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Transcript of DNA Basics
Programs all cell activities
Each contains 1 big DNA molecule There are 4 important
biological molecules... Carbohydrates
Nucleic acids DNA is a nucleic acid. Structurally nucleic acids are made of polymers (each is made up of many small, repeating molecular units called nucleotides)
When nucleotides are linked together we call them polynucleotides } polynucleotides polymers Nucleotides are made up of 3 components: (deoxyribose) (make up the backbone) 4 different nitrogen bases: sugar/phosphate backbone oxygen base pairs } base sequence } 2 chains connected by nitrogenous bases via relatively weak hydrogen bonds Can only hook up with a specific other base. How big is DNA? Chromosome #1 (our largest)
has 247 million base pairs!
Each somatic cell has 46 DNA molecules in its nucleus (~6 billion base pairs/cell!) So what's RNA? Similar to DNA but not exactly the same... 3 major differences: 1 2 3 Different sugar... binds with adenine important for production of proteins and replication of DNA ! Our cells can make 10,000 copies in a couple of hours! How does DNA copy itself? How does this happen!? slices open hydrogen bonds between base pairs place where splitting starts=
replication fork "good guy" "bad guy" unwound strands used as templates for 2 new strands... (Because strands go in different directions, making a new DNA for leading strand is a lot easier) To copy the leading strand, RNA primase starts it out and then DNA polymerase just adds matching nucleotides the whole way down the molecule.
To copy the lagging strand is a pain...
DNA polymerase can only copy strands in the 5'-3' direction (takes a lot longer)