Unit 8: Nucleic AcidThe Genetic Material

DNA• Deoxyribose nucleic acid

type of nucleic acid• DNA function

– to hold genetic code – Genetic code = genetic

instructions to make proteins

• DNA is found in nucleus of eukaryotic cells

Bases:

Adenine Guanine

Thymine Cytosine

RNA• Single stranded

• Found outside of nucleus to make proteins.

Bases:

Adenine Cytosine

Uracil Guanine

Searching for Genetic Material• Gregor Mendel (1866):

– discovered that inherited traits are determined by discrete units, or 'genes,’ - passed on from the parents.

• Freidrich Miescher(1868): – discovered DNA– Isolated something new

from the nuclei of eukaryotic cells

• Later called DNA!!!

Discovering the structure of DNA

Rosalind Franklin (1952)

•Obtained sharp X-ray photographs of DNA (Photo 51)•Watson and Crick used her data revealed its helical shape

•Watson and Crick went on to win Nobel Prize (1962) for their DNA model

Photo 51

How did PHOTO 51 reveal DNA’s helical shape?

•  X-rays passing through a helix diffract at angles perpendicular to helix making an "X" pattern, which favors an equal diameter "helix".

Discovering the structure of DNA James Watson & Francis Crick (1953)

•Discovered double helix structure•Solved the three-dimensional structure of the DNA molecule

Watson Constructing Bair Pairs movie

http://www.hhmi.org/biointeractive/dna/animations.html

DNA replication

• Replication – making a copy of DNA before the cell divides (Mitosis).

• DNA polymerase – enzyme that joins individual nucleotides to produce a new copy of DNA

Steps to DNA replication

1. Enzyme (helicase) unzips the DNA.

2. DNA polymerase (enzyme) matches the correct nucleotide to each side of the unzipped DNA.

3. DNA polymerase – proofreads their replication to make sure they did not make any mistakes.

RNA synthesisRibose nucleic acid

• RNA polymerase copies only one strand of the DNA in order to make the single-stranded RNA.

Protein Synthesis• Translation – reading RNA in order to

get the correct amino acid.

• Codon – group of 3 bases.

• Amino acids are added for every three bases to build a protein.

• https://www.youtube.com/watch?v=1YDTOcAVJrE

Adenine Ribose 3 Phosphate groups

Cell Energy:•Cells usable source of energy is called ATP•ATP stands for adenosine triphosphate

• ADP stands for adenosine diphosphate

Adenine Ribose 2 Phosphate groups

• All energy is stored in the bonds of compounds—breaking the bond releases the energy

• When the cell has energy available it can store this energy by adding a phosphate group to ADP, producing ATP

• ATP is converted into ADP by breaking the bond between the second and third phosphate groups and releasing energy for cellular processes.

• https://www.youtube.com/watch?v=00jbG_cfGuQ