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BISC 2 - Genetics, Ecology, Evolution > Molecular Genetics LearnSmart > Flashcards

Molecular Genetics LearnSmart Flashcards

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1
Q

Match the following steps of transcription with their descriptions.

A
  • Initiation - RNA polymerase binds to the gene’s promoter.
  • Elongation - RNA polymerase moves down the template strand, adding nucleotides and producing a complementary RNA molecule.
  • Termination - RNA polymerase separates from the DNA and the newly synthesized RNA is released.
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2
Q

Put the steps in the order that they occur during initiation of translation, beginning with the first step at the top.

A
  1. The “cap” end of the mRNA bonds with a small ribosomal subunit.
  2. A tRNA carrying the amino acid methionine binds to the AUG start codon.
  3. The large ribosomal subunit attaches to the small ribosomal subunit.
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3
Q

In the “central dogma” describing the flow of genetic information from DNA to protein, DNA is copied to RNA in a process called ____, and the information in RNA is used to direct the synthesis of a protein in a process called ____.

A

transcription; translation.

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4
Q

What are coding regions of eukaryotic mRNA that are translated?

A

exons

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5
Q

Select all of the reasons that gene regulation is advantageous in multicellular organisms.

A
  • Not all cells need all proteins encoded in the genome.

- It saves energy.

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6
Q

A variant of a gene is referred to as a(n)

A

allele

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7
Q

On a tRNA molecule, the ____ is a three-base sequence that is complementary to and binds to an mRNA codon during translation.

A

anticodon

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8
Q

Select all of the following that are true regarding mutations.

A
  • Mutations can occur in a promoter region.

- Mutations are alterations in DNA sequences.

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9
Q

In eukaryotes, RNA polymerase cannot bind to the promoter and initiate transcription without the presence of regulatory proteins called

A

transcription factors

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10
Q

During transcription, what reads the template strand within a gene and adds complementary bases?

A

RNA polymerase

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11
Q

Put the following steps in the order that they occur during transcription initiation in eukaryotes, beginning with the first step at the top.

A
  1. A transcription factor binds to the TATA box of the promoter.
  2. The TATA binding protein attracts other transcription factors.
  3. RNA polymerase is able to bind to the promoter at the start of the gene and begin transcription.
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12
Q

Match the number on the left with the correct step in the process of translation.

A

First - Initiation
Second - Elongation
Third - Termination

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13
Q

A codon consists of three ____ that correspond to one ____.

A

mRNA bases; amino acid

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14
Q

In bacterial operons, a DNA sequence that exists between the promoter and the protein coding region is called the ____ and is where a repressor protein can bind.

A

operator

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15
Q

During the elongation phase of translation, a ____ bond is formed between the incoming ____ acid and the growing polypeptide chain, and empty tRNAs are released from the ribosome to be reused.

A

covalent; amino

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16
Q

Select all of the following that occur at the lac operon when lactose is present.

A

-Transcription of the lac genes occurs.
-Molecules of the mRNA are produced.
Lactose binds to the repressor protein.

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17
Q

Messenger RNA contains ____, which are triplets of bases that act as “code-words” corresponding to the ____ acid monomers that make up a polypeptide.

A

codons; amino

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18
Q

____ in DNA may arise spontaneously as errors in replication, or they can be induced by chemicals called mutagens.

A

Mutations

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19
Q

Which of the following are true with respect to mutations? Select all that apply.

A
  • Some mutations can increase an organism’s reproductive success.
  • Some mutations produce detrimental alleles.
  • Mutations provide the raw material for evolution.
  • Mutations can cause drug resistance in bacteria.
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20
Q

Select all of the following that are ways to control gene expression after trnaslation.

A
  • Degrading proteins
  • Preventing a protein from reaching its correct destination
  • Block modifications or alterations to proteins
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21
Q

In ____ mutations, nucleotides are added or deleted by a number other than a multiple of three, such that the reading frame of the gene is disrupted.

A

frameshift

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22
Q

During transcription, RNA nucleotide bases are added to the growing mRNA strand as dictated by the complementary bases on the ____ strand of the DNA.

A

template

23
Q

Match each type of RNA with its correct description.

A
  • mRNA - carries the information that specifies a protein
  • tRNA - connector molecule that binds to an mRNA codon and to an amino acid
  • rRNA - structural component of the ribosome
24
Q

After translation is complete, the newly synthesized protein must ____ as determined by some regions of the amino acid chain.

A

fold into its functional shape

25
Q

____ RNA is a type of RNA that serves as a “connector” between mRNA codon and a particular amino acid.

A

Transfer (t)

26
Q

Gene expression is the production of

A

an RNA molecule or protein

27
Q

Select all of the following that are true about E. coli bacteria in an environment lacking lactose.

