Unit 8: Nucleic
The Genetic Material
• Deoxyribose nucleic
acid type of nucleic acid
• DNA function
– to hold genetic code
– Genetic code = genetic
instructions to make
• DNA is found in nucleus of
• Single stranded
• Found outside of
nucleus to make
Searching for Genetic Material
• Gregor Mendel
– discovered that inherited
traits are determined by
discrete units, or 'genes,’ passed on from the parents.
– discovered DNA
– Isolated something new
from the nuclei of
• Later called DNA!!!
Discovering the structure of
•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
How did PHOTO 51
reveal DNA’s helical
• 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
•Discovered double helix structure
•Solved the three-dimensional structure
of the DNA molecule
Watson Constructing Bair Pairs movie
• 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.
Ribose nucleic acid
• Transcription - RNA polymerase copies
only one strand of the DNA in order to
make the single-stranded RNA.
• 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.
• Adenine & Guanine
• Double ringed
• Cytosine, Thymine, Uracil
• Cells usable source of energy is called ATP
• ATP stands for adenosine triphosphate
3 Phosphate groups
• ADP stands for adenosine diphosphate
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 is converted into ADP by breaking the bond between
the second and third phosphate groups and releasing
energy for cellular processes.