BIO 235 Exam 4 UPDATED ACTUAL Exam Questions and CORRECT Answers

BIO 235 Exam 4 UPDATED ACTUAL Exam
Questions and CORRECT Answers
Helicase - CORRECT ANSWER - Unwinds DNA in both directions



Gyrase - CORRECT ANSWER - topoisomerase that relieves supercoiling ahead of
replication fork


Single Stranded Binding proteins do what? - CORRECT ANSWER - Stabilize single
stranded DNA


Primase - CORRECT ANSWER - Enzyme that makes RNA primers



DNA polymerase cannot? - CORRECT ANSWER - Reconstruct the 5' end of a DNA
strand


this poses problems for linear chromosome integrity


Telomeres - CORRECT ANSWER - Repetitive DNA sequences TTAGGG
-no protein coding
-binds two types


Two types of proteins that binds in telomeres - CORRECT ANSWER - -Protective
proteins
-telomerase enzyme


Telomerase enzyme - CORRECT ANSWER - ribonucleoprotein



ribonucleoprotein - CORRECT ANSWER - composed of RNA and protein

, Binding of telomerase to TTAGGG - CORRECT ANSWER - Addition of RNA extends
ends
-carries its own DNA template as well....to finish DNA strand


Telomerase is key in determining what? - CORRECT ANSWER - Life-span of cell



Telomerase in immortalized cells - CORRECT ANSWER - ie germ line, cancer, yeast...


-Telomeres are fully reconstructed with each DNA replication


Telomerase in somatic cells - CORRECT ANSWER - Virtually absent
-shortened with every cell division
-somatic cells divide 30-50 times then die


in yeast, deletion of telomerase gene leads to what? - CORRECT ANSWER - Shortening
of chromosomes at each cell division


Telomerase activity in cancer cells? - CORRECT ANSWER - High activity



Telomerase activity in somatic cells which cancer derives? - CORRECT ANSWER - low
activity or absent


If you can block telomerase activity, you can do what? - CORRECT ANSWER - STOP
CANCER!


Nobel prize in medicine: - CORRECT ANSWER - Elizabeth Blackburn, Carol Greider,
Jack Szostak.