BSC 108 Exam 3 Kennedy-Latest Questions &
Answers.
The structure of a strand of DNA. - ANS it is a double helix, like a twisted ladder.
the ladder rings are nucleotide subunits and they have a covalent bond to the sugar
phosphate backbone (made of deoxyribose and a phosphate group)
What are the nucleotide subunits? - ANS adenine, guanine, cytosine, and thymine
How are the subunits held together? - ANS through a hydrogen bond
What are the nucleotide subunits compliments? - ANS Adenine and thymine
cytosine and guanine
How does DNA replicate? - ANS the parent strand breaks off into two and then
enzymes (DNA polymerases) attach the complimentary nucleotide to each side,
creating two separate daughter strands
What is the location site of where DNA replication begins on the double helix called? -
ANS the origins of replication
What is created when replication proceeds in both directions? - ANS replication
bubbles, they are created because at the origin the replication process proceeds in
other directions, creating a bubble.
What is the replication forks? - ANS It is the location where the parent cells is
separating and the complimentary nucleotide is being added creating the two new
strands
How does DNA determine specific traits (phenotypes)? - ANS Phenotypes arise from
the actions of a wide variety of proteins. To get these proteins this is what happens.
DNA transfers genetic information through transcription to RNA. Then through
translation genetic info is transferred from RNA into a polypeptide (protein strand)
What is the structure of RNA? - ANS It is a single-stranded nucleic acid.
it is the same as DNA except it uses ribose instead of deoxyribose in the sugar
phosphate backbone and it uses uracil instead of thymine
tRNA - ANS transfer RNA: translation of the genetic message carried in the mRNA into
the amino acid language of proteins (converts the three-letter words, codons, of nucleic
acids to the amino acid words of proteins)
What is the function of mRNA? - ANS Messenger molecules carry the coding
sequences for protein synthesis and are called transcripts.
, rRNA - ANS ribsosomal RNA
makes up ribosomes which are the organelles in the cytoplasm that coordinate the
functioning of mRNA and tRNA and actually make polypeptides
What two processes do genes code for specific proteins? - ANS transcription and
translation
What is transcription and where does it take place? - ANS Transcription is the synthesis
of mRNA under the direction of DNA, nucleus
What is translation and where does it take place? - ANS It is the synthesis of a
polypeptide (later becomes a protein) under the direction of mRNA
occurs on ribosomes in the cytoplasm
What is the structure of tRNA? - ANS It is made of a single strand of RNA. consisting of
about 80 nucleotides. Chain twists and folds upon itself, forming several double-
stranded regions in which short stretches of RNA base-pair with other stretches. one
end has a special triplet of bases called anticodons. it is complementary to a codon
triplet on mRNA. on the other side there is an amino acid attachment site.
What is a mutation? - ANS It is a change in the genetic material (the nucleotide
sequence) of a cell's DNA.
What is a point mutation? - ANS It is a change in once base pair of a gene.
What is a plasmid? - ANS A small ring of self-replicating DNA separate from the larger
chromosomes. Plasmids are most frequently derived from bacteria. they can carry any
gene and are passed from generation to generation. making them perfect for genetic
cloning.
What is a genetically modified organism? - ANS It is an organism that has acquired one
or more genes by artificial means.
What is a transgenic organism? - ANS it is an organism that contains genes from
another organism, typically of another species.
What is a restriction enzyme? - ANS A bacterial enzyme that cuts up foreign DNA at
one very specific nucleotide sequence. ysed in DNA technology to cut DNA molecules
in reproducible ways.
What is a PCR (polymerase chain reaction)? - ANS a technique used to obtain many
copies of a DNA molecule or many copies of part of a DNA molecule. A small amount of
DNA mixed with the enzyme DNA polymerase, DNA nucleotides, and a few other
ingredients replicates repeatedly in a test tube.
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