AP Biology Chapter 16/17 Review
Erwin Chargaff's Rule (1950)
- DNA composition varies from one species to the next (making it a more credible candidate) - The amount of A=T, C=G (approximately)
Primase
- RNA polymerase - lays down RNA primer
DNA ligase
- enzyme used during replication to attach Okazaki fragments to each other; leading strand to lagging strand
DNA polymerase
- enzyme used to position nucleotides during DNA replication - replaces RNA primer with DNA - can repair mistakes in DNA base pairing
Where do mutations come from?
- mutagens, chemicals, drugs - light - errors in normal cell processes - biological agents
Topoisomerase
- snips one or both strands of template DNA - relieves tension created by helicase - prevents tangling or breaking of the template DNA
Helicase
- unwinds double-stranded DNA, using ATP - creates and widens the replication bubble
Watson and Crick (1953)
- used cardboard and metal to build a model of DNA - franklin's X-ray crystallographic images of DNA enabled Watson to deduce that DNA was helical and to determine the width and spacing of the nitrogenous bases (Purines pair with pyrimidines) - using Chargaff's Rule, they paired A=T, C=G
If a segment of DNA is 5'-TAC GAT TAG-3', the RNA that results from the transcription of this segment will be
3'-AUG CUA AUC-5'
A tobacco plant can be made to express a gene from fireflies, resulting in the emission of light. Which of the following is the basis for this phenomenon?
Transcription and translation are fundamentally similar in both fireflies and tobacco plants
Cells that contain only circular chromosomes are most probably which of the following?
bacterial cells
tRNA
binds amino acids and brings them to the ribosome
Fredrick Griffith (1928)
determined that cells can be transformed; genetic material from one cell can go into another cell and the traits can be expressed
Analysis of DNA sequences from two individuals of the same species results in a greater estimate of genetic variability than does analysis of amino acid sequences from the same individuals because
different DNA sequences can code for the same amino acid
RNA polymerase
enzyme used in synthesis of mRNA
tRNA molecules deliver amino acids to ribosomes where the amino acid next
is covalently bonded to a growing polypeptide
rRNA
major component of ribosome
Transcription
process in which RNA is produced using a DNA template
Translation
process in which a protein is assembled at a ribosome
Transformation
process in which naked DNA is taken up to be a bacterial or yeast cell
mRNA
read by ribosome, as a template for making proteins
Antibiotics interfere with prokaryotic cell functions. Streptomycin is an antibiotic that affects the small ribosomal subunit in prokaryotes. Specifically, streptomycin interferes with the proper binding of tRNA to mRNA in prokaryotic ribosomes. Which of the following best predicts the most direct effect of exposing prokaryotic cells to streptomycin?
synthesis of polypeptides will be inhibited
What normally leads to the production of functional messenger RNA in eukaryotic cells?
the removal of portions of RNA known as intervening sequences (introns)
Ribosome
translation occurs here
Avery, MacLeod, and McCarty (1944)
used Griffith's basic experiment but focused on separating the components of the heat-killed (S cells) into DNA, RNA, carbohydrates, and protein to determine which one transformed the bacteria and killed the mouse
Hershey-Chase Experiment (1952)
used a bacteriophage: a virus that infects a bacteria
Rosalind Franklin (1952)
used x-ray diffraction to take pictures of DNA (photo 51) and determined phosphates were on the outside of the structure