lecture 9 Flashcards
1
Q
what are the roles of nucleic acids?
A
- DNA (provides directions for its own replication)
- RNA
2
Q
what is DNA?
A
- deoxyribonucleic acid
- provides directions for its own replication
- directs synthesis of mRNA and thus controls protein synthesis
- this occurs in ribosomes
3
Q
what is the structure of nucleic acids?
A
- polynucleotides (polymers)
- each consisting of nucleotide (monomer)
- nitrogenous base, pentose suge and phosphate group
- nucleoside is side without phosphate
4
Q
what are the types of nitrogenous bases?
A
- pyrimidines (cytosine; thymine,DNA; uracil,RNA)
- single six-membered ring
- purines (adenin, guanine)
- six-membered ring fused to 5 member ring
5
Q
what are nucleotide polymers?
A
- linked to uild polynucleotide
- adjacent joing by covalent between OH on 3C of one nucleotide and phosphate on 5C on next
- links create backbone of sugar-phosphate
- nitrogenous base appendages
6
Q
explain the DNA double helix
A
- two polynucleotides spiraling around imaginary axis (dbl helix)
- two backbones run opposite 5C-3C directions (antiparallel)
- DNA molecule has many genes
- A with T; G with C
7
Q
how can DNA explain evolution?
A
- linear sequence of nucleotides in DNA passed from parents to offspring
- closely related species=similar DNA
