Heterochromatin Study guides, Class notes & Summaries

histones are rich in which 2 AA's (Ans- lysine & argenine Barr bodies (what, type of chromatin) (Ans- inactive X chromosomes heterochromatin (highly condensed, sterically inaccessible) less condensed, transcriptionally active, sterically accessible chromatin (Ans- euchromatin DNA methylation at CpG islands (Ans- represses transcription "CpG Methylation makes DNA Mute" DNA methylation (what is methylated and why?) (Ans- template strand cytosine and adenine are methylate...

Cell division is used for which of the following ? Reproduction of single-celled organisms, growth of multicellular organisms, repair and replacement of cells, and sperm and egg production Asexual and sexual reproduction differs in that sexual reproduction_____________ Can produce great variation among the offspring (Meiosis) Asexual Reproduction ____________ Produces offspring genetically identical to the parent (Mitosis) Most of the time, DNA is in the form of____________ Euchromatin W...

USMLE Biochemistry Exam Questions with Correct Answers Heterochromatin - ANSWER Highly Condensed DNA Transcriptionally inactive Ex. Barr bodies (inactivated X chromosomes) Euchromatin - ANSWER Less condensed DNA Transcriptionally active DNA Methylation - ANSWER Occurs at *CpG Islands* to repress transcription 'CpG Methylation Makes DNA MUTE' Template strand *cytosine* and *adenine* are methylated, which allow mismatch repair enzymes to distingu...

Histones are rich in which 2 amino acids? - correct answerLysine Arginine What histone protein is responsible for binding to the nucleosome and to the "linker" DNA thereby stabilizing the chromatin fiber? - correct answerH1 When does DNA and histone synthesis occur in the cell cycle? - correct answerS-phase Will the following be increased or decreased or neutral in heterochromatin?

histones are rich in which 2 AA's - correct answer lysine & argenine Barr bodies (what, type of chromatin) - correct answer inactive X chromosomes heterochromatin (highly condensed, sterically inaccessible) less condensed, transcriptionally active, sterically accessible chromatin - correct answer euchromatin DNA methylation at CpG islands - correct answer represses transcription "CpG Methylation makes DNA Mute" DNA methylation (what is methylated and why?) - correct answer tem...

Pyrimidine dimers formed in DNA due to UV radiation can be repaired by? SOS repair Double strand break repair Mismatch repair Photoreactivation repair (nucleotide excision repair) Base excision repair - CORRECT ANSWER Photoreactivation repair (nucleotide excision repair) Which of the following repair mechanisms uses methyl groups to distinguish between parental and daughter strands? Answers: Mismatch repair Photoreactivation repair (Nucleotide excision repair) SOS repair Doub...

The paramecium discussed in class contained an organelle called the contractile vacuole. This is the presumed precursor of the: - Correct answer-kidney A cell that is anchorage-dependent for growth will also exhibit contact inhibition. - Correct answer-true In your own multicellular body, cells with different functions have different DNA. - Correct answer-false The contractile vacuole of the paramecium is possibly an evolutionary precursor of the kidney. - Correct answer-true The paramec...

Pyrimidine dimers formed in DNA due to UV radiation can be repaired by? SOS repair Double strand break repair Mismatch repair Photoreactivation repair (nucleotide excision repair) Base excision repair - CORRECT ANSWER Photoreactivation repair (nucleotide excision repair) Which of the following repair mechanisms uses methyl groups to distinguish between parental and daughter strands? Answers: Mismatch repair Photoreactivation repair (Nucleotide excision repair) SOS repair Doubl...

Heterochromatin correct answers form of DNA - tightly coiled, usually peripherally placed in the nucleus, dark-staining, inactive - not involved in RNA synthesis Euchromatin correct answers form of DNA - partially/fully uncoiled, centrally placed, light staining, active - involved in RNA synthesis Basophilic correct answers stains readily with basic dyes (e.g haemotoxylin is a basic dye that stains the nucleus - which is basophilic - blue/purple) Nuclear envelope correct answers double-...

USMLE Step 1- Biochemistry Exam Questions & Answers 2023/2024 Histones are rich in which 2 amino acids? - ANSWER-Lysine Arginine What histone protein is responsible for binding to the nucleosome and to the "linker" DNA thereby stabilizing the chromatin fiber? - ANSWER-H1 When does DNA and histone synthesis occur in the cell cycle? - ANSWER-S-phase Will the following be increased or decreased or neutral in heterochromatin? methylation acetylation - ANSWER-methylation increased ...