DNA & Biotech

what is dna? stands of "deoxyribonucleic acid"

made up of repeating nucleotide subunits;

each nucleotide has a 5-carbon sugar, a phosphate group, and a nitrogenous base

nitrogenous bases composed of alternating phosphate-sugar groups

"rungs of ladder" - complementary nitrogen bases

4 nitrogenous bases adenine, thymine, guanine, cytosine

nitrogenous bases that ALWAYS go together adenine + thymine

guanine + cytosine

dna structure double helix - 2 spirals wound around each other

plus sign - hydrogen bond; hydrogen bonds are weak so they are easily broken during dna replication

purine adenosine & guanine (TWO RINGS)

pyrimidine cytosine & thymine (ONE RING)

chargaff's rule 1:1 base pairing of purine: pyrimidine

amount of guanine = amount of cytosine

amount of adenine = amount of thymine

dna sequence gene - protein - cellular job

proteins (enzymes) do everything!

histones DNA is wrapped around proteins called histones

replication of DNA occurs during the S PHASE of the cell cycle

copying of chromatids

semi-conservative vs. conservative dna replication If you get one strand of dna from your mom and one strand of dna from your dad, then it's semi-conservative dna replication. If you get both strands of dna from one parent, then it would be considered conservative dna replication.

steps of semi-conservative dna replication original dna unwinds/unzips

an enzyme called HELICASE breaks weak hydrogen bonds between complementary bases. This process is called INITIATION.

new nucleotides attach at exposed nitrogen bases according to paring rules with the help of DNA POLYMERASE. This process is called ELONGATION.

enzymes called LIGASE link nucleotides by bonding sugars and phosphates. This process is called TERMINATION.

results of dna replication two IDENTICAL dna molecules have been produced

these are now called "daughters".

Each one has one "new" and one "old" strand.

rna stands for ribonucleic acid

cells can make more of it so if it gets destroyed

3 components of rna phosphate group

ribose sugar

nitrogen-containing base

components of the nitrogen-containing base in rna a, URACIL, c, g

RNA does NOT contain THYMINE

nitrogen-containing bases for rna a-u, g-c

3 types of rna mRNA, tRNA, rRNA