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Molec Bio > 17 > Flashcards

17 Flashcards

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Biology 101 flashcards
1
Q

All of the following are part of a prokaryotic cell EXCEPT ________.
A) DNA
B) a cell wall
C) a plasma membrane
D) ribosomes
E) an endoplasmic reticulum

A

E) an endoplasmic reticulum

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2
Q

In a bacterium, we will find DNA in ________.
A) a membrane-enclosed nucleus
B) mitochondria
C) the endoplasmic reticulum
D) the nucleoid
E) ribosomes

A

D) the nucleoid

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3
Q

Which of the following cell types would be expected to contain DNA, ribosomes,
rough endoplasmic reticulum, and cytoplasm?
A) Bacterial cells
B) Plant cells
C) Animal cells
D) Both plant and animal cells
E) Both bacterial and animal cells

A

D) Both plant and animal cells

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4
Q

Large numbers of ribosomes are present in cells that specialize in producing which
of the following molecules?
A) Lipids
B) Glycogen
C) Proteins
D) Cellulose
E) Nucleic acids

A

C) Proteins

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5
Q

A larger than regular proportion of smooth endoplasmic reticulum would be
present in cells that specialize in producing which of the following molecules?
A) Lipids
B) Glycogen
C) Proteins
D) Cellulose
E) Nucleic acids

A

A) Lipids

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6
Q

Which structure is the site of the synthesis of proteins that may be exported from
the cell?
A) Rough ER
B) Lysosomes
C) Plasmodesmata
D) Golgi vesicles
E) Free cytoplasmic ribosomes

A

A) Rough ER

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7
Q

What is the function of the nuclear pore complex found in eukaryotes?
A) It regulates the movement of proteins and RNAs into and out of the nucleus.
B) It synthesizes the proteins required to copy DNA and make mRNA.
C) It selectively transports molecules out of the nucleus but prevents all inbound molecules
from entering the nucleus.
D) It assembles ribosomes from raw materials that are synthesized in the nucleus

A

A) It regulates the movement of proteins and RNAs into and out of the nucleus.

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8
Q

Which of the following is a major difference between prokaryotic cells and
eukaryotic cells?
A) Prokaryotes have cells but eukaryotes do not.
B) Eukaryotic cells have more intracellular organelles than prokaryotes.
C) Prokaryotes are not able to carry out aerobic respiration, relying instead on anaerobic
metabolism.
D) Prokaryotes are generally larger than eukaryotes.

A

B) Eukaryotic cells have more intracellular organelles than prokaryotes

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9
Q

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

A

C) mRNA

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10
Q

Which molecule or reaction supplies the energy for polymerization of nucleotides in
the process of transcription?
A) The interaction between RNA polymerase and the promoter
B) The phosphate bonds in the nucleotide triphosphates that serve as substrates
C) The energy released when hydrogen bonds are broken as the DNA molecule is unwound
D) ATP onl

A

B) The phosphate bonds in the nucleotide triphosphates that serve as substrates

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11
Q

What is responsible for termination of transcription in eukaryotic protein-coding
genes?
A) A polyadenylation, or poly (A), signal
B) A termination loop composed of guanine
C) A sigma factor
D) A portion of the polymerase holoenzyme
E) Three nonsense mutations in sequence

A

A) A polyadenylation, or poly (A), signal

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12
Q

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

A

B) several transcription factors have bound to the promoter

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13
Q

There should be a strong positive correlation between the rate of protein synthesis
and ________.
A) the quantity of DNA polymerase
B) the quantity of RNA polymerase
C) the size of mRNA
D) the number of ribosomes

A

D) the number of ribosomes

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14
Q

Termination of transcription in bacteria occurs when ________.
A) a hairpin secondary structure forms in the RNA transcript, and it separates from the
RNA polymerase
B) a deoxyribonucleotide is base-paired to the 3’ end of the transcript, signaling completion
C) large and small subunits of the RNA polymerase dissociate
D) the 5’ cap structure on the nascent (new) RNA molecule loops back and interferes with
RNA polymerase

A

A) a hairpin secondary structure forms in the RNA transcript, and it separates from the
RNA polymerase

