3 regulation of biochemical pathways Flashcards
polymerase chain reaction (PCR)
- amplify (make more copies) of a segment of DNA
- depends on DNA polymerase – Taq polymerase
- uses TaqP to double amount of DNA w each cycle
steps in PCR
- denature
- anneal
- extension
denature
- DNA sample is heated (94°C)
– breaks hydrogen bonds b/w the complementary strands - separates DNA into 2 strands of DNA
anneal
- primers (short segments of single-stranded DNA) are added
- primers bind to target DNA, initiating DNA synthesis
– (55°C) cooling allows for bonding
extension
- TaqP starts at the primers and extends them using the nucleotides (72°C)
– forms 2 complete double strands
step 1 of CRISPR-Cas9
- bacteriophage binds to the outside of the bacteria cell
- injects viral DNA into cytoplasm
! has to have had a previous attack occur
! has to be a second encounter
step 2 of CRISPR-Cas9
sequences from the CRISPR clusters in the bacterial genome are transcribed into guide DNA
step 3 of CRISPR-Cas9
- CRISPR RNA (crRNA) + tracer RNA (trcrRNA) = guide RNA (gRNA)
- gRNA forms a complex w the Cas9 enzyme
step 4 of CRISPR-Cas9
gRNA + Cas9 complex binds w bacteriophage DNA at the PAM site
step 5 of CRISPR-Cas9
- Cas9 unzips the bacteriophage DNA
- if gRNA is complementary w DNA then it binds w complementary sequence on the DNA
step 6 of CRISPR-Cas9
- Cas9 cleaves the DNA several nucleotides from the PAM site
- results in viral DNA being disrupted and cannot reproduce
- successfully defended itself :p
genetically modified organisms (GMO)
organisms that have had their DNA directly manipulated
transgenic organisms
a subset of GMOs that have DNA from a different species
e.g recombinant plasmid —> transformed bacteria
purpose of transgenic organisms
- quicker growth
- pest-resistance
- herbicide resistance
biochemical pathways
series of interconnected biochemical reactions
e.g. photosynthesis, cellular respiration
photosynthesis
6CO2 + 6H2O —> C6H12O6 + 6O2
- involves 2 stages; products of the 1st are the reactants of the 2nd
rubisco
the key enzyme of the photosynthesis pathway, relatively slow
- acts on just 3-10 substrate molecules/second
- compensates by having a high concentration of rubisco in the cell’s chloroplasts
cellular respiration
C6H12O6 + 6O2 —> 6CO2 + 6H2O
- involves 3 stages where the products are the reactants of the next
role of enzymes in biochemical pathways
- proteins that catalyse chemical reactions
- substrate – specific
- have an active site
- works best in certain conditions
- NOT used up in reactions
enzyme action
enzyme + substrate —> enzyme-substrate complex —> enzyme + products
types of reactions
anabolic: occurs when smaller substrates are joined to form larger products
- energy is used (e.g. photosynthesis)
catabolic: occurs when a large substrate is broken down into smaller products
- energy is released (e.g. cellular respiration)
ethical concepts
- integrity
- justice
- beneficence
- non-maleficence
- respect
gel electrophoresis
