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34 terms

BIOL test 2

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animal cells have "sacrificial" ends on their chromosomes that determine the number of times a cell can divide. these ends are called:
telomeres
cytokinesis:
refers to the division of a cell's cytoplasm
a nucleotide requires three phosphates in order to be added to the growing DNA strand. why?
the energy from the cleavage of the first two phosphates provides the energy to covalently link the nucleotides together
which of the following nucleotide bases are present in equal amounts in DNA?
- adenine and thymine
- guanine and cytosine
during the polymerase chain reaction (PCR), two strands of DNA are separated by:
exposure to heat
a major difference between DNA and RNA is that:
all of these are correct
a frameshift mutation:
results from an insertion or deletion in a DNA sequence
errors sometimes occur when DNA duplicates itself. why might that be a good thing?
most errors in DNA are bad, but some create new, useful versions of genes that can be acted on by natural selection
which of the following correctly describes the locations of transcription and translation within a eukaryotic cell?
DNA is transcribed in the nucleus, then the mRNA transcript is transported to the cytosol to be translated into protein
a VNTR is:
a region of DNA containing short, repeated sequences that is used to determine the relatedness of individuals
DNA is a macromolecule that stores information. Which component of the nucleotide contains this information?
the base
Bt corn is a genetically engineered plant. What feature gives it value as a crop plant?
the plant produces a toin designed to kill corn borers
cancer cells are different from other cells in that they have lost their "contact inhibition." "Contact inhibition" means:
most cells stop dividing when they bump up against other cells or collections of cells
the majority of a eukaryotic cell's life is spent in an "in-between-division" stage referred to as:
interphase
in most bacteria, the DNA is carried:
in a single circular chromosome
gene therapy involves:
introducing non-defective genes into the cells of an individual with a genetic disorder
the combination of DNA from two or more sources is called:
recombinant DNA
one of the possible concerns about genetically modified foods is that they might kill organisms that we don't want to kill. which of the following is an example of this phenomenon?
the pollen from plants containing insect-killing Bt genes can be blown onto other plants. insects that we don't want to kill, such as monarch butterflies, may be killed by such pollen.
during transcription, at the point where the DNA strand being copied has an adenine, ___ is added to the mRNA
a uracil
restriction enzymes that are used in biotechnology come from:
bacteria
cells have a variety of different characteristics, despite the fact that all of the cells in your body have the same DNA. this is due to differences in ___
gene expression
a codon is:
the triplet code in RNA which determines the identity of a corresponding amino acid
in humans, ___ of our DNA is coding DNA
less than 5%
the complementary base pairs in a DNA molecule are stabilized by:
weak hydrogen bonds
semi-conservative replication of DNA means that:
half of the DNA each daughter cell recieves comes directly from the original parent cell's DNA double helix
an important difference between mRNA and DNA is:
mRNA contains uracil instead of thymine, which is found in DNA
the first gene therapy experiments were undertaken in an attempt to cure otherwise fatal genetic diseases in children. what type of incurable genetic disease was the first gene therapy trial attempting to cure?
Severe Combined Immune Deficiency (SCID)
to get from a gene to a protein, two processes must occur: transcription, in which ___, and translation, in which ___.
a copy of the gene's sequence of bases is made; that copy is used to direct the production of a protein
the process of using the information encoded in mRNA molecules to assemble polypeptides from amino acids is called:
translation
cloning involves:
taking the nucleus out of an egg cell and replacing it with the nucleus of a somatic cell
the expression of a gene to form a polypeptide occurs in two major steps. what are these two steps in their correct chronological order?
transcription and then translation
transgenic bacteria are bacteria:
that have a sequence of DNA from another organism inserted into them
one of the four nucleotide bases in DNA is replaced by a different base in RNA. which base is it and what is it replaced by?
thymine, replaced by uracil
in order for a eukaryotic cell to undergo reproduction and divide, certain steps must be successfully completed. select from the choices below the one that is NOT one of these necessary steps.
there must be proper reshuffling of the genetic material in order to provide diversity within the gametes