DNA

http://www.youtube.com/watch?v=35FwmiPE9tI

DNA A nucleic acid that stores and transmits genetic information from one generation to the next. Is the hereditary material in humans and almost all other organisms. Molecule that controls a cell’s function

DNA Nearly every cell type in a person’s body has the same DNA. Most DNA is located in the cell nucleus (where it is called nuclear DNA), but a small amount of DNA can also be found in the mitochondria (where it is called mitochondrial DNA or mtDNA).

DeoxyriboNucleic Acid Nucleic Acid – A complex molecule that is made up of smaller nucleotides Each nucleotide is made up of three segments, a sugar, a phosphate, and a nitrogen base.

DNA Components and Structure The sugar is a 5 carbon sugar named deoxyribose

DNA Components and Structure A Phosphate group

DNA Components and Structure A Nitrogen base Two bases are Adenine Guanine They are similar to each other

DNA Components and Structure Nitrogen base 2 other bases are Thymine Cytosine They are similar to each other

A DNA (nucleic acid) molecule 1,000,000 nucleotides long would have ??? Sugar molecules How many different types of sugar? ??? Phosphate molecules How many different types of phosphate? ??? Nitrogen base molecules How many different types of nitrogen base?

Shape double helix two strands wound around each other A ladder that has been twisted Shape is due to the shape of the molecules, and their specific bonding angles

Base pairing MEMORIZE Adenine bonds or pairs with Thymine Guanine bonds or pairs with Cytosine This is the base pairing rule – other combinations will not happen in DNA

Nitrogen Bases Purines Pyrimidines 2 rings Adenine Guanine 1 ring Thymine Cytosine

Sketch into notes

Big Numbers The human genome contains 3164.7 million (3.2 billion) chemical nucleotide bases (A, C, T, and G). http://www.ornl.gov/sci/techresources/Human_Genome/posters/chromosome/faqs.shtml

More Big Numbers Human chromosomes range in length from 47 to 245 million base pairs. With few exceptions (e.g., red blood cells), each of the trillions of cells in the human body contains a complete set of chromosomes--the genome. If all the bases in the human genome were spread out 1 millimeter apart, they would extend from Memphis to Los Angeles.

Question Why are there 4 nitrogen bases in DNA? Why is one side of a DNA molecule A_T_T_A_C_G_A_T_C_C_G_A, instead of A_A_A_A_A_A_A_A_A_A_A_A?

ANSWER The different combinations, or sequence of different nitrogen bases are the code – They code for different instructions or traits in the cell, or organism

Website http://www.dnaftb.org/15/concept/

DNA Replication Copying of the DNA molecule Must happen before a cell divides Happens during ?? Phase of cell cycle

Base Pairing and Replication Each individual strand of DNA has the information to reconstruct the other half Since each strand can make the other, they are called complementary In prokaryotes, replication usually begins at a single point and proceeds in both directions In eukaryotes, In larger eukaryotes, replication happens at hundreds of places at one time

Replication DNA molecule separates in to two strands Two new complementary strands are made following base pairing rules Each strand of DNA acts as a template, or model for a new strand When finished, the two identical copies of DNA have one “original” strand, and one “new” strand

What/How A series of enzymes makes this happen Unzip DNA Connect new nucleotides DNA polymerase proofreads and joins individual nucleotides together Several enzymes/proteins have roles in the replication process – more complicated than your book discusses

http://www.wehi.edu.au/education/wehitv/molecular_visualisations_of_dna/

What is the deal with mammalian red blood cells? These cells' cytoplasm is rich in hemoglobin, an iron-containing biomolecule that can bind oxygen and is responsible for the blood's red color. In humans, mature red blood cells are oval and flexible biconcave disks. They lack a cell nucleus and most organelles to accommodate maximum space for hemoglobin.

No Nucleus Means no DNA. As erythrocytes mature they extrude their nuclei order to provide more space for hemoglobin. In mammals, erythrocytes also lose all other cellular organelles such as their mitochondria, Golgi apparatus and endoplasmic reticulum.

Animations http://www.johnkyrk.com/DNAreplication.html http://www.youtube.com/watch?v=hC_8y8fNkCw https://www.youtube.com/watch?v=zdDkiRw1PdU

Mr. W “rap” http://www.youtube.com/watch?v=wdhL-T6tQco