From DNA to Proteins: How cells read the genome Flashcards

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1
Q

Gene Expression

A

Process where cells read out the instructions (nucleotide sequence) in their genes

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2
Q

What is the first step in gene expression?

A

Transcription

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3
Q

Portions of __________ are transcribed into RNA

A

DNA sequence

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4
Q

Transcription

A

Cells copy the nucleotide sequence of the gene into RNA molecule

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5
Q

RNA differs from DNA by containing _______ instead of thymine (T) in DNA (RNA has all the other bases like A, C, & G)

A

Uracil (U)

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6
Q

RNA

A

Is a linear polymer made of four different nucleotides (bases) linked together by phosphodiester bonds

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7
Q

The formation in genes that are expressed/ copied into RNA are done through the __________ since RNA is like DNA & can form complentary base pairs with A & U

A

Nucleotide Sequence

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8
Q

The structure of RNA is a large ________ molecule

A

Single - Stranded

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9
Q

Since RNA is a single-stranded molecule it can _______ into a variety of shapes

A

Fold up

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10
Q

_________ produces RNA that is complentary to one strand of DNA

A

Transcription

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11
Q

What is the process of transcription?

A

Begins by opening up a small portion of the DNA molecule & one of the two strands of the DNA molecule is used a template for making (synthesis) of RNA

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12
Q

The __________ of the RNA is based on the base pairing with the __________

A

Nucleotide sequence, the DNA template strand

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13
Q

What enzyme forms the RNA strand in transcription?

A

RNA polymerase

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14
Q

RNA transcript

A

The RNA chain that is produced by transcription

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15
Q

___________ is similar to RNA transcription

A

DNA replication

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16
Q

How does DNA replication differ from RNA transcription?

A

The RNA strand is removed from the complentary DNA strand (which allow DNA to re-form its double-helix structure)

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17
Q

Why is RNA only a single - stranded molecule?

A

Because its only transcribed from one DNA strand

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18
Q

RNA polymerase

A

Forms the RNA molecule (like DNA polymerase make DNA)

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19
Q

The _______ unzips the DNA strand & forms the RNA molecule in the 5’ to 3’ direction

A

RNA polymerase

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20
Q

Since RNA is _______ from DNA once its synthesis means that many RNA copies can come from the same gene (The synthesis of the next RNA is started before the first RNA is completed)

A

Removed

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21
Q

Unlike DNA polymerase in DNA replication, RNA polymerase can __________________

A

Start an RNA chain without a primer & doesnt proofread itself

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22
Q

Messenger RNA (mRNAs)

A

The RNA molecules that were formed by genes & also synthesis proteins (carry genetic information from the gene to make proteins)

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23
Q

_____________ refers to the process by which the information (the nucleotide sequence) of DNA is converted into a product either as proteins or RNA

A

Gene Expression

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24
Q

If the final product is a ________ then gene expression includes both transcription & translation

A

Proteins

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25
Q

If the final product is _________ then gene expression just requires transcription

A

RNA

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26
Q

When translating the nucleotide sequence into proteins, _________ & ________ are used

A

Ribosomal RNA (rRNAs) & Transfer RNA (tRNAs)

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27
Q

Ribosomal RNA (rRNAs)

A

Form the structural & catalytic core of the ribosomes which translate mRNAs into proteins

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28
Q

Transfer RNA (tRNAs)

A

Act as adaptors that select specific amino acids & hold them in place on a ribosome for their incorption into proteins

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29
Q

Signals in ______ tell the RNA polymerase where to _______ & _______ transcription

A

DNA, start & stop

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30
Q

To begin transcription ____________ have to be able to recognize the start of a gene & bind to that place

A

RNA polymerase

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31
Q

How does RNA polymerase recognize the transcription site in bacteria?

A

The RNA polymerase collide with the DNA molecule & weakly attach itself to move along the DNA strand till it finds a promter & once it finds the promoter it binds tightly to it & start transcription in front of the promoter

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32
Q

Promoter (start site)

A

Contains a specific sequence of nucleotides thats the starting point for RNA synthesis

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33
Q

What happens when the RNA polymerse finds the promoter?

