Bio final

A particular triplet of bases in the template strand of DNA is 5' AGT 3'. The corresponding codon for the mRNA transcribed is _____.

3' UCA 5'

Put the following events of bacterial transcription in chronological order. 1. Sigma binds to the promoter region. 2. The double helix of DNA is unwound, breaking hydrogen bonds between complementary strands. 3. Sigma binds to RNA polymerase. 4. Sigma is released. 5. Transcription begins.

3, 1 ,2, 5, 4

Thylakoids, DNA, and ribosomes are all components found in _____. A.) chloroplasts B.) mitochondria C.) lysosomes D.) vacuoles E.) nuclei

A. chloroplasts

If the sequence ATGCATGTCAATTGA were mutated such that a base were inserted after the first G and the third T were deleted, how many amino acids would be changed in the mutant protein? A.) Three. B.) Two. C.) One. D.) None.

B

All proteins are synthesized by ribosomes in the cell. Some ribosomes float freely in the cytosol, while others are bound to the surface of the endoplasmic reticulum. Most proteins made by free ribosomes function in the cytosol. Proteins made by bound ribosomes either function within the endomembrane system or pass through it and are secreted from the cell. Which of the following proteins are synthesized by bound ribosomes? A.) DNA polymerase B.) insulin C.) ribosomal protein D.) actin E.) ER protein F.) lysosomal enzyme

B, E, and F

During RNA processing a(n) _____ is added to the 3' end of the RNA. A.) 3' untranslated region B.) a long string of adenine nucleotides C.) 5' untranslated region D.) coding segment E.) modified guanine nucleotide

B. a long string of adenine nucleotides

Accuracy in the translation of mRNA into the primary structure of a polypeptide depends on specificity in the _____. A.) binding of the anticodon to small subunit of the ribosome B.) binding of the anticodon to the codon and the attachment of amino acids to tRNAs C.) binding of ribosomes to mRNA D.) shape of the A and P sites of ribosomes E.) attachment of amino acids to rRNAs

B. binding of the anticodon to the and the attachment of amino acids to tRNAs

Which of the following is the first event to take place in translation in eukaryotes? A.) base pairing of activated methionine-tRNA to AUG of the messenger RNA B.) the small subunit of the ribosome recognizing and attaching to the 5' cap of mRNA C.) binding of the larger ribosomal subunit to smaller ribosomal subunits D.) covalent bonding between the first two amino acids E.) elongation of the polypeptide

B. the small subunit of the ribosome recognizing and attaching to the 5' cap of mRNA

Which statement most accurately describes what happens to proteins that lack an ER signal sequence? A.) They are inserted into the ER membrane but do not enter the ER lumen. B.) They are released into the cytosol. C.) They bypass the ER but enter the Golgi apparatus. D.) They are inserted into the plasma membrane.

B. they are released into the cytosol

David Pribnow studied the base sequences of promoters in bacteria and bacterial viruses. He found two conserved regions in these promoters (the -10 box and the -35 box). These two regions of the promoter _____. A.) attach the correct nucleotide triphosphate to the template DNA strand B.) bind the sigma subunit that is associated with RNA polymerase C.) signal the initiation site D.) separate the two DNA strands

B.) bind the sigma subunit that is associated with RNA polymerase

If a mutated DNA sequence produces a protein that differs in one central amino acid from the normal protein, which of the following kinds of mutations could have occurred? A.) None. B.) An addition mutation C.) An addition mutation and a deletion mutation. D.) A deletion mutation.

C.

Which answer is accurate concerning how (1) nucleotides vs. (2) large proteins move through the nuclear pore complex? A.) (2): No input of energy required. B.) (1) and (2): Input of energy required. C.) (1): No input of energy required. D.) (1) and (2): Nuclear-localization signal (NLS) required.

C. (1): No input of energy required

Genotype is to______ as phenotype is to _________

DNA sequence; physical traits that are products of the amino acid sequences produced.

During RNA processing a(n) _____ is added to the 5' end of the RNA. A.) 3' untranslated region B.) a long string of adenine nucleotides C.) 5' untranslated region D.) coding segment E.) modified guanine nucleotide

E. modified guanine nucleotide

True or false? Large proteins containing a nuclear localization signal (NLS) bind to the nuclear pore and enter the nucleus without any expenditure of energy.

