First Aid pg 66, 68-69 Biochem Flashcards Preview

FIRST aid 2015 - Sahaja > First Aid pg 66, 68-69 Biochem > Flashcards

Flashcards in First Aid pg 66, 68-69 Biochem Deck (17):

DIfference between transition and transversion point mutations?

ƒƒ Transition—purine to purine (e.g., A to G) or pyrimidine to pyrimidine (e.g., C to T).
ƒƒ Transversion—purine to pyrimidine (e.g., A to T) or pyrimidine to purine (e.g., C to G).


What is a silent mutation? What property of tRNA codons allows for silent mutations?

Nucleotide substitution but codes for same
(synonymous) amino acid; often base change
in 3rd position of codon (tRNA wobble).


Pt comes in with severe joint and muscle pain especially in the legs and pelvis. He also has a fever and higher white blood cells count. Culture results show a lactose negative motile bacilli. What type of underlying gene mutation does this patient most likely have? Which Chromosome

Pt has osteomyelitis caused by salmonella - indicating he has Sickle Cell disease. Caused by a Missense mutation of B globin gene (Glu-->Val), which is on Chr 11


A woman brings her 4 yr old child into your office, concerned bc he isn't walking well. He is continuing to use props and lift himself up with his arms instead of getting up smoothly. What types of gene mutations are likely in this patient? (Bonus if u know inheritance) Likely cause of death in the long run?

Child is demonstrating waddling gait, and Gower manuveur - has Duchenne musc dystrophy. XLR. Due to frameshift or nonsense mutations of dystrophin gene. Dilated cardiomyopathy most likely cause of death


Two parents come into your office due to concerns of possibly passing on genetic diseases, as they are thinking about having a child. Both parents are of Ashkenazi Jewish heritage. Which disease that can present with developmental delay and increased gangliosides should they be concerned about? What type of genetic mutation is most common?

Tay Sachs - frameshift mutation


Splice site mutations are seen with which heme pathology?

Some forms of Beta thalassemia


What two changes leads to increase transcription of the lac operon?

Low glucose and high lactose

Low glucose Ž  adenylyl cyclase activity Ž  generation of cAMP from ATP Ž activation of
catabolite activator protein (CAP) Ž  transcription.

ƒƒHigh lactose Ž unbinds repressor protein from repressor/operator site Ž  transcription.


If lactose is low, what prevents transcription of lac operon?

Represser protein stays attached to the operator site, preventing transcription


Inducer of inactivation of represser protein of lac operon done by? -( What inactivates represser)?



Which regulators of gene expression are located up and downstream of a gene locus?

Promoter - upstream
Enhancer/silencer - up or downstream, or even within the intron of the gene


Where does RNA polymerase II bind?



Promoter mutation would affect gene expression how?

Dramatic decrease in level of gene transcription


What is the name of the initial RNA transcript?

hnRNA - heterogenous nuclear RNA --> then converted to mRNA


2 post transcriptional modifications?

ƒƒ Capping of 5′ end (addition of
7-methylguanosine cap)
ƒƒ Polyadenylation of 3′ end (≈ 200 A’s)
ƒƒ Splicing out of introns
Capped, tailed, and spliced transcript is called


Location of mRNA quality control and storage?

P-bodies (make sure you did it Properly. Or, Peabody is the award for best in radio/media)


What is contained in a P body?

P-bodies, which contain exonucleases,
decapping enzymes, and microRNAs;


Patient presents with hand s that tend to change color with different ambient temperatures and get very cold at times. They are prescribed CCB for their issue. It is determined that the patient has Raynaud's secondary to two different diseases associated with auto-Ab vs ribonucleoproteins. Which diseases and what are the Ab?

Antibodies to spliceosomal snRNPs (anti-
Smith antibodies) are highly specific for
SLE. Anti-U1 RNP antibodies are highly
associated with mixed connective tissue
disease (MCTD).