Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
106 Cards in this Set
- Front
- Back
How does the T2 virus infect E.coli? What is left behind on the exterior of the cell?
|
- injects its genes into the cell and directs the production of new virus particles
- protein coat of original parent virus ("ghost") |
|
Which experiment supported that DNA, not protein is the genetic material? Explain it.
|
- Hershey-Chase experiment
- virus' DNA labelled with radioactive P, protein with S - radioactive protein found in ghosts and radioactive DNA found in cells |
|
Which experiment confirmed that DNA replication is a semi-conservative process?
|
Meselson-Stahl
|
|
What is the central dogma?
|
DNA --> RNA --> Protein
|
|
Which method can be used to observe oxygen levels in the brain?
|
Positron Emission Tomography
|
|
Describe the experiment that discovered how many bases act as a codon and specify an amino acid.
|
- 1, 2, and 3 base deletions
- only 3 base deletion produced a functional protein - 1 and 2 base deletions caused a shift in the reading frame |
|
How many codons are there and how many amino acids do they code for?
|
64, 20
|
|
What is the start codon? Which amino acid does it code for?
|
AUG, methionine
|
|
What are the 3 stop codons?
|
UGA, UAA, UAG
|
|
The genetic code is redundant. What does this mean?
|
More than one codon codes for each of the 20 amino acids. Helps to prevent mutation.
|
|
The genetic code is unambiguous. What does this mean?
|
one codon never codes for more than one amino acid
|
|
DNA replication is very accurate. What is the average rate of error?
|
less than one mistake per billion bases
|
|
Which enzyme can proofread after synthesis is complete and how can it do this?
|
DNA polymerase III. Acts as an exonuclease that removes deoxyribonucleotides from DNA
|
|
How can UV light cause a kink in the DNA strand?
|
excites bonds, covalent bonds switch and bind, can cause thymine dimers
|
|
How can you repair dimers?
|
nuclear excision repair
|
|
What are some medical implications of cross-linking agents?
|
- fight cancer by preventing replication
- can treat psioriasis |
|
Explain nucleotide excision repair.
|
- system recognizes damage
- enzymes remove single-stranded DNA - complimentary DNA strands acts as template for resynthesis - DNA polymerase fills in gaps in 5'-3' direction - DNA ligase links new and old nucleotides |
|
Name the rare autosomal recessive disease characterized by the development of skin lesions.
|
XP (Xeroderma pigmentosum)
|
|
What causes XP?
|
- mutations of one of several nucleotide excision repair systems
- cells cannot repair DNA damagect by UV radiation |
|
How many times could the DNA from all the cells of your body stretch from McMaster to the moon and back if it were lined up end to end?
|
1000s of times
|
|
How much exposure does an Airport Body Scanner deliver? What is this dose equal to?
|
- 0.05 uSv
- 2 mins of flying at 30 000 ft/ half a banana |
|
What are introns?
|
Non-coding regions of RNA
|
|
What occurs during RNA processing?
|
- introns removed
- ends receive a cap and a poly A tail |
|
Inside ribosomes, mRNAs are translated to proteins via which intermediary molecules?
|
tRNAs
|
|
During transcription in bacteria, mRNA is synthesized by _________ which synthesizes the _________ strand.
|
RNA polymerase, template strand
|
|
What are the three phases of transcription in bacteria?
|
initiation, elongation, termination
|
|
What is a holoenzyme? Give an example.
|
- composed of a core enzyme and other required proteins
- synthesizes first step of transcription (initiation) in bacteria Ex. prokaryotic RNA polymerase |
|
What tells RNA polymerase where to bind and when to start synthesizing RNA for the initiation phase of transcription in bacteria?
|
sigma subunit
|
|
In which direction does RNA polymerase move along the template strand during elongation of transcription?
|
5'-3'
|
|
How is the end of transcription signaled?
|
termination phase: RNA polymerase encounters transcription termination signal on template, signal causes hairpin to form which causes RNA polymerase to release
|
|
Which specific sections of DNA iniate transcription of bacterial genes and where are they found? What recognizes them?
|
- promoters
- 10 and 35 bases upstream on non-template strand - sigma |
|
What opens up the double helix in bacteria?
|
sigma
|
|
The template strand in bacteria is threaded through _________
|
the RNA polymerase active site
|
|
How does RNA polymerization begin?
|
ribonucleoside triphosphate (NTP) pairs with a complementary base on DNA template strand
|
|
How is a Philadelphia chromosome created?
|
Translocation between 9 and 22
|
|
What does FISH stand for?
|
Fluorescence In Situ Hybridization
|
|
What does BCR stand for? What chromosome is it on?
|
Breakpoint Cluster Region, 22
|
|
What does ABL stand for? What chromosome is it on?
|
Abelson Tyrosine Kinase, 9
|
|
How does Gleevec help CML patients?