False it requires energy

The initiator tRNA attaches at the ribosome's _____ site.

P

An aminoacyl-tRNA that enters the A site of the ribosome will next occupy which site?

P site

Of the three modes of gene regulation ( transcriptional control, translational control, and post-translational control), which is the fastest in response time?

Post-translational, because it involves modification of an already synthesized protein.

What is the Golgi apparatus function?

Protein modification/sorting, and cisternal maturation

What is the most probable outcome of a frameshift mutation?

They either add or delete a nucleotide so the gene product is truncated (shortened)

A particular triplet of bases in the coding sequence of DNA is AAA. The anticodon on the tRNA that binds the mRNA codon is _____.

UUU

What determines which base is to be added to an RNA strand during transcription?

base pairing between the DNA template strand and the RNA nucleotides

Ribosomes can attach to prokaryotic messenger RNA _____.

before transcription is complete

what is a polypeptide?

chain of amino acids

Codons are three-base sequences that specify the addition of a single amino acid. How do eukaryotic codons and prokaryotic codons compare?

codons are a nearly universal language among all organisms

Translation occurs in the _____.

cytoplasm

The RNA segments joined to one another by spliceosomes are _____.

exons

true or false? all point mutations result in a change of phenotype.

false

True or false? A codon is a group of three bases that can specify more than one amino acid.

false; because a codon is a group of three bases that can specify more than one amino acid.

mutations that alter the meaning of the subsequent codon are called?

frameshift mutation

The statement "DNA → RNA → Proteins" ________.

is known as the central dogma

What happens to RNA polymerase II after it has completed transcription of a gene?

it is free to bind to another promoter and begin transcription

What is smooth ER's function?

lipid synthesis, calcium iron storage, and poison detoxification

what is the rough ER's purpose?

protein synthesis

what is the order of the endomembrane system? 1. endoplasmic reticulum 2. lysosome 3. plasma membrane 4. trans Golgi apparatus 5. cis Golgi apparatus 6. medial Golgi apparatus 7. peroxisome

protein synthesis - 1 - 5 - 6 - 4 - 3 - extracellular space

what is a mutation?

random, heritable changes in DNA

what is an intron?

sequence of DNA that is not involved in coding for a protein

Proteins coded for by nuclear DNA but found within mitochondria move from the cytoplasm into mitochondria using _____.

signal sequences (peptides)

A point mutation that occurred within an intron would most likely be characterized as a __________.

silent mutation because an intron doesn't involve coding.

What is the process called that converts the genetic information stored in DNA to an RNA copy?

transcription

What name is given to the process in which a strand of DNA is used as a template for the manufacture of a strand of pre-mRNA?

transcription

Which of the following observations may have resulted in the hypothesis that a codon is made up of three bases?

A codon of three bases in length, from four different bases, would code for a maximum of sixty-four different amino acids.

During elongation, which site in the ribosome represents the location where a codon is being read?

A site

Transcription begins at a promoter. What is a promoter?

A site in DNA that recruits the RNA Polymerase

Which of the following occurs in prokaryotes but not in eukaryotes? A.) concurrent transcription and translation B.) gene regulation C.) translation in the absence of a ribosome D.) post-transcriptional splicing

A. concurrent (happening at the same time) transcription and translation

How is a mutation in a bacterial cell that deletes three base pairs 10 base pairs upstream from the +1 site likely to affect transcription and why? A.) Initiation will be inhibited because sigma cannot bind to the promoter. B.) A three-base-pair deletion is too small to have an effect. C.) Termination will not occur because hairpin secondary structure cannot form. D.) Initiation will be inhibited because RNA polymerase core enzyme cannot bind to the promoter.

A. initiation will be inhibited because sigma cannot bind to the promoter

Which of the following contains hydrolytic enzymes? A.) lysosome B.) Golgi apparatus C.) vacuole D.) peroxisome E.) mitochondrion

A. lysosome

which of the following statements about mutations is FALSE? A.) A knock-out mutation results in a total absence of the mutated protein. B.) Addition and deletion mutations disrupt the primary structure of proteins. C.) A deletion mutation results in the loss of a base in the DNA sequence. D.) An addition mutation results in an added base in the DNA sequence.

