vsauce science friday &list=uu6nsfpj9htcz5t-n3rm3-ha &list=uu6nsfpj9htcz5t-n3rm3-ha
TRANSCRIPT
![Page 1: Vsauce Science Friday &list=UU6nSFpj9HTCZ5t-N3Rm3-HA &list=UU6nSFpj9HTCZ5t-N3Rm3-HA](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649ef65503460f94c0a7e0/html5/thumbnails/1.jpg)
Vsauce Science Friday
http://www.youtube.com/watch?v=2lR7s1Y6Zig&list=UU6nSFpj9HTCZ5t-N3Rm3-HA
![Page 2: Vsauce Science Friday &list=UU6nSFpj9HTCZ5t-N3Rm3-HA &list=UU6nSFpj9HTCZ5t-N3Rm3-HA](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649ef65503460f94c0a7e0/html5/thumbnails/2.jpg)
Bell-Ringer
What do we call the monomer that makes up DNA?
What two substances make up the DNA Backbone?
What are the names of the four bases that make up DNA?
![Page 3: Vsauce Science Friday &list=UU6nSFpj9HTCZ5t-N3Rm3-HA &list=UU6nSFpj9HTCZ5t-N3Rm3-HA](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649ef65503460f94c0a7e0/html5/thumbnails/3.jpg)
DNA’s Discovery and Structure
![Page 4: Vsauce Science Friday &list=UU6nSFpj9HTCZ5t-N3Rm3-HA &list=UU6nSFpj9HTCZ5t-N3Rm3-HA](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649ef65503460f94c0a7e0/html5/thumbnails/4.jpg)
Important Scientists in the “Race for the Double Helix”
James Watson & Francis Crick (1953)– Created the first accurate model of DNA– Won the Nobel Prize
![Page 5: Vsauce Science Friday &list=UU6nSFpj9HTCZ5t-N3Rm3-HA &list=UU6nSFpj9HTCZ5t-N3Rm3-HA](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649ef65503460f94c0a7e0/html5/thumbnails/5.jpg)
DNA’s Structure
DNA is a double helix – this makes DNA look like a “twisted ladder”.
Each molecule of DNA is composed of a “backbone” on the outside and bases that point towards the middle of the molecule.
The monomer for DNA is the nucleotide
![Page 6: Vsauce Science Friday &list=UU6nSFpj9HTCZ5t-N3Rm3-HA &list=UU6nSFpj9HTCZ5t-N3Rm3-HA](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649ef65503460f94c0a7e0/html5/thumbnails/6.jpg)
Nitrogenous Bases
DNA is made of nitrogenous bases.These four bases are:
– adenine (A) – cytosine (C) – guanine (G)– thymine (T)
![Page 7: Vsauce Science Friday &list=UU6nSFpj9HTCZ5t-N3Rm3-HA &list=UU6nSFpj9HTCZ5t-N3Rm3-HA](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649ef65503460f94c0a7e0/html5/thumbnails/7.jpg)
DNA Bases
Purines – double-ringed molecule– Ex. Adenine and Guanine
Pyrimidines – single-ringed molecule– Ex. Cytosine and Thymine
![Page 8: Vsauce Science Friday &list=UU6nSFpj9HTCZ5t-N3Rm3-HA &list=UU6nSFpj9HTCZ5t-N3Rm3-HA](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649ef65503460f94c0a7e0/html5/thumbnails/8.jpg)
• Complementary Base-Pairing Rules
DNA is built following the complementary base-pairing rules.
These state that:– A always pairs with T– T always pairs with A– C always pairs with G– G always pairs with C
In RNA, adenine (A) pairs with uracil (U). We will look at this in a later lesson.
![Page 9: Vsauce Science Friday &list=UU6nSFpj9HTCZ5t-N3Rm3-HA &list=UU6nSFpj9HTCZ5t-N3Rm3-HA](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649ef65503460f94c0a7e0/html5/thumbnails/9.jpg)
Sugar-Phosphate Backbone
![Page 10: Vsauce Science Friday &list=UU6nSFpj9HTCZ5t-N3Rm3-HA &list=UU6nSFpj9HTCZ5t-N3Rm3-HA](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649ef65503460f94c0a7e0/html5/thumbnails/10.jpg)
Crashcourse DNA Video
http://www.youtube.com/watch?v=8kK2zwjRV0M
![Page 11: Vsauce Science Friday &list=UU6nSFpj9HTCZ5t-N3Rm3-HA &list=UU6nSFpj9HTCZ5t-N3Rm3-HA](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649ef65503460f94c0a7e0/html5/thumbnails/11.jpg)
DNA Replication
Replication = Duplication– Happens in the S phase of Interphase– Must replicate before mitosis or meiosis I
Part of the double helix is unwound Replication in long and small pieces
(Okazaki fragments)Enzyme stitches pieces together later
![Page 12: Vsauce Science Friday &list=UU6nSFpj9HTCZ5t-N3Rm3-HA &list=UU6nSFpj9HTCZ5t-N3Rm3-HA](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649ef65503460f94c0a7e0/html5/thumbnails/12.jpg)
Semi-Conservative Replication
One-half of each new molecule of DNA is old (template strand)
One-half of new molecule of DNA is new (complementary strand)
![Page 13: Vsauce Science Friday &list=UU6nSFpj9HTCZ5t-N3Rm3-HA &list=UU6nSFpj9HTCZ5t-N3Rm3-HA](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649ef65503460f94c0a7e0/html5/thumbnails/13.jpg)
DNA ReplicationDNA Replication
