DNA Flashcards
What does DNA stand for?
Deoxyribonucleic acid
Building blocks of DNA
Nucleotides - phosphate, pentose sugar, nitrogenous bases
What are the base pairs
Adenine and Thymine - 2 hydrogen bonds
Guanine and Cytosine - 3 hydrogen bonds
A and G are bigger molecules
Genes
section of DNA
code for protein (enzymes)
holds genetic information
aprox. 20,000 genes
DNA shape
DNA ladder molecular shape is a double helix
Antiparallel DNA strands twist to make a double helix
Chromosome structure
each chromosome is made up of DNA tightly coiled around histones which support its structure
46 chromosomes, 23 pairs
Advantages of modeling
- see structures not normally seen
- see how things work together
Disadvantages of modeling
- Over simplify
- Doesn’t show complexity
Disadvantages of modeling
- Over simplify
- Doesn’t show complexity
Oswald Avery
extracted DNA from a bacterium and transferred the herditable to another bacterium
first indication that DNA carried hereditary information
Erwin Chargaff
Composition of DNA varied
always the same amount of A’s to T’s and C’s to G’s
- paired with one another
Rosalind Franklin
studied x-ray pictures of DNA
showed DNA was a corkscrew shape
- helix and two or three chains
James Watson and Francis Crick
A’s go with T’s and G’s with C’s through hydrogen bonds
created model of DNA with phosphates, sugars and base pairs
- Watson and Crick model
What do bases create
Amino-acid (aa) - protein made up of approx. 20 aa
3 bases code for one aa
