Unit # 1 : DNA + Protein Synthesis
True or false: DNA polymerase is used during transcription along with RNA polymerase.
False: DNA polymerase is used during DNA replication, but RNA polymerase is used during transcription
True or false: Only one RNA polymerase can transcribe a gene at any given time.
False: Multiple RNA polymerases can transcribe a gene at the same time.
True or false: Polyribosomes increase efficiency of transcription.
False: Translation, not transcription is made more efficient.
Prokaryotic cells have ______ DNA and their DNA replications proceeds in a ______ direction.
circular; 5' to 3'
Which of the following are possible functions of introns?
could encourage crossing-over in meiosis could be exons in other molecules could give rise to microRNAs could regulate mRNA translation
Select the choices that characterize DNA replication in eukaryotes.
creates replication bubbles involves linear chromosomes has numerous origins of replication
Taking pre-mRNA and changing it to a final mRNA transcript requires multiple steps of RNA ______ , like removal of introns.
processing
To initiate transcription, RNA polymerase binds to the ______ region of the gene.
promoter
RNA polymerase has all the following in common with DNA polymerase:
nucleotides are joined together nucleotides are added to the 3' end a growing strand runs in a 5' to 3' direction
A biotechnology company named Synthorax has expanded the genetic alphabet by creating two new forms of ______ called X and Y.
nucleotides or bases
DNA is composed of units called ______ , each of which contains a phosphate group, a 5-carbon sugar, and one of 4 nitrogen-containing bases.
nucleotides or nucleotide
The original parent strand from which a complementary strand is made is called the ______ strand
template
The parental strand of DNA serving as the guide for a complementary DNA daughter strand is called the ______ strand.
template
Polyribosomes are strings of ribosomes simultaneously ______________ strand.
translating an mRNA
Initiation occurs prior to elongation, both are part of the process of ______
translation
The process which occurs on ribosomes, either free in the cytoplasm or bound to the endoplasmic reticulum is called ______
translation
The process which uses mRNA, tRNA, and ribosomes to synthesize proteins is called ______
translation
Complimentary bases are held together in the DNA strand by ______ bonds.
hydrogen or H
DNA nucleotides come in ______ different varieties.
four or 4
In eukaryotes, transcription occurs in the ____________, and translation occurs in the ___________.
nucleus, cytoplasm
The two purines bases in DNA are
guanine and adenine
The hypothesis among scientists in the 1950's was that proteins were the genetic material because proteins can contain up to _____.
20 amino acids
How many binding sites for tRNA are found on a ribosome?
3 or three
If each codon were composed of only 1 nucleotide, how many amino acids are possible?
4
To provide genetic variation, the genetic material must undergo changes called ______
mutations or mutation
The major types of RNA are tRNA, mRNA and ______
rRNA
The synthesis of new DNA double helix molecules from a pre-existing parent molecule is called _______.
DNA replication
Which choice identifies the flow of information according to the central dogma of molecular biology?
DNA to RNA to protein
During the 1940s, scientists considered what two molecules most likely to be genetic material?
DNA, protein
Which of the following are important traits of the genetic code?
Degenerate Contains start/stop signals Unambiguous
Select the items that describe events occurring during the termination phase of translation.
Ribosomal subunits dissociate. Release factor binds to stop codon. Protein product is released.
Who contributed to the determination of the shape of the DNA molecule through x-ray crystallography?
Rosalind Franklin
Which term best describes the genetic code?
Universal
What is the function of the promoter?
guides RNA polymerase to the strand to be transcribed defines the start of transcription defines the direction of transcription
The field of proteomics is dedicated to understanding
how proteins are modified by the ER and golgi apparatus. how proteins function in metabolic pathways. the structure of proteins.
A completed polypeptide is released during the phase of translation called ______
termination
The polypeptide increases in size once amino acid at a time during the phase of translation called ______
elongation
Translation allows additional amino acids to be added to the growing polypeptide during the _____ phase.
elongation
Alternative mRNA splicing states that a segment could be a(n) coding ______ in one transcript for one protein, but a(n) noncoding ______ in another.
exon + intron
A modified and finished form of a messenger RNA molecule is called an mRNA _______.
transcript
Ribosomes participating in production of proteins destined for secretion from the cell are located:
on the endoplasmic reticulum
Which of the following would contain the most nucleotide bases, if all from the same eukaryotic gene?