A
  • The repressor bings to the operator of the lac operon.

- The three genes of the lac operon are not transcribed.

28
Q

A(n) ____ is a three-base sequence on the tRNA that binds to the ____ on the mRNA.

A

anticodon; codon

29
Q

Select all of the ways that cells can make DNA less available for transcription:.

A
  • Tag DNA with methyl groups

- Wind or fold DNA in a way that makes it unavailable

30
Q

Using the following table, which of the following mRNA sequences would encode for the polypeptide Met-Ser-His-Arg-Gin? Select all that apply.

A
  • AUGUCCCAUCGUCAA
  • AUGUCUCACCGUCAA
  • AUGUCUCAUCGUCAA
  • AUGUCUCAUCGUCAG
31
Q

What sequence of nucleotides has undergone an insertion mutation compared to the original DNA sequence shown here: AGGTCTAGAGCC

A

AGGTTCTCTAGAGCC

32
Q

What process describes the removal of portions of mRNA after transcription to produce mRNA consisting of regions to be translated?

A

intron removal and splicing together of exons

33
Q

Genes that control the formation of an organism’s body parts and therefore profoundly influence animal evolution are called ___ genes.

A

homeotic

34
Q

A specific sequence on the DNA called a ____ sequence signals the end of a gene during transcription.

A

terminator

35
Q

Proteins combine with ____ to form a ribosome.

A

rRNA

36
Q

What method of gene expression regulation allows one gene to code for multiple proteins due to different combinations of exons spliced together?

A

mRNA processing

37
Q

Epigenetics is the study of ____ that affect gene expression but do not change the DNA sequence.

A

DNA modificatons

38
Q

How are mutations important in medicine, agriculture, and other applied sciences?

A
  • Mutations can lead to antibiotic resistance in bacteria.
  • Agricultural scientists use mutations to create new varieties of crops.
  • Mutations allow scientists to learn the normal function of genes.
39
Q

Select all the reasons why the protein product of translation may be nonfunctional.

A
  • The amino acid sequence of the protein is altered.
  • The polypeptide misfolds or clumps.
  • The DNA sequence is altered due to mutation.
40
Q

Not all mRNA molecules are equally stable. ow does this fact affect gene regulation?

A
  • An mRNA molecule may persist long enough to be translated many times.
  • An mRNA molecule may be degraded before it is translated.
41
Q

Select all of the ways that a cell can maximize the efficiency of protein synthesis.

A
  • The cell may produce multiple copies of each mRNA.

- Many ribosomes may simultaneously translate the same mRNA molecule.

42
Q

When is a substitution mutation “silent”?

A

When the replaced DNA base does not change the protein encoded by the gene.

43
Q

During translation initiation, the first codon to specify a particular amino acid is usually ____, which encodes the amino acid ____.

A

AUG; methionine

44
Q

Select all the types of protein modification that can occur after translation to produce a functional protein.

A
  • cutting of the protein by enzymes

- joining with other polypeptides

45
Q

Select all of the following that are true about prokaryotic versus eukaryotic gene expression.

A
  • In eukaryotes, mRNA is altered before it is translated.

- In prokaryotes, translation of an mRNA can begin before transcription of the mRNA is complete.

46
Q

Select all of the following that are used during translation.

A
  • mRNA
  • tRNA
  • ribosome
47
Q

In eukaryotes, the cap and poly A tail on the mature mRNA ensure that

A

ribosomes attach to the correct end of the mRNA for translation.

48
Q

Whereas ____ wipes away most epigenetic markers on the genome, ____ does not; therefore, identical twins may accumulate epigenetic differences throughout life.

A

fertilization; cell division

49
Q

Select all of the following that can be a direct product of transcription.

A
  • tRNA
  • rRNA
  • mRNA
50
Q

Only producing proteins that are needed allows a cell to

A

save energy.

51
Q

Select all of the following that are true about the termination stage of translation.

A
  • The polypeptide is released
  • The large and small ribosomal subunits separate
  • A release factor protein prompts the release of the last tRNA from the ribosome
52
Q

If an mRNA was blocked from exiting the nucleus, what would happen to expression of the gene from which the RNA transcript was made?

A

The gene would be silenced

53
Q

What type of illness is characterized by unregulated cell division and can be caused by defective transcription factors?

A

cancer

54
Q

Insertions or deletions of large parts of chromosomes are considered mutations.

A

True

BISC 2 - Genetics, Ecology, Evolution (5 decks)

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