Molecular Genetics US Medical PG Flashcards - Medical Study Cards
Master Molecular Genetics with OnCourse flashcards. These spaced repetition flashcards are designed for medical students preparing for NEET PG, USMLE Step 1, USMLE Step 2, MBBS exams, and other medical licensing examinations.
Molecular Genetics Flashcard Deck - 10 Cards
Flashcard 391: What are the following markers?
-Ras
-c-Jun
-B1 - adrenoreceptor
-S- 100
-Adenylate cyclase
-C-fos
Answer: Ras: Protooncogene activates MAP kinase pathway, affect transcription, has GTPase gene product. (associated with colon, pancreatic, and lung cancer.)
-c-Jun: The protein that binds to DNA in southwestern blot (double stranded DNA probe).
-B1-adrenoreceptor: Gs protein couple receptor.
-Adenylate cyclase: cleaves ATP to form cAMP.
-S-100: calcium binding proteins.
-c-Fos: Proteins that bind to DNA to form double stranded DNA probe in Southwestern blot.
Flashcard 392: Match the following with their specific definition?
-Unwinding of double helix
-Removal of supercoils
-Stabilization of unwound template strands
-Synthesis of RNA primer
-5' to 3 DNA synthesis & 3' to 5' exonuclease activity
-Removes RNA primer
-Has 5' to 3' exonuclease activity
-Joining of Okazaki fragments
-Similar work to DNA polymerase 3
-Connect the lagging strands together.
Answer: Unwinding of double helix: Helicase
-Removal of supercoils: DNA gyrase (Topoisomerase 2)
-Stabilization of unwound template strands: single stranded DNA binding protein
-Synthesis of RNA primer: Primase (RNA polymerase)
-5' to 3 DNA synthesis & 3' to 5' exonuclease activity: DNA polymerase 3
-Removes RNA primer: DNA polymerase 1
-Has 5' to 3' exonuclease activity: DNA polymerase 1
-Joining of Okazaki fragments: DNA ligase
-Similar work to DNA polymerase 3: DNA polymerase 1, & 2
-Connect the lagging strands together: DNA ligase
Flashcard 393: A 2 y/o boy comes with easy bruising.
-Parent stated he develops marked bruising & open wounds following minor trauma.
-Skin is difficult to suture due to its extreme fragility.
-Physical exam: Hyperextensible skin, multiple ecchymoses over the forearms.
- Skin biopsy: defect in extracellular processing of collagen.
-Which steps of collagen synthesis is most likely impaired in this patient?
Answer: N-terminal propeptide removal or N & C terminal propeptide removal.
due to defect in procollagen peptidases (defect in collagen 3 & 5) that lead to Ehlers-Danlos syndrome.
(hyperextensible skin, joint laxity, tissue fragility)
Flashcard 394: True or False in relation to sickle cell anemia?
a.) HbS decreases Beta -globin interaction with 2,3-diphosphoglycerate
b.) HbS impairs oxygen binding to the heme moiety
c.) HbS allows hydrophobic interaction among hemoglobin molecules.
Answer: a.) & b.) False, otherwise HbS will have a higher affinity for oxygen or higher affinity for 2,3 BPG. HbS causes partial destruction of the hememolecules that prevent from carry lots of oxygen.
c.) True, due to Glu (-) (polar) ---> Val (No charge) (non polar)
Flashcard 395: What are the speed of the followings in gel eletrophoresis in relation to normal hemoglobin (HbA)?
-Framshift mutation
-Missense mutation
-Nonsense mutation
-Silent mutation
-Trinucleotide expansion
Answer: Frameshift mutation: involves in Alpha thalassema (Duchenne M. D.). Will contain HbH that will move faster than HbA.
-Missense mutation: Most likely occurs in HbC anemia or sickle cell anemia (due to change of amino acids). will occurs slower than HbS, & HbA.
-Nonsense mutation: Will create smaller protein due to early stop on translation (duchenne M. D.). They will tend to move faster.
-Silent mutation: will not affect protein since they will code for the same amino acid
-Trinucleotide expansions: will result in a large proteins, they will move slower than HbA.
Flashcard 396: In a research, they isolate small circular DNA that resemble a bacterial chromosome from exocrine panreatic cells..
-Further analysis shows that these molecules code for proteins, transfer RNA, & ribosomal RNA.
-From which of the following cellular structures did these DNA molecules most likely originate?
Answer: D.) Mitochondria
Key: Mitochondria contains circular DNA chromosomes that resembles bacterial (prokaryotic) chromosomes. Inherited from Mother.
Mutation in mitochondrial DNA could cause disease to pass from mother to offsprings.
A.) Rough Endoplasmic reticulum: contains multiple ribosomes to synthesize proteins.
B.) Nucleolus: site of synthesis of ribosomal components.
C.) Nucleus: contains euchromatin (chromosomes) inside of it.
E.) Exocrine granules: usually contains enzymes and other proteins package for secretion.
Flashcard 397: 24 y/o woman is diagnosed with gestational diabetes mellitus during her 1st pregnancy.
-Mother & younger sister had high blood surgars during pregnancy.
-If this patient's gestational hyperglycemia is genetically predisposed, she is most likely to have decreased activity in what enzyme?
Answer: Glucokinase
Glucokinase need to phosphorylate glucose to breakdown in glycolysis in order to release ATP to close down the K channel, which lead to influx of Ca that causes release of insulin.
due to Maturity Onset Diabetes of the Young (MODY)
(hereditary mutation of glucokinase gene)
Key: Her mother & her younger sister had diabetes too during their pregnancy, very young.
Flashcard 398: What types of nuclease activity will present in the following enzymes?
-DNA polymerase 1
-DNA polymerase 3
Answer: DNA polymerase 1: 5' to 3' exonuclease activity
DNA polymerase 3: 3' to 5' exonuclease activity
Flashcard 399: In an experiment, individual bacterial colonies lack a specific enzyme involed in DNA replication.
-This specific enzyme is responsible for removing short fragments of RNA that are base paired to the DNA template.
-Which enzymes is most likely deficient in this strain of E. coli?
Answer: DNA polymerase 1.
because it removes primers & replaced them with DNA nucleotides.
** Key: Don't confuse with Primers. Primers add DNA nucleotide while DNA polymerase 1 removes primers.
Flashcard 400: 6 y/o African American boy comes in by his parents due to easy fatigability.
-Physical exam: splenomegaly, CBC: mild anemia.
-Hemoglobin electrophoresis for the patient are shown below compared to individuals with normal hemoglobin and know sickle cell disease.
What mutation is most likely cause of this patient's condition?
Answer: Missense mutation
due to HbC hemolytic anemia
Speed on gel electrophoresis: A,S,C
HbA: normal
HbS: sickle cell anemia
HbC: Mild hemolytic anemia.
Keywords: Molecular Genetics flashcards, medical flashcards, NEET PG preparation, USMLE Step 1 flashcards, Anki alternative, spaced repetition medical, OnCourse flashcards
