*BIOLOGY LECTURE EXAM 3*

Question 1

What is the forth type of biological molecule and what does DNA stand for?

Answer 1

Nucleic Acid

Deoxyribose Nucleic Acid

Question 2

Draw and label a nucleotide.

Answer 2

ON NOTES!

Question 3

What did Rosalind Franklin do to contribute to the discovery of DNA structure?

Answer 3

Took photo 51 that showed that DNA was double helix

Question 4

What components make up chromatin?

Answer 4

DNA & histone proteins

Question 5

Draw and label the two classes and four type of nitrogenous bases in DNA?

Answer 5

ON NOTES!

Question 6

Draw and label a small section of DNA with four different base pairs?

Answer 6

ON NOTES!

Question 7

Whose rules are you following when your paring up these nitrogenous bases?

Answer 7

Chargaff

Question 8

Why does DNA replication occur?

Answer 8

Cell is about to divide, so both cells have the same amount of DNA

Question 9

What are the three stages of DNA replication?

Answer 9

Initiation, Elongation, & Termination

Question 10

Where do origin of replication occur along the double helix and why?

Answer 10

Areas that are rich in adenine and thymine because they require less energy to break apart

Question 11

What enzyme unwinds the DNA and what does it need to work?

Answer 11

Helicase & ATP

Question 12

What enzyme cuts, repairs, and alleviates the stress of supercoils?

Answer 12

Topoisomerase

Question 13

Why are these enzymes (Topoisomerase) important from a medicinal perspective?

Answer 13

Because antibiotics target topoisomerase

Question 14

What does DNA polymerase type III need to synthesize new DNA? What is the only direction that it can do this in?

Answer 14

It needs a 3’ OH of RNA primer; 5’ to 3’

Question 15

Describe the initial difference between the leading strand and the lagging strand of the DNA replication fork?

Answer 15

The leading strand is made up of one RNA primer and a continuous new strand of DNA; the lagging strand is made up of RNA primers and DNA stretches called Okazaki fragments.

Question 16

What enzyme cuts out RNA primers and inserts new DNA nucleotides in their place?

Answer 16

DNA Polymerase Type I

Question 17

What enzyme seals the newly synthesized DNA strands together?

Answer 17

Ligase

Question 18

Where does termination of DNA replication occur?

Answer 18

Where replication forks merge and telomeres

Question 19

Replicated DNA is made up one old or parental strand of DNA and one new one what is this model of replication called?

Answer 19

Semi-conservative

Question 20

What does RNA stand for and how is it different structurally than DNA?

Answer 20

Ribonucleic Acid & it’s single stranded versus DNA which is double stranded

Question 21

How is the genetic code for the DNA expressed in a living organism?

Answer 21

RNA & proteins

Question 22

What are the tree essential roles that proteins fulfill?

Answer 22

Metabolic, Structure & Transport

Question 23

Does all DNA code for proteins?

Answer 23

No

Question 24

Where does transcription occur?

Answer 24

In the nucleus

Question 25

What is the first stage of transcription of mRNA and what happens in this stage?

Answer 25

Initiation | -RNA polymerase II attaches on to a PROMOTOR sequence on the DNA

Question 26

What is the second stage of transcription and what happens in this stage?

Answer 26

Elongation -RNA polymerase II opens the DNA reads the template strand in a 3'- 5' direction and attaches RNA nucleotides in the 5'- 3' direction

Question 27

What is different about RNA nitrogenous bases?

Answer 27

Uracil instead of Thymine

Question 28

What is the third stage of transcription and what happens in this stage?

Answer 28

Termination | -RNA polymerase II synthesizes a poly adenylation signal (AAUAAA), and enzymes move in to cut the hnRNA strand

Question 29

What modifications does this hnRNA need to become mRNA?

Answer 29

- Guanosine cap added to the 5' end - SNRP's cut out the introns that do not code for amino acids, leaving only the exons, that will code for amino acids - Poly A tail added to the 3' end

Question 30

What happens next to this mRNA?

Answer 30

Leaves the nucleus to go get translated on the ribosomes

Question 31

What are codons? How many are their? How many code for amino acids? Which ones don't code for amino acids?

Answer 31

Triplets of nucleotides 64 61 Stop codons

Question 32

What are anticodons and where are they?

Answer 32

Triplets of nucleotides complementary to codons & on the tRNA

Question 33

What does it mean to charge a tRNA?

Answer 33

Add an amino acid to 3' end

Question 34

What is a ribosome made of?

Answer 34

rRNA & proteins

Question 35

What is the first stage of translation and what happens in this stage?

Answer 35

Initiation: - Small ribosomal subunit binds to AUG, the start codon. - The first tRNA, charged with the amino acid, methionine, binds its anticodon (UAC) with the start codon. - Large ribosomal subunit binds to small ribosomal subunit, with the first charged tRNA in the P site.

Question 36

What is the second stage of translation and what happens in this stage?

Answer 36

Elongation: - A second charged tRNA is bonded to the codon in the A site. - The amino acid (methionine) on the first tRNA in the P site is added to the amino acid on the second tRNA in the A site. - The first, now uncharged, P site tRNA moves to the E site, where it is expelled from the ribosome. - The second A site tRNA moves to the P site, and a third charged tRNA is bonded to the next codon in the A site. - The two amino acids on the second tRNA in the P site are added to the amino acid on the third tRNA in the A site. - The same process repeats until the stop codon is reached.

Question 37

What are we initially building in this stage?

Answer 37

Polypeptide

Question 38

What is the third stage of translation and what happens in this stage?

Answer 38

Termination: - A stop codon (UGA, UAA, UAG) enters the A site. - The Release Factor binds to the stop codon and cuts off the polypeptide.

Question 39

What are the four structures of proteins which one is the most complex and why?

Answer 39

Primary, Secondary, Tertiary, Quaternary | Quaternary because it's a combination of all four

Question 40

Describe SARS-CoV-2 pathophysiology?

Answer 40

Spike proteins bond with ACE2 proteins in our alveoli this allows for the virus to enter the cell, Type II pneumocyte, and replicate itself using our cells ribosomes eventually collapsing the alveoli

Question 41

Describe how covid-19 mRNA vaccines work?

Answer 41

Small sections of the viruses mRNA are incased within phospholipids and enter our cells there the mRNA uses our cells ribosomes to translate ONLY the spike protein our immune system discovers these foreign proteins and produce antibodies that will bond to them and to real spike proteins that are connected to an actual Covid virion inhibiting it from entering our cells and replicating

Question 42

What is the specific bacterial immune system called that we are using to perfect gene editing that will possibly eliminate diseases such as blood disorders, cancer, aids, and will change the future of medicine, agricultural, and humanity as we know it?

Answer 42

CRISPR Cas9 technology