3 regulation of biochemical pathways

Question 1

polymerase chain reaction (PCR)

Answer 1

• 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

Question 2

steps in PCR

Answer 2

1. denature
2. anneal
3. extension

Question 3

denature

Answer 3

• DNA sample is heated (94°C)
  – breaks hydrogen bonds b/w the complementary strands
• separates DNA into 2 strands of DNA

Question 4

anneal

Answer 4

• primers (short segments of single-stranded DNA) are added
• primers bind to target DNA, initiating DNA synthesis
  – (55°C) cooling allows for bonding

Question 5

extension

Answer 5

• TaqP starts at the primers and extends them using the nucleotides (72°C)
  – forms 2 complete double strands

Question 6

step 1 of CRISPR-Cas9

Answer 6

• 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

Question 7

step 2 of CRISPR-Cas9

Answer 7

sequences from the CRISPR clusters in the bacterial genome are transcribed into guide DNA

Question 8

step 3 of CRISPR-Cas9

Answer 8

• CRISPR RNA (crRNA) + tracer RNA (trcrRNA) = guide RNA (gRNA)
• gRNA forms a complex w the Cas9 enzyme

Question 9

step 4 of CRISPR-Cas9

Answer 9

gRNA + Cas9 complex binds w bacteriophage DNA at the PAM site

Question 10

step 5 of CRISPR-Cas9

Answer 10

• Cas9 unzips the bacteriophage DNA
• if gRNA is complementary w DNA then it binds w complementary sequence on the DNA

Question 11

step 6 of CRISPR-Cas9

Answer 11

• Cas9 cleaves the DNA several nucleotides from the PAM site
• results in viral DNA being disrupted and cannot reproduce
• successfully defended itself :p

Question 12

genetically modified organisms (GMO)

Answer 12

organisms that have had their DNA directly manipulated

Question 13

transgenic organisms

Answer 13

a subset of GMOs that have DNA from a different species

e.g recombinant plasmid —> transformed bacteria

Question 14

purpose of transgenic organisms

Answer 14

• quicker growth
• pest-resistance
• herbicide resistance

Question 15

biochemical pathways

Answer 15

series of interconnected biochemical reactions

e.g. photosynthesis, cellular respiration

Question 16

photosynthesis

Answer 16

6CO2 + 6H2O —> C6H12O6 + 6O2

• involves 2 stages; products of the 1st are the reactants of the 2nd

Question 17

rubisco

Answer 17

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

Question 18

cellular respiration

Answer 18

C6H12O6 + 6O2 —> 6CO2 + 6H2O

• involves 3 stages where the products are the reactants of the next

Question 19

role of enzymes in biochemical pathways

Answer 19

• proteins that catalyse chemical reactions
• substrate – specific
• have an active site
• works best in certain conditions
• NOT used up in reactions

Question 20

enzyme action

Answer 20

enzyme + substrate —> enzyme-substrate complex —> enzyme + products

Question 21

types of reactions

Answer 21

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)

Question 22

ethical concepts

Answer 22

• integrity
• justice
• beneficence
• non-maleficence
• respect

Question 23

gel electrophoresis