A.) A knockout mutation refers to the loss of a protein's function but not necessarily its complete absence.

In eukaryotic cells, transcription cannot begin until _____. A.) several transcription factors have bound to the promoter B.) the two DNA strands have completely separated and exposed the promoter C.) the 5' caps are removed from the mRNA D.) DNA nucleases have isolated the transcription unit E.) the DNA introns are removed from the template

A.) several transcription factors have bound to the promoter

There are 61 codons that each specify the addition of a specific amino acid, and 3 stop codons for which there is no corresponding amino acid. However, there are only about 40 tRNA molecules, representing 40 anticodons. How is that possible?

An anticodon forms hydrogen bonds with the codon; it must match the first two bases of the codon but is less specific with respect to the third base.

Which of the following macromolecules leaves the nucleus of a eukaryotic cell through pores in the nuclear membrane? A.) DNA B.) phospholipids C.) mRNA D.) amino acids

C. mRNA

Which plant cell organelle contains its own DNA and ribosomes? A.) Golgi apparatus B.) peroxisome C.) mitochondrion D.) vacuole E.) glyoxysome

C. mitochondrion

Which one of the following statements about RNA processing is true? A.) RNA splicing can be catalyzed by tRNA. B.) Exons are cut out before mRNA leaves the nucleus. C.) Ribozymes may function in RNA splicing. D.) A primary transcript is often much shorter than the final RNA molecule that leaves the nucleus.

C. ribozymes may function in RNA splicing

Which of the following statements about the nuclear envelope is false? A.) Nuclear pores are made up of a group of proteins that are collectively called the nuclear pore complex. B.) The nuclear envelope is composed of two lipid bilayers. C.) The nuclear envelope is continuous with the Golgi apparatus. D.) Molecules pass into and out of the nucleus through nuclear pores.

C. the nuclear envelope is continuous with the Golgi apparatus

The tRNA anticodon, GAC, is complementary to the mRNA codon with the sequence _____.

CUG

Which of the following terms best describes the relationship between the newly synthesized RNA molecule and the DNA template strand?

Complementary

DNA does not store the information to synthesize which of the following? A.) DNA B.) Proteins C.) Messenger RNA D.) Organelles

D.

Which of the following features is a significant difference in the function of DNA polymerases versus RNA polymerases? A.) RNA polymerase, but not DNA polymerase, is an enzyme. B.) Only RNA polymerase adds nucleotide precursors (dNTPs) to a growing chain. C.) DNA polymerase extends the growing chain in the 5' to 3' direction, whereas RNA polymerase extends growing chains from 3' to 5'. D.) RNA polymerase does not require a primer to add new nucleotides.

D. RNA polymerase does not require a primer to ass new nucleotides

Scientists have found that polypeptides which are normally synthesized in the endoplasmic reticulum are about 20 amino acids longer when they are synthesized by ribosomes not attached to the endoplasmic reticulum. What is a possible explanation for the greater length of these polypeptides? A.) Ribosomes attached to the endoplasmic reticulum require fewer amino acids to function. B.) The 20-amino-acid sequence helps the endoplasmic reticulum package these proteins for shipping to the Golgi. C.) The protein has a different function in the cytosol than in the endoplasmic reticulum. D.) The 20 amino acids serve as a signal (peptide) sequence that directs the forming polypeptides to the endoplasmic reticulum, where they are cleaved off during processing.

D. The 20 amino acids serve as a signal (peptide) sequence that directs the forming polypeptides to the ER, where they are cleaved off during processing.

What is the most likely pathway taken by a newly synthesized protein that will be secreted by a cell? A.) Golgi → ER → lysosome B.) ER → lysosomes → vesicles that fuse with plasma membrane C.) nucleus → ER → Golgi D.) ER → Golgi → vesicles that fuse with plasma membrane E.) ER → Golgi → nucleus

D.) ER -> Golgi -> vesicles that fuse with plasma

You want to engineer a eukaryotic gene into bacterial colony and have it expressed. What must be included in addition to the coding exons of the gene? A.) eukaryotic tRNAs B.) eukaryotic polymerases C.) eukaryotic ribosomal subunits D.) a bacterial promoter sequence E.) the introns

D.) bacterial promoter sequence

What are the steps (in the correct order) that link a change in the base sequence of a gene to a change in the phenotype of an organism like a mouse or a human?

