DNA Structure & Function (DNA replication)

• The ability of DNA polymerase to detect that it has made an error, and remove the incorrect base before continuing

  proofreading
• Damaged bases are identified and removed, and replaced with correct bases

  nucleotide excision repair
• Newly replicated DNA is scanned looking for errors. If an error is found, a small portion of the DNA is removed and re-synthesized

  mismatch repair
• Eukaryotic DNA is wrapped around histone proteins, and these histones must be removed and then replaced during replication


  true
• What was the major conclusion from the Hershey-Chase bacteriophage experiments?

  DNA was the genetic material, not protein
• A new mutation in a person's liver cells (somatic cells) will be passed on to the next generation if that person has children

  false
• Key experiments called transformation experiments showed that the unknown chemical components from one type of bacterial could be transferred to another type, resulting in the change of the new bacteria's characteristics
• The rate of replication measures how many nucleotides can be added to a growing DNA strand per second. Eukaryotes have much more DNA than prokaryotes, and have a much faster rate of replication

  false
• A mutation which results in the change of one nucleotide of the DNA is called a

  point mutation
• Mutations caused by DNA damage due to

  benzopyrene (a chemical) from cigarette smoke and carcinogenic (cancer-causing) chemicals
• Adds new DNA nucleotides to replace primers after their removal


  polymerase I
• Builds primers made of RNA to starts each new DNA strand

  primase
• Main enzyme that builds DNA by adding nucleotides in the 5'- 3' direction

  polymerase III
• Seals gaps between DNA fragments by creating final phosphodiester bond


  DNA ligase
• Opens up the DNA double helix at the replication forks

  helicase
• What are Chargaff's rules?

  A=T & G=C
• DNA replicates itself semi conservatively, which means that only half of the genetic information is copies and passed to the next cell, and half is lost


  false
• The 2 strands of DNA being replicated at the replication fork must grow differently because of constraints on how DNA can be assembled and built. These constraints are:

  DNA must be built in the 5' to 3' direction & DNA strands must be anti-parallel
• The process of DNA replication refers to the complete and accurate copying of a cell's DNA prior to cell division


  true
• Activating telomerase in cells is being studies as a potential way to

  reverse effects of aging
• What is the function of telomeres?


  they protect genes from being deleted as cells divide
• The ends of eukaryotic chromosomes are often made up of a longs string of repetitive sequences. These end structures are called

  telomeres
• The main DNA building enzyme is called DNA polymerase. It builds new strands of DNA by adding complementary nucleotides to the 3' (-OH) end of a growing strand
• How many origins of replication are in the human genome (total in all 23 pairs of chromosomes)?

  up to 100,000
• DNA replication begins at a specific site on the DNA called the

  origin of replication
• What happens to the telomeres after multiple rounds of cell division if there is no telomerase enzyme in the cells?

  they shorten
• Features of DNA structure

  DNA is usually present in cells as a double helix and the 2 strands of the double helix are antiparallel