Ch.3 Protein Synthesis (Transcription & Translation)

Each individual gene does which of the following? carries the instructions for making a single polypeptide codes for one amino acid controls the expression of several traits controls protein synthesis

carries the instructions for making a single polypeptide Indeed, a single gene codes for, or carries, the instructions for making a single polypeptide.

The site of translation is ribosomes in the cell cytoplasm. the cell nucleus. the plasma membrane. the Golgi apparatus. ribosomes in the cell nucleus.

Ribosomes in the cell cytoplasm Translation occurs at ribosomes in the cell cytoplasm.

Each number above molecule B refers to a codon. What sequence of DNA nitrogen bases would produce the mRNA codon UAG? ATC CTA UAG AUC

ATC Respectively, uracil, adenine, and guanine in RNA (UAG) are complementary to adenine, thymine, and cytosine (ATC) in DNA.

Which of the following must be present for transcription to occur? amino acids RNA nucleotides DNA nucleotides DNA polymerase

RNA nucleotides Since transcription involves synthesizing an mRNA strand, RNA nucleotides must be present.

What process allows for the production of molecule B from a template consisting of molecule A? replication transport translation transcription

Transcription Transcription is the synthesis of RNA using DNA as a template.

Which one of the following does not play a role in translation? Amino acids tRNA Anticodon DNA Ribosomes

DNA DNA contains the instructions for making proteins, but these instructions are transcribed to RNA before translation occurs.

If the nucleotide or base sequence of the DNA strand used as a template for messenger RNA synthesis is ACGTT, then what would be the sequence of bases in the corresponding mRNA? ACGTT TGCAA UGCAA GUACC

UGCAA

The region of molecule B that encodes a polypeptide is 24 nucleotides in length. Consider another such molecule with a coding region of 300 nucleotides. What is a reasonable estimate for the length of the corresponding polypeptide that will be produced during protein synthesis? 30 amino acids 100 amino acids 300 amino acids 900 amino acids

100 amino acids Each amino acid corresponds to a codon of 3 nucleotides. Therefore, a coding region of 300 nucleotides contains 100 codons and will produce a polypeptide of 100 amino acids in length.

Which of the following events occurs during transcription? A cap is added to the RNA molecule. Those segments of the RNA strand that do not actually code for the protein are removed. mRNA binds to a ribosome in the cytoplasm. The message in mRNA is translated into a protein. A molecule of RNA is formed based on the sequence of nucleotides in DNA.

A molecule of RNA is formed based on the sequence of nucleotides in DNA. During transcription, RNA nucleotides line up with their complementary DNA partners, transcribing the information in DNA into RNA

Which of the following builds new strands of DNA? DNA helicase the leading strand of DNA the replication fork DNA polymerase the lagging strand of DNA

DNA Polymerase DNA polymerase is an enzyme that builds new strands of DNA. It does this by adding DNA nucleotides one at a time.

Telomeres are the regions of chromosomes that code for the protein ubiquitin. True False

False

In order for a cell to divide, all of its chromosomes must be duplicated in a process called DNA replication. During which phase of the cell cycle does DNA replication occur? mitosis interphase prophase cytokinesis

Interphase Interphase is composed of four phases: G0, G1, S, and G2. DNA replication occurs during S phase.

During DNA replication, which nucleotide will bind to an A nucleotide in the original or parental DNA strand? G A U T C

T During DNA replication, A only binds with T and T only binds with A.

Which of the following does not occur during RNA processing? Adenine nucleotides are added to the end of the RNA strand, forming a tail. A modified guanine nucleotide is added to the beginning of the RNA strand as a cap. Segments of RNA that do code for the protein are reconnected. Segments of the RNA strand that do not actually code for the protein are removed. mRNA attaches to the small subunit of a ribosome.

mRNA attaches to the small subunit of a ribosome.

What is the function of mRNA during translation? mRNA carries an anticodon that is complementary to one or more tRNA codons. mRNA carries amino acids to the ribosome. mRNA carries the code for a polypeptide's sequence of amino acids. mRNA creates peptide bonds between amino acids.

mRNA carries the code for a polypeptide's sequence of amino acids. Translation involves a number of different RNA molecules. It is mRNA that carries the code for the polypeptide's sequence of amino acids. The code for each amino acid is a three-base sequence called a codon.

Which of the following is a correct statement about mRNA? Segments of mRNA that code for protein are removed before translation. mRNA binds directly to amino acids during translation. mRNA includes a cap that consists of extra adenine nucleotides. mRNA moves from the nucleus to the cytoplasm following RNA processing. mRNA is transcribed from DNA in the cytoplasm.

mRNA moves from the nucleus to the cytoplasm following RNA processing. mRNA undergoes RNA processing in the nucleus and then moves to the cytoplasm for translation.

A gene can best be defined as ________. a three-base triplet that specifies a particular amino acid an RNA messenger that codes for a particular polypeptide a segment of DNA that carries the instructions for one polypeptide chain noncoding segments of DNA up to 100,000 nucleotides long

a segment of DNA that carries the instructions for one polypeptide chain

Which letter is pointing to an mRNA molecule? A B C D

B Molecule B is a complement of the DNA template (A) and contains ribonucleotides, as indicated by the presence of uracil (U). This is consistent with molecule B being an mRNA molecule.

Which protein joins together the Okazaki fragments of DNA in the lagging strand? the leading strand RNA the replication fork DNA polymerase DNA ligase

DNA Ligase DNA ligase joins the Okazaki fragments in the lagging strand, turning it into a continuous strand.