• Enzyme Enzyme HelicaseHelicase unwinds unwinds and separates the 2 DNA and separates the 2 DNA strands by breaking the strands by breaking the weak hydrogen bondsweak hydrogen bonds
• DNA polymerase can then add the new nucleotides
copyright cmassengale13
![Page 14: Vsauce Science Friday &list=UU6nSFpj9HTCZ5t-N3Rm3-HA &list=UU6nSFpj9HTCZ5t-N3Rm3-HA](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649ef65503460f94c0a7e0/html5/thumbnails/14.jpg)
copyright cmassengale14
![Page 15: Vsauce Science Friday &list=UU6nSFpj9HTCZ5t-N3Rm3-HA &list=UU6nSFpj9HTCZ5t-N3Rm3-HA](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649ef65503460f94c0a7e0/html5/thumbnails/15.jpg)
DNA Replication Animations
http://www.youtube.com/watch?v=5_vzY7H9GYk – Simple Animation
http://www.youtube.com/watch?v=teV62zrm2P0 – Detailed Animation
copyright cmassengale15
![Page 16: Vsauce Science Friday &list=UU6nSFpj9HTCZ5t-N3Rm3-HA &list=UU6nSFpj9HTCZ5t-N3Rm3-HA](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649ef65503460f94c0a7e0/html5/thumbnails/16.jpg)
DNA ReplicationDNA Replication
• Begins atBegins at Origins of ReplicationOrigins of Replication• Two strands open forming Two strands open forming Replication Replication
Forks (Y-shaped region)Forks (Y-shaped region)• New strands grow at the forksNew strands grow at the forks
copyright cmassengale16
ReplicationReplicationForkFork
Parental DNA MoleculeParental DNA Molecule
3’
5’
3’
5’
![Page 17: Vsauce Science Friday &list=UU6nSFpj9HTCZ5t-N3Rm3-HA &list=UU6nSFpj9HTCZ5t-N3Rm3-HA](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649ef65503460f94c0a7e0/html5/thumbnails/17.jpg)
DNA ReplicationDNA Replication
• DNA polymeraseDNA polymerase can only add can only add nucleotides to the nucleotides to the 3’ end3’ end of the DNA of the DNA
• This causes the This causes the NEWNEW strand to be built in strand to be built in a a 5’ to 3’ direction5’ to 3’ direction
copyright cmassengale17
RNARNAPrimerPrimerDNA PolymeraseDNA Polymerase
NucleotideNucleotide
5’
5’ 3’
![Page 18: Vsauce Science Friday &list=UU6nSFpj9HTCZ5t-N3Rm3-HA &list=UU6nSFpj9HTCZ5t-N3Rm3-HA](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649ef65503460f94c0a7e0/html5/thumbnails/18.jpg)
Synthesis of the New DNA Synthesis of the New DNA StrandsStrands
• The The Leading StrandLeading Strand is synthesized as a single single strandstrand from the point of origin toward the opening replication fork
copyright cmassengale18
RNARNAPrimerPrimerDNA PolymeraseDNA PolymeraseNucleotidesNucleotides
3’5’
5’
![Page 19: Vsauce Science Friday &list=UU6nSFpj9HTCZ5t-N3Rm3-HA &list=UU6nSFpj9HTCZ5t-N3Rm3-HA](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649ef65503460f94c0a7e0/html5/thumbnails/19.jpg)
Synthesis of the New DNA Synthesis of the New DNA StrandsStrands
• The The Lagging StrandLagging Strand is is synthesized discontinuouslydiscontinuously against overall direction of replication
• This strand is made in MANY short segments It is replicated from the replication fork toward the origin
copyright cmassengale19
![Page 20: Vsauce Science Friday &list=UU6nSFpj9HTCZ5t-N3Rm3-HA &list=UU6nSFpj9HTCZ5t-N3Rm3-HA](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649ef65503460f94c0a7e0/html5/thumbnails/20.jpg)
Lagging Strand SegmentsLagging Strand Segments
• Okazaki FragmentsOkazaki Fragments - - series of short segments on the lagging strandlagging strand
• Must be joined together by an Must be joined together by an enzymeenzyme
copyright cmassengale20 Lagging Strand
RNARNAPrimerPrimer
DNADNAPolymerasePolymerase
3’
3’
5’
5’
Okazaki FragmentOkazaki Fragment
![Page 21: Vsauce Science Friday &list=UU6nSFpj9HTCZ5t-N3Rm3-HA &list=UU6nSFpj9HTCZ5t-N3Rm3-HA](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649ef65503460f94c0a7e0/html5/thumbnails/21.jpg)
What is a Gene?
A length of DNA on a chromosomeMay be in several parts
– Exon – the expressed parts of the DNA sequence
– Intron – the intervening, “junk DNA”, not expressed
Parts are cut, put together and then used to make RNA and proteins
![Page 22: Vsauce Science Friday &list=UU6nSFpj9HTCZ5t-N3Rm3-HA &list=UU6nSFpj9HTCZ5t-N3Rm3-HA](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649ef65503460f94c0a7e0/html5/thumbnails/22.jpg)
Odd Types of Genes
Multigene familiesTransposons (Barbara McClintock)Protective Genes
Viruses may give us new DNA that can be kept over time to cause new evolutionary changes!