DNA & Proteins Flashcards
What is a primary protein structure?
A linear sequence of amino acids linked by peptide bonds, determines 3D configuration.
What is a secondary protein structure?
The alpha helix and beta-pleated sheet.
What is a tertiary protein structure?
Overall 3D conformation of protein.
What is a quaternary protein structure?
3D structure of a protein composed of multiple subunits.
What is haploinsufficiency?
Half the amount of protein product is produced.
What is Knudson’s two hit hypothesis?
Where a normal gene just needs 1 mutation for abnormal protein to by produced by both.
Properties of a peptide bond?
Very stable, flexible around carbons, partial double bond, usually 1 preferred conformation.
What are the 5 forces holding proteins together?
Van der Waal, hydrogen, hydrophobic, ionic, disulphide.
What are immunoglobulins?
Antibodies that are large, Y-shaped protein produced mainly by plasma cells that is used by the immune system to neutralize pathogens such as pathogenic bacteria and viruses.
How many bonds can A-T make?
2
How many bonds can G-C make?
3
Which direction does DNA polymerase read DNA
5’-3’ Direction.
What is RNA primer?
Adds an additional RNA primer that gives DNA polymerase a starting point.
What are the 2 strands of DNA called once opened?
Leading and lagging strand.
What does P53 do?
Detects DNA damage and initiates repair mechanisms, pauses cell cycle until repair is carried out, if not fixed it commands call to commit suicide.
What are the 4 bases in DNA?
adenine (A), cytosine (C), guanine (G), or thymine (T).
What are tge 4 bases in RNA?
Adenine, Guanine, Uracil and Cytosine
Which base is swapped in RNA
Thymins in DNA is swapped for uracil in RNA
What are the 2 parts of protein synthesis?
Transcription and translation.
What is transcription?
Transcription is the first step in gene expression. It involves copying a gene’s DNA sequence to make an RNA molecule.
Transcription is performed by enzymes called RNA polymerases, which link nucleotides to form an RNA strand (using a DNA strand as a template).
What are the 3 steps of transcription?
Initiation: RNA polymerase binds to a sequence of DNA called the promoter once bound, RNA polymerase separates the DNA strands, providing the single-stranded template needed for transcription.
Elongation: One strand of DNA, the template strand, acts as a template for RNA polymerase. As it “reads” this template one base at a time, the polymerase builds an RNA molecule out of complementary nucleotides.
Termination: Sequences called terminators signal that the RNA transcript is complete. Once they are transcribed, they cause the transcript to be released from the RNA polymerase.
What is translation?
In translation, the codons of an mRNA are read in order (from the 5’ end to the 3’ end) by molecules called transfer RNAs, or tRNAs.
Each tRNA has an anticodon, a set of three nucleotides that binds to a matching mRNA codon through base pairing. The other end of the tRNA carries the amino acid that’s specified by the codon.
What are the 3 steps of translation?
Initiation (“beginning”): in this stage, the ribosome gets together with the mRNA and the first tRNA so translation can begin.
Elongation (“middle”): in this stage, amino acids are brought to the ribosome by tRNAs and linked together to form a chain.
Termination (“end”): in the last stage, the finished polypeptide is released to go and do its job in the cell.
What are the 2 types of nucleic acid and what are their functions?
DNA, RNA. Responsible for storage, expression, transmittion of genetic information.
Triplets that dont specify for amino acids are called?
‘Stop signals’
The _____ deicdes which DNA strand is used?
Promoter
A 3 base sequence in RNA that specifies for an amino acid is called a ____?
Codon
What are coding and non coding sequences called?
Coding: Exons
Non coding: Introns
What happens in splicing?
Removal of introns, after splicing RNA is called mRNA. Occurs in the nucleus and is performed by proteins and RNA known as a spliceosome.
tRNA 3 letter code sequence is called an ____?
Anticodon
