Bio Final Review

Base Pairs of DNA

A-T; G-C

Base Pairs of RNA

A-U; G-C

What causes base pairs between DNA and RNA

Hydrogen Bonding

What is the amount of Adenine or Cystosine equal in a cell

Thymine or Guanine

What does Helicase do during replications

It seperates the DNA strands, at the replication fork

What is Primase’s role in replication?

It starts new strands of RNA, called Primers

What does DNA Polymerase do in DNA replication?

It adds nucleotides to the 3’ end of the RNA primer

What does Ligase do during replication

It connects newly created pieces of DNA together

In a replication bubble, what are leading and lagging strand?

Leading strand continously builds toward the replication fork, whereas the lagging strand builds away from the fork

What direction is DNA built?

Built of the 3’ end

How is DNA built?

By adding nucleotides to the 3’ end of the primer

What are the steps of gene expression and where do they take place, in a prokaryote?

Transcription then translation; happens in the cytoplasm

What are the steps of gene expression and where do they take place, in a Eukaryote?

Transcription (happens in the nucleus) then Modification of mRNA (i.e. Splicing and addition of 5’ cap and a 3’ tail; all happening in the nucleus) and then Translation (happens in a ribsome located in the cytoplasm)

What’s transcription?

Using DNA to build mRNA

What’s translation?

Using mRNA to build a protein

What is the splicing of mRNA?

The removal of introns from the mRNA

What are Exons and introns?

Exons are sequences located in DNA that code for proteins and need to be translated; Introns are sequences located in DNA that need to be removed before translation

When can Transcription and Translation occur in a Prokaryote?

At the same time (note that this can’t be true for a Eukaryote)

What’s an mRNA and its role in Gene Expression

Its the message from a section of DNA on how to build typically one protein (note sometimes it can be more than one due to Operons)

What are Operons?

A sequence of DNA with only 1 promoter that has multiple genes coding for multiple proteins

What are tRNAs and what’s their role in gene expression?

Pieces of RNA that translate mRNA into Proteins by matching the mRNA’s codon with the tRNA’s anticodon and specific amino acid

What are codons in an mRNA

a section of 3 bases that is later translated into a specific Amino Acid

What are rRNA in gene expression

RNA that make a major part of the structure of a ribosome

What signals in the DNA chain control the start/stop of translation?

Promoters + Terminators

What signals in the mRNA chain control the start/stop of transcription?

Start Codons (always AUG) + Stop Codons

What’s the Coding strand?

DNA strand that complements the template strand that should also match the mRNA strand that’s transcribed (except replace T with U)

What’s the Template strand?

DNA strand that’s base pair complement is used to create mRNA.

What are the 3 types of substitution mutations?

Nonsense mutations change the og Nucleotide and then replace the current amino acid with a stop codon; Silent Mutations change the nucleotide but not the amino acid the nucleotide helped code for; Misense mutations change the nucleotide and the amino acid (originally coded for) but there’s a chance that the change in amino acid doesn’t affect the function of the protein