Flashcards in DNA/RNA LO Deck (64)
What are the purines?
adenine, guanine (PURe As Gold)
what are the pyrimidines?
cytosine, thymine, and uracil
what is ribose?
5 carbon sugar that is the primary building block of ribonucleic acids
how is deoxyribose different than ribose?
deoxyribose has been dehydroxylated at the 2' position
what is a nucleoside?
central ribose sugar and a base attached to it at the 1' position
what is a nucleotide?
a nucleoside with at least one phosphate group attached to the 5' position of the ribose
what is the universal energy currency in the body?
what is the solubility relationship between pyrimidines and purines?
pyrimidine > purine
in regards to solubility
what is the solubility relationship between nucleosides, bases, and nucleotides?
nucleotide > nucleoside > bases
in regards to solubility
between bases and nucleosides, which is less soluble?
base is less soluble than nucleoside
Gout is caused by the build up of ________ which is a precipitant of _______
uric acid, purines
The low solubility of purines and their accumulation leads to which 2 diseases covered in lecture?
Lesch-Nyhan disease and gout
in regards to the deoxyribose, why is the direction 5' to 3' polarity?
5' end has phosphate and 3' end has hydroxyl group. phosphate at the 5' end will bind with the hydroxyl group at the 3' end
What did the Avery, McCloud, and McCarty experiment find?
established DNA as the genetic material with their pneumococcus experiments. (smooth strain killed mice, rough strain did not. DNA from heat killed S cultured with R then killed mice BAM!)
what did the Franklin and Wilkins find and how?
helical structure of DNA through x-ray diffraction
what are Watson and Crick known for?
definitive double-helical structure
What are Chargaff's rules?
1. Molar ratios of total purines and total pyrimidines are roughly equal (G+A = C+T)
2. the molar ratios of adenine to thymine, and guanine to cytosine are roughly equal (G=C, A=T)
3. G+C / A+T ratio is different for different organisms
Describe the Watson-Crick model for DNA structure
2 strands in right handed helix
sugar/phosphate groups on the outside of helix (hydrophilic)
bases paired and stacked on the inside (hydrophobic)
major groove and minor groove
10 bp per turn of helix
horizontal distance covered by A-T is almost identical to G-C
what 3 factors within the double helix help stabilize the electrostatic repulsion of the phosphate groups?
1. neutralized by positively charged species in cell (magnesium)
2. base pair linkages provide stability
3. base pairs stack on top of one another which allows for delocalization of electrons
what does increasing the salt concentration do to the stability of the DNA?
increases the stability of DNA
what do extreme pH do to the stability of the DNA?
decreases the stability through altering the ionization of the bases which form H-bonds
what does increasing the length of the DNA strand do to the stability?
what does a higher GC content do to the stability of the DNA?
where is circular DNA found?
prokaryotes and mitochondra
What occurs during methylation of base pairs?
methyl group is added to cytosine or adenine DNA nucleotides
what are the consequences of DNA methylation?
decreases gene activity and there is abnormal gene regulation
what is the major covalent modifcation of human DNA?
methylation of C at CpG sequences
when does methylation of cytosine mostly occur?
when cytosine is adjacent to a guanine
what does deamination of methylcytosine yield?