Show Menu
Cheatography
  1. Home >
  2. Cheat Sheets >

AP Bio Chpt. 17 Cheat Sheet by

DNA transforms Bacteria

Frederick Griffith studied two strains of pneumonia
pathogenic and nonpat­hogenic
heat-k­illed pathogenic + nonpat­hogenic bacteria
= pathogenic bacteria (live diseas­e-c­ausing)
transf­orm­ation
change in genotype and phenotype due to assimi­lation of external DNA by a cell
scientists studied to find the genetic material of chromo­somes - protein vs. DNA

DNA transforms Bacteria (cont.)

Oswald Avery also proved that DNA was the molecule that transf­ormed bacteria

Viruses

DNA or RNA in a protein coat
infect by taking over a cell's metabolic machinery
Bacter­iop­hages
viruses that infect bacteria
Henry and Chase showed that DNA was the genetic material that infected the bacteria
Used radioa­ctive isotope markers to label DNA and proteins of phages. Phage DNA entered the bacteria cell, but protein did not.

Chargaff's Rule

concen­tration of … [A] = [T] [C] = [G]

Rosalind Franklin

x-ray crysta­llo­graphy
image of DNA produced by x-rays diffra­cting when passing through DNA fibers
DNA is a double helix, with two anti-p­arallel sugar-­pho­sphate backbones, and nitrog­enous bases in the molecule's interior
anti-p­arallel - subunits run in opposite directions
  

DNA is a polymer of nucle­otides

compon­ents: nitrog­enous base, deoxyr­ibose sugar, phosphate group
bases: adenine, guanine, thymine, cytosine

Structure of DNA

DNA is a polymer of nucleo­tides connected by covalent bonds
4 nitrog­enous bases:
Purines (double ring) [A] [G]
Pyrimi­dines (single ring) - [C] [T]
DNA base pairing
PURINE always pairs with PYRIMIDINE
2 of the same would be too wide/n­arrow
3 hydrogen bonds between C and G
2 hydrogen bonds between A and T

DNA Replic­ation

S phase of Interphase
DNA made from existing DNA strand
semico­nse­rvative model
one parent strand serves as a template to a comple­mentary strand
 
half of parent strand is conserved in each daughter strand
- Meselson and Stahl

DNA Replic­ation (cont.)

origins of replic­ation
where replic­ation of DNA molecule begins
bacterial chromosome
circular, single origin
eukaryotic chromosome
linear, thousands of origins
replic­ation fork
Y-shaped region formed by unwinding of parent strands
- reference drawings to unders­tanding rest of replic­ation -
  

Proofr­eading DNA

DNA polymerase
proofreads each nucleotide as it's covalently bonded
mismatch repair
other enzymes remove and repair incorrect nucleo­tides
nucleotide excision repair
mutated strand is cut out by enzyme nuclease, and the gap is filled with DNA polymerase and ligase
- seen in skin cells when correcting thymine dimmers cause by UV rays

Evolution Signif­icance of DNA Nucleo­tides

Mutations occur when uncorr­ected mismatched nucleo­tides are replicated and passed onto a daughter cell. Usually harmful and permanent genetic changes that support natural selection.

Replic­ation at Molecule Ends

- reference drawings -

Inside a Chromosome

eukaryotic cell
one long DNA double helix with large amnt. of protein =
chromatin
the long DNA fits in the nucleus through packing
- reference drawings -
 

Metadata

  • Languages:
  • Published: 6th December, 2016

Comments

No comments yet. Add yours below!

Add a Comment

Your Comment

Please enter your name.

    Please enter your email address

      Please enter your Comment.

          Related Cheat Sheets

          Cell Structure and Function Cheat Sheet
          Fundamental unit of life Cheat Sheet

          More Cheat Sheets by annadanpd