- Most videos are a courtesy of Howard Hughes Medical Institute (HHMI)
- Concepts can be also found at wikipedia
Monday, May 18, 2015
Acknowledges
What is DNA?
- DNA is a polymer of nucleotide monomers.
- A polymer is a large molecule composed of many repeated subunits (wikipedia).
- A monomer is a molecule that may bind chemically to other molecules to form a polymer (wikipedia).
- A molecule is an electrically neutral group of two or more atoms held together by chemical bonds (wikipedia).
- Nucleotides are organic molecules that serve as the monomers, or subunits, of nucleic acids like DNA and RNA (wikipedia).
DNA Example
The Chemical Structure of DNA
- Watch the video: http://bcove.me/m3newyri
Nucleotides
- The building blocks of nucleic acids
- Composed of:
- A nitrogenous base
- A five-carbon sugar (ribose or deoxyribose)
- At least one phosphate group
- A nucleoside and a phosphate group create a nucleotide
Nucleotides
- Carry packages of energy within the cell in the form of nucleoside triphosphates (ATP, GTP, CTP, UTP)
Nucleotides
Building Blocks of DNA
- Watch the video: http://link.hhmi.org/services/player/bcpid1876525637001?bckey=AQ~,AAAArZFA_pE,D1__qX58jerI2jGitJBc_zBPvdgXTuAq&bctid=2116972010001
Chargaff's Ratio
- 1950, Chargaff discovered that in DNA the ratio of Adenine to Thymine is equal as the ratio of cytosine to guanine
- This is Chargaff's ratio
- Important to discover the structure of DNA
Chargaff's Ratio
- Watch the video: http://bcove.me/jajuxtu4
Jame's Watson Models
- Made cardboard models to understand how DNA nucleotides are paired
- He understood how hydrogen atoms of paired nucleotides interact and form a symmetrical structure that fits the double-helix model
Watson's Constructing Base Pair Models
- Watch the video: http://bcove.me/tr11x4m4
Paired DNA Strands
- DNA has a double structure
- When untwisted it looks like two parallel strands
- Each strand is a linear sequence of A, C, G, T
- The order carries coded instructions
- Each strand is the complement of the other
- A complements T
- C complements G
Paired DNA Strands
- Watch the video: http://bcove.me/y4hm6p7w
Coding Sequence in DNA
- Human Genome 3 billion letters
- Only 1% directly codes for proteins
- About 25% make up genes and their regulatory elements
- Function of remaining letters is unclear
Coding Sequence in DNA
- Watch the video: http://bcove.me/sb6a91yt
DNA Replication
- Process of producing 2 identical replicas from 1 original DNA molecule
- The basis of biological inheritance
- Cellular proof-reading
- Error checking
- Near perfect fidelity replication
- Replication begins at specific locations
- Origins of replications in the genome
DNA Replication
- Replication
- Watch the video http://bcove.me/gqzhvsru
DNA Replication - Molecular Level
- Replication Basic detail
- Watch the video http://bcove.me/x3ukmq4x
DNA Replication - Advanced Detail
- Replication Advanced detail
- How the strands replicate
- Watch the video [http://bcove.me/byqhourx]
Polimerase
- Enzyme that synthesizes long chains or polymers of nucleic acids.
- Two types
- DNA polymerase
- RNA polymerase
- Used to assemble DNA and RNA molecules
- Copy a DNA or RNA template strand using base-pairing interactions
Polymerase Chain Reaction
- Watch the video [http://bcove.me/i1y8en7d]
DNA Packing
- DNA is packed in the nucleus of every cell
- DNA wraps around special proteins called histones that form loops of DNA called nucleosomes
- Nucleosomes coil and stack together to form fibers called chromatin
- Chromatin forms larger loops and coils to form chromosomes
DNA Packing
- Watch the video [http://bcove.me/e6nqokpn]