Mutations
What is the difference between Aneuploidy and Euploidy?
Aneuploidy is 2n +/- x chromosomes while Euploidy is multiples of N. One or more chromosomes lost vs sets of chromosomes lost.
What is the difference between Ribose and Deoxyribose?
Difference between Nucleosides and Nucleotides?
Ribose has a hydroxyl group (-OH) on the second carbon atom, while deoxyribose has a hydrogen atom at that position.
Nucleoside contains a nitrogenous base and pentose sugar. The molecules is composed of purine or pyrimidine base and ribose or deoxyribose sugar. Nucleotide is just a nucleoside with a phosphate group added.
Which experiment showed that DNA replication is semiconservative in eukaryotes? How did they do it?
Taylor-Woods-Hughes. They monitored process of replication with labeled 3H-thymidine and performed autoradiography.
What are Polytene Chromosomes?
Represent paired homologs. It is DNA of paired homologs that undergoes many rounds of replication without strand separation or cytoplasmic division. They create puff regions and are found in salivary, rectal, midgut, and excretory tubules tissue.
What are the two consensus sequences in E. coli promoters?
TTGACA and TATTAAT (Pribnow box). Positioned at -35 and -10 in front of the transcription start site.
Nondisjunction in Meiosis 1 causes what?
Sister chromatids or paired homologs fail to disjoin.
Bonus: What does nondisjunction in Meiosis 2 cause?
What type of bonds are between Adenine and Thymine? Guanine and Cytosine? How many for each?
A-T: Double hydrogen bond
G-C: Triple hydrogen bond
What type of cells are DNA Polymerase I, II, and III in? What are the uses for each polymerase?
Prokaryotic Cells
All three can elongate DNA strand (primer), all three possess 3'-5' exonuclease activity which can proofread newly synthesized DNA and remove/replace incorrect nucleotides.
Only DNA polymerase 1 has exonuclease activity from 5' to 3'. They excise primers.
Bonus: What are the ones in Eukaryotes?
What is a positively changed protein that is associated with chromosomal DNA in eukaryotes? What do these proteins create?
Histones. Large amount of lysine and arginine. They create nucleosomes which are fibers composed of linear array of spherical particles. They look like beads on a string.
What are the two types of transcription termination in Prokaryotes?
Intrinsic of rho(p)-independent termination: Termination transcribed into RNA causes newly formed transcription to fold back on itself (hairpin. RNA polymerase stalls at the hairpin and weak binding between A-U pairs at the end of hairpin cause RNA polymerase to fall off.
Rho(p)-dependent termination: RHO binds to the newly synthesized mRNA and follows RNA polymerase. RNA polymerase stalls at hairpin. Rho termination factor bumps into RNA polymerase and causes it to fall off.
What is one syndrome related to monosomy? One syndrome related to Trisomy?
Turner Syndrome and Down Syndrome respectively.
Bonus: What genes/chromosomes are they impacting?
What are the three major classes of RNAs? What are their purpose?
rRNAs: Structural components of ribosomes for protein synthesis
mRNAs: Template for protein synthesis. Carry genetic info from gene to ribosome
tRNAs: Carry amino acids for protein synthesis
What are the three steps of PCR?
Denaturing, Annealing, Synthesizing
What is Euchromatin and Heterochromatin? What are some ways that you can swap between the two in DNA?
Euchromatin is uncoiled and active. Appears unstained during interphase.
Heterochromatin are condensed areas that are mostly inactive. Appears stained in interphase. Genetically inactive, replicates later in S phase than euchromatin. Telomere maintains chromosome integrity and centromeres are involved in chromosome movement.
E to H: DNA methylation, Histone methylation, Histone deacetylation, corepressor complexes
H to E: Histone methylation, Histone acetylation, Loss of H1, coactivator complexes.
What are the three forms of Eukaryotic Post Transcriptional Modification?
Methyl cap, Poly a tail, and splicing
What are fragile sites?
These are sites more susceptible to chromosome breakage when cultured in the absence of folic acid and other chemicals. Indicates regions of non-tightly coiled chromatin.
Bonus: What is a syndrome related to this?
What type of bonds link nucleotides? Where are they for carbon? Which functional groups are at said carbons?
Phosphodiester bonds. Nucleotides are linked by phosphodiester bonds between phosphate group at C5 position and OH group on C3 position
What is the purpose of Telomeres? What makes telomeres? Where is this enzyme located at?
To give inert chromosomal ends that protect intact eucaryotic chromosomes from improper fusion or degradation. Telomerase makes telomeres and they are inactive in most eukaryotic somatic cells. However, they are active in stem and malignant cells. (Maybe germ cells).
What are the three chemical modifications that we learned in histone tails and chromatin fiber? What do they generally do?
Acetylation, Methylation, Phosphorylation.
Acetylation reduces biding between histone tails and DNA which increase gene expression.
Methylation: Adds methyl groups to arginine and tyrosine residues in histones and can either increase or reduce gene expression. Usually reduces however.
Phosphorylation: Enzyme kinase. Adds phosphate groups to hydroxyl groups of amino acids serine and histidine.
What are overlapping genes?
The idea that a single mRNA has multiple initiation points which creates different reading frames. This can specify more than one polypeptide
What is paracentric and pericentric inversion?
Paracentric inversion is when the centromere is not part of the inverted segment. Pericentric inversion is when the centromere is part of the inverted segment.
Bonus: How do these inversion impact the creation of recombinant progeny? Differences of recombinant gametes with pericentric and paracentric?
Telomeres RNA and RNA primers: Involved in DNA replication at chromosome ends
SnRNA: Small nuclear RNA that process mRNAs
Antisense RNA, micro RNA, siRNA: Involved in gene regulation
Label this figure in its entirety. No word bank cause hehe.
A: Primase
B: Single-stranded binding protein
C: DNA Polymerase 3
D: 3' end
E: 5' end
F: RNA Primer
G: Helicase
H: Primase
I: DNA Polymerase 1
J: DNA ligase
K: Lagging
L: Leading
What is satellite DNA?
What are centromeres?
What are kinetochore proteins?
Satellite DNA are highly repetitive and consist of short repeated sequences. It makes up variable proportion of total DNA and are found in heterochromatic centromere regions of chromosomes. Not found in prokaryotes.
Centromeres are the separation of homologs during mitosis and meiosis depends on centromeres. They are also the primary constrictions along eukaryotic chromosomes
Kinetochore proteins are a region that binds to spindle fiber microtubules during cell division
What are polycistronic RNAs? Are they in prokaryotes or eukaryotes?
Polycistronic RNAs are when a single mRNA can have multiple translation initiation and termination sequences to create numerous proteins/genes. They are only in prokaryotes.
Bonus: How is the transition from transcription to translation different in prokaryotes and eukaryotes?