Molecular Genetics Flashcards
(53 cards)
What is DNA ELI?
DNA is deoxyribonucleic acid, that is found in the nucleus as genetic material, and is carrier of genetic information.
Why is deoxyribonucleic acid important?
It codes instructions to make a protein.
What is the structure of DNA (generalized)
DNA is a double helix composed of two chains of complementary nucleotides.
What are the monomers?
THE MONOMERS ARE NUCLEOTIDES! They are the building blocks of nucleic acids.
What is a nucleotide made up of?
- P-group or phosphate group
- Pentose sugar (deoxiribose)
- base.
What are two main types of bases in nucleotides?
Two types of nucleotides bases are the following:
Purine (R)- It is composed of two rings: Guanine and Adenine
Pyrimidine(Y)- It is composed of ONE ring: Thymine Cytosine
What is the DNA structure composed of (detailed/in depth)?
2 antiparallel strands of nucleotides,
1.The BACKBONE is made of alternating phosphates and sugars which are held together by strong covalent bonds.
- Rungs are made up of bases which are held together by weak hydrogen bonds.
What is Chargaff’s base pairing rule?
The percent of purines = the percent of pyrimidines
What is DNA replication and when does it occur?
It is a process by which the DNA copies itself and it occurs during the S phase of Interphase in Mitosis and Meiosis.
What are the origins of replication?
The specific starting point where DNA replication begins.
What is the first step to DNA replication?
The first step is unwinding or UNZIPPING. The original DNA acts as the template and an enzyme called HELICASE, which breaks the h-bonds between nucleotides which frees them and creates a REPLICATION FORK.
However it needs another enzyme to kick start this reaction, and that is PRIMASE.
What is the second step?
Complementary base pairing
Both antiparallel strands are replicated. The leading strand, gets replicated smoothly because the polymerase follows the helicase from 5 prime to 3 prime and the bases get copied.
HOWEVER! The lagging strand is antiparallel and the polymerase can’t just “slide” its way through lagging strand since it is going in an opposite direction from five prime to three prime. SO it must copy one section at a time as more template is made available. THIS IS CALLED OKAZAKI FRAGMENTS. Ligase will make sure that everything is connected in the end. Therefore a polynucleotide is created.
Conclusion…
Helicase unwinds the helix and separates the strands
Primase “kick starts” the reaction, polymerase III copies each strand (continuously on lagging and okazaki fragments on lagging)
What is editase?
PROOFREADER THAT CORRECTS POLYMERASE MISTAKES!
Tell me about the Central Dogma.
DNA molecules hold the genetic instructions for genes, and each gene consists of about 1000 DNA base pairs which are instructions to produce a single protein. HOWEVER…
And Eli what about however???
DNA is too large and complex to leave the nucleus so it gets converted into messenger RNA which is then interpreted by the ribosome into an amino acid sequence (protein) this is known as the Central Dogma
What is RNA?
RNA or, Ribonucleic Acid, is a nucleic acid that is generally single stranded and plays a role in transferring DNA to PROTEIN FORMING SYSTEMS of the cell.
What are the three types of RNA?
Messenger RNA- Takes coded instruction from DNA to ribosome
Transfer RNA- Carries specific AA to ribosome.
Ribosomal RNA- Makes up Ribosome which makes the protein.
What Transcription?
The process by which messenger RNA is synthesized from a template of DNA.
Steps of Transcription please.
- Helicase binds to a specific sequence of the gene and with the help of proteins called transcription factors it unzips the two strands apart and this is called elongation.
- The two strands made is called the template strand, which is used to make the mRNA, and the non-template strand which will do nothing except connect to make the DNA again.
- In the template strand, an enzyme called RNA polymerase, doesn’t need a primer, it simply initiates mRNA at the promoter or the start point and synthesizes it as it goes.
- Once RNA polymerase reaches the end of the gene termination occurs, and the enzyme detaches from the gene and the DNA is returned to its original state.
- The mRNA will leave the nucleus, it will find a ribosome. This is where translation occurs.
What is RNA made up of?
- Phosphate group
- Ribose
- Nitrogenous base
What is a triplet, codon and anticodon?
Triplet- 3 base letters of DNA
Codon- 3 letters on RNA complementary to DNA
Anticodon- 3 nucleotides on Trna
What is 5’ to 3’ in DNA?
5 prime end has a p-group attached to the 5th carbon in deoxyribose, and 3 prime end has hydroxyl group attached to 3rd carbon atom in deoxyribose.
