DNA Replication
When is DNA replication occurring?
During S phase.
What is the purpose of transcription?
To get RNA molecules
What does a tRNA molecule do?
transfers amino acids to the ribosomes to make proteins
What consists of a nucleotide?
sugar, phosphate, and base
What is a codon?
A coding unit that consists of 3 nucleotides and specifies a amino acid for a polypeptide to form.
Semiconservative Replication- one strand of the old and one new
Where exactly is transcription occurring?
In the nucleolus of the nucleus.
In the cytoplasm of eukaryotic cells specifically on the rough ER.
What complementary base pairs go with each other in DNA? RNA? What are their ring structures?
DNA: AT and GC
RNA: AU and GC
AG- 2 ring
CUT- 1 ring
What is the start codon?
AUG- Methionine
How many origins of replication in prokaryotes? In eukaryotes?
pro- 1
eu- numerous
What is produced in transcription?
A mRNA molecule
Does the mRNA or the tRNA have the codon?
The mRNA. The tRNA has the anticodon but the mRNA decides the amino acid.
How many hydrogen bonds between A and T?
How many between G and C?
AT- 2 H bonds
GC- 3 H bonds
What is it called when the information goes from DNA to RNA to a protein?
Central Dogma of Molecular Biology
Explain the process of replication in the leading strand of DNA.
1. DNA Helicase
2. SSB
3.DNA Primase
4. DNA Polymerase
What are 3 functions of introns?
1. no function- not needed for final mRNA
2. control transcription
3. control translation- prevent translation
What do the stop codons code for?
The do not have an amino acid like the start codon, but the codons will have release factors bind to them that help cleave the polypeptide from the tRNA.
Who are the people who discovered DNA's structure?
What happened and what did they use?
Rosalind Franklin, James Watson, and Francis Crick.
Watson and Crick stole Franklin's data and figured out that DNA is a double helix from the X-ray diffraction pattern results.
The Genetic Code is ________.
Universal
Explain the process of replication in the lagging strand.
1. DNA Helicase
2. Single-stranded Binding Proteins (SSB)
3. DNA Primase
4. DNA Polymerase in Okazaki Fragments
5. DNA Ligase
Explain the whole process of transcription from beginning to end.
complementary RNA base pairs are transcribed using the template strand of DNA. RNA polymerase joins nucleotides together in 5' to 3' direction when it attaches to the promoter. Keeps replicating until a DNA stop sequence is reached and the mRNA is released. Post transcription for the pre-mRNA, introns are taken out by a spliceosome so it is left with only exons.
Explain the whole process of translation.
mRNA associates with ribosomes, tRNA anticodons pick up their respective amino acids. The mRNA goes into the ribosome subunit and joins with the tRNA molecules at the A site and then moves the the P site where the polypeptide is continually formed while the tRNA is ejected in the E site. This continues until the stop codon occurs and a release factor cleaves the polypeptide from the tRNA. Then the polypeptide forms and folds into a protein. The ribosome dissociates until it is needed again and the mRNA is released.
What does Chargaff's rule say?
The amount of A and T will be equal to each other and the amount of G and C will be equal to each other. The amount of these bases will vary in each species.
What are the 3 key features of the Genetic Code?
1. Code is degenerate- most amino acids have more than one codon
2. Code is unambiguous- each codon only codes for one amino acid
3. Code has start and stop signals- one start codon, but 3 stop codons