A
  1. The RNA polymerase opens up the double - helix in front of the promoter where one of the two DNA strands acts as a template for complentary base - paring with the RNA formed by the RNA polymerase
  2. The RNA polymerase continues to make the RNA molecule till it reaches a second singal spot which is the terminator spot (stop site) where the the polymerase stops & releases the RNA strand
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34
Q

Bacteria promoter (start site) & the terminators (stop site) have ___________ that are recognize by the RNA polymerase (like AUG)

A

Specific nucleotides sequence

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35
Q

The _______ in bacteria is responsible for finding the promoter sequence in DNA & once it finds the promoter it binds to the DNA strand keeping it open

A

Sigma Factor

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36
Q

Since the RNA polymerase can only form the RNA molecule in the ____ to _____ direction it usuallly chooses the DNA strand that is in the 3’ to 5’ direction

A

5’ to 3’

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37
Q

What are the three types of RNA polymerase that are needed for translation in eukaryotic cells?

A
  1. RNA polymerase 1
  2. RNA polymerase 2
  3. RNA polymerase 3
38
Q

RNA polymerase 2

A

Transcribes all the proteins

39
Q

RNA polymerase 2 in eukaryotic cells can’t start transcription without the _____________

A

General Transcription factors

40
Q

General Transcription Factors

A

Are accesory proteins that assemble on the promoter where they position the RNA polymerasse & pull apart the DNA double-helix to expose the template strand allowng the RNA polymerase to begin transcription (have a similar rol to the sigma factor in bacteria)

41
Q

The process of a ______________ at a promoter begins by binding the general factor TFIID to a short segment of DNA that has mostly the bases of A & T (Its called the TATA Box)

A

General Transcription factor

42
Q

Once the ______ is binded to DNA it serves as a landmark for other transfer factor proteins to assembly on the promoter

A

TFIID

43
Q

Once the TFIID has binded to the _______ the other factors assemble along with RNA polymerase 2 to form a complete transcription initiation complex

A

TATA Box

44
Q

Once RNA polymerase has been placed on the promoter it is released by the addition of ___________ to it “tails”

A

Phosphate groups

45
Q

The action of adding ________ to RNA polymerase 2 is started by the general transcription factor TFIIH

A

Phosphate groups

46
Q

Once RNA polymerase 2 is finished transcribing a gene its released from the DNA & its _____________ on its tail is stripped off by proteins called phosphatase

A

Phosphate groups (Only dephosphorylated forms of RNA polyermase 2 can be re-used to make an RNA molecule)

47
Q

Eukaryotic mRNAs are made in the _________

A

Nucleus

48
Q

__________ takes place in the nucleus of eukaryotic cells

A

Transcription

49
Q

______________ occurs in the cytosol, so for eukaryotic mRNAs to be _________ into proteins they must be transfered out of the nucleus through small pores in the nuclear envelope

A

Translation, translated

50
Q

Before the mRNA can be exported to the cytosol the eukaryotic RNA must go through what three processes?

A
  1. Capping
  2. Splicing
  3. Polyadenlation
51
Q

The __________ responsible for RNA processing are on the phosphorylated tail of the RNA polymerase & are processing the RNA transcript as its being made

A

Enzymes

52
Q

______________ of the tail of RNA polymerase 2 allows RNA processing proteins to assemble there

A

Phosphorylation

53
Q

What two processes occur on an RNA transcript as its being processed into an mRNA?

