Genes Flashcards

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1
Q

What is genetic code?

A

A set of rules that nucleotides follow that determines how genetic information stored is .transcribed and translated into protiens.

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2
Q

What does genetic code consist of?

A

Universal: All organisms use the same sets of codons used for amino acids
Non-overlapping triplet nature All triplet and codons are read independantly
UnambigousEach codon codes for only one amino acid
Degenerate Amino acids may be coded by multiple different codons.

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3
Q

What is grouping of three nucleotides in DNA called?

A

Triplets

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4
Q

What is the grouping of three nucleotides in RNA called?

A

Codon

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5
Q

Do all codons code for the protiens structure?

A

Nahhhhh brother wbt STOP AND START codons in protiens synthesis.

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6
Q

What is the start codon in protiens and stop codons

A

AUG ( Methionine)
Stop codons:
UAA,UAG,UGA

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7
Q

What is Gene expression?

A

It is when a part of a gene is used by the cell for gene products or non coding strands of RNA

Remeber this doesnt ALWAYS mean PROTIEN

the non cododing thing yeah is like for tRNA and rRNA

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8
Q

What are the 3 basic steps for Protien Synthesis(In eukaryotes)

A

1.Transcription
2.RNA processing
3.Translation

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9
Q

What is Transcription

Definiton?

A

Transcription is the making of pre/mRNA which contains information needed based off DNA by the help of RNA polymerase.

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10
Q

What happens in Transcription?

FULL MARK ANSWER

A
  1. RNA polymerase and transcription factors attatch to the promoter reigion and DNA is then unzipped by the polymerase
  2. The template strand of DNA is read across in a 3’-5’ , adding free floating COMPLEMENTARY nucleotides to the bases on the template strand. to synthesise a mRNA strand In a 5’-3’ direction, where uracil is paired with adenine.
    The RNA polymerase stops transcription when it reaches the termination sequence of the gene, which then pre-MRNA is relased.
    DNA is recoiled and winded back.
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11
Q

What strand is read by rna polymerase in DNA

A

Template strand

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12
Q

Explain RNA processing

A

Splicing occurs, where the introns in the pre-mrna is removed by spliceomes and the exons are spliced together
A 5’ methyl cap is added and a 3’ poly-Adenine tail is added.

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13
Q

Why is RNA processing done, like the addition thinng

A

To prevent the mRNA from degrading and to assist from binding to the ribosome during translation

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14
Q

Explain Translation in protien synthesis

A

1.Ribsome binds to the 5’ end of the mRNA strand, and a TRNA molecule anticodon pairs with the start codon and brings the first amino acid.
2.Ribosome reads througout the mRNA strand brings trna anticodons that are complemntary to the codons of the mrna strand and brings the specific amino acids, forming a growing polypeptide chain connected by peptide bonds via condensation reactions.
3.When the stop codon is read translation terminates and the ribososome detatches and the polypeptide chain is released to be folded in endoplasmic reticulum.

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15
Q

what happens to the trna molecule after delivering a amino acid

A

it detatches and goes away to pick up the respective amino acid in the cell

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16
Q

What is upstram and downstream

A

5’ is up
3’ is down

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17
Q

What is gene regulation?

A

It is the control of gene expression by turning on and off transcription of a gene product.

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18
Q

Why is gene regulation important?

A
  1. Saves energy by not producing gene products when not needed
  2. Prevents accumalation of protiens, which can be toxic to the cell
  3. Allows cells to differentiate and specilalise during embryo development.
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19
Q

What are the two types of genes involved in gene regulation?

A
  1. Structural genes
  2. Regulatory genes
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20
Q

What is structural genes

A

Segments of dna that codes for protiens that have a role in the function or structure of cell

eg like haemaglobin , enzymes and shi

21
Q

What are regulatory genes?

A

They are segments of DNA that is responsible for producing protiens that control the expression of other genes

22
Q

Where structural genes usually found on a gene

A

downstream 3’

23
Q

What can regulatory protiens even do

A
  1. Turn OF AND On gene expression
  2. Increase and decrease gene expression by affecting transcription
  3. Can control types of post-transcriptional modification
24
Q

What components are in prokaryote genes

A
  1. Promoter
  2. Operator
  3. Exons (only)
  4. Termination sequence
25
Q

What components of a prokaryote gene is not in a eukaryotic gene

A
  1. Operator reigion
  2. Exons only
26
Q

What is a promoter reigon

what is it called in eukaryotes aswell

A

It is the sequence of DNA that is found upstream where RNA polymerse binds,
in eukaryotes its called the ‘TATA box’

27
Q

What is the termination sequence?

A

It is an sequence of DNA that indicates the stopping of transcription

28
Q

What is a operator reigion?

YOOOOO PROKARYOTIC OR EUKARYOTIC?

A

They are found in prokaryotic genes used for a binding site for repressor protiens, which inhibit gene expression.

29
Q

What is an operon?

Only found in prokaryotes remember

A

An operon is an a cluster of linked genes that all share one promoter and therefore transcribed all at the same time.
The genes involved in the operon can be turned on and off by the operator sequence.

30
Q

What components is the operon basically

A
  1. promoter
  2. operator
  3. structural genes
31
Q

what bacteria produces tryptophan and when does it begin creating it.

A

E.coli creates that amino acid when level of tryptophan is low.

32
Q

So what would be the trp operon?

A

Dna sequence that regulates the expression of the structural genes that code for TRYPTOPHAN

33
Q

what is trp operon controlled by?

A

A regulatroy gene upstream.

34
Q

In repression does it always have to be that active protien binds to the operator reigon?

A

No sometimes like in lac operon, inactive repressor protien is larrady blocking transcription, unless activated.

35
Q

What is the leader reigion?

A

Downstream of the promoter and operator- to regulate gene exepression in prokaryotes

36
Q

Explain repression in trp operon

A
  1. When trptophan levels are high, two trp molecules bind to the repressor protien, which induces a confirmational change in its shape, allowing the repressor protien to bind to the operator reigion, blocking RNA polymerase from starting transcription.

talk about upstream/downstream

37
Q

why is tryptophan regulated in the cell by repression?

A

to conserve energy

38
Q

you need to do attenuation btw too

A
39
Q

During what step of protien synthesis do we start considering Uracil being swapped with thymine?

A

DUring transcription

40
Q

What is the structure of an ribosome

A

protien and rRNA

41
Q

Enzymes are always protiens?

TRUE OR FALSE

A

False

42
Q

What is the structural differnece of DNA compared to ecoli(example) and human dna

A

Ecoli dna is circular whereas human is linear

43
Q

What is the steps for non coding strands of RNA

A

Transcription and RNA processing

44
Q

Eukaryotes also have Operons yes?

A

NO

45
Q

wHAT DOES the regulatory gene express?

A

A inactive repressor protien

46
Q

If a premature stop codon occurs in mRNA, what happens?

A

Prooduces a non functional protien which a different shape

47
Q

What is a good reason for bands not appearing in gel electrophoresis?

A

Improper loading of DNA into the wells

48
Q

What do you say, if they ask hey why does rna polymerase bind to the TWMPLATE strand?

A

tHIS IS because the nucleotides on the mRNA strand is based off the nucleotides from templatem strand, a change in this would form incorrect sequwnce of nucleotides
andddddd
the sequence on tmeplate strand upsteam of dna has a promoter reigon that enables the RNA polymerase to bind to it.

49
Q

where does RNA polymerase bind to?

A

Upstream promoter reigion