1. SC-100 Class 25 Molecular Genetics
Molecular genetics is the study of the actual hereditary material: Nucleic Acids
The Two Nucleic Acids:
DNA, Deoxyribonucleic acid
RNA, Ribonucleic acid

2. Natural Polymers Previously we saw:
Chains of Amino Acids form Proteins
Chains of Sugars form Carbohydrates
Now we observe:
Chains of Nucleotides form Nucleic Acids

3. ATP - Adenosine Triphosphate
(Adenine)
(Ribose)
ATP - Adenosine Triphosphate

4. A Nucleotide
Adenosine Phosphate
(Ribose)
(Adenine)

8. RNA Each nucleotide in RNA consists of The Sugar Ribose
A Phosphate group
One of FOUR bases:
Adenine (A)
Uracil (U)
Guanine (G)
Cytosine (C)

9. DNA Each nucleotide in DNA consists of The Sugar Deoxyribose
A Phosphate group
One of FOUR bases:
Adenine (A)
Thymine (T) <<<
Guanine (G)
Cytosine (C)

11. DNA
The DNA Molecule is a double strand of nucleotides held together by hydrogen bonds between the bases of each strand.
Geometry and charge distribution determine that the possible base pairing are
A-T and G-C
Ladder shape twists to a double helix.

14. DNA REPLICATION DNA Molecule unzips DNA nucleotides become exposed
Complementary free nucleotides attracted to open sites
New bonds formed with free nucleotides
Identical DNA molecules produced

16. DNA REPLICATION

17. Three Types of RNA in Protein Synthesis
mRNA-messenger RNA- Has a copy of the base sequence for one gene
tRNA- transfer RNA-Three Base sequence (Codon) that attracts a specific amino acid
rRNA-ribosomal RNA- form ribosome where protein synthesis occurs
Base Pairings for RNA A-U and G-C

18. Transcription of DNA into mRNA

20. Protein Synthesis Segment of DNA unzips Three kinds of RNA produced
mRNA rRNA tRNA
carries genetic message produces ribosomes transports amino acids
New polypeptide chain produced
Further processing by organelles produces protein

21. Genetic Code Number of tRNA molecules: 3 bases
4 x 4 x 4 = 64
Number of combinations needed:
= Number of Amino Acids + “stop”
= = 21
21 < 64 so we have enough combinations with three bases. (Note two is not enough.)

22. UCAG UUU UAU CUU CAU AUU AAU GUU GAU UUC UAC CUC CAC AUC AAC GUC GAC
UUA UAA CUA CAA AUA AAA GUA GAA
UUG UAG CUG CAG AUG AAG GUG GAG
UCU UGU CCU CGU ACU AGU GCU GGU
UCC UGC CCC CGC ACC AGC GCC GGC
UCA UGA CCA CGA ACA AGA GCA GGA
UCG UGG CCG CGG ACG AGG GCG GGG

26. The sequence of bases in the mRNA maps to the sequence of amino acids assembled by the tRNA.

27. Genes and the Genetic Code
Gene: The unit of biological inheritance.
A section of the DNA molecule
The information to make one protein
All living things on Earth us the same Genetic Code.