In a double-stranded DNA molecule, which of the following base ratios always equal
1?
A. (A+T)/(G+C)
B. C/G
C. (A+G)/(C+T)
D. (G+T)/(A+C) - ANSWER: B, C, and D
What does it mean to say that double-stranded nucleic acids are antiparallel? -
ANSWER: It means that one strand is going "up" (3' to 5') while the other is going
"down" (5' to 3')
How many rings do purines have? - ANSWER: two
What holds the two sides of the DNA helix together? - ANSWER: hydrogen bond
In a strand of DNA, the percentage of thymine is 30%. What is the percentage of
cytosine? Adenine? Guanine? - ANSWER: Cytosine: 20%
Adenine: 30%
Guanine: 20%
Griffith's Transformation Experiment - ANSWER: - concluded that R-strain bacteria
must have taken up what he called a "transforming principle" from the heat-killed S
bacteria, which allowed them to "transform" into smooth-coated bacteria and
become virulent
Avery, MacLeod, McCarty Experiments - ANSWER: - showed that DNA (not proteins)
can transform the properties of cells, clarifying the chemical nature of genes
Hershey and Chase Experiment - ANSWER: - concluded that when bacteriophages,
which are composed of DNA and protein, infect bacteria, their DNA enters the host
bacterial cell, but most of their protein does not
What were the order of the experiments that determined the presence of genetic
material in DNA? - ANSWER: 1. Griffith
2. Avery, MacLeod, McCarty
3. Hershey and Chase
cytokinesis - ANSWER: - the cytoplasmic division of a cell, bringing about the
separation into two daughter cells
anaphase II - ANSWER: - mosaicked sister chromatids separate
sister chromatids - ANSWER: - identical copies of a chromatid joined by a common
centromere
, metaphase I - ANSWER: - paired chromosomes align along the center of the cell
metaphase II - ANSWER: - mosaicked chromosomes align along the center of the cell
kinetochore - ANSWER: - where spindle fibers attach during cell division
anaphase I - ANSWER: - mosaicked sister chromatids move to opposite ends of the
cell
telophase - ANSWER: - when chromosomes move in opposite directions so two new
cells can be formed from one
metaphase - ANSWER: - chromosomes align along the cell's equatorial plan and
spindle fibers attach to the centromeres of each chromosome
homologous chromosomes - ANSWER: two chromosomes, one of paternal origin, the
other of maternal origin, that are identical in appearance
haploid - ANSWER: - a cell that contains a single set of chromosomes
prophase - ANSWER: - chromatin condenses into visible chromosomes, the nuclear
envelope breaks down, and spindle fibers begin to form
telophase I - ANSWER: - paired homologous chromosomes separate
telophase II - ANSWER: - homologous chromosomes move to opposite ends of the
cell
anaphase - ANSWER: - sister chromatids are separated
chromatin - ANSWER: - the material in which chromosomes are made up of
prophase I - ANSWER: - cross over occurs
chromosomes - ANSWER: - a threadlike structure of nucleic acids and protein
carrying genetic information
diploid - ANSWER: - the presence of two complete sets of chromosomes
gametogenesis - ANSWER: - the process in which cells undergo meiosis to form
gametes
In what phase do chromosomes first become visible? - ANSWER: prophase
DNA is in what form during interphase? - ANSWER: uncondensed