Basics of Genetics
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Transcript of Basics of Genetics
Basics of Genetics
Part 1
Introduction
• Cells come from existing cells – the cell theory• “Like produces like” – dogs produce pups not
kittensBut how???????
• Heredity- transmission of traits from one generation to the next
• Genetics- the science of heredity usually dealing with the molecular basis
DNA
• Genetics: Study of heredity and DNA• Discovered in the late 1800’s (not known as genetic
material yet.) (Proteins)• Limited by technology– Located inside nucleus of cell (also in mitochondria,
chloroplast, virus and bacteria).– Purpose of DNA is to code for proteins.– Made up of a phosphate, sugar and nucleotide bases.– Arranged in a double helix (twisted ladder).
• Watson and Crick (1953)
II. DNA
A. StructureNucleotide
Phosphate group + Sugar + Nitrogen base
DNA cont.
• Four nucleotide bases:– Adenine A always pairs w/ T– Thymine– Guanine G always pairs w/ C– Cytosine Complimentary base pairs– 2-3 billion base pairs in DNA
• Chargraff’s ratio: #A = #T and #G = #C
RNA
• Acts as an intermediary between DNA and protein.– Common in cytoplasm of the cell.– Transfers code from DNA to ribosome (where
protein is made).– Made of phosphate, sugar and nucleotide bases.– Single stranded.
RNA cont.
• Four nucleotide bases:– Adenine A always pairs w/ U– Uracil (replaces thymine)– Guanine G always pairs w/ C– Cytosine
RNA cont.
• Three types of RNA– mRNA- (messenger) carries information from DNA
to ribosome– tRNA- (transfer) carries amino acids to ribosome– rRNA- (ribosomal) assembles amino acids to make
protein
3 Important Processes
• Replication: DNA making copies of itself• Transcription: DNA makes RNA• Translation: Protein synthesis (making
proteins)
Comparing DNA and RNA
• DNA– Deoxyribose (sugar)– Double stranded– Thymine– Located in nucleus
• RNA– Ribose (sugar)– Single stranded– Uracil– Found in cytoplasm
3. After amino acids have bonded, the tRNA leaves.- Continues until STOP codon- Protein synthesis is done- New protein is released
• DNA code TGA ______________ _______________
• mRNA codon _____________ UCU _______________
• tRNA anticodon`_____________ ________________ _______________
• Amino acid ____________ ______________ tryptophan
• DNA code CAT ______________ _______________
• mRNA codon _____________ GUU _______________
• tRNA anticodon`_____________ ________________ _______________
• Amino acid ____________ ______________ methionine
Sickle Cell Anemia