Study Guide for DNA, Transcription, and Translation Quiz

Study Guide for DNA, Transcription, and Translation Quiz

DNA Structure:

• What is meant when we call DNA “antiparallel”

• 5 prime end five–phosphate

• 3 prime end hydroxide

• Differences in the structure of DNA in prokaryotes and eukaryotes

1. Prokaryotes have circular chromosomes, eukaryotes have linear chromosomes

2. Prokaryote genome smaller than eukaryotic genome

3. Eukaryotic genome in nucleus, prokaryote in cytosol

• Base pairing rules and how it differs between DNA and RNA

• Puries 2 ring with pyrimidines

• A T

• G C

• Rna- A U

DNA Replication:

• Key enzymes involved:

• Helicase- unzips dna strands

• DNA Polymerase- builds DNA

• Primase- makes primer for DNA polymerase

• Topoisomerase- relaxes dna coil

• Ligase- glues dna together

• What direction DNA is synthesized and why 

DNA is synthesized in the 5’ to 3’ direction because DNA polymerase can only add nucleotides to the hydroxyl end of the last nucleotide, so it keeps building on the back of the 3’ end meaning it goes 5’ to 3’.

• What is meant by DNA replication being semi-conservative

DNA is semi conservative meaning that new DNA molecules consist of 1 of the original strands from the previous DNA and one new strand.

• The differences between the leading and lagging strand

Leading stand moves TOWARD the opening of the DNA fork, building 5-3. So it doesn't have to keep jumping back.

The Lagging strand moves AWAY from the DNA fork and since it move 5-3 prime it has to keep jumping back every time more DNA is unzipped.

Transcription: FIRST. IN THE NUCLEOUS

Transcription is the process where RNA polymerase synthesizes a single stranded mRNA strand using the DNA template.

Next the mRNA transcript is edited in the NUCLEOUS:

Spliceosomes cut out introns but keep exons.

Poly-A-tail is added to the 3’ end to help stabilize the mRNA and help it out of the nucleus.

GPT cap is added to the 5’ end for protection and to help the mRNA attach to the ribosome.

• How is it different in prokaryotes and eukaryotes

• The function of RNA polymerase

• How new nucleotides match up to form the new mRNA strand

• What direction is the mRNA synthesized 5-3

• The difference between the template and coding strand of DNA template -DNA, coding RNA

• RNA Processing:

  • When/where this happens (part of cell/eukaryotes vs prokaryotes)

  • What is added to the ends of the mRNA molecule

  • Introns vs Exons and what happens to them

  • Spliceosomes- remove introns

  • Alternative Splicing

Translation: SECOND IN THE RIBOSOME

mRNA attaches to the ribosome.

Then, tRNA reads the codons of the mRNA and connects its anticodon, bringing the corresponding amino acid. (initiation begins with a start codon)

As tRNA brings more amino acids, they are added by rRNA, making the amino acid chain longer is called elongation.

At the end of the mRNA there should be a stop codon which signals termination, so tRNA will not bring any more amino acids. 

• How it is different in prokaryotes vs eukaryotes

• Codons vs Anticodons and where they are found

Codons are on mRNA

Anticodons are on tRNA

• Be able to read/use a codon chart (is this code the same or different in all living things)

SAME in all organisms

• tRNA (basic structure and the role it plays)- tRNA matches codons

• rRNA (what is it and where is it found)

• The three phases and what triggers each (just the basics)

  • Initiation (start codon) methionine AUG

  • Elongation (matching of mRNA codons and tRNA anticodons to bring in amino acids)

  • Termination (stop codon)

DIFFERENT:

Prokaryotes do transcription and translation at the same time (Because they don't have a nucleus everything is in the cytoplasm)

AND because mRNA transcripts prokaryotes don't go through RNA processing (adding of GTP caps and poly A tails, spliceosomes cutting introns)

SAME: 

The genetic code is the same!

Nucleotides, codons, ect