DNA -> RNA -> protein

Mutations at the scale of chromosomes include?

Inversions, translocations, and duplications

What does it mean when we say the genetic code is redundant?

More than one codon can specify the addition of the same amino acid.

In the process of transcription ____

RNA is synthesized

What name is given to the process in which pre-mRNA is edited into mRNA?

RNA processing

Suppose that an induced mutation removes most of the 5' end of the 5' UTR of an mRNA. What is most likely to happen?

Removal of the 5' UTR also removes the 5' cap and the mRNA will quickly degrade.

The ribosome-binding site of prokaryotes is also known as the ________.

ShineDalagarno sequence

A mutation that results in premature termination of translation _____.

a nonsense mutation

What is responsible for termination of transcription in eukaryotic protein-coding genes?

a poly(A) signal

How does termination of translation take place?

a stop codon is reached

Polypeptides are assembled from _____.

amino acids

Which of the following is NOT synthesized from a DNA template? A. amino acids B. messenger RNA C. ribosomal RNA D. transfer RNA

amino acids

What enzyme catalyzes the attachment of an amino acid to tRNA?

aminoacyl-tRNA synthetase

If a DNA sequence is altered from TAGCTGA to TAGTGA, what kind of mutation has occurred?

deletion

According to the central dogma, what molecule should go in the blank? DNA → _____ → Proteins

mRNA

RNA processing converts the RNA transcript into _____.

mRNA

what is the purpose of lysosomes?

macromolecule digestion and autophagy

Mutations that alter the amino acid sequence specified by a codon are called?

missense mutations

The mutation resulting in sickle cell disease changes one base pair of DNA so that a codon now codes for a different amino acid, making it an example of a ________.

missense mutations

Why is the smooth endoplasmic reticulum unable to synthesize proteins?

no ribosomes are attached to its surface

Anna has identified a mutant that produces a protein that is much smaller than the wild-type protein. What type of mutation best explains this phenotype?

nonsense because it causes an early stop codon.

mutations that cause early stop codons are called?

nonsense mutations

Which mutation(s) would not change the remainder of the reading frame of a gene sequence that follows the mutation(s)? A.) One addition mutation. B.) One addition and two deletion mutations. C.) One addition and one deletion mutation. D.) One deletion mutation.

one addition and one deletion

A small protein (molecular weight = 25,000 daltons) is injected into a cell and observed in the nucleus a short time later. What type of transport has taken place?

passive transport

Mutations affecting single bases are called what?

point mutation

mutations that do not change the meaning of a codon are called?

silent mutations

Spliceosomes are composed of _____.

small RNAs and proteins

Which sections in mature RNA do not code for amino acids?

the 5'cap and the poly(A) tail at the 3' end of RNA

Why would a small protein have an NLS, when it naturally diffuses across the nuclear pore complex without one?

the NLS will be used to actively import the proteins into the nucleus, leaving very little protein in the cytoplasm

How does the simple primary and secondary structure of DNA hold the information needed to code for the many features of multicellular organisms?

the base sequence of DNA carries the info needed to code for proteins.

All three domains (Bacteria, Archaea, and Eukarya) follow the same genetic code. Therefore, which of the following statements would most likely be correct?

the genetic code evolved before the different domains diverged.

There should be a strong positive correlation between the rate of protein synthesis and _____.

the number of ribosomes

Which molecule or reaction supplies the energy for polymerization of nucleotides in the process of transcription?

the phosphate bonds in the nucleotide triphosphates that serve as substrates

Which of the following statements best describes the promoter of a protein-coding gene?

the promoter is a non transcribed region of a gene.

Which of the following accurately describes the effects of mutations on fitness?

they can be negative, positive, or neutral

Of the three modes of gene regulation ( transcriptional control, translational control, and post-translational control) which is the most efficient in resource use?

transcriptional control, because it c an stop gene expression at the earliest possible step

Beginning within the nucleus, the first step leading to the synthesis of a polypeptide is _____.

transferring of info from DNA to mRNA. (transcription: typically the first step)

What name is given to the process in which the information encoded in a strand of mRNA is used to construct a protein?

translation