Biology Ch. 13

In a nucleotide, the nitrogenous base is attached to the sugar's _____ carbon and the phosphate group is attached to the sugar's _____ carbon.

1' ... 5'

Can you match these biology terms with their definitions? Drag the terms on the left to the appropriate blanks on the right to complete the sentences.

1. The enzyme RNA polymerase synthesizes an RNA strand by first unwinding a DNA molecule and then stringing together a series of RNA nucleotides complementary to it. 2. The process by which the genetic information encoded in DNA is copied into messenger RNA (mRNA) is called transcription. 3. In eukaryote genes, nucleotide segments that code for proteins, called exons, are interrupted by noncoding segments, called introns. 4. A(n) anticodon is a sequence of three bases on a molecule of transfer RNA (tRNA) that is complementary to a coding triplet of messenger RNA (mRNA) bases. 5. Amino acids are added one at a time to the growing protein chain, or polypeptide, on a ribosome. 6. The process by which information encoded in messenger RNA (mRNA) is used to assemble a protein is called translation.

Nucleic acids are assembled in the _____ direction.

5' to 3'

The direction of synthesis of an RNA transcript is _____.

5' —> 3'

Considering the table of mRNA codons, how many unique tRNA molecules must there be to translate mRNA into protein?

61

A protein consists of 300 amino acids. How many bases will be necessary in the processed mRNA, to code for this protein? Assume introns have been extracted from the processed mRNA.

903

Which of the following events occurs during transcription?

A molecule of RNA is formed based on the sequence of nucleotides in DNA

In the accompanying image, a nucleotide is indicated by the letter _____.

B

Which of these is a tRNA?

B

A nitrogenous base is indicated by the letter _____.

C

Which of these is(are) pyrimidines?

C, D, and E

Which of the following reflect the anticodon code carried by the transfer RNA when the mRNA codon is GUA? Examine the table of mRNA codons and match your answer to the respective amino acid that the unique tRNA will deliver to the site of protein synthesis.

CAU - valine

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

CUG

Which of the following statements could explain why women do not show twice as much genetic expression from the presence of two X chromosomes compared to men who only have a single X chromosome?

Cells in women have one X condensed.

Which of these is a regulatory gene?

D

In the diagram below, the two blue strands represent _____.

DNA

Which one of the following does not play a role in translation?

DNA

Which of these is a difference between a DNA and an RNA molecule?

DNA is double-stranded, whereas RNA is single-stranded.

Which of these correctly illustrates the pairing of DNA and RNA nucleotides?

GTTACG CAAUGC

What does it mean if a gene is "expressed"?

It is transcribed and translated.

What is the primary job of DNA?

It provides blueprints for proteins.

The operon model of the regulation of gene expression in bacteria was proposed by _____

Jacob and Monod

The genetic code is often described as redundant. What feature of the genetic code does this reference?

Most amino acids have more than one codon.

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

P

In the diagram below, the gray unit represents _____.

RNA polymerase

How does RNA polymerase know where to start transcribing a gene?

RNA polymerase binds to the promoter of the gene.

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

RNA processing

Which of the following statements about ribosomes is correct?

Ribosomes are made from RNA and protein. They are used to synthesize proteins.

After the transcription process is completed, what happens to the RNA polymerase enzyme?

The RNA polymerase may move to a different gene or the same gene. It just transcribed to start a new process of transcription, staying in the nucleus.

What is the relationship between the template strand and the mRNA transcribed from it?

The mRNA molecule is complementary to the DNA sequence. Base pairing between DNA and RNA is the same, except that uracil in RNA is the complementary base pair for adenine in the DNA.

The picture shows a ribosome translating mRNA. What event will happen next?

The met amino acid will be attached to the val amino acid by a peptide bond.

The protein pepsin is produced in the cells lining the stomach but not in cheek cells. Why is this?

There are no transcription factors for pepsin in cheek cells.

If transcription and translation were applied to a book, which statement would correctly describe the process of each?

Transcription is making an encrypted copy, and translation is converting the encrypted code into a chapter-like composition.

Which anticodon would match the codon AAG?

UUC

There are many types of mutations involving the mRNA code that can result in a protein being nonfunctional or destroyed. Which type of mutation would most likely result in a prematurely terminated protein?

a substitution or insertion mutation that causes a stop codon to terminate translation early in the process

Which of the following is an identified mechanism used in gene expression for silencing or deactivating a gene's effect? This mechanism essentially stops transcription.

adding methyl groups to the promoter of an insulin gene in cells other than the pancreas

Polypeptides are assembled from _____.

amino acids

Which of the following is a good reason for mRNA to be single-stranded, instead of double-stranded like DNA?

because a complementary strand of RNA would prevent the binding of tRNA anticodons to the codon

Eukaryotes use mRNA to carry the sequence for a protein to the ribosomes outside of the nucleus. Why then don't prokaryotes translate DNA directly, rather than use mRNA, which in eukaryotes is the code that passes from the interior of the nucleus to the site of protein synthesis?

because control of transcription of mRNA is a major method of controlling gene expression

Which of the following mutations will have the largest effect on the expression of this gene? 1-ATG, 2-GTC, 3-GCA, 4-TGT, 5-TAG

deleting the A in position 1

During which phase of gene expression does gene editing occur to remove introns?

following transcription, but while still inside the nucleus

What would cause a region of DNA to have no expressed genes?

if the DNA were condensed

What is the name of the process shown in the diagram?

initiation (of translation)

Adding one nucleotide into the middle of a sequence causes what type of mutation?

insertion

RNA processing converts the RNA transcript into _____.

mRNA

Which of the following elements is not part of the preinitiation complex?

mRNA

Which of the following does not occur during RNA processing?

mRNA attaches to the small subunit of a ribosome

Which of the following is a correct statement about mRNA?

mRNA moves from the nucleus to the cytoplasm following RNA processing.

Use the genetic code (Table 13.3 in the textbook) to translate the following strand of DNA: TACACCTAA.

methionine, tryptophan, isoleucine

In the presence of a regulatory protein the lac operon is _____.

not transcribed

This is an image of a(n) _____.

nucleotide

The letter A indicates a _____.

phosphate group

Which of the following is the most energy-efficient mechanism to prevent a protein from taking action?

prevent transcription of the mRNA

Which of these is NOT a component of the lac operon?

regulatory gene only

The site of translation is

ribosomes in the cell cytoplasm

You can tell that this is an image of a DNA nucleotide and not an RNA nucleotide because you see a _____.

sugar with two, and not three, oxygen atoms

During translation, which component is directly responsible for reading the sequence of nucleotides so it may be translated into a sequence of amino acids?

tRNA

Regulatory proteins bind to _____.

the operator

In the diagram below, the green unit represents _____.

the promoter

Which of these nitrogenous bases is found in DNA but not in RNA?

thymine

In a DNA double helix an adenine of one strand always pairs with a(n) _____ of the complementary strand, and a guanine of one strand always pairs with a(n) _____ of the complementary strand.

thymine ... cytosine

What is another name for production of RNA by reading the DNA code?

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

In eukaryotic cells the first step in protein synthesis is the _____.

transferring of information from DNA to messenger RNA

Gene regulation can involve steps or processes both inside the nucleus and in the cytoplasm. Which step of regulation happens at the site of ribosomes?

translation

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

translation