I. The stucture of DNA
A. Double-stranded
1. nucleotides + deoxyribose-Phosphate
2. Strands anti-parallel
B. Complementary base pairing.
A-T 2 hydrogen bonds
C-G 3 hydrogen bonds
II. Central Dogma: DNA-> RNA-> Protein (not so true)
- DNA is transcriped to RNA, and RNA is translated into protein
1.Gene: sequence of bases in organism's genome that corresponds to one protein (this is not technically a good definition of gene)
2. One Gene not = one trait
Organism's traits depends on protein
III. TRANSCRIPTION: DNA —> RNA (TRANSCRIPTION FROM RNA POLYMERASE: enzyme that makes RNA polymers)
- result of transcription of DNA by RNA polymerase is single-stranded mRNA (rRNA and tRNA are also transcribed)
RNA v.s DNA
-mRNA single stranded
-RNA used uracil not thymine
-RNA have ribose instead of dioxyribose phosphate backbone
IV. Translation: RNA —> proteins
A. codons: set of 3 bases in mRNA(that came from transcription) that correspond to each amino acid (64 different sets)
i. Redundancy: more possible codons than amino acids so more than one codon per amino acid
ii. Anticodons: swatch of 3 bases complimentary to a mRNA codon, part of tRNA that brings in correct aa. For each codon
b. Amino acids: what proteins are comprised of
c. Ribosomes: where translation of mRNA to an aa chain (polypeptide) happens, all living organisms have them
V. Mutations
• Change in DNA sequence which may or may not lead to change in phenotype (expressed gene) of the organism
-You can change DNA sequences but not the phenotype b/c you can get the same amino acid for the mutated part
A. Are mutations bad? Neither Good nor bad, usually result in silent mutation.
VI. interactions between gene and environment
- ex: under UV light we change our gene expression to produce more melanin (which makes us tan)
• B. pleiotropy: change in one gene leads to many different effects
i. Blue-eyed white cats
-have to found to be deaf
ii. The Russian Fox Farm experiment
-docile foxes acted and looked like pet dogs
-could be in the change of just one gene or to one expression of the gene
