DNA Structure and Replication: Crash Course Biology #10

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Hank introduces us to that wondrous molecule deoxyribonucleic acid – also known as DNA – and explains how it replicates itself in our cells.

References:
http://www.nature.com/nature/dna50/watsoncrick.pdf
http://publications.nigms.nih.gov/thenewgenetics/chapter1.html
http://rst.gsfc.nasa.gov/Sect20/A12.html
http://www.nature.com/scitable/topicpage/discovery-of-dna-structure-and-function-watson-397
http://www.uic.edu/classes/phys/phys461/phys450/ANJUM04/
http://www.buzzle.com/articles/dna-replication-steps.html
http://www.dnareplication.info/stepsofdnareplication.php
How much DNA?
http://www.sdsc.edu/ScienceWomen/franklin.html
http://www.fmi.ch/members/marilyn.vaccaro/ewww/dna.pioneer.excerpt.htm
http://www.strangescience.net/rfranklin.htm

1:41 link to Biological Molecules http://www.youtube.com/watch?v=H8WJ2KENlK0

Table of Contents:
1) Nucleic Acids 1:30
2) DNA
-A) Polymers 1:53
-B) Three Ingredients 2:12
-C) Base Pairs 3:45
-D) Base Sequences 4:13
3) Pop Quiz 5:07
4) RNA 5:36
-A) Three Differences from DNA 5:43
5) Biolography 6:16
6) Replication 8:49
-A) Helicase and Unzipping 9:22
-B) Leading Strand 9:38
-C) DNA Polymerase 10:08
-D) RNA Primase 10:24
-E) Lagging Strand 10:46
-F) Okazaki Fragments 11:07
-F) DNA Ligase 11:47

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25 Comments

  1. When he’s actually just holding a short stubby string and talking to it, then actually adding the dna strand when editing the vid 😂😂

  2. Im fairly certain that the DNA strands run in the 5' to 3' direction. Not the other way around. Then again I am watching this video to understand it better so who knows.

  3. Summary-
    Dna- deoxyribonucleic acid, stretching them end to end they would reach the sun 600 times. They r a 6 billion letter code. Dna is made of small repeating units (polymers) called nucleotides. Link them together and u have a polynucleotide. A nucleotide is made of-
    • A five carbon sugar molecule called deoxyribose
    • A phosphate group
    • One of 4 nitrogen bases- adenine, thymine go together and cytosine and guanine go together. G and C pairing is stronger
    Structure of dna is double helix(a twisted ladder) its main support is the sugar and phosphate binding together to form 2 twin backbones. These run in opposite directions, O2 pointing up and O2 pointing down. The left hand chain is from 5 prime to 3 prime and the opposite on the right hand chain.
    Rna- has only 1 sugar phosphate backbone
    • so it is a single stranded molecule, sugar is ribose (one O2 more)not deoxyribose
    • Has uracil instead of thymine
    Replication- copying of cells, helicase is an enzyme that unwinds the hydrogen bonds of the nitrogen bases, the point where the splitting starts is the replication fork. Top strand- leading strand and bottom strand called lagging strand. These go in opposite directions such that making dna from leading strand is easier than for lagging strand.
    Leading strand- rna polymerase, an enzyme adds matching nitrogen bases. Rna primase provides a primase which helps the enzyme to make a new dna strand.
    Lagging strand- rna polymerase can only copy dna in 5 prime to 3 prime direction so the copying is done in segments and using many other dna polymerase eg dna ligase

  4. It's crazy the amount of things your body autonomically controls, I can see sometimes why more ignorant people would think we are created by a higher being. The intrinsic intelligence inside every cell, something that isn't even sentient can create something that we as humans have still not mastered.

  5. good luck on the science exam you have on monday, and your only studying cause you failed the maths one you had today, and dont want to repeat that

  6. teacher: assigns 9 papers due in 4 days
    me: I'm only 15 I'm too young to dieeeeee
    youtube: click on this video is you want to know about the structure of DNA
    me: stares at it for about 60 seconds
    me:*clicks on video and drinks coffee so I don't fall asleep for 3 days*

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