Topic 2-2 Flashcards
the “gold standard” technique to resolve the 3D structures of molecules such as proteins
x-ray crystallography
in DNA, base pairs are:
complementary. A pairs with T, C pairs with G
what is DNA composed of?
two nucelotide polymer antiparallel strands, and a sugar phosphate backbone
how are base pairs held together in dsDNA?
hydrogen bonds
what is the advantage to having hydrogen bonds (as opposed to covalent bonds) hold base pairs together?
allows separation of the molecules for replication
solving the 3D structure of DNA explained ______ rules about the ratios between A, T, C, and G bases
Chargaff’s
what is the biggest difference in the ribose sugars of DNA and RNA?
in RNA, the 2’ carbon has a hydroxyl group attached, and in DNA, the 2’ carbon has a hydrogen
why do purine bases only pair with pyrimidine bases (as opposed to other purines and vice verse)?
maintains specific diameter of the DNA molecule
which purine base pairs with which pyrimidine base is dictated by:
the number of hydrogen bonds they form
how many hydrogen bonds form between adenine and thymine?
2
how many hydrogen bonds form between cytosine and guanine?
3
in nucleotides, the phosphate group is bound to the ______ carbon of the deoxyribose sugar.
5’
during DNA synthesis, the phosphate group of one nucleotide is covalently bonded to:
the 3’ carbone of another nucleotide
what are the two exceptions to the central dogma?
1) major information pathways: information can be transferred from one DNA molecule to another
2) special information pathways: in some viruses, information can be transferred from one RNA molecule to another
why is our genetic material made of DNA and not RNA?
DNA is more stable due to the 2’H, and RNA is more reactive due to the 2’OH (forms more H-bonds)
in single strands of nucleotides, when sequences of nucleotides on the same strand are inverted complements, this is known as:
hairpin structure
RNA molecules may contain numerous _______, allowing them to fold up into complex structures
hairpins
complx secondary structures in RNA allow it to take on:
catalytic activity
is DNA capable of catalytic activity?
no
does RNA polymerase require a primer to start synthesis?
no
can copy RNA into DNA
reverse transcriptases
what is the RNA world hypothesis?
it is thought that the first genetic material in the first life forms was likely RNA, and not DNA