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gene expression Flashcards

1
Q

name the 3 compnents of a nucleotide

A
  • phosphate group
  • deoxyribose
  • nitrogenous base
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2
Q

what is transcription?

A

the formation of pre mrna with a complementary sequence of bases to the dna , occurs in the nucleus

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3
Q

what is the process of splicing?

A

removing non coding introns and leave only the coding exons

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4
Q

what bases are found in DNA?

A

A,T,C,G

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5
Q

what bases are found in mRNA?

A

A,U,C,G

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6
Q

where is DNSA found?

A

in the nucleus

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7
Q

where is mRNA found?

A

in the cytoplasm

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8
Q

describe the process involved in stimulation of gene transcription

A
  • each transcription factor has a site that bind to a specific base sequence of the DNA in the nucleus
  • binding og the transcriptional factor to thew promoter region allows the attatchment of RNA polymerase to the dna and transcription is stimulated
  • messenger rna is produced and the genetic code it carries is then translated into a polypeptide
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9
Q

define the promoter region

A

the site of a transcriptional factor that binds to a specific base sequence in the nucleus

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10
Q

describe oestrogen

A

lipid soluble
steroid hormone
transported in the blood stream

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11
Q

describe how oestrogen can bind

A

like a substrate and an enzyme

they have complemetary shape

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12
Q

how does oestrogen initiate transcription?

A
  • combines with receptor site on transcription factor
  • this removes an inhibitor molecule that normally blocks the DNA binding site
  • allowing the transcriptional factors to bind to the DNA promoter region
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13
Q

what does RNAi stand for?

A

small interfering RNA

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14
Q

define RNA interference

A

the inhibition of gene expression at the translation stage

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15
Q

suggest why RNA interference is important in a cell

A
  • linit or stop the production of a specific protein potentially
  • to prevent mRNA containing a mutation from being translated
  • to prevent mRNA from a virus being translated
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16
Q

what makes RNAi?

A

special regulatory genes

17
Q

what cuts mRNA in two?

A

RNAi binding to specidic mRNA molecules with a complementary base sequence by complementary base pairing

18
Q

when mRNA is cut in two , what does that mean?

A

mRNA can no longer be translated so protein synthesis stops

19
Q

what are the two main functions of stem cells?

A
  • they are undifferentiated but can differentiate into specialised cells
  • they can replace themselves
20
Q

name the 4 types of stem cells

A
  • totipotent
  • pluripotent
  • multipotent
  • unipotent
21
Q

describe the difference between pluripotent and unipotent

A

pluripotent cells can differentiate into almost alll cells of the adult body (except placental cells) while unipotent stem cells can only form a single type of cell in the adult body

22
Q

describe totipotent cells

A

cells that can divdie to produce any cell in the body

-in mamals they are found in embryos

23
Q

describe pluripotent cells

A

cells that can divide in unlimited numbers and can differentiate into almost any specialised cell
-in mammals they are found in the embriys

24
Q

describe multipotent cells

A

cells that can divide to form only a limited number of different cell types
- foudn in mature mammals

25
Q

describe unipotent cells

A

have the lowest differential potential, only one type of cell or tissue
-found in mature mammals

26
Q

why are stem cells good for treating human disorders

A

they can be extracted and then grown in culture in the labatory
and then used to replace damaged cells or tissues in a patient

27
Q

other than ethical issues, give an advantage of using multipotent rather than embryonic stem cells for this process

A

no transplant rejection if stem cells is obtained from patients own tissue

28
Q

other than ethical issues, give an disadvantage of using multipotent rather than embryonic stem cells for this process

A

the stem cells can only develop into a limited number of cell types, depending on which tissue they were obtained from.

29
Q

give a defintion for the term methylation

A

methylation is the addition of a methyl group to a molecule

30
Q

who does increased methylation inhibit transcription?

A

-preventing transcription factors from binding to the DNA
-attracting proteins that decrease acetylation of histones therefore resulting in condensation of the chromatin.
genes become inaccessible to transcription factors

31
Q

summarise the effects of acetylalation of methylation on transcription

A

acetylation activates transcription

methylation messes with transcription

gene expression (1 decks)

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