http://www.ch.ic.ac.uk/local/projects/burgoine/cell-DNA.jpg

http://learn.genetics.utah.edu/content/cells/scale/

Knowing about the structure of DNA helps scientists understand its function

Functions of DNA: Carry on from one generation to the next

determine the characteristics of an organism

copy itself every time a cell divided

http://consciouslifestyles.files.wordpress.com/2011/10/baby-elephant-protect-wildlife.jpg http://www.edupic.net/Images/Mitosis/telophase.png

Nucleotides and Bases Nucleotides are the building blocks of

DNA Four different types of nucleotides –

each with a nitrogen base Represent the four bases with the

letters A, T, C, and G

Bases match up to each other. Equal amounts of A and T. Same with C and G. (A=T

and C=G)A Biochemist named Chargaff was the first to record

experiments showing this matchup of bases

http://science.howstuffworks.com/life/cellular-microscopic/dna1.htm

http://daddystractor.files.wordpress.com/2013/06/dna2.gif

Double Helix Double Helix: two parallel strands twisted together The strand is made of phosphate and sugar Bases are in between the strands (like rungs on a

ladder)

Rosalind Franklin in the 50’s Used X-Ray beams to take diffraction images of

the structure of the DNA molecule.

Before technology that could show us DNA up close, scientists had different ideas about what DNA might look like

Watson

Crick

developed a model showing DNA in a parallel structure called a double helix

Watson and Crick were the first to publish a model of what DNA looks like

Read about Franklins images

Talked to Chargaff about base pairs

Their model was hypothesis, but since then hundreds of experiments have supported it.

New technology shows DNA up close and supports their model

http://www.pbs.org/wgbh/nova/education/body/extracting-mummy-dna.html

DNA Replication: The Process in which a cell copies its DNA DNA has to copy itself every time a cell

divides DNA holds information that tells a cell

what to do This is why DNA has to be present in

every cell

The structure of DNA makes replication easy The DNA molecule unwinds into two separate

strands and then new strands are made. An enzyme called Helicase makes the DNA

molecule “unzip” a little bit Enzymes: special proteins that kick start

biochemical reactions in the body

http://upload.wikimedia.org/wikipedia/commons/8/84/DNA_bubbles2.png

http://www2.estrellamountain.edu/faculty/farabee/BIOBK/diagrep_2.gif

The “unzipped” part of the DNA helix is where replication occurs An enzyme called DNA Polymerase attaches nucleotides to the

matching base on the exposed strand This continues all the way down each strand until the new

strands are made The DNA then ‘zips’ back into the double helix form

http://www.youtube.com/watch?v=zdDkiRw1PdU

http://www.youtube.com/watch?v=GcrndR-zdyMb ( first 2 minutes)

http://www.pbs.org/wgbh/nova/education/body/forensic-dna-analysis.html

DNA solves murder mysteries (7 min vid)

Covers DNA Replication

Functions of DNA: Carry on from one generation to the next copy itself every time a cell divided

determine the characteristics of an organism

DNA Replication, Mitosis/Meiosis

We need DNA because we need proteins Practically everything a cell does (liver cells, skin cells, bone cells,

and so forth) is based on proteins.

http://legacy.owensboro.kctcs.edu/gcaplan/anat2/histology/rbc4.jpg

http://biologytb.net23.net/text/chapter11/11images/11-12.gif

DNA and RNA work together in protein synthesis DNA has specific codes for the

proteins needed in the body of a living thing

RNA does the dirty work for DNA

RNA RNA is another nucleic acid and is very similar to DNA in

structure and composition RNA has one strand instead of two RNA has U instead of T

http://commons.wikimedia.org/wiki/File%3ADifference_DNA_RNA-EN.svg

http://barleyworld.org/sites/default/files/figure-09-10.jpg

There are different types of RNA that do different things Messenger RNA (mRNA) carries

genetic information around

Transfer RNA (tRNA) brings amino acids to build proteins with

The DNA molecule unwinds into two separate strands Helicase (enzyme) make the DNA molecule “unzip”

RNA nucleotides match up to the nucleotides on one of the DNA strands Since RNA has U instead of T, it will look slightly

different.

Transcription: Formation of messenger RNA using a DNA template

http://biologytb.net23.net/text/chapter11/11images/11-14.gif

Transcription: Formation of messenger RNA using a DNA template

RNA Translation: The synthesis of proteins using the genetic information encoded in RNA

Information went DNA RNA during transcription Now the genetic information has to be “translated” from a nucleotide code

into actual proteins The sequence of nucleotide bases is a code for what proteins need to be

made The code says which amino acids to put together (Amino acids are

what proteins are made of)

RNA Translation: The synthesis of proteins using the genetic information encoded in RNA

http://3.bp.blogspot.com/-TlKEq-Yd_uI/Ufon00C9PTI/AAAAAAAAA5o/AlD5pX8GRcc/s1600/biobook_cells_21.png

Mutations Sometimes there is a random error in DNA replication

The wrong base is put in the wrong place, a base is skipped, or bases aren’t matched up right Whenever a change is made in the sequence of DNA we call it a Mutation

Mutation: A change in the nucleotide sequence of an organism’s DNA, ultimately creating genetic diversity.

http://evolution.berkeley.edu/evolibrary/images/evo/dna-mutation.gif