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15
Q

Which of the following occurs in prokaryotes but NOT in eukaryotes?
A) Posttranscriptional splicing
B) Concurrent transcription and translation
C) Translation in the absence of a ribosome
D) Gene regulation

A

B) Concurrent transcription and translation

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16
Q

Codons are three-base sequences that specify the addition of a single amino acid.
How do eukaryotic codons and prokaryotic codons compare?
A) Prokaryotic codons usually contain different bases than those of eukaryotes.
B) Prokaryotic codons usually specify different amino acids than those of eukaryotes.
C) The translation of codons is mediated by tRNAs in eukaryotes, but translation requires
no intermediate molecules such as tRNAs in prokaryotes.
D) Codons are a nearly universal language among all organisms

A

D) Codons are a nearly universal language among all organisms

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17
Q

Ribosomes can attach to prokaryotic messenger RNA ________.
A) once posttranscriptional modification is complete
B) before transcription is complete
C) once replication is complete
D) once the primary transcript has been released from RNA polymerase16

A

B) before transcription is complete

18
Q

After eukaryotic mRNAs are made they undergo posttranscriptional modifications.
Which of the following are examples of the processes that happen to the mRNAs?
A) Removal of UTRs
B) Attachment of a cap to the 3’ end of the mRNA
C) Attachment of the poly A tail to the 5’ end of the mRNA
D) Removal of the introns
E) Removal of the exons

A

D) Removal of the introns

19
Q

Which of the following statements about mRNA processing is FALSE?
A) Mature mRNAs have a modified guanine nucleotide added to their 5’ end.
B) Mature mRNAs have 100-250 adenine nucleotides added to their 3’ end.17
C) The caps found in mature mRNAs are involved in protecting the RNA from degradation.
D) The caps play a role in binding to the ribosome and translation.
E) mRNA processing occurs in the cytosol.

A

E) mRNA processing occurs in the cytosol.

20
Q

In comparing DNA replication with RNA transcription in the same eukaryotic cell,
only DNA replication ________.
A) uses RNA polymerase
B) makes a new molecule from its 5’ end to its 3’ end
C) occurs in the nucleus of the cell
D) incorporates the entire template molecule in the product

A

D) incorporates the entire template molecule in the product

21
Q

Which of the following is present in a prokaryotic cell?
A) Mitochondrion
B) Ribosome
C) Nuclear envelope
D) Chloroplast
E) ER

A

B) Ribosome

22
Q

Which of the following is NOT found in a prokaryote?
A) DNA
B) A cell wall
C) A mitochondrion
D) A plasma membrane

A

C) A mitochondrion

23
Q

The nuclear lamina is an array of filaments on the inner side of the nuclear
membrane. If a method were found that could cause the lamina to fall into disarray,
what would you most likely expect to be the immediate consequence?
A) The loss of all nuclear function
B) The inability of the nucleus to divide during cell division
C) A change in the shape of the nucleus
D) Failure of chromosomes to carry genetic information
E) Inability of the ribosomes to produce proteins

A

C) A change in the shape of the nucleus

24
Q

A cell with a predominance of free ribosomes is most likely ________.
A) primarily producing proteins for secretion
B) primarily producing proteins in the cytosol
C) constructing an extensive cell wall or extracellular matrix
D) digesting large food particles
E) enlarging its vacuole

A

B) primarily producing proteins in the cytosol

25
Q

Which type of organelle or structure is primarily involved in the synthesis of oils,
phospholipids, and steroids?
A) Ribosome
B) Lysosome
C) Smooth endoplasmic reticulum
D) Mitochondrion
E) Contractile vacuole

A

C) Smooth endoplasmic reticulum

26
Q

Why is the smooth endoplasmic reticulum unable to synthesize proteins?
A) No ribosomes are attached to its surface.
B) There is no supply of free amino acids that it can easily access.14
C) It stores calcium, which is a known inhibitor of protein synthesis.
D) It has no DNA to direct synthesis of proteins.

A

A) No ribosomes are attached to its surface.

