DNA Lesson 2 DNA Replication

Lesson 2 
DNA Replication
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Lesson 2 
DNA Replication

Slide 1 - Diapositive

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Slide 2 - Diapositive

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2. DNA Replication
Learning Goals
You can explain why DNA replication takes place
You can describe how DNA replication takes place 
You can explain how data obtained by DNA analysis can ascertain the degree of kinship between species


Slide 3 - Diapositive

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Key words
DNA replication                                              
Helicase
DNA polymerase
RNA primase
Leading strand
Lagging strand
Replication bubble
Single Strand Binding protein



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Next video
0:00 - 04:80 Structure and function of DNA
04:80 - 12:59 DNA Replication (This lesson)

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2

Slide 6 - Vidéo

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05:18
What is the opposite strand of:
5' AGGTCCG '3 ?
A
5' TCCAGGC '3
B
3' TCCAGGC '5
C
'3 AGGTCCG '5

Slide 7 - Quiz

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06:09
Name the three differences between DNA and RNA

Slide 8 - Question ouverte

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Which feature of our genetic material is not universal for all living creatures?
A
the linkage of phosphate and desoxyribose
B
The presence of 4 nitrogen bases: A, C, T en G
C
The presence of two complementary strands
D
The nucleotide sequence

Slide 9 - Quiz

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DNA Replication = copying DNA so cell division can occur (= part of mitosis)
Mitosis or cell division starts with the synthesis of extra cell material (G1) , followed by doubling of its chromosomes (S phase) = replication, then more growth (G2) and verifying if the new cell parts (=chromosomes) are evenly distributed and lastly dividing the material over 2 cells (M = mitosis)

Slide 10 - Diapositive

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DNA Replication by DNA polymerase 
(p. 50)
= Synthesis direction

Slide 11 - Diapositive

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DNA replication = the doubling of the DNA during the S-phase of the cell cycle
Synthesis of a new nucelotide chain is assimilation
This costs energy or …..? Produced in....?
It is a chemical reaction
Enzymes are involved: which enzyme opens the double helix? Which enzyme attaches the nucleotides to the existing DNA strand? Where does the replication start?

How do you know, based on its name, that helicase is an enzyme? What kind of substance is an enzyme? Where will it be synthetised?  Enzymes are sensitive to...?

Slide 12 - Diapositive

Energy or ATP
Energy is produced in mitochondria

Opens helix: Helicase
Attaching new nucleotides: DNA polymerase
Start: RNA primase

Name ends with -ase = enzyme
Enzyme = protein
Synthetised in ribosome
Sensitivity to pH and temperature because of their 3D structure
Refreshing: structure of DNA
A new nucleotide always attaches on C3 (phosphate in between).               -->
C3 -->
1.
2.
3.
4.

Slide 13 - Diapositive

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Step 1 DNA replication
Before replication of one cell is possible all nuclear DNA needs to be copied: 46 chromosomes --> 92 chromosomes.
Step 1. Splicing of the double helix by helicase

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Which cells cannot replicate?
A
Nerve cells
B
Muscle cells
C
Epithelial cells
D
Red blood cells

Slide 15 - Quiz

Red blood cells have no nucleus, their origin starts in stem cells
Step 2 DNA Replication
DNA polymerase attaches to a RNA primer and starts adding nucleotides to form a new double strand

Slide 16 - Diapositive

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DNA replication: attaching to C3 atoms 
(remember slide 8)
Reading -->.                                                                   <-- Building
Okazaki fragment 
(next slide)

Slide 17 - Diapositive

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Single Strand Binding protein
Single Strand Binding proteins prevent the newly divided single strand DNA in the replication bubble to re-attach again to the other single strand 

Slide 18 - Diapositive

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            Order the 6 steps of replication 
1
2
3
4
5
6
Primase synthetises short RNA primers that function as starting point for DNA polymerase
RNA primers are replaced by DNA nucleotides
replication start at a replication startingpoint
Single Strand Binding proteins prevent DNA from becoming double stranded again
Helicase breaks hydrogen bonds en makes dsDNA ssDNA
DNA polymerase binds to a primer en lengthens this on the '3 end

Slide 19 - Question de remorquage

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Slide 20 - Lien

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Primase
RNA Primer
SSBP's
DNA-polymerase
Helicase

Slide 21 - Question de remorquage

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Replication bubble: 
Leading and lagging strand

Slide 22 - Diapositive

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Result of S phase:
2 identical copies to distribute evenly over two nuclei

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DNA helicase
A
synthesizes Hydrogen bonds
B
helps DNA polymerase to bind to DNA
C
unzips the DNA molecule
D
catalyses Hydrogen bonds

Slide 24 - Quiz

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DNA polymerase
A
unzips the DNA
B
forms the new sugar phosphate backbone
C
joins A's and T's and G's and C's
D
proofreads the DNA to prevent mistakes

Slide 25 - Quiz

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0

Slide 26 - Vidéo

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StudyGo
50-52
See magister and Classroom

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Learning Goals
You can explain why DNA replication takes place
You can describe how  DNA replication takes place 
You can explain how data obtained by DNA analysis can ascertain the degree of kinship between species


Slide 29 - Diapositive

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