A
  1. Capping
  2. Polyadenylation
54
Q

Capping

A

Modifies the 5’ end of the RNA transcript (Also protects it from being degraded from certain enzymes)

55
Q

Polyadenylation

A

Adding adenines to the end on the pre-mRNA to protect it from being degraded from certain enzymes

56
Q

In eukaryotics, proteining coding genes are interrupted by non-coding sequences called ________

A

Introns

57
Q

Introns

A

Its an intervening sequence that interrupts protein-coding

58
Q

_________ are removed from pre-mRNAs by RNA splicing

A

Introns

59
Q

RNA splicing

A

The introns are removed from the newly synthesized RNA & the exons are stitched together

60
Q

Once the RNA transcripted has been ______ & its 5’ & 3’ ends have been modified the RNA is a fully functional mRNA molecule that can be translated into proteins

A

Spliced

61
Q

RNA splicing is carried out by ___________

A

Small nuclear RNA (snRNAs)

62
Q

Small nuclear RNAs (SnRNAs)

A

Recongize splice -site sequence through base-paring between their RNA components & the sequence in the pre-mRNA & carry out splicing

63
Q

The ____________ form the core of the spliceosome

A

SnRNA (Small nuclear RNA)

64
Q

Spliceosome

A

Is an assmebly of RNA & proteins molecules that carry out RNA splicing in the nucleus

65
Q

An mRNA sequence is decoded/ read in sets of three nucleotides called _________

A

Condons

66
Q

Translation

A

The converison of the information from RNA into proteins

67
Q

The translation of mRNA into proteins depends on adaptor molecules called ______________

A

Transfer RNAs (tRNAs)

68
Q

______ molecules match the right amino acid to the codons in mRNA

A

tRNAs

69
Q

Transfer RNA (tRNAs)

A

Bind to a condon on one side & bind to an amino acid on the other side

70
Q

Translation occurs in the ___________ of eukaryotic cells?

A

Cytoplasm

71
Q

Translation of mRNA is driven by a _____________ where it reads the sequence on the mRNA

A

Ribosome

72
Q

Anticodon

A

Set of three consecutive nucleotide that bind through base - pairing to the complementary codon in an mRNA molecule

73
Q

The tRNA is an L shape where it has two regions: one forms the __________ & the other is where the __________ that matches the codon is convalently attached to the tRNA

A

Anti-codon, Amino Acid

74
Q

For tRNA molecules to be an adaptor it must be linked to the right amino acid therefore it depends on ______________

A

Aminoacyl-tRNA synthetase

75
Q

Aminoacyl-tRNA synthetase

A

An enzyme that convalently links each amino acid to the right set of tRNA molecules

76
Q

Ribosomes

A

Is made of small proteins (ribosomal proteins) & RNA molecules called ribosomal RNAs (rRNAs)

77
Q

Eukaryotic & Prokaryotic ribosomes are made up of one _________ & ________

A

Large subunit & Small subunit

78
Q

The ___________ matches the tRNAs to the codons on the mRNA

A

Small subunits

79
Q

The __________ forms the peptode bonds that linkl the amino acids together into a polypeptide chain

A

Large subunit

80
Q

The two ______ come together on an mRNA molecule near its 5’ end to start the synthesis of a protein & as the mRNA moves forward in the 5’ to 3’ direction the ribosomes translate its nucleotide sequence(codons) into an amino acid sequence using the tRNA as adaptors

A

Subunits

81
Q

What are the 3 binding sites in the ribosome?

A
  1. A site
  2. P site
  3. E site
82
Q

What purposes that AUG serve?

A
  1. To tell the ribosomes to start translation
  2. To tell the ribosome to make methionine
83
Q

Reading frame

A

Set of ordered triplets nucleotides (the codons)

84
Q

Point Mutations

A

Simplest type of mutation (Can cause dieases)

85
Q

Deletion

A

Loss of one or more bases

86
Q

Insertion

A

Addition of one or more bases

87
Q

Frameshift mutation

A

Inserting or deleting a base can cause a shift in the reading frame

88
Q

Some tRNAs bind to more than one codon like a _________

A

Wobble

89
Q

Wobble

A

A mismatch nucleotide pair (like G-U)

90
Q

Exons

A

Smaller regions in the pre-mRNA & its what used to snythesis proteins