Lecture 31 Flashcards
rRNA
ribosomal RNA
tRNA
transfer RNA
3 components of nucleotide
nitrogenous base, pentose, 1+ phosphates
the molecule without a phosphate group
nucleoside
how many rings does pyrimidine have
1
how many rings does purine have
2
how many purines are there
2
what are the 2 purines
adenine, guanine
how many pyrimidines are there e
3
what are the 3 pyrimidines
cytosine, thymine, uracil (RNA)
structural units of DNA
deoxyribonucleotides
structural units of RNA
ribonucleotides
2 pathways that lead to nucleotides
de novo, salvage
recycle the free bases and nucleosides released from nucleic acid breakdown
salvage pathway
what metabolic precursors does de novo start with
amino acids, ribose 5 phosphate, CO2, NH3
in de novo, purine bases are syn while attached to what
ribose
de novo, pyrimidine ring is synthesized as..
orotate
what provides the most amino groups in de novo
GLn
precursor for purines de novo
glycine
glycine is the precursor for what
purines
precursor for pyrimidines de novo
aspartate
aspartate is precursor for what
pyrmindines
purine syn step 1
PRPP to 5-phospho - beta - d ribosylamine
enzyme of step 1 purine synthesis
glutamine-PRPP-amidotransferase
what goes into and comes out step 1 purine synthesis
glutamine goes in, glutamate and PPi comes out
first intermediate with complete purine ring
inosinate
abbreviation for inosinate
IMP
what can IMP be used to synthesize
AMP and GMP
AMP or GMP synthesis regulated by..
feedback inhibition from purine nucleotide products
what donates the amino group for AMP
aspartate
what donates the amino group for GMP
glutamine
in salvage cycle, what two things can be used to make AMP/GMP
guanine, hypoxanthinine
in pyrimidine synthesis, what is the first thing done
first making the pyrimidine ring
what form is the first pyrimidine ring in
orotate
what is attached after the pyrimidine ring formation (pyrmindine synthesis)
ribose 5 phosphate
what provide the atoms for ring structure
aspartate and carbamoyl phosphate
what is the regulator of pyrminidine synthesis
first enzymatic step
what is the first enzymatic step of pyrimidine synthesis
aspartate to n-carbamoylaspartate
enzyme of first step of pyrimidine synthesis
aspartate trans carbamoylase
what two things are regulating the first step of pyrmindine synthesis
carbamoyl phosphate, CTP
what two things are required for deoxyribonucleotide synthesis
ribonucleotide reductase, NADPH
thymidylate synthesis does what
adds methyl to dUMP, giving thymine
what does thymidylate synthesis require
folate (vitamin b9
folic acid deficiency leads to what
reduced thymidylate synthesis
folic acid deficiency occurs in what percent of human population
about 10%
reduced thymidylate synthesis causes…
uracil to be incorporated into DNA
repair mechanisms remove uracil in the DNA how
creating strand breaks, therefore affecting the structure and function of the DNA
pathways for degradation of pyrimidines lead to what
NH4+ production, urea synthesis
in pyrimidine catabolism, carbons of thymine are degraded to..
succinylcholine CoA
carbons of cytosine and uracil are degraded to…
acetyl CoA