Which statement about DNA replication is FALSE? DNA ligase adds nucleotides to the lagging strand. Because the two strands of original or parental DNA run in opposite directions, the new strands must be made in different ways. The two strands of original or parental DNA are separated during DNA replication. The lagging strand is made of a series of fragments that must be joined together to make a continuous strand. DNA polymerase III builds a new strand by adding DNA nucleotides one at a time.

DNA ligase adds nucleotides to the lagging strand. This statement is FALSE. DNA ligase joins the Okazaki fragments in the lagging strand, turning it into a continuous strand. It does not add nucleotides to the lagging strand.

Which of the following is not a step in polypeptide (protein) synthesis? DNA replication RNA processing transcription translation

DNA replication DNA replication occurs prior to cell division, but it is not a step in polypeptide (protein) synthesis.

Which of the following statements about genes is not correct? They are part of your chromosomes. They are composed of DNA. Each single chromosome contains one single gene. They are located in the nucleus.

Each single chromosome contains one single gene. Each chromosome contains many genes

What is the role of aminoacyl-tRNA synthetase in protein synthesis? It creates the peptide bonds that bind the amino acids into a peptide chain. It matches mRNA nucleotides to unzipped DNA strands. It binds to initiator tRNA and a new mRNA strand to begin the translation process. It binds the correct amino acid to a specific tRNA molecule.

It binds the correct amino acid to a specific tRNA molecule. In order for protein synthesis to occur, each type of tRNA must be associated with its specific amino acid. Then the tRNA can bring that amino acid to the ribosome.

Which of the following is not true of DNA? It is found in the nucleus. It contains the instructions for protein synthesis. It carries amino acids to the ribosome. It contains our genes.

It carries amino acids to the ribosome. DNA does not leave the nucleus, so it does not go to the ribosomes, which are in the cytoplasm

Which of the following statements is correct regarding RNA? There is exactly one specific type of mRNA for each amino acid. If the base sequence of DNA is ATTGCA, the messenger RNA template will be UCCAGU. Messenger RNA, transfer RNA, and ribosomal RNA play a role in protein synthesis. rRNA is always attached to the rough ER.

Messenger RNA, transfer RNA, and ribosomal RNA play a role in protein synthesis.

Which statement best describes strand characteristics as it relates to DNA replication? The leading strand is built continuously, and the lagging strand is built in pieces. The leading and lagging strands are both built continuously. The lagging strand is built continuously, and the leading strand is built in pieces. The leading and lagging strands are both built in fragments.

The leading strand is built continuously, and the lagging strand is built in pieces. This statement is correct! Because strands in a DNA double helix run in opposite directions, the new strands must be made in different ways. The leading strand is built continuously.

How is the translation step of protein synthesis terminated? A tRNA molecule carrying methionine signals the breaking of the bond between the polypeptide and the tRNA in the P site. The signal recognition particle (SRP) binds the ribosome-mRNA complex to the endoplasmic reticulum. The ribosome stops building a polypeptide when it gets to the final codon on the mRNA strand. The ribosome reaches a stop codon in the mRNA strand.

The ribosome reaches a stop codon in the mRNA strand. When a stop codon (AUG, UAA, or UAG) enters the A site, the bond between the polypeptide and the tRNA is broken. The polypeptide is released and may then go through post-translational processing

Which of the following is an incorrect description? Messenger RNA (mRNA) participates in transcription. Ribosomal RNA (rRNA) is part of the ribosome. Transfer RNA (tRNA) transfers the instructions for protein synthesis to the ribosome. DNA determines the amino acid sequence of our proteins

Transfer RNA (tRNA) transfers the instructions for protein synthesis to the ribosome. The tRNA transfers amino acids to the ribosome so they can be placed according to the DNA instructions that were brought to the ribosome by the mRNA. This process is translation.

Apoptosis is programmed cell death; cancer cells do not undergo this process. True False

True

What is protein synthesis? the process by which a parent cell produces daughter cells an ongoing process by which cells make structural or functional proteins the process of replicating a DNA strand an event that occurs only during mitosis

an ongoing process by which cells make structural or functional proteins This process is one of the most important metabolic activities of a cell. The proteins it produces largely determine the structure and function of that cell.

Riboswitches are folded RNAs that act as switches to turn protein synthesis on or off in response to ________. specific codes from the DNA the presence or absence of ubiquitins changes in the environment specific tRNAs

changes in the environment

__________ is a molecule that brings amino acids to the ribosome during translation. rRNA mRNA DNA t-RNA

t-RNA Transfer RNA (tRNA) are small, roughly L-shaped molecules that ferry amino acids to the ribosomes. There they decode mRNA's message for the amino acid sequence of the polypeptide to be built, a process called translation.

The RNA responsible for bringing the amino acids to the ribosome for protein formation is ________. tRNA ssRNA mRNA rRNA

tRNA

Which statement best describes the function of tRNA in translation? tRNA transfers mRNA to the ribosome. tRNA carries amino acids to the ribosome. tRNA carries the code for a polypeptide's sequence of amino acids. tRNA creates peptide bonds between amino acids.

tRNA carries amino acids to the ribosome. During translation, each new amino acid is carried to the ribosome by a tRNA molecule. Each tRNA molecule carries a particular amino acid. This amino acid is dictated by the particular anticodon that the tRNA molecule contains. For a particular mRNA codon, only one tRNA molecule contains the complementary anticodon necessary to bind. Once bound, the amino acid is transferred from the tRNA molecule to the growing polypeptide.