sample3MT2Key

sample3MT2Key - Bio 115 Midterm #2 Name_ Instructions:...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Bio 115 Name__________________ Midterm #2 ________________________________________________________________________ page 1 page total: Instructions: Write your name in ink at the top of every page. Do not write on the back of pages. Restrict your answers to the space provided. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Answer the following questions with "true" or "false". For each "true" answer, give an example or explanation that supports the statement. For each "false" answer, explain why the statement is false. (3 points each) 1. Regulating Poly-A tail length is a mechanism for controlling mRNA lifetime. True. For example, short Poly-A tails are associated with short half-life and long Poly-A tails are associated with long half-life. 2. Histone H1 is necessary for assembly of the 10 nm chromatin fiber. False. Histone H1 is involved in 30 nm fiber assembly. Only histones H2, H3 and H4 are needed to form nucleosomes for 10 nm fiber (“beads on a string”) formation. 3. ATP-dependent chromatin remodeling machines alter chromatin structure by modifying histone tails. False. CRMs alter nucleosome positioning. Histone modifying enzymes (histone acetyltransferases, etc.) modify histone tails. 4. The stop codon UAG in a messenger RNA is recognized by a tRNA with a CUA anticodon. False. Stop codons are recognized by a protein (RF1). 5. DNase I hypersensitive sites are usually located in heterochromatin. False. DNase I hypersensitive sites are associated with actively transcribed genes in euchromatin. 6. Only RNA polymerase II transcripts go through extensive RNA processing. False. Both Pol I (rRNA transcripts) and Pol III (tRNA transcripts) are processed. They are chemically modified and cleaved at specific sequences to generate mature transcripts.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Bio 115 Name__________________ Midterm #2 ________________________________________________________________________ page 2 page total: 6. Binding of the origin recognition complex triggers DNA replication in yeast. False. DNA replication is triggered by factors (licensing factor) coupled to cell-cycle control. 7. The sliding clamp increases the processivity of DNA helicase during replication. False. The sliding clamp increases processivity of DNA polymerase. 8. An IRES can bypass the need for a cap in eukaryotic translation initiation. True. An IRES is an internal ribosome entry site that can recruit the small ribosome subunit to the mRNA to scan for an AUG. 9. EF-Tu (eEF1) does not chaperone all charged tRNAs to the ribosome during translation. True. EF-Tu does not chaperone the initiator tRNAiMet. eIf2 does this. 10. Chain terminating nucleotides cannot be incorporated into growing DNA chains because they lack phosphates. False. Chain terminating nucleotides lack a 3’OH.
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This document was uploaded on 08/12/2009.

Page1 / 7

sample3MT2Key - Bio 115 Midterm #2 Name_ Instructions:...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online