Nucleic Acids and DNA 🧬 Flashcards
What are introns?
Non-coding regions of DNA that play a large part in regulating gene expression, usually contains sequence that repeats.
Spliced out of the RNA during protein synthesis.
Not contained in prokaryote
What are exons?
The coding regions.
What does it mean by DNA being degenerate?
Multiple codons can code for same amino acid
What does the term universal suggest about DNA?
Triplet code is source/same for every organism.
What is the role of DNA?
Contains genetic information which code to make proteins.
What nitrogenous bases are pyrimidines?
Pyrimidines——-> 1 carbon ring structure
Thymine
Uracil
Cytosine
What nitrogenous bases are purines?
Purines——–> 2 carbon ring structures.
Adenine
Guanine
What is meant by the term ‘anti-parallel’?
DNA always read from the 5’ to 3’ strand direction.
DNA polymerase = only bind to 3’ strand.
Work in only one direction.
Antisense strand runs from 3’ to 5’ ——-> makes a mRNA strand which has same base sequence of the sense strand which codes for correct amino acid.
What is the semi conservative module?
Idea that OG strand of DNA acts as a template for the synthesis of the new strand of DNA.
One parent strand and one new daughter strand of DNA.
How did research into DNA being semi conservative come about?
OG DNA = N-14.
~~~would be lighter in the centrifuge.
Free DNA nucleotides =N-15
~~~~ would sink in centrifuge
Centrifuge——>separate substances based on their densities.
What were the results?
Parent strand =All N-14
First generation = N-14/N-15 mix
Second generation = Half N-14/N-15 and other half =N-15
What is DNA replication?
Before cell divides DNA must be copied to ensure all cells have same genetic information.
How is DNA replicated?
DNA gyrase —->unwinds DNA.
DNA helicase breaks hydrogen bonds between the polynucleotide strands.
Each strand acts as template.
Free-floating DNA nucleotides join to exposed bases on each OG strand ~~~~ complementary base pairing.
Nucleotides joined together by DNA polymerase.
Hydrogen bonds form between bases of OG strand and new strand.
Formation of double helix.
What is the role of DNA polymerase?
Catalyses formation of sugar phosphate backbone.
What is transcription?
First stage of protein synthesis.
mRNA strand made in nucleus to leave nuclear pore.
Process of transcription.
H bonds broken between complementary base pairs
Free RNA nucleotides pair with the exposed bases.
Uracil base pairs with Adenine.
RNA polymerase joins with RNA nucleotide forming a phosphodiester bonds —–> mRNA made.
mRNA leaves nuclear pore ~~~ goes to ribosome for translation.
What are codons?
A sequence of 3 bases that code for one amino acid.
In DNA
What are anticodons?
Sequence of 3 bases on tRNA that is complementary to a specific codon on mRNA.
Process of translation.
mRNA binds to ribosome at the start codon.
tRNA with complementary anticodon binds to mRNA start codon.
tRNA will carry an amino acid corresponding that codon.
Amino acids form peptide bonds between one another.
Ribosomes act as a binding site for mRNA and tRNA and catalyse assembly of the protein via enzyme peptidyl transferase.
What is ATP?
Used for energy transfer of all living things.
Known as ——–> universal energy currency.
