inserted into its genome

primary protein structure

the acquence of amino acids in a polypeptide drain/held by peptide bonds

secondary structure

amino acid chain interactions between amino acid carring formation of alpha helixes and beta pleated sheets

tertiary structure

functinoal 3D protein, secondary structure folds because of interactions between “R groups” and bonds of amino acids

quaternary structure

proteins made up by more than one polypeptide

anabolic reaction

combines sample molecules to more complex molecules small to big

catabolic reaction

breaks down complex molecules into simpler molecules big to small

coenzymes

small organic non protein molecules. Assist enzymes by binding to enzymes. Functioning as carriers of energy, electrons and proteins

genes

a sequence of nucleotide bases which code for specific proteins/polypeptide

promoter region of a gene

upstream binding site for RNA polymerase, allows for transcription-starting position and direction of transcription

introns of a gene

non coding DNA, removed during RNA processing

exons of a gene

coding DNA, transcribed and translated into the final protein

termination of a gene

sequence of DNA that signals end of transcripition

operator region of a gene

binding site for repressor protein, inhibits gene expression

leader region of a gene

upstream of the coding regions, downstream of the promoter and operator

gene expression

gene, segments of DNA are transcribed into molecules of mRNA, which are then translated into the amino acid sequences that make up proteins

RNA processing

split and splicing of pre=mRNA to form mature mRNA

transcription

creation of pre-mRNA

RNA processing

pre-mRNA to mRNA

translation

mRNA into polypeptide

protein secretory pathway

exports proteins via exocytosis for use in the extracellular environment

secretory vesicle

releases products via exocytosis from golgi to plasma

golgi apparatus

modifies, packages and stores, transports proteins

transport vesicles

transport proteins from RER to golgi apparatus

step 0 PSP

gene is transcribed into mRNA. mRNA moves to cytosol to be translated at ribosome

step 1 PSP

polypeptide enters lumen of RER

step 2 PSP

polypeptide moves through RER folding and modification occurs

step 3 PSP

polypeptide is packaged into transport vesicles and sent to golgi

step 4 of PSP

golgi recieves vesicles further modications occur to polypeptide to form a protein

step 5 of PSP

protein is packaged into secretory vesicle sent to plasma membrane

step 6 of PSP

protein is released into extracellular environment via exocytosis

gene regulation

process of turning genes on/off: inhibiting or activating gene expression. Preventing over or underexpression of a protein

TRP operon

a series of genes within bacteria that encode for production of amino acid:

polymerase chain reaction

DNA manipulation technique that amplifies DNA by making multiple identical copies

step 1 for PCR

denaturing: DNA is heated to 90-95 which separates DNA strands by breaking hydrogen bonds

step 2 of PCR

annealing: single-stranded DNA is cooled to 50-55 to allow primers to anneal to complementary sequences

step 3 of PCR

elongation: mixture is heater to 72 Taq polymerase binds to primer synthesising complementary strands of DNA

stage 4 of PCR

repeat: cycle is repeated to increase copies

ligases

join two fragments of DNA/RNA together acting as molecular glue

step 1 of manipulating DNA

restriction enzyme cuts DNA

step 2 of manipulating DNA

fragments are blunt or sticky ends

step 3 of maipulating DNA

fragments with matching base pairs stick together

stage 4 of manipulating DNA

ligase seals the gaps

plasmid

small circular piece of DNA in bacteria

recombinant plasmids

a form of artifical DNA created by inserting foreign DNA fragment into plasmid vector

step 1 creating recombinant plasmid

identify same sticket end restriction site in plasmid and target gene (DNA)

step 2 creating recombinant plasmid

plasmid and donor DNA are cut with same restriction enzyme creating complementary sticky ends/cut

step 3 creating recombinant plasmid

DNA and plasmid are mixed together

step 4 creating recombinant plasmid

DNA ligase joins the phosphodiester bonds in backbone of the recombinant plasmid

Gel electrophoresis

laberatory methods used to seperate mixtures of DNA fragments, RNA or proteins according to molecular size

CRISPR-Cas9

natural occuring sequence found in DNA of bacteria. Genome editing tool that cuts DNA at precise locations

step 1 CRISPR-Cas9 in gene editing

create a synthetic/single gRNA complementary to target DNA sequence

step 2 CRISPR-Cas9 in gene editing

combine sgRNA with Cas 9 enzyme = CRISPR-Cas9 complex

step 3 CRISPR-Cas9 in gene editing

inject complex into target cells

step 4 CRISPR-Cas9 in gene editing

complex finds PAM site checks sgRNA aganist DNA

step 5 CRISPR-Cas9 in gene editing

Cas 9 cuts DNA at specific sites

step 6 CRISPR-Cas9 in gene editing

cell will attempt to repair

step 7 CRISPR-Cas9 in gene editing

repairing cell may introduce new nucleotides

GMO

organism who’s DNA has been altered using genetic engineering tech

TGO

genetically modified organism that contains genes from other species

transformed bacteria

bacteria with plasmid containing a new gene and resistant to specific antibiotic resistance

photosynthesis

the process of converting light energy into chemical energy stored in glucose

location of photosynthesis

chloroplast

equation for photosynthesis

6CO2 + 12H2O > C6H1206 + 602 + 6H2O

location of light dependent stage

grana of the chloroplast

inputs of the light dependent stage

water, ADP,Pi and NADP+

outputs of light dependent stage

oxygen, NADPH and ATP

location of the light independent stage

stroma of a chloroplast

inputs of the light independent stage

carbon dioxide, NADPH and ATP

outputs of the light independent stage

glucose, ADP, Pi and NADP

chlorophyll

a green pigment located in the grana which absorbs and traps light energy

role of rubisco

is to bind CO2 and ‘fix’ the carbon into organic molecules in order to produce glucose

photorespiration

when rubisco binds to O2 rather then CO2

C3 plants

susceptible to photorespiration in hotter/drier conditions

C4

maintains a high conc of CO2, is advantageous in hot humid environments but uses more energy

CAM plants

maintains a high conc of CO2 even though stomata are closed

what plants limit photorespiration

C4 and CAM plants

separation of inital CO2 fixation and remainder of calvin cycle in C4 plants

between cells

separation of inital CO2 fixation and remainder of calvin cycle in CAM plants

between night and day

C3 plants are best suited to what environment

morderate, or cool and wet environments

C4 plants are best suited to what environment

hot, sunnt habitats

CAM plants are best suited to what environment

very hot, dry habitats

factors affecting photosynthesis rate

conc of CO2, light intensity, light colour, water availibility

factors affecting enzyzme function (PEST)

pH, enzyme inhibitors, substrate conc, temp

cellular respiration

the process of converting chemical energy stored in nutrients (glucose) into a useable form of energy (ATP)

anaerobic fermentation

does not require oxygen or a mitochondria and is less efficient