Introns + exons
Adenine and guanine are nitrogen-containing bases called ______
purines
Thymine and cytosine are nitrogen-containing bases called ______
pyrimidines
Ribosomes are made of proteins and a type of nucleic acid abbreviated ______
rRNA
This nucleic acid molecule is joined with proteins, and is produced in the nucleolus of a nucleus, where a portion of DNA serves as a template for its formation.
rRNA
Which of the following are reasons for post-transcriptional modification of mRNA?
remove noncoding regions protect the mRNA transcript from enzymes facilitate transport out of the nucleus
James Watson and Francis Crick contributed greatly to our knowledge of the structure of the molecule known as
DNA or deoxyribonucleic acid
Which of the following is the correct enzyme that is used for proofreading the replication of DNA?
DNA polymerase
What are components of a nucleotide?
Nitrogen-containing base Phosphate 5-carbon sugar
The genetic material for life must be ______ so it can be accurately replicated over and over again.
a stable molecule
During the final stage of translation, a release factor binds to ______
a stop codon
Which of the following are the tRNA binding sites on ribosomes?
amino acid peptide exit
Just as the double strands of DNA, the codon-anticodon pairs match up with the 3' and 5' ends on opposite sides in a(n) _______ conformation.
antiparallel
Which of the following are similarities between DNA polymerase and RNA polymerase?
both add nucleotides to the 3' end of the new strand both are types of proteins
In prokaryotes, replication can occur in two directions at once because the DNA molecule is ______
circular , circle, or round
The two pyrimidine bases are:
cytosine and thymine
The coding portions of a gene that are joined during mRNA processing are called ______
exons
Eukaryotic organisms have ______ DNA and DNA replication occurs ______.
linear; bidirectionally
rRNA strands are transcribed from a template strand of DNA found in the _______.
nucleolus
The building blocks of DNA are ______
nucleotides
Select the choices indicating differences between RNA and DNA.
only RNA contains the base "Uracil" DNA is double-stranded, but RNA is single-stranded only RNA contains the sugar "ribose"
The enzyme that is used to proofread DNA as it is being synthesized is DNA ______
polymerase
During the termination stage of translation a completed ______ is released.
polypeptide
Strings of ribosomes simultaneously translating a mRNA strand are called ______
polyribosomes
Which of the following are true of transcription but not translation?
produces RNA occurs in eukaryotic nuclei
Which of the following are types of RNA?
ribosomal RNA transfer RNA messenger RNA
To end translation a release factor binds to a ______ codon.
stop
Because a set of three nucleotide bases called a codon codes for a particular amino acid, the genetic code is said to be a ______ code.
triplet
Each mRNA codon has only one meaning (codes for one amino acid or start/stop), therefore the genetic code is considered ______
unambiguous
It is necessary for genetic material to be able to undergo mutations in order to provide genetic ______ for evolution to occur.
variation
Match the term with its definition. pre-mRNA <--- exons <--- introns <---
---> RNA that has not been processed yet ---> RNA that will be used for translation ---> RNA that will be removed before translation
DNA helicase <--- single-stranded binding protein (SSB) <--- DNA primase <--- DNA polymerase <--- DNA ligase <---
---> Separates double-stranded DNA into single strands. ---> Keeps single stranded DNA apart. ---> Synthesizes short RNA strands. ---> Synthesizes DNA, removes RNA and proofreads DNA. ---> Attaches DNA fragments.
What is the name of the enzyme complex responsible for synthesizing a new RNA molecule through nucleotide binding?
RNA polymerase
Rosalind Franklin was instrumental in the discovery that the three-dimensional shape of a DNA molecule was a(n) ______
double helix
An anticodon is the compliment of the ______.
codon
The study of the set of proteins that an organism produces is called ______
Proteomics
Who first demonstrated that DNA was the genetic material?
Avery, MacLeod, and McCarty
The process of synthesizing an RNA strand from a DNA template strand is called ______
transcription
What determines the sequence of an rRNA strand?
transcription from DNA template
Which of the following would contain the fewest base pairs, if starting with the same size eukaryotic gene?
A post-modification mRNA transcript
DNA base pairs
A-T G-C T-A C-G
Select all that apply Select the characteristics that the genetic material must be able to store information for. A. development B. structure C. metabolic activities D. environmental conditions
A. development B. structure C. metabolic activities
What would the mRNA transcript's sequence be if a section of the DNA strand contained the sequence TATGCCCG?
AUACGGGC
Why would the number of guanines in an organism's DNA be equal to its number of cytosines?
Because cytosine pairs with guanine in DNA
Which bacteriologist jump-started the search for DNA in the 1920s? A. Thomas Hunt Morgan B. Frederick Griffith C. Gregor Mendel D. James Watson
B. Frederick Griffith
Select the choices indicating similarities between RNA and DNA.
