CSCOPE Unit 08 Lesson 01 There are hundreds of different types of cells in your body and each type has a unique function Were going to compare some different types of cells to see how much they have in common ID: 757135
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Slide1
Gene Expression and Cell Differentiation
CSCOPE
Unit: 08 Lesson: 01Slide2
There are hundreds of different types of cells in your body, and each type has a unique function. We’re going to compare some different types of cells to see how much they have in common. Slide3
Your Best Guess
For each pair of cells in your body, you are going to predict what percentage of DNA is the same in the two types of cells. Record your prediction in your science notebooks. Slide4
same in your blood cells and nerve cells?
What percentage of the DNA is the
Images Courtesy of Wikimedia CommonsSlide5
What percentage of the DNA is the
s
ame in your rods (eye) and lung cells?
Images Courtesy of Wikimedia CommonsSlide6
What percentage of the DNA is the
s
ame in your liver and bone cells? Slide7
same in your blood cells and nerve cells?
What percentage of the DNA is the
Answer:
100%
Images Courtesy of Wikimedia CommonsSlide8
What percentage of the DNA is the
s
ame in your rods (eye) and lung cells?
Answer:
100%Slide9
What percentage of the DNA is the
s
ame in your liver and bone cells?
Answer:
100%
Images Courtesy of Wikimedia CommonsSlide10
Hmmm…
How can these cells, that have very different functions, have the exact same DNA in the nucleus?Slide11
Hmmm…
How does the body use the exact same set of instructions to make such different structures?Slide12
Taking a step back…
HOW does DNA specify for
traits in an organism?
HOW does DNA instruct cells?Slide13
Animations
Insert appropriate animations here (see Advance Preparation).Slide14
Carrying Information in DNA
Core Concepts
DNA triplets code for one amino acid
.
Amino acids link together to
form_______.
Genes code for polypeptides that control things such as:
The expression traits (how we look)
The function of the cell
Other genes
A very small percentage of the human genome actually codes
for_______.Slide15
Now, we are going to do some activities that will help you better understand:
1. Gene expression
2. How gene expression is regulated
3. How regulation of gene expression
causes cells to become different
4. How environmental factors play a
roll in cell differentiationSlide16
What Does Gene Expression Mean?
Let’s look at different ways it is regulated.
(Graphic courtesy of Marianne Dobrovolny)Slide17
Different Cells Have Different Functions… How?
Embed a video clip on epigenetics here.Slide18
Epigenetics
What causes cells with the same DNA to differentiate?
What is one way to turn genes on and off?
What causes changes in epigenetics? For example, why do identical twins continue to become more different in terms of their epigenetics as they get older? Slide19
Gene RegulationSlide20
Gene Regulation:
Modification of Genome (DNA)
Sections of DNA called
_______ can
be moved to different chromosomes.
Chemical factors can structurally change the DNA, turning it on or off.
Chemical processes: DNA methylation & histone modification
Epigenome
Gene regulation at the
_____level
happens in eukaryotes and rarely, if ever, in prokaryotes.Slide21
Epigenome
The term
epigenome
is derived from the Greek word
epi
,
which literally means "above" the genome.
The
epigenome consists of chemical compounds that modify, or mark, the genome in a way that tells it what to do, where to do it, and when to do it (i.e., turn genes on and off)
Different
cells have different epigenetic marks.
The_______ causes
changes in our epigenetics.Slide22
EpigenomeSlide23
In a fetus, cells with the exact same DNA are directed to differentiate by chemical signals that cause certain genes to be switched on or off in.
Cell DifferentiationSlide24
Gene RegulationSlide25
Gene Regulation:
Transcriptional Regulation
Transcriptional factors (regulatory proteins) turn transcription on and off or increase and decrease.
This mechanism happens in eukaryotes and prokaryotes.Slide26
Prokaryotes:
Transcriptional Regulation
________–
functioning unit of DNA containing the following:
A set of genes (DNA the codes for mRNA)
Regulatory sections (DNA that controls the expression of the gene) Slide27
Prokaryotes:
Transcriptional Regulation
This gene is
“turned on.”Slide28
Prokaryotes:
Transcriptional Regulation
This gene is
“turned off.”Slide29
Eukaryote:
Transcriptional Regulation
Much more complicated and involves:
Many regulatory proteins (transcription factors)
Enhancers and TATA BoxSlide30
Eukaryote:
Transcriptional Regulation
This gene is
“turned on.”Slide31
Gene RegulationSlide32
One gene can result in several different proteins through a process called: Alternate mRNA Splicing
Posttranscriptional Control:
mRNA ProcessingSlide33
Posttranscriptional Control:
Non-Coding RNA
IMPORTANT:
Not all DNA codes for mRNA that then translates into proteins!!!
Some DNA codes for non-coding RNA (
ncRNA
). This ncRNA plays a very important role in gene expression.
Some examples of ncRNA you are familiar with and others you are not:
tRNA – helps in translation
rRNA – helps in translation
miroRNA – prevents translation from happening
siRNA – destroys mRNA molecules
snRNA – helps splice exons together during mRNA processingSlide34
Gene RegulationSlide35
Translational Regulation:
These mechanisms prevent the synthesis of proteins.
Example:
Regulatory proteins bind to specific sequences in the mRNA and prevent ribosomes from attaching.
Happens in eukaryotes and prokaryotesSlide36
Gene RegulationSlide37
Protein Modification:
Proteins are chemically modified (ex. folded ) after they are made.
These chemical mechanisms can cause the folding process of proteins to change therefore altering how that protein will be expressed.Slide38
Gene RegulationSlide39
DNA Microarrays
This technology helps scientists understand the differences in different types of cells, despite the fact that they have the exact same DNA.Slide40
In your
s
cience notebooks,
complete the following sentence:
DNA microarrays help scientists study the human genome by…
Slide41
Information Sources
National
Institutes of Health. National Human Genome Research Institute. “Talking Glossary of Genetic Terms.
” Retrieved October 16, 2011, from http://www.genome.gov/glossary
/ http
://www.genome.gov/glossary/?id=
167
NOVA scienceNOW. “Epigenetics.” Retrieved September 16, 2012 from
http://video.pbs.org/video/1525107473#