Cell-free extracts from S-strain cells of S. pneumoniae were frac oned to ______________ DNA, RNA,
protein, and other cell components. Each frac ons was then mixed with ______________ cells of S.
pneumoniae. Its ability to change these into cells with _________________ proper es resembling the
___________ cells was tested by injec ng the mixture into mice. Only the frac on containing ________
was able to ______________ the ______________ cells to _____________(or __________) cells that
could kill mice. - purify, R-strain, pathogenic, S-Strain, DNA, transform, R-strain, pathogenic, s-strain
In what decade did scien sts first iden fy chromosomes? - 1880s
Mito c chromosomes were first visualized with the use of very simple tools: a basic light microscope and
some dyes. Which of the following characteris cs of mito c chromosomes reflects how they were
named?
(a) mo on
(b) color
(c) shape
(d) loca on - (b) color
In the 1940s, proteins were thought to be the more likely molecules to house gene c informa on. What
was the primary reason that DNA was not originally believed to be the gene c material?
(a) DNA was a high density of nega ve charges
(b) Nucleo des were known to be a source of chemical energy for the cell.
(c) Both protein and nucleic acids were found to be components of chromosomes.
(d) DNA was found to contain only four different chemical building blocks. - (d) DNA was found to contain
only four different chemical building blocks
In a DNA double helix, ___________________________.
(a) the two DNA strands are iden cal
(b) purines pair with purines
(c) thymine pairs with cystosine
(d) the two DNA strands run an parallel - (d) the two DNA strands run an parallel
, You are a virologist studying the evolu on of viral genomes. You are studying two newly isolated virus
strains and have sequenced their genomes. You find that the genome of strain 1 contains 25% A, 55% G,
20% C, and 10% T. You report that you have isolated a virus with a single stranded DNA genome. Based
on what evidence can you make this conclusion?
(a) single-stranded genomes always have a large percentage of purines
(b) using the formula: G-A=C+T
(c) Double-stranded genomes have equal amounts of A and T - (c) Double-stranded genomes have equal
amounts of A and T
True or false?
DNA molecules, like proteins, consist of a single, long polymeric chain that is assembled from small
monomeric subunits. - False. DNA is double stranded and made of two polymers that are
complementary in sequence
True or False?
The polarity of a DNA strand results from the polarity of the nucleo de subunits. - true
True or false?
There are five different nucleo des that become incorporated into a DNA strand. - False. There are four
different nucleo des that are used to make a DNA polymer.
A fi h nucleo de, _______, is found in RNA replacing thymine nucleo des in the DNA sequence. - uracil
True or false?
Hydrogen bonds between each nucleo de hold individual DNA strands together. - False. Nucleo des are
linked covalently through phosphodiester bonds. Hydrogen bonding between nucleo des from opposite
strands holds the DNA together.
Which scien st or team of scien sts first demonstrated that cells contain some component that can be
transferred to a new popula on of cells and permanently causes changes in the new cells?
(a) Griffith