2: DNA structure Flashcards
Importance of DNA (3)
-causes genetic disease
-for selective breeding
-DNA testing, confirming pedigree lines
Mendel’s gene discovery
Genes are hereditary factors responsible for traits.
Alleles are different forms of genes.
Mendel’s rules of inheritance
1) Alleles of the same gene seperate during gamete formation.
2) Alleles of different genes are inherited seperately
3 functions of genetic material(DNA)
(Miescher’s dicovery)
Genotypic function: replicate
Phenotypic function: gene expression
Evolutionary function: natural selsction and adaptation
Structure of DNA
(wilkins and rosalin franklin discovery)
DNA molecules are made of two chains of nucleotides in a helix.
Base pairs hold the two chains together: AT,GC.
The nucleotides are linked in a chain through phosphodiester bonds(covalent bonds).
DNA exists as a helix of two antiparallel strands interacting with weak hydrogen bonds.
What is a gene?
Genes: made of DNA
DNA: made of nucleic acid
Nucleic acid: building blocks are nucleotides
When are DNA most easily seen?
when condensed during metaphase
Deoxyribonuclease (DNase)
enzyme that hydroxylses DNA to nuclotides
How do you fit DNA molecules into a cell?
Form protein-DNA complexes with histiones called nucleosomes, and 6 nucleosomes form a turn on a solenoid-like stucture that is the chromatin fibre; the fibre packs as loops on a scaffold of protein
