Biology Vce 2016 Unit 4 Aos1 (Gene Regulation)

Front 1

somatic cells

Back 1

23 pairs (46 chromosomes)

diploid

Front 2

sex cells

Back 2

23 chromosomes

haploid

Front 3

if all cells have the same DNA, why aren't all cells of an individual the same?

Back 3

cells do not express all of their genes of their genome at the same time. even when they're expressed, their is evidence that there are controls over how fast specific genes are transcribed and translated

Front 4

genome

Back 4

complete set of genes in a cell or organism

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proteome

Back 5

all the proteins in a cell or organism

Front 6

structure of a gene

Back 6

coding region of a gene contains the information for making a protein.

- the coding parts are known as exons

- regions on either side of coding region are called flanking regions

- coding region is interrupted by introns

Front 7

exons

Back 7

any part of a gene that will encode a part of the final mature RNA produced by that gene after introns have been removed by RNA splicing

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intron

Back 8

noncoding sections of an RNA transcript, or the DNA encoding it, that are spliced out before the RNA molecule is translated into a protein

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flanking region

Back 9

It is the region of DNA that is not transcribed into RNA.

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upstream region

Back 10

- coming before the gene

- promoter

- contains many Ts and As

- this region is involved in the start of the decoding process and the rate of transcription

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downstream region

Back 11

- coming after the gene

- DNA coding region

- contains end transcription

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structural genes

Back 12

code for a particular protein

Front 13

regulator genes

Back 13

code for proteins that control the function of structural genes

Front 14

switching genes on and off

Back 14

genes only need to be switched on if the protein they code for is required by the cell and/or organism; otherwise genes are switched off

Front 15

lac operon

Back 15

E.coli bacteria can metabolise both lactose and glucose - glucose is preferred as it can be put straight into cellular respiration

when lactose is present but glucose is not, the bacterium can metabolise lactose by producing enzymes that break it down, turning on the genes to do so

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operon

Back 16

a group of closely related genes that act together and code for enzymes regulating a particular metabolic pathway

- controls whether a gene is switched on or off

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operon structure

Back 17

comprises a number of different genes

- structural genes

- promoter gene

- operator gene

- regulator gene

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structural genes

Back 18

code for production of enzymes involved in a particular set of metabolic reactions

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promoter gene

Back 19

recognition site to which RNA polymerase binds to

Front 20

operator gene

Back 20

controls production of mRNA

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regulator gene

Back 21

outside operon, can produce a repressor molecule which can block the operator gene

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lac operon

step 1 - production of the repressor protein

Back 22

- regulator gene produces a protein called a repressor.

- with no lactose, the repressor blocks the binding site of RNA polymerase

- genes coding for the enzymes for lactose metabolism are not transcribed

Front 23

lac operon

step 2 - inducer binds to repressor protein

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- inducer binds to repressor, preventing it from binding to the operator

- RNA polymerase can then bind and the structural genes can be transcribed

- reversible reaction that happens only if the inducer is in high concentration

Front 24

lac operon

lactose not present

Back 24

regulator gene -> repressor protein -> binds to operator -> RNA polymerase cannot bind -> transcription is blocked

Front 25

lac operon

lactose is present

Back 25

reg gene -> repressor protein -> binds to lactose -> prevents repressor protein binding to operator -> RNA polymerase can bind -> transcription occurs

Front 26

intron retention

Back 26

keeping same or all introns after transcription

Front 27

exon juggling

Back 27

changing order of exons after transcription