Enzymes, haemoglobin and DNA Flashcards
What is an isoenzyme? What is a coenzyme?
Enzymes with a different structure and sequence but catalyses same reaction.
Bind with enzyme proteins to form the active enzyme- can be metal ions/ organic.
What are activation-transfer coenzymes? What are oxidation-reduction coenzymes?
Form a covalent bond and are regenerated at the end of the reaction
Involved in reactions where electrons are transferred from one compound to another.
What is myoglobin?
Found in the muscle and serves as a reserve supply of oxygen and helps O2 movement in muscles.
At the core of haemoglobin and myoglobin, what is there? Termed as what? Iron can be seen as what?
A porphyrin ring which holds an iron atom
A heme
Iron= oxygen binding site, seen as a coenzyme
Factors influencing haemoglobin saturation? Disease which does this?
Partial pressure of O2 and CO2 in blood, temperature and H+.
Sickle cell anaemia- sticky, sickle-shaped red blood cells. Caused by mutation in haemoglobin.
Disulphide bonds define loop characteristics of what antibody? Variable and constant regions have what?
Ig
Heavy and light chains- VH and VL, CH and CL
DNA is synthesised on daughter strand on what ends? Daughter strand is synthesised from what end? Why?
From 5’ to 3’
From 5’ to 3’- phosphate at 5’ is used by enzyme as source of energy for reaction to occur
During DNA replication, which enzyme unwinds the double helix by relieving the supercoils? Which enzyme separates the DNA apart by breaking H-bonds? Which synthesises DNA on daughter strand? Starts from where?
Topoisomerase.
DNA helicase
DNA polymerase
At a primer
What does single strand binding protein (SSB) do?
What does the primase enzyme do?
Keeps two strands of DNA apart whilst synthesis of new DNA occurs- prevents annealing.
RNA polymerase that synthesises the short RNA primers needed to start strand replication process.
What does RNAase H do? Two what are produced at beginning of DNA replication? What enzyme joins the short DNA pieces together into one strand?
Removes RNA primers that previously began DNA strand synthesis.
Replication forks.
Ligase joins Okazaki fragments together
At the beginning of transcription, what proteins bind to the promoter region? A transcription complex forms around where?
Transcription factors
The TATA box (reads thymine, adenine, thymine, adenine etc.) on 5’ end of the 1st exon
Which enzyme unwinds the double helix? Which enzyme separates the strands? Free mRNA nucleotides bind to complementary bases on what? What binds to thymine?
Topoisomerase
DNA helicase
The template strand
Uracil instead of adenine
What enzyme joins the mRNA nucleotides catalysing phosphodiester bonds? Antiparallel mRNA strand has what? Transcription stops where?
RNA polymerase
5’CAP head and a 3’Poly A tail
At the stop codon
mRNA leaves the nucleus and attaches to what? First mRNA codon is used as template to bind to what? Amino acid brought on tRNA on what end?
An 80S ribosome
tRNA molecules at their anticodon
3’ end
Usual start codon? Stop codons? What does ribosome recognise on mRNA?
AUG. UGA, UAG and UAA.
CAP on the 5’ end
What is exon shuffling?
Where axons are not in the same order allow new proteins to be made e.g. the immune system.
What are factors turning off expression of genes?
Activation of repressors- inhibitors of RNA polymerase binding, enzymes no longer activated and transcription proteins no longer produced.
Types of DNA deletions?
In frame= complete codon is removed, out of frame- sequence shifts to right once meaning reading frame is changed. In frame= later onset death typically.
What is a missense mutation?
Point mutation resulting in a codon coding for a different amino acid. Can result in silent mutation and a non functional protein.
