Something to think about When a species reproduces there is genetic continuity maintained from one generation to the next WHAT is responsible for this continuity HOW does this continuity happen ID: 916508
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Slide1
DNA and RNA Replication
Unit 6
Slide2Something to think about..
When a species reproduces, there is genetic continuity maintained from one generation to the next.
WHAT
is responsible for this continuity?
HOW does this continuity happen?
Slide3What is DNA?
DNA = Deoxyribo
N
ucleic
Acid
Genetic material present in
ALL organisms
Different for each individualFound in nucleusPolymer- nucleic acids Monomer = nucleotidesWhat three ‘parts’ are nucleotides made of? a. Phosphate group b. Sugar c. nitrogen base (A,T,C,G)
Slide4Nucleotides
Monomer made of the following 3 parts:1. a 5-Carbon sugar group (deoxyribose
)
2. a
phosphate group3. a
nitrogen
base – 4 different possibilities!
(5 Carbon sugar)
Slide54 Nitrogen Bases
Purines
Pyrimidines
Adenine, Guanine
Cytosine, Thymine
A, G
C, T
2 carbon rings1 carbon ring
“
Pur
e
A
s
G
old”
Slide6Nitrogen Base Pairing
Adenine ALWAYS pairs with Thymine2 hydrogen bonds
Cytosine ALWAYS pairs with
Guanine
3 hydrogen bonds
“AT C-G”
Slide7DNA Code
The order of the 4 nitrogen bases is what causes each individual’s DNA to be
unique
!
Pictured below are small segments of DNA from three organisms, how do they compare?
Plant Mammal Bacteria
Slide8DNA Code
If we looked at the total DNA of each of the below organisms, which would have DNA with the least amount of base pairs? Why?
Plant Mammal Bacteria
Slide9Structure of DNA
Double Helix
Slide10Double Helix
Which 2 scientists are credited with the discovery of the structure of DNA?James Watson & Francis Crick (1953)Double Helix
Nobel Prize for Medicine
in 1962
Slide11Structure of DNA
Double Stranded“Backbone” = alternating phosphates and sugars
(
deoxyriboses
)Middle Portion = bases
A-T (bonded by 2 H-bonds)
C-G (bonded by 3 H-bonds)
In 3D: forms twisted ladder (spiral staircase)
Slide12Double Helix
Slide13On the diagram on the right, circle
1 nucleotide
Slide14DNA Replication
DNA copyingWhy?in order for genetic material
to be passed on to the next generation and to preserve
genetic continuity
4 Steps
Slide15DNA Replication
“Unzip DNA twisted ladder” (HELICASE
)
Break H bonds between bases
Slide16DNA Replication
Match correct nucleotides according to base pair rules (DNA POLYMERASE
)
There are free floating nucleotides
in nucleusRemember: A-T, G-C
Slide17DNA Replication
Bonding-hydrogen bonds form between bases; and phosphates bond to sugar molecules to form the ‘
backbone
’ of DNA
Bonding continues until
2 new strands
have
completely formedRESULT = 2 copies of the original DNA molecule
Slide18DNA Replication
Pink = parent strand
Blue =
daughter
strands
Slide19DNA Replication
DNA Replication Simulation