27
Q

Which of the following produces and modifies polysaccharides that will be secreted?
A) Lysosome
B) Vacuole
C) Mitochondrion
D) Golgi apparatus
E) Peroxisome8

A

D) Golgi apparatus

28
Q

Which organelle is the primary site of ATP synthesis in eukaryotic cells?
A) Lysosome
B) Vacuole
C) Mitochondrion
D) Golgi apparatus
E) Peroxisome

A

C) Mitochondrion

29
Q

Which of the following components is found in a prokaryotic cell, but NOT
necessarily in a eukaryotic cell?
A) Ribosomes
B) Cell wall
C) Chromosomal DNA
D) Cytoplasm
E) Plasma membrane

A

B) Cell wall

30
Q

Which of the following are FALSE regarding transcription?
A) It builds a new nucleic acid in the 5’ to 3’ direction.
B) It requires a primer to be attached at the transcription initiation site.
C) Prokaryotes have one RNA polymerase; eukaryotes have three RNA polymerases.
D) It requires specific promoter sequences for proper initiation

A

B) It requires a primer to be attached at the transcription initiation site.

31
Q

Which of the following is the first event to take place in translation in eukaryotes?
A) Elongation of the polypeptide
B) Base pairing of activated methionine-tRNA to AUG of the messenger RNA
C) Binding of the larger ribosomal subunit to smaller ribosomal subunits
D) Covalent bonding between the first two amino acids
E) The small subunit of the ribosome recognizing and attaching to the 5’ cap of mRNA

A

E) The small subunit of the ribosome recognizing and attaching to the 5’ cap of mRNA

32
Q

Suppose that you have a mutation that modifies the nucleotides at the exon-intron
borders. This results in a mature mRNA that includes an intron. What would be the
result of this at the organismal level?
A) The organism would have no effect, since the ribosomes cannot bind to messages
containing introns.
B) The organism would have no effect, since there are no anticodons in the tRNAs that
correspond to the codons in the intron mRNA.
C) The introns sequences would get removed during posttranslational modifications.
D) The information in the intron would be translated and this would result in additional
amino acids being incorporated into the protein and possibly frameshift mutations

A

D) The information in the intron would be translated and this would result in additional
amino acids being incorporated into the protein and possibly frameshift mutations

33
Q

What molecules in the spliceosome catalyze the intron removal reactions?
A) RNA polymerases
B) snRNAs
C) tRNA
D) Introns

A

B) snRNAs

34
Q

What molecule functions as the template for 3’ poly-A tail synthesis in eukaryotes?
A) The template strand in the DNA
B) The nontemplate strand in the DNA
C) The mRNA acts as its own template.
D) No template is necessary for 3’ poly-A tail synthesis.

A

D) No template is necessary for 3’ poly-A tail synthesis.

35
Q

Which of the following influence the amount of protein that is translated in a cell?
I) The rate of mRNA synthesis
II) The rate of mRNA degradation
III) The number of ribosomes attached to the mRNA
IV) The type of ribosomes present in the cell
A) I and II only
B) II and III only
C) I, II, and IV only
D) I, II, and III only
E) II, III, and IV only

A

D) I, II, and III only

36
Q

Which of the following statements is TRUE about protein synthesis in prokaryotes?
A) Extensive RNA processing is required before prokaryotic transcripts can be translated.
B) Translation can begin while transcription is still in progress.
C) Prokaryotic cells have complicated mechanisms for targeting proteins to the appropriate
cellular organelles.
D) Translation requires antibiotic activity.
E) Unlike eukaryotes, prokaryotes require no initiation or elongation factors.

A

B) Translation can begin while transcription is still in progress.

37
Q

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

A

E) binding of the anticodon to the codon and the attachment of amino acids to tRNAs

38
Q

If the sequence in the coding strand of DNA for a particular amino acid is 5’AGT3’ ,
then the anticodon on the corresponding tRNA would be ________.
A) 5’ACU3’
B) 5’TCA3’
C) 5’UCA3’
D) 5’AGU3’
E) 5’ACT3’

A

A) 5’ACU3’

39
Q

In the figure, what is the function of the AGU (shown in light gray) on the loop of the
tRNA?
A) It attaches to the amino acid.
B) It base pairs with a codon of mRNA.
C) It stabilizes the tRNA-amino acid complex.
D) It is the active site of this ribozyme

A

B) It base pairs with a codon of mRNA

40
Q

What is the name of the molecule shown in the figure?
A) A ribosome
B) An mRNA
C) A tRNA
D) The spliceosome

A

C) A tRNA

Molec Bio (4 decks)

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