8c Flashcards

1
Q

what is the purpose of gene expression?

A

explaining how cells decode and use the info in their gametes

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2
Q

what are the 2 sequential processes that allow information encoded in genes to be copies as RNA and expressed as proteins?

A

Transcription and translation

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3
Q

Explain what is meant by the “one gene–one polypeptide hypothesis,”?

A

suggests that each gene in an organism’s DNA is responsible for encoding a single polypeptide or protein.

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4
Q

One gene - one enzyme (polypeptide) hypothesis was originally proposed by? and later on?

A

Archibald Garrod in 1901
beadle and Tatum(1941)

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5
Q

central dogma?

A

states that genetic information flows from DNA to RNA (transcription) and then from RNA to protein (translation)

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6
Q

define transcription

A

process by which the information encoded in DNA is made into a complementary RNA

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7
Q

define mRNA

A

The segments of DNA transcribed into RNA molecules that can encode proteins

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8
Q

Define ncRNA

A

segments of DNA copied into RNA that are not involved in encoding proteins

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9
Q

define translation

A

process of synthesizing a specific protein by using the info encoded in the mRNA on a ribosome.

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10
Q

_________ are building blocks of proteins?

A

polypeptides

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11
Q

Most of genes are__________ into mRNA, and then the mRNA is ___________ into polypeptide.

A

transcribed
translated

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12
Q

where does central dogma occurs in prokaryotes and why?

A

both transcription and translation occur in the cytoplasm due to the absence of nucleus

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13
Q

where does transcription and translation occurs in eukaryotes?

A

transcription -nucleus
translation - ribosomes - rough endoplasmic membrane-cytoplasm

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14
Q

define gene

A

organized unit of DNA sequences that enables a segment of DNA to be transcribed into RNA and ultimately formation of a functional product.

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15
Q

what are the 4 things that a gene is composed of?

A

promoter
regulatory sequences
transcribed region
terminator

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16
Q

promoter?

A

site in the DNA where RNA polymerase binds to begin transcription

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17
Q

regulatory proteins

A

sites binding to regulatory proteins control whether a gene is turned on or off.

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18
Q

transcribed region

A

region of a DNA that is transcribed into an RNA molecule

19
Q

terminator?

A

signals the end of gene transcription and encourages RNA polymerase to cease synthesis, releasing the transcribed RNA molecule.

20
Q

what is required for initiation of transcription?

A

transcription factors (TFs) binding to the promoter region

21
Q

function of RNA polymerase?

A

catalyzes the synthesis of RNA from a DNA template during transcription

22
Q

what facilitates binding of RNA polymerase to the promoter region?

A

Transcription factors(TRs)

23
Q

In eukaryotes, the promoter often contains a ________ box, while in prokaryotes, it includes a _________ box (________) + what’s the use of these elements

A

TATA
Pribnow box, TATAAT
help initiate and regulate the transcription of genetic information.

24
Q

in a given gene during translation how many strands a as template

A

only one aka the template strand

25
Q

how is the dna template read

A

3’ - 5’

26
Q

In what direction is the RNA synthesized

A

5’ - 3’

27
Q

what are the 3 stages of transcription

A

Transcription initiation
transcription elongation
transcription termination

28
Q

_____________ unwinds the DNA

A

RNA polymerase II

29
Q

products of transcription?

A

RNAs(mRNA,tRNA,rRNA)

30
Q

define elongation in transcription

A

where RNA polymerase reads the DNA template and sequentially adds complementary RNA nucleotides to synthesize the growing RNA chain in the 5’ to 3’ direction.

31
Q

what nucleotide incorporates thymine into RNA during elongation of transcription?

A

uracil

32
Q

where does transcription ends?

A

termination site(terminator)

33
Q

transcription ends with an _______ signal for _______.

A

AAUAAA
polyadenylation

34
Q

define polyadenylation

A

addition of a poly-A tail to the 3’ end of an mRNA molecule during transcription. This modification enhances mRNA stability and facilitates its export from the nucleus and translation in the cytoplasm.

35
Q

what are the 2 types of termination in translation?

A

1.Rho independent (intrinsic) termination
2. Rho (ATPase) dependent termination

36
Q

define, Rho (ATPase) dependent termination

A

occurs when the rho protein disassociates the RNA polymerase and moves it off of the template.

37
Q

define, Rho independent (intrinsic) termination

A

when the RNA forms a hairpin structure which displaces RNA polymerase and stops transcription.

38
Q

_________- transcription is more complex

A

eukaryotic

39
Q

what is the location of transcription in prokaryotic vs eukaryotic

A

prokaryotic- cytoplasm
eukaryotic- nucleus

40
Q

initiation of transcription in prokaryotic vc eukaryotic?

A

prokaryotic- a single sigma factor
eukaryotic- 5 generational transcriptional factors

41
Q

what type of polymerase is involved in transcription for prokaryotes vs eukaryotes?

A

prokaryotes- a single type of
eukaryotes- three types of (I, II & III)

42
Q

What is transcribed by the diff polymerase of eukaryotes?

A

RNA POLYMERASE I: transcribes RNA GENES
RNA POLYMERASE II :mRNA, miRNA, snRNA, and snoRNA genes
RNA POLYMERASE III : tRNA and 5S rRNA genes

43
Q
A