Mitosis
Somatic cells undergo this process for cell division.
Mitosis
This cell division has two rounds total.
Meiosis?
What is the end product of transcription?
mRNA transcript
What are the A, P, and E sites on the ribosome?
A site: where the tRNA enters the ribosome
P site: holds the growing polypeptide chain
E site: where the 'empty' tRNA exits
What is base excision repair in DNA?
Excision repair is when abnormal nucleotides are removed and replaced by repair endonuclease enzymes.
What is the name of the enzyme involved in adding DNA nucleotides to the daughter DNA strand (in prokaryotic DNA replication)?
DNA polymerase III
Meiosis ___ is called the Reduction Division.
I
What is the name of the enzyme that adds RNA nucleotides to make mRNA?
RNA polymerase
What is the initiator tRNA in translation in prokaryotes and eukaryotes?
Prokaryotes use fMet (N-Formylmethionine), a special form of methionine.
Eukaryotes use regular methionine in their initiator tRNA.
What are the 3 checkpoints in the mitotic cell cycle?
G1-S phase, G2-Metaphase, and Metaphase-Anaphase checkpoints.
What are the three kinds of microtubules within the mitotic spindle and what do they each do?
Kinetochore microtubules: attach to the centromere and separate sister chromatids
Astral microtubules: short star-like microtubules that keep the centrosomes at the pole
Polar microtubules: extend from each pole and overlap with each other to lengthen the cell
Which division of meiosis is most similar to mitosis? Meiosis I or II?
Meiosis II
(Double Jeopardy)
What is the rho factor and how do molecules without the rho factor terminate transcription?
Rho factor: enzyme that moves down the mRNA transcript and unwinds it from the DNA template as transcription takes place
Without the rho factor, the mRNA transcript will contain a sequence that's rich in G-C bonds, which bond together to form a hairpin loop that pulls the RNA molecule away from the DNA.
What is the Wobble Hypothesis?
Ability of tRNAs to recognize more than one codon, since the first 2 bases are the most important in coding for a specific amino acid. While the 3rd base is somewhat disregarded.
What are the differences between mitosis and meiosis?
Meiosis produces 4 haploid non-identical cells, mitosis produces 2 diploid identical cells. Crossing over takes place in meiosis only. Homologs join together and separate in meiosis only.
What's the difference between mitosis in animal cells vs. plant cells?
Animal cells form a contractile ring that pinches the cytoplasm and cell into two.
Plant cells form a cell plate in the middle of the cell, which eventually fuses with the cell wall. This occurs since the cell wall is too rigid so it can't break.
What is nondisjunction, how does it affect aneuploidy, and what is aneuploidy?
Nondisjunction is an error meiosis where the homologs do not separate, resulting in a gamete having extra chromosomes and another having less chromosomes than normal. As a result, aneuploidy takes place, since aneuploidy is a condition of having an abnormal number of chromosomes.
What are the functions of the 2 modifications that take place under RNA processing in eukaryotes?
5' cap: protects mRNA from being degraded by enzymes and positions mRNA on ribosome for TL
3' Poly (a) tail: protects mRNA from being degraded, helps ribosomes locate mRNA,
What are the five main components needed for translation?
1. mRNA
2. tRNA
3. Ribosome
4. Protein factors (eukaryotes)
5. Amino-acyl tRNA synthetase
What is the role of cyclin in regulating the cell cycle/mitosis?
Cyclin activates Cyclin-Dependent Kinases (Cdks), and these kinases phosphorylate proteins involved in different stages of cell cycle so that they take place.
(Double Jeopardy)
List the steps of mitosis and describes what happens in each step briefly.
Prophase: DNA condenses
Prometaphase: Nuclear envelope fragments, spindle attaches to chromosomes
Metaphase: Chromosomes align on metaphase plate
Anaphase: A) Chromatids separate and move to the poles B) Centrosomes move to the poles of the cell and cell elongates
Telophase: (Reverse prophase) Chromosomes decondense, nuclear envelope reforms
What occurs in Prophase I of Meiosis I? What is the synaptonemal complex?
Prophase I: DNA condenses into chromosomes, synapsis and crossing over occur between homologs, and the nuclear envelope breaks down
Synaptonemal complex: zipper like protein that holds both of the homologs together for crossing over to occur
RNA polymerase's sigma factor will bind to the promoter sequence of the template DNA strand. RNA pol. unwinds the 2x helix and begins adding RNA nucleoside triphosphates (NTPs). RNA pol. does this by catalyzing the formation of phosphodiester bonds between the NTPs to make the mRNA transcript.
Describe the elongation step of translation.
1. Second tRNA binds to the A site
2. Peptide bond gets formed between the amino acid held at the P site and at the A site
3. Translocation occurs, where the tRNA at the A site moves to the P site, tRNA at the P site moves to the E site, and a new tRNA can come in at the A site
List 4 of the 6 proteins/enzymes involved in DNA replication.
1. DNA helicase
2. DNA gyrase / topoisomerase
3. Single Stranded Binding proteins (SSB)
4. Primase
5. DNA pol. I and III
6. DNA ligase