DNA Replication
How many new strands of DNA are made?
2
Difference between chromatid and chromosome
chromatid: one of two identical halves of chromosome (one half of X)
chromosome: packaged DNA
What is the difference between protein synthesis in prokaryotes and eukaryotes?
prokaryotes: transcription and translation occur in cytoplasm, can occur at same time
eukaryotes: transcription/RNA processing in nucleus, translation in cytoplasm on free ribosome
Where does tRNA enter and what does it carry?
A site on ribosome and carries anticodon and amino acid
What is the purpose of meiosis?
genetic variation!; create 4 daughter cells with slightly different DNA in each (occurs through independent assortment, crossover recombination)
What end are nucleotides added to?
3' end
What is our chromosome/mitosis equation?
ploidy n = total chromosomes
ploidy # = total / n
What are you making from transcription and what enzyme is involved?
making RNA using RNA polymerase
Describe the stages of translation
initiation: small and large subunits of ribosome come together so tRNA and mRNA can come in
elongation: tRNA delivers new amino acids to form polypeptide
termination: tRNA brings stop codon so polypeptide can be hydrolyzed and released from ribosome
What ploidy and how many chromosomes do you end up with after meiosis
haploid cells with 23 chromosomes
What is the difference between DNA replication, transcription, and translation
DNA replication: copying DNA in a semi-conservative fashion; still creating DNA (occurs during mitosis and meiosis)
transcription: DNA to RNA
translation: RNA to proteins
What checkpoints are occurring at G1 and G2?
G1: no DNA damage, cell big enough
G2: no DNA damage, DNA replicated properly
Describe each stage of transcription
initiation: RNA polymerase binds to promoter, unwinds DNA
elongation: RNA polymerase add nucleotides
termination: RNA polymerase reaches DNA sequence that is termination signal and hairpin loop causes RNA strand to separate from DNA
What is the order the sites of the large ribosome and what are each of their functions?
1. A site: arrival of tRNA
2. P site: formation of polypeptide
3. E site: exiting of tRNA
What is the difference between mitosis and meiosis?
-create 4 daughter cells with meiosis
-go through phases twice in meiosis
-first round of meiosis includes crossover and recombination
-meiosis I homologous chromosomes separate, meiosis II sister chromatids separate
-no DNA replication during meiosis II
What are the enzymes involved in DNA replication and their functions?
helicase: unzips DNA
primase: makes RNA primer
DNA polymerase: adds new nucleotides to 3' end
topoisomerase: unwinds DNA
lipase: connects Okazaki fragments of lagging strand
single-strand binding protein: keeps leading and lagging strands separate
Draw a cell with equation of 3n=6
cell should have 6 chromosomes with 2 different sizes and shades, but 3 of each
What are the sequence of events for RNA processing?
1. add 5' cap
2. splice out introns with splicosomes
3. add poly-A tail to 3' end
Describe and draw the cycle of a tRNA coming in and leaving the ribosome
1. ribosome comes into A site
2. peptide bond forms between new amino acid and polypeptide
3. polypeptide is transferred over to the tRNA that just came in
4. ribosome shifts to right, so old tRNA exits through E site and new ribosome is in P site leaving A site open for a brand new tRNA
How many sperm are made during meiosis and how many eggs?
sperm = 4 (half will be girls and half will be boys)
egg = 1 (1 egg and 3 polar bodies)
Draw a transcription bubble, label leading, lagging, and enzymes
good job
Draw every stage of mitosis
Draw out DNA, pre-mRNA, and mature mRNA strands with labels
DNA: need regulatory regions, exons, introns
pre-mRNA: need exons and introns
mature mRNA: 5' cap, exons only, and poly-A tail
If your large and small subunits were unable to come together, how would this affect protein synthesis?
mRNA would be able to be made and sent out, but translation as a whole would not be able to be carried out
Draw out stages of meiosis and star differences between mitosis and meiosis and heart differences between Meiosis I and Meiosis II
Meiosis I
Prophase I: chromosomes pair up, crossover/recombination*<3
Metaphase I: homologous pairs line up
Anaphase I: homologous PAIRS separate*<3
Telophase and Cytokinesis I: form 2 daughter cells that are haploid with 23 chromosomes
Meiosis II:
Prophase II: chromosomes condense again
Metaphase II: chromosomes in middle
Anaphase II: CHROMATIDS separate
Telophase and Cytokinesis: 4 haploid cells