Both contain 4 types of nucleotide bases. Both are nucleic acids. Both are polymers of nucleotides.
What is Frederick Griffith's (a bacteriologist from 1920) contribution to genetics?
He observed transformed bacteria in mice
What type of RNA is needed to begin translation?
Initiator tRNA
Which of the following directly plays a part in translation initiation?
Initiator tRNA Small ribosomal subunit Messenger RNA Large ribosomal subunit
Which of the following would produce the most protein product?
Polyribosomes translating an mRNA transcript
What is the function of DNA polymerase?
Proofreads newly formed DNA. Removes RNA primers. Synthesizes DNA in the leading strand. Synthesizes DNA in the lagging strand.
What are differences between prokaryotic and eukaryotic DNA replication?
The prokaryotic genome is replicated much faster than the eukaryotic genome Prokaryotes have only one origin of replication
True or false: It is possible to transfer genes from one type of organism to another type of organism.
True: Genes can be transferred because the universal nature of the genetic code.
Which of the following best describes the advantage of several RNA polymerases transcribing the same gene simultaneously?
To produce more transcripts of the needed gene in a shorter time
What is the source of particular sequences of tRNA, mRNA, and rRNA?
Transcription from DNA
If a certain section of a template strand of DNA had the sequence AATGCCCG, the mRNA transcript's sequence would be
UUACGGGC
Which two of the following summarize Chargaff's rules about DNA?
Within a species, the number of guanine equals the number of cytosine, and the number of thymine equals the number of adenine. The amount of A, T, G, and C in DNA varies between species.
Which of the following are post-transcriptional modifications of mRNA?
addition of Poly-A tail introns are taken out addition of a 5' cap
One modification to mRNA transcripts is the addition of a tail that is composed of the ______ nucleotide base
adenine or adenosine
Which of the following are implications of the universality of the genetic code?
gives us insight into evolutionary relationships allows for genetic engineering
The genetic material must have the characteristic of being able to store genetic ______ about development, cell structure, and metabolism.
information, data, directions, direction, codes, or info
Which nucleic acid is the physical carrier of individual amino acids?
tRNA
Which version of RNA transfers amino acids to the ribosome?
tRNA
Which of the following play a part in translational elongation?
tRNA Elongation factors mRNA
Because of DNA polymerases' proofreading abilities, the overall error rate in replication is about ________ base pairs.
1 in 100 million
Without the special "proofreading" abilities of DNA polymerase, approximately how many errors would occur during DNA replication?
1 in 100,000 base pairs
Rank the following termination events in sequential order. Place the first event at the top of the list.
1. Release factor binds to stop codon 2. Protein product is released 3. Ribosomal subunits dissociate
List the sequential steps of DNA replication in prokaryotes. Place the 1st step at the top of the list.
1. The double helix is separated and unwound 2. DNA polymerases begins the copying process. 3. DNA polymerases meet at the termination region.
Place these steps in DNA replication in the correct sequence beginning with the first step at the top.
1. Unwinding the DNA double helix 2. Complementary base pairing 3. Joining nucleotides to the growing DNA strand
List the steps of translation in the correct order placing the first step at the top of the list.
1. initiation 2. elongation 3. termination
A codon is composed of ______ nucleotides
3, three, or triplet
Which of the following are characteristics of the genetic material that early scientists were seeking? A. Must be made of nucleic acids B. Storage of genetic information C. Able to undergo mutations D. A stable molecule
B. Storage of genetic information C. Able to undergo mutations D. A stable molecule
Why must the genetic material be a stable molecule? A. so it can encode genetic information. B. so genetic material can pass from generation to generation C. so replication can be accurate
B. so genetic material can pass from generation to generation C. so replication can be accurate
What is the best explanation as to why the number of adenines in an organism's DNA is equal to its number of thymines? Multiple choice question.
Because adenine pairs with thymine in DNA
Which of the following are similarities between prokaryotic and eukaryotic DNA replication?
Both are semiconservative Both happen from the 5' to 3' direction Both result in 2 copies from one parent molecule Both involve DNA polymerase
The amount of A, T, G, and C varies by species. Within a species the amount of A = T, and G = C. These are _____ rules.
Chargaff's
In the 1940s, scientists had concluded that the genetic material was most likely either ______ or ______
DNA, protein
Which of the following were direct contributions of the work of James Watson and Francis Crick?
Deduced the double helix shape of deoxyribonucleic acid Determined that sugars and phosphates formed backbones in the DNA Determined that nucleotides were paired inside the double helix
Which of the following facilitates the binding of tRNA anticodons to mRNA codons?
Elongation factors
A certain portion of a protein has the amino acid sequence Lys-Gly-Leu. What was the original source of this particular sequence?
