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Gene Expression and Cell Differentiation Gene Expression and Cell Differentiation

Gene Expression and Cell Differentiation - PowerPoint Presentation

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Gene Expression and Cell Differentiation - PPT Presentation

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

gene dna regulation cells dna gene cells regulation expression genome proteins percentage mrna transcriptional genes prokaryotes epigenetics epigenome courtesy

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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#