Cytoskeleton - network of actin fibers, microtubules and intermediate fibers
intertwined and holds the cell together
What is an anticodon? - the area on the tRNA that bonds to the mRNA codon with
opposite bases
Describe the important characteristics of the Miller-Urey experiment regarding
pre-biotic earth - They started in a lab with the molecules thought to be dominant
on early earth, CH4, NH3, H2, H2O, and possible CO2
And put them in similar environments to that on early earth, one with high
electrical and heat energy. But they made
Sure to include no O2. Oxygen would have changed the outcome of the experiment
because without oxygen
polymerization ran rampant, thus with no oxygen, oxidation, an efficient way to
break down molecules, was not
happening. This leads to great chemical creativity the the building on the
biomolecules.
endergonic reaction - requires energy input
EX: dehydration/condensation
exergonic reaction - releases energy
EX: hydrolysis
actin filaments - -made of two intertwined stands
,-help maintain: tension bearing elements, used for changing cell shape and muscle
contractions
-are dynamic: can grow and shrink by polymerization or depolymerization and thus
are less stable
intermediate filaments - -are composed of mostly the protein vimentin
-anchors organelles in place
-are static: cannot grow and shrink, more stable
what are the important features of microtubules? - - are hallow tubes that can be
used as train tracks for moving vesicles
-are composed of tubulin
-maintain cell shape: are "girders" that resist compression
-help chromosome movements in the cell, cell mobility (flagella)
-are dynamic: can grow and shrink by polymerization or depolymerization and thus
are less stable
three differences between transcription and translation in bacteria vs eukaryotes -
number of proteins coded for on one mRNA: bacteria has one or more, eukaryotes
have only one
, location of translation: bacteria has translation and transcription in the same place,
eukaryotes have transcription in the nucleus and translation outside the nucleus
mRNA processing: in bacteria its not apparent, in eukaryotes there is cap, tail and
splicing of introns
post-transcription processing - eukaryotes modify primary mRNA to make mature
mRNA
What is the 5' cap? - made of a modified nucleotide binded to mRNA phosphate to
phosphate
what is the 3' poly A tail? - 50-250 A's long
when does crossing over occur? - prophase I of meiosis
When does independent assortment occur? - Metaphase I
why do eukaryotes need he 5' cap and 3' tail? - -the cap and tail protect the mRNA
on the way from nucleus to ribosome
-provides a ticket for exit out of the nucleus (this is called "targeting/labeling")
what are introns? - sequences that are removed and recycled into nucleotides
what are exons? - expressed or used to make mature mRNA