113779
Description
Flashcards by sammi_taylor01, updated more than 1 year ago
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Created by sammi_taylor01
over 11 years ago
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| Question | Answer |
| What are the two main stages of cell division? | nuclear division and cell division |
| What must occur before a cell divides? | It's DNA must be replicated in order for the daughter cells to contain enough genetic information to produce enzymes and other substances they may need. |
| Why is DNA semi-conservative? | 50% is from the original DNA strand and 50% is from a new DNA strand |
| What type of bonds are between the four organic bases | hydrogen bonds between A and T as well as between G and C |
| What enzyme is used to break down the hydrogen bonds and which enzyme is used to put them base pairs together again? | DNA helicase- unzips the genes DNA polymerase- puts the genes back together |
| Explain the steps to DNA replication. | helicase breaks down hydrogen bonds, double helix separates, polynucleotide strand is then joined with other nucleotides via DNA polymerase to form 50% new and 50% original strand. |
| If an inhibitor of DNA polymerase were introduced into a cell, explain what the effect would be on DNA replication. | The linking together of new nucleotides could not take place. While the nucleotides would match up to be complementary, they would not join together to form new strands. |
| What's the evidence for semi-conservative replication | Watson and Crick used DNA that contained Nitrogen- some 14N and some 15N |
| Why was bacteria chosen to be used for this experiment? | It divides rapidly and you can extract their DNA easily (via centrifugation) |
| What happens with the medium containing 14N and 15N bacteria | 14N is light so will float 15N is heavier so will be closer to the bottom |
| What happens when 14N and 15N grow and allow to replicate once? | They are bound together and form in between where the 15N and the 14N formed. |
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