Cell Bio Quizzes Flashcards
which of the following is a purine base?
- cytosine
- guanine
- uracil
- thymine
guanine
the role of topoisomerase during replication is to
introduce single stranded DNA breaks to prevent supercoiling
how many origins of replication does eukaryotic chromosome normally have?
many
which of the following codes for proteins?
- sRNA
- mRNA
- rRNA
- tRNA
mRNA
the codon is a combination of how many nucleotides?
3
which steps of eukaryotic gene expression occurs in the cytosol?
translation
among DNA molecules presented below, which one would start melting first if the temperature keeps increasing?
- they all would melt together as the relative number of G-C and A-T pairs does not affect the temp at which DNA strands get separated
- one that has more G-C pairs than A-T pairs
- one that has more A-T pairs than G-C
- one that has equal number of G-C and A-T pairs
one that has more A-T pairs than G-C pairs
in karyotype, chromosomes are usually numbered by…?
their length
how does the cell solve the end problem of linear chromosome replication?
there is a special enzyme that extends chromosome ends
RNA is different from DNA because…
- they may have different bases
- DNA molecules are synthesized from nucleotide monophosphates while RNAs are synthesized from diphosphates
- have different type of phosphate bonds
- DNA strands are anti-parallel while RNA strands are parallel
they may have different bases
in order to be imported into the nucleus, the cytosolic protein has to…
contain a special amino acid motif
for which step of endocytosis the dynamin, a protein also known to be important for mitochondria fission, is responsible?
pinching the endocytic vesicle off the plasma membrane
which nucleotide residue may normally be found at the 3’ end of eukaryotic mature mRNA?
A (ADENINE)
a mature eukaryotic mRNA has a ___ at the 5’ end
cap
which molecule or group is covalently attached to the cytosolic protein targeted for proteasomal degradation?
Ubiquitin