Homunculus - a sperm containing a preformation, in proportion and fully formed
Preformation - sex cells contain miniature adult
Epigenesis - an organism arises from an egg that differentiates into adult structures during
embryogenesis.
Genetics and genes
Genetics is study of inherited traits
Inherited traits are determined by the elements of heredity - genes (DNA)
Genes are segments of the DNA
DNA is the molecule of heredity
Traits are affected by multiple genes - polygenic trait
History
1866 - Mendel discovered 'factors', recognized that got passed as discreet units
1869 - Friedrich Miescher discovered DNA
DNA Structure
Nucleotides = building blocks of DNA = phosphate + sugar + base
Adenine and Thymine
Guanine and Cytosine
Sugar = 5 carbon deoxyribose
Purines - Adenine and Guanine
o Double ring structure
Pyrimidines - Thymine and Cytosine
o Single ring structure
Paired strands are antiparallel
DNA Replication
DNA unzips and single strands can now act as a template for complementary daughter strands
Enzymes - proteins encoded by genes which serve as a biological catalysts for metabolic activities
Polypeptide - a chain of linked amino acids
Central Dogma
DNA codes for RNA = transcription
RNA codes for proteins = translation
Messenger RNA is produced from transcription
RNA contains base uracil instead of thymine
RNA has 5 sugars and DNA has 4
Translation
The synthesis of a polypeptide chain composed of a linear chain of amino acids which is
specified by the sequence of codons in mRNA
Occurs in ribosome
a cell interprets codons along mRNA molecule
mRNA contains genetic code in 3 base codons for specific amino acids
Transfer RNA contains 3 base sequences - anticodon
tRNA transfers amino acids from cytoplasm's pool to a ribosome
Ribosome then adds the amino acid carried by tRNA to the end of the polypeptide chain
Preformation - sex cells contain miniature adult
Epigenesis - an organism arises from an egg that differentiates into adult structures during
embryogenesis.
Genetics and genes
Genetics is study of inherited traits
Inherited traits are determined by the elements of heredity - genes (DNA)
Genes are segments of the DNA
DNA is the molecule of heredity
Traits are affected by multiple genes - polygenic trait
History
1866 - Mendel discovered 'factors', recognized that got passed as discreet units
1869 - Friedrich Miescher discovered DNA
DNA Structure
Nucleotides = building blocks of DNA = phosphate + sugar + base
Adenine and Thymine
Guanine and Cytosine
Sugar = 5 carbon deoxyribose
Purines - Adenine and Guanine
o Double ring structure
Pyrimidines - Thymine and Cytosine
o Single ring structure
Paired strands are antiparallel
DNA Replication
DNA unzips and single strands can now act as a template for complementary daughter strands
Enzymes - proteins encoded by genes which serve as a biological catalysts for metabolic activities
Polypeptide - a chain of linked amino acids
Central Dogma
DNA codes for RNA = transcription
RNA codes for proteins = translation
Messenger RNA is produced from transcription
RNA contains base uracil instead of thymine
RNA has 5 sugars and DNA has 4
Translation
The synthesis of a polypeptide chain composed of a linear chain of amino acids which is
specified by the sequence of codons in mRNA
Occurs in ribosome
a cell interprets codons along mRNA molecule
mRNA contains genetic code in 3 base codons for specific amino acids
Transfer RNA contains 3 base sequences - anticodon
tRNA transfers amino acids from cytoplasm's pool to a ribosome
Ribosome then adds the amino acid carried by tRNA to the end of the polypeptide chain
