Transcript Chapter 10.2

Gene Regulation and Structure
Grade 10 Biology
Spring 2011
 Describe
how the lac operon is turned on
and off
 Summarize the role of transcription factors
in regulating eukaryotic gene expression
 Describe how eukaryotic genes are organized
 Evaluate three ways that point mutations
can alter genetic material
 __________
have about ______ genes
 ________ have about _______ genes
 Not all of genes are _________ and
___________ at the same time

So as not to waste energy and materials
 Both
are able to ________ gene expression
depending on cell’s needs
 E.


Coli
_______________
Gene regulation well undestood- lac operon gene
 E.
Coli is in the __________ tract
 Lactose from milk enters and becomes
available to E. Coli
 E. Coli (________) can absorb ______ and
break it down for ________
 Recognizing, consuming, and breaking
down lactose, into glucose and galactose,
requires __________________________
__________________________
3
lactose _________ ______are located next
to each other
 Controlled by the same _________ site
 On-off switch


“turns on” (transcribes and then translates) the 3
genes when ________ is ________
“turns off” genes when ________ is not available
 __________:


Piece of DNA that overlaps ________ site and
serves as on-off switch
Able to _________ RNA polymerase’s access to 3
lactose metabolizing genes
 ___________:

Area in which RNA __________ binds and allows
the genes to be ________________
 ___________


__________:
Protein that binds to an _______ and physically
______ RNA _________ from binding to
__________ site
Stops ___________ of genes in operon
 __________:

A group of genes that code for the ________
involved in the same function, their _________
site, and the _________ that controls them all
 Lac

Operon:
Operon that ________ the __________ of lactose
 __________
protein turns the _______ off
 Repressor protein binds to the ________ and
blocks RNA _______ from binding to the
_________ site
 Blocking of RNA polymerase _____ the
___________ of genes in the operon
 Lactose
binds to _______ protein and
changes repressor proteins _______
 Change of shape causes repressor protein to
____ _____ of the _________
 Now the RNA ________ is free to ____ to the
promoter (no longer blocked)
 RNA polymerase can _________ the genes
that ____ for the lactose metabolizing
enzymes
 By
producing the ________ only when the
nutrient is _________, the bacterium (E. coli)
saves _______
 Lets
watch a video to review the lac operon!
 Contain
more DNA than ____________
 Must ___________ turn genes on and off
 ________ are not common in eukaryotes
 Instead, genes with related functions are
often scattered on different ___________
 Because
there is a _________ envelope that
physically separates __________ from
_____________ more opportunities for gene
regulation
 Gene




regulation can occur:
Before _______________
_________ transcription
_________ transcription
And after mRNA leaves the _______ or after
translation, when protein is ___________
 Most
gene regulation in eukaryotes controls
the onset of ____________

When RNA polymerase binds to a gene
 Use
regulatory proteins- called __________
___________
 But many more _______ involved and more
complex
 Transcription


factors:
Help arrange ____ ___________in the correct
position on the ___________
Gene can be __________ by many different
transcription factors
_________: sequence of DNA that can be bound by a
_____________ ___________
 Located __________ of nucleotide bases away from
__________
 Loop in DNA may bring ________ and its attached
transcription factor (________) into _______ with
the transcription factors and RNA polymerase at the
promoter

 In
___________ many genes are interrupted
by introns
 ________: long segments of nucleotides that
have no _______ information
 ______: portions of a gene that are
translated (__________) into ___________
 After
gene is transcribed, _________ in mRNA
are cut out by ____________
 Splicosomes: complex assemblies of ___ and
__________
 Exons that remain are “________” back
together by splicosome to form a smaller
mRNA molecule
 mRNA is then _____________
 Each
_______ encodes part of _________
 By having introns and exons cells can
occasionally _______ exons to make new
________
 Play an ___________ role
 Thousands of proteins that occur seem to
have arisen from a few thousand ______
 Some genes exist in ___________ ______
 __________:

change in the DNA of a gene
Rare
 Mutations
in _________ can be passed on to
offspring, those in _____ _____(somatic
cells) cannot
 _____
____________:
mutations that move an
_____ gene to a new
location


Disrupt genes ________, gene
is exposed to new regulatory
conditions
Ex. You move to France and
can’t speak French
 Two
1.
2.
types of Gene Rearrangements:
__________: genes are carried by moving
transposons
___________ _________: portions of the
chromosome containing a gene may be
rearranged during meiosis
 ____
________: mutations that change a
gene


Usually result in the placement of the wrong
_____ ______during protein assembly
Usually ________ protein’s function
 Three
types of Gene Alterations:
_____ ________: single nucleotide changes
________ _________: sizable length of DNA
is inserted into a gene
1.
2.

Often result when mobile segments of DNA
(transposons) move randomly from one position to
another on a chromosome
_______ ________: segments of gene are lost
3.

Often during meiosis
Point Mutation
Deletion Mutation
Insertion Mutation
 Genetic
message is read as a series of ______
nucleotide
 ________ and ________ can _____ the triplet
groupings
 Ex. Delete the C from this sentence, keep
letters in triplets


THE CAT ATE
THE ATA TE  meaningless
 ________
________: mutation that causes
gene to be read in the ______ 3-nucleotide
sequence
 http://www.youtube.com/watch?v=gqvYOr78
THo
Activity Modeling Introns and Exons (p. 218)
 Procedure:

Place a 15-20cm strip of masking tape on your desk.
Tape represents a gene.
 Use 2 colours to write the words APPROPRIATLY
JOINED on the tape exactly as shown. Space the
letters so that they take up the entire length of the
tape. The segments in one colour represent introns;
those in the other colour represent exons.
 Lift the tape. Working from left to right, cut apart
the groups of letters written in the same colour. Stick
the pieces of tape to your desk, making two strips
according to colour and joining the pieces in their
original order.

 Activity
Modeling Introns and Exons (p. 218)
 Analysis


Determine from the resulting two strips which
strip is made of introns and which is made of
exons
Predict what might happen to a protein if an
intron were not removed