Chapter 17: Gene Expression (from gene to protein) Part 1 Flashcards

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1
Q

Gene Expression

A

process by which genes direct protein synthesis, by means of transcription and translation

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2
Q

Archibald Garrod

A

suggested that genes dictate phenotypes by enzymes that catalyze specific chemical reactions

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3
Q

“one gene-one enzyme” hypothesis

A

function of a gene is to dictate the synthesis of an enzyme

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4
Q

transcription

A

synthesis of RNA using information in the DNA, writes the blueprint for the protein

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5
Q

translation

A

synthesis of a polypeptide using the information in the mRNA, ribosomes are starts of translation, builds the protein

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6
Q

mRNA

A

carries genetic message from the DNA to the protein-synthesizing machinery of the cell, synthesized from transcription

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7
Q

Ribosomes Primary transcript

A

Initial RNA that’s produced from transcription prior to processing

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8
Q

Triplet Code

A

Series of non-overlapping 3 nucleotide words, called codons. Basically the gene sequence.

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9
Q

Codon

A

mRNA based triplets, read 5’-3’, specifies a particular amino acids to be placed at the corresponding place on a polypeptide

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10
Q

Template strand of DNA

A

3’-5’, used to translate into mRNA

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11
Q

Coding strand of DNA

A

nucleotides here are exactly the same as mRNA triplets, except where T is replaced by U

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12
Q

Discuss/Explain the progress of knowledge from Garrod’s “genes code for enzymes” to the “one gene- one polypeptide” hypotheses.

A

Garrod hypothesized that inherited disease reflect an inability to make a particular enzyme. Later, research supported that gene’s do dictate the production of enzymes in the “one gene-one polypeptide” hypothesis: the functions of a gene is to dictate the production of a specific enzyme. Biochemists learned that cells make and break molecules via metabolic pathways (reactions catalyzed by specific enzymes). Tatum and Beadle supported this hypothesis further with an experiment, in which they caused genetic mutations to molds and discovered that the mutations were unable to synthesize arginine. Meaning that the mutated genes changed the “blue-print” to exclude the enzyme that synthesizes arginine. One gene dictates the synthesis of one polypeptide (protein).

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13
Q

Describe the difference between protein synthesis in prokaryotes (bacteria) and eukaryotes.

A

In prokaryotes, translation can happen before transcription is finished, because there are no bound membranes keeping everything in one spot. So the RNA being synthesized is being translated as it is created. In eukaryotic cells, there are very specific steps. The RNA and mRNA is made in the nucleus, the RNA is capped with a poly A tail, then 10-35 more nucleotides are added at the end. Then the mRNA slips through a pore into the cytoplasm to meet the ribosomes.

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14
Q

Using a codon chart, be able to create a strand of mRNA to a polypeptide.

A

.

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15
Q

What are the 3 stages of DNA transcription.

A

Intiation: promoters define starting point on a strand Elongation of the codes: RNA polymerase unzips at 10-20 bases at a time, nucleotides are added to the 3’ end of RNA
Termination of reading that DNA:

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16
Q

What are the purposes for the alteration at the ends of mRNA?

A

Not sure. Still researching it. They think the poly A tail and the 5’ cap are there for 3 reasons: to facilitate the transfer into the cytoplasm through pores in the nucleus, to protect rna from hyrolytic enzymes, help RNA attach to the 5’ end of other ribosomes

17
Q

Reading Frame

A

Correct groupings that codons are in for polypeptide production

18
Q

Promoters

A

Signal the transcription start point on a strand and extend several dozen nucleotide pairs upstream

19
Q

Transcription Factors

A

mediate the binding of RNA polymerase (unzips your genes) and the initiation of transcription. kinda like glue for the rna polymerase

20
Q

Transcription initiation complex

A

the completed assembly of all the transcription factors and the RNA polymerase bound to a promoter (TATA box)

21
Q

TATA box

A

Series of triplets, used as a promoter, on the DNA strand. Series of Thymine Adenine.

22
Q

RNA processing

A

“cleaning up” the pre-RNA. Sequences of nucleotides that aren’t used for polypeptide synthesis are removed

23
Q

Introns

A
Intervening sequences (non-coding), won't code for a polypeptide.
Cleaned up by RNA processing/splicing
24
Q

Exons

A

Express genes, translated into other

25
Q

RNA splicing

A

Removes introns, joins to clean RNA molecule

26
Q

Splicosomes

A

Protein complex with smaller RNAs. Splices RNA introns.

27
Q

Ribozymes

A

RNA molecules that function as enzymes