It was directed by the bases on the template DNA.
A template portion of a DNA template strand has the sequence GAACCT. Assuming no modification, what would be the sequence of amino acids in the protein product (use the mRNA codon table)?
Leucine - glycine
A triplet code for amino acids is made up of ______.
RNA nucleotides
Based on your understanding of the central dogma of molecular biology, match the following processes with the correct description.
Translation: RNA is used to produce protein. Replication: DNA is used as a template to produce duplicate molecules of DNA. Transcription: DNA is used as a template to produce RNA.
True or false: DNA can store information, can be replicated and can undergo rare changes.
True
True or false: A purine base normally pairs with a pyrimidine base.
True. A (purine) pairs with T (pyrimidine) and G (purine) pairs with C (pyrimidine).
True or false: The DNA double helix is made up of one older strand and one newer strand.
True: DNA replication is semiconservative - meaning one strand is older (parent strand) and one strand is newer.
True or false: Prokaryotic DNA replication can occur either unidirectionally or bidirectionally.
True: In prokaryotes replication can occur in a single direction or in opposite directions.
True or false: A change in the DNA code will result in a change in the RNA code.
True: RNA is made from DNA. If DNA changes, so will the RNA.
True or false: The genetic code is, with few exceptions, universal.
True: There are very few exceptions to the genetic code.
What are steps in DNA replication?
Unwinding the DNA double helix Joining nucleotides to the growing DNA strand Complementary base pairing
Suppose a pre-mRNA transcript has three exons: E1, E2, E3. After RNA processing, one mRNA transcript is made up of E1-E2-E3, and another is made up of E1-E2 only. These two different transcripts are a result of
alternative RNA splicing.
For genes that code for proteins, the mRNA sequence determines the sequence of _______________ in a protein.
amino acids
Incorporating new nucleotides into DNA can provide it with the ability to code for a greater number of ______
amino acids
During the process of translation, a codon matches up with its complement, a(n) ______
anticodon
The term that refers to the strands of a DNA molecule being oriented in opposite directions is ______
antiparallel
When two molecular strands are connected but oriented in opposite directions, the strands are said to be ______.
antiparallel
Around 1950, the hypothesis that proteins were the genetic material was backed up by what evidence?
associated with chromosomes contain 20 different amino acids for variety of information
An opening in eukaryotic DNA, containing two forks at the site of replication is called a replication ______.
bubble
The production and usage of a gene's product is called gene ______
expression
Scientists were searching for the source of biological information about inheritance and development. When they found it, they called it the:
genetic code
The field of proteomics is dedicated to understanding ______
how proteins are modified by the ER and golgi apparatus. the structure of proteins. how proteins function in metabolic pathways.
The first stage of translation, during which ribosomes assemble around mRNA is called ______
initiation
The three, major steps of translation (in order) are ______, ______, and ______
initiation, elongation, and termination
A spliceosome uses a ribozyme to cut and remove __________ from pre-mRNA.
introns
The structure that allows a cell to pick and choose which exons will go into a particular mRNA is the ______
introns
Select the characteristics of translation.
involves a mRNA molecule results in a protein product
The process of copying a DNA molecule so that there are two copies of the same DNA is called DNA ______
replication
There is a point on a replicating prokaryotic or eukaryotic DNA strand at which separation of the strands occurs to allow for enzyme activity. What is it called?
replication fork
mRNA will carry a message from DNA to the ______.
ribosome
RNA molecules that assist with intron splicing are called _______
ribozymes
Ribosomes attached to the endoplasmic reticulum are synthesizing proteins destined for __________.
secretion from the cell
DNA replication produces a resulting daughter DNA that consists of one parent strand and one daughter strand. DNA replication is referred to as ______ replication
semiconservative or semi-conservative
Which of the following is/are true of both transcription and translation?
several, identical products can be produced from one strand RNA is involved involve nucleic acids occur in eukaryotes and prokaryotes
Why must the genetic material be a stable molecule?
so genetic material can pass from generation to generation so replication can be accurate
Why must the genetic material be a stable molecule?
so genetic material can pass from generation to generation so replication can be accurate
The codon near which the small ribosomal subunit attaches to the mRNA molecule to be translated, which codes for methionine (AUG) is called the ______ codon.
start
During translation initiation, the small ribosomal subunit and initiator tRNA attach in the vicinity of the _____.
start codon
For a protein, gene expression requires _______ In the nucleus and __________ at ribosome to take place.
transcription + translation
An mRNA transcript
was made from a DNA template. was produced by RNA polymerase can be used for translation.
