CHAPTER 9—FROM DNA TO PROTEIN
There are how many different types of amino acids?
20 different amino acids
The genetic code is made up of units consisting of how many nucleotides?
3 nucleotides
How many different RNA codons are listed on the Genetic Code chart?
64 different RNA codons
The two steps of transCription followed by transLation.
describe the flow of genetic information
Of all the different codons that exist, three of them
do not specify a particular amino acid and provide instructions such as STOP.
DNA & RNA are alike in a. pentose sugar. b. nitrogenous bases. c. number of strands. d. function in genetics. e. none of these.
e. None of these
Ricin is
e. a substance found in castor bean seeds & a protein that inactivates ribosomes.
During the termination stage a. a STOP codon enters the ribosome. b. release factors bind the ribosome. c. ribosomal subunits separate. d. mRNA detaches from the ribosome and the polypeptide chain. e. all of these occur.
e. all of these occur during the termination stage
A gene mutation a. is a change in the nucleotide sequence of DNA. b. may arise spontaneously. c. can occur in any organism. d. may be caused by environmental agents. e. is described by all of these.
e. is described by all of these
Which stage of transLation is shown in the figure
elongation
A frameshift mutation results in a/an
error in mRNA splicing
The portion of the DNA mol that is not translated and is a non-coding portion of DNA is called
exons
The portion of the DNA molecule that is transLated is composed of
exons
. Before messenger RNA is mature,
a cap and a tail are provided
Frameshift mutations may involve
addition or deletion of one or more base pairs
A polysome is
an mRNA molecule with several ribosomes attached
The relationship between strands of RNA & DNA is
complementary
Ribosomal subunits
converge only when mRNA is to be translated
Which of the following carries amino acids to the ribosomes?
tRNA
A single mutation involving the second letter of codon AUA would convert it to this codon.
AAA
This codon is complementary to the Anti-codon UUU
AAA
If the 4th base from the left (C) in RNA were deleted, what would the new 4th codon be?
AGA
. If the fourth base from the left (C) in RNA were deleted, what would the new 3rd codon be?
AGG
This codon specifies an amino acid and indicates the beginning of a coding region.
AUG
Which of the following statements is true? a. Gene mutations occur independently of each other. b. Gene mutations are relatively rare. c. Ionizing radiation causes chromosome damage & free radical formation. d. Mutations are random; that is, it's impossible to predict exactly when a specific gene will mutate, but an expected frequency can be assigned. e. All of these are true
All are true
What molecules carry protein-assembly instructions from the nucleus to the cytoplasm.
Messenger RNA
All of the different kinds of RNA are transCribed in the
Nucleus
Which event occurs during the elongation stage? a. Peptide bonds form.
Peptide bonds form, & anticodons bind to complementary codons.
The helix structure on the right of the figure represents
RNA
Which of the following dominates in the process of transCription?
RNA polymerase
The form of RNA that carries the code from DNA to the site of protein assembly is called
Transfer RNA
A DNA codon of ATT would be complementary to this RNA codon.
UAA
This codon terminates a coding region.
UAA
If the DNA triplets are ATGCGT, the mRNA codons are
UACGCA
The anticodon AAA would pair with this codon.
UUU
This codon specifies the amino acid phenylalanine.
UUU
What amino acid is carried by the 2nd anti-codon in the figure?
Valine
Four of the five answers listed below are components of a nucleotide EXCEPT? a. pentose sugar b. amino acid c. pyrimidine d. phosphate group e. purine
b. amino acid
Ricin is toxic because it
inactivates ribosomes
When a gene transCription occurs, which of the following is produced?
messenger RNA
The 1st amino acid of a new polypeptide chain is
methionine
The sequence of amino acids specified by the mRNA codons AUGCGUCCA is
methionine ---> arginine ----> proline.
The structure in the figure depicts which of the following?
multiple ribosomes on a strand of mRNA
What stage of translation occurs when ribosomal subunits & tRNAs converge around a mRNA transcript?
peptide bond formation
Which event of transLation is shown in the figure?
peptide bond formation?
TransCription starts at a region of DNA called a(n)
promoter
In this depiction of transCription: the ____ strand is ____ because it ____.
the lower strand is RNA because it contains uracil.
If the DNA nucleotides read ATGCGTGAC, the amino acid sequence of the resulting polypeptide would be
tyrosine ---> alanine ----> leucine.
