Lec 11: Special synthesis (unrelated topic)

Question 1

When was penicillin discovered?

Answer 1

1928

Question 2

What are the two classes of antibiotics?

Answer 2

Bacteriostatic agents, bactericidal agents

Question 3

What is a bacteriostatic agents?

Answer 3

restrict growth and reproduction

Question 4

What is a bactericidal agent?

Answer 4

Causes bacterial cell death

Question 5

What are the primary components of neosporin?

Answer 5

Bacitracin, neomycin and polymyxin B.

Question 6

What does Bacitracin do?

Answer 6

Cell wall inhibitor good against Gram+ bac

Question 7

What does Neomycin do?

Answer 7

Attack ribosome

Question 8

What does Polymyxin B do?

Answer 8

punch holes in cell membrane, best for gram negative bacteria.

Question 9

What do antibiotics that target the ribosome do?

Answer 9

They slow down the ribosome thus making the fidelity low. Making more mistakes. Slower the ribosome the more chance our RNA is discovered and chewed up.

Question 10

What does Puromycin do?

Answer 10

Causes the premature release of nascent polypeptide chains by its addition to the growing chain end. (looks like a release factor just not as specific)

Question 11

Since ribosomes of euk mitchondria often resemble those of bacteria in their sensitivity to inhibitors, what happens?

Answer 11

Some of these antibiotics can have a deleterious effect on human mitochondria

Question 12

What is the paradox pertaining to DNA or protein?

Answer 12

DNA is the genetic material but it is reliant of proteins to do replication, proteins catalyze chemical reactions bbut nucleic acids code for proteins, so which came first? DNA or Protein?

Question 13

What was one plausible solution to the paradox?

Answer 13

It was RNA.

Question 14

What does the RNA world hypothesis state?

Answer 14

Made by Orgel, Crick, Woese (1960s) states that RNA not DNA is the original genetic material, Watson-crick base pairing rules have always been used. RNA not protein catalyzed the first chemical rxns needed to create life

Question 15

What are some supporting evidence the RNA world hypothesis?

Answer 15

1.Ribosomes: RNA evolution is rapid due to the reactive nature of its structure. Ribozymes can pretty much do anything. 2. Evolutionary relics still persist in our cells: DNA is just a specialized variation of RNA that is better suited for storage of info. Vitamin and cofactors (GTP/ATP) are based on nucleotides all use ribose as the sugar. When synthesizing new nucleotdies we make the ribose based nucleotides first then we go to deoxyribose version.

Question 16

What are some flaws to the RNA world hypothesis?

Answer 16

1. This current complexity couldnt have risen from just one type of marcromolecule the RNA. 2. Introns early vs introns late debate.

Question 17

What is the introns early vs introns late debate?

Answer 17

Introns early: introns promote recomination in trans of proteins. Prok lost their introns due to purifying selection when genome were streamlined to permit rapid replication.
Introns late: Introns are an invetion of euk. Introns are present in mitochondrial and chloroplast genomes, reinforcing that introns evolved simultaneously with eukaryotes

Question 18

Which is the result of the introns early vs introns late debate?

Answer 18

No conclusion but introns late is more plausible