DNA

• What are the requirements for genetic material?


  • Able to store lots of information
  • Stable
  • Inheritable
  • Able to be replicated
• What is DNA classified as?


  A polymer
• What are the components of a nucleoside monophosphate (NMP)?


  A base, a sugar, and one phosphate group
• How many nitrogenous bases are there in DNA?


  Four
• What are the four nitrogenous bases in DNA?


  Adenine, guanine, cytosine, thymine
• What type of rings do purines and pyrimidines have?


  Purines have double rings, pyrimidines have single rings
• How can you remember the nitrogenous bases in DNA?


  Using the phrase "Pur e a s g old (AG) C u t the Py (CT)"
• What type of sugar is used in DNA?

  Deoxyribose
• What role does the phosphate group play in DNA?


  It helps to form the backbone of the DNA molecule
• What type of bonds are formed between nucleoside monophosphates in DNA?


  Strong phosphodiester bonds
• What was the assumption about DNA prior to 1953?


  • DNA was thought to be made up of just one strand/one polymer
• Who published that proteins could form α-helices in 1951?


  Linus Pauling
• What technique did Rosalind Franklin and Raymond Gosling use to study DNA?


  1. ray diffraction
• What did the X-ray diffraction confirm about DNA?


  That DNA formed an α-helix
• How many chains does DNA consist of?


  Two chains
• What does it mean for DNA chains to be antiparallel?


  They run in opposite directions
• What is the significance of DNA being antiparallel?


  It enables twice the amount of biological information to be stored
• What base pairs with thymine in DNA?


  Adenine
• What base pairs with cytosine in DNA?


  Guanine
• How many hydrogen bonds are formed between thymine and adenine?


  Two hydrogen bonds
• How many hydrogen bonds are formed between cytosine and guanine?


  Three hydrogen bonds
• What is the structure of DNA?


  • Made up of two chains (polymers of NMPs)
  • Chains run in opposite directions (antiparallel)
  • 5’ end has the phosphate group
  • 3’ end has the sugar
  • Base pairs held together by hydrogen bonds
  • Alternating sugar and phosphate groups make the backbone
• What are the major and minor grooves in DNA?

  Major groove and minor groove
• How do proteins access DNA sequences?


  Through the major grooves
• What provides stability to the DNA molecule?

  Strong covalent phosphodiester bonds and stable hydrogen bonds
• Where can students find suggested reading for further study?

  Chapter 2, pages 11-19
• How is DNA stored in the cell?


  As chromosomes
• What does each chromosome consist of?


  One DNA molecule tightly wrapped around histone protein complexes
• What is the combination of DNA and histones called?

  Nucleosome
• Why is DNA packaged into chromosomes?


  For structural support, compact shape, and gene regulation
• How many pairs of chromosomes does each cell have?


  23 pairs
• From whom does each chromosome in a pair come?


  One chromosome is inherited from each parent
• What type of cell has two copies of each chromosome?


  Diploid cell
• What must cells do during cell division regarding DNA?


  Cells must duplicate or replicate their DNA
• What do daughter cells need after cell division?


  The full set of chromosomes
• When does DNA replication occur in the cell cycle?


  During the S-phase of interphase
• What are the three stages of DNA replication?

  Initiation, elongation, termination
• What happens if DNA replication does not occur?


  The cell cycle cannot happen or is faulty
• What is the first step in DNA replication initiation?


  Origin selection
• What complex selects the replication origins?


  The Origin Recognition Complex (ORC)