Flashcards in Protein Synthesis, Mitosis & Meiosis Deck (25):
What are the two stages of protein synthesis?
What are the matching base pairs for DNA?
Thyamine -- adenine
Guanine -- cytosine
What are the matching base pairs for RNA?
Adenine -- uracil
Guanine -- cytosine
Where does transcription occur?
Unzips DNA so it can be transcribed
What are the steps of transcription?
Starting at promoter sequence, RNA polymerase reads one strand of DNA.
From base triplets on DNA, creates complementary codons. Continues until reaches terminator region.
Pre-mRNA gets edited by snRNPs and then travels to cytoplasm for translation.
Transcribes DNA. Reads segment and creates complementary RNA.
Small nuclear ribonuclear proteins
Responsible for splicing pre-mRNA (editing out the introns).
"Useless" segments of RNA
Useful segments of RNA
A segment of RNA can be spliced in different ways, so identical RNA sequences can end up producing a multitude of proteins.
Steps of Translation
mRNA attaches to rRNA.
Initiator tRNA (UAC) attaches to AUG on mRNA. Ribosomal subunits come together to start synthesis. Initiator tRNA fits into P site.
Another tRNA matches up with next codon in A site. The amino acid it carries will create a peptide bond with the methionine carried by the initiator tRNA.
Initiator tRNA, it's job done, releases the methionine, departs from P site. Second tRNA moves from A site to P site. Next codon is matched to tRNA in A site, new AA attached , yadda yadda yadda.
Continues until stop codon reached.
The amino acid produced by initiator tRNA. Codon: AUG. Anticodon: UAC
Produced when multiple ribosomes attach to the same mRNA to produce multiple copies of the same amino acid chain.
Homologous vs sister chromotids
Homologous: same chromosome (ie chromosome 23 or 16), but not identical (in humans, one would come
from each parent).
Sister: identical. Created when chromatid cloned during S phase of interphase.
Phases of interphase
1. G1. Organelles (not chromosomes) replicated.
2. S. DNA replication. Now cell has 96 chromatids.
3. G2. Cell grows. Centrosome replication complete. DNA checked for errors.
Chromatin condense into characteristic X shape, held together by centromeres.
Nuclear envelope dissolves.
Helps stabilize chromosome centromere.
Chromosomes line up along metaphasic plate.
Mitotic spindles pull chromosomes toward each pole. Centromeres split apart. One of each sister pair will move to each pole.
Cleavage furrow develops.
Chromatids arrive at poles. Cleavage furrow deepens.
Nuclear envelope reforms, plasma membrane regenerated, and two identical daughter cells exist.
Sister chromatids of homologous chromosomes create tetrads through synapses.
Genetic recombination/crossing over occurs.
Homologous chromosomes line up at metaphasic plate
Homologous chromosomes separate to either pole (different from mitosis, in which sister chromatids are separated).