|
prevents phosphorylation by tyrosine kinases (BCR & ABL)
|
|
What is a G banding karyotype?
|
GC rich regions are darker
|
|
How is transcription in eukaryotes initiated?
|
- by basal transcription factors which math RNA polymerase with appropriate promoter region
|
|
What are the 3 types of RNA polymerase found in eukaryotic cells and what does each transcribe/code for?
|
- RNA pol I = rRNA
- RNA pol II = proteins - RNA pol III = tRNA |
|
How are introns removed?
|
by splicing
|
|
How is a spliceosome formed and what is its function?
|
- by small nuclear ribonucleoproteins (snRNPS)
- catalyzes splicing reaction of introns from primary RNA transcript |
|
What is the purpose of adding a 5' cap to RNA transcripts?
|
recognition signal for translation machinery
|
|
How is the amount of protein made maximized in prokaryotes?
|
- transcription and translation tightly coupled due to lack of compartmentalization
|
|
What does the P site in a ribosome hold?
|
the tRNA with the growing polypeptide chain attached
|
|
Which site holds a tRNA that is about to exit the ribosome?
|
E site
|
|
Which experiment lead to the discovery that there are 3 RNA polymerases?
|
alpha-amanitin from death cap mushrooms at high and low concentrations
|
|
What is a point mutation?
|
single base change
|
|
What is a missense mutation?
|
- change in amino acid sequence of the protein has occured
- deleterious: reduce fitness |
|
What are silent mutations?
|
- do not change amino acid sequence
- neutral: do not affect fitness |
|
What is the benefit of carrying the sickle trait?
|
malaria resistance
|
|
What is polyploidy?
|
change in # of each type of chromosome present
|
|
What is aneuploidy?
|
addition or deletion of a chromosome
|
|
How big is an X chromosome?
|
- slightly smaller than blood cell
- larger than bacteria - larger than mitochondria |
|
What is inversion?
|
- chromosome level mutation
- chromosomal segment detaches, flips and reattaches to chromosome |
|
What is translocation?
|
chromosomal segment detaches and becomes attached to a different chromosome
|
|
Which type of inversion does not involve the centromere?
|
paracentric (as opposed to pericentric)
|
|
What is a dicentric chromosome?
|
- has two centromeres
|
|
How can a dicentric chromosome assay be useful?
|
To determine how much radiation you got.
|
|
What causes an XX male?
|
SRY (sex determining Y gene) translocated to X chromosome
|
|
How can GFP (Green Fluorescent Protein) help us learn more about radiation-induced cancer?
|
DNA instructs cell to produce the GFP attached to the RAD51 protein
|
|
Name and describe the three mechanisms of gene expression regulation.
|
- transcriptional control: slow but efficient
- translational control: allows a cell to quickly change when proteins are produced - post-translational control: most rapid response but energetically expensive |
|
Which population is more likely to abort a child missing two fingers?
|
public
|
|
Which population is more likely to abort a with Down's Syndrome?
|
doctors
|
|
Which population is more likely to abort a child that will develop cancer in their early 30s?
|
public
|
|
Which population is more likely to abort a child with low IQ?
|
about equal (between public, doctors and ethicists)
|
|
Would the majority of people rather know or mnot know if they will develop a disease later in life?
|
about equal
|
|
PCR requires primers. Differentiate between the two primers.
|
- one is complementary to a sequence on one strand, upstream of target
- other is complementary to a sequence on the other strand downstream of target - they both bind to a single-strand target |
|
During PCR, the primers bind and allow which enzyme to work?
|
DNA polymerase
|
|
What are the three steps of PCR?
|
denaturation, annealing, extension
|
|
Describe the steps of PCR, including temperatures.
|
- denaturation occurs at 95, bonds break, strands separate
- at ~60, primers form H bonds with single strands - 72 = optimal temp for taq polymerase to synthesize the complementary DNA strand using dNTPs - primers provide 3' OH end - amout of DNA doubles each time |
|
What percentage of people are hypersensitive to radiation?
|
5-10 %
|
|
What are some adverse effects of radiotherapy?
|
- erythema
- fibrosis - loss of organ function |
|
What was the cobalt bomb?
|
grand-daddy of all the radiation therapy machines found in modern cancer facilities
|
|
What is stereotactic surgery?
|
lienar accelerator, brain tumour treatment
|
|
How many grey can the average person withstand?
|
1/2 a grey
|
|
How many grey are required to kill tissue?
|
2
|
|
What percentage of men over 85 have some degree of prostate cancer?
|
100%
|
|
What is a PSA test? What are normal and high levels?
|
- measures the level of PSA in the bloodstream
- normal: 0-4 ng/ml - high: 20+ ng/ml |
|
What did the study involving radiation-induced apoptosis as a tool to predict radiation sensitivity find?
|
- small intravariation
- large intervariation |
|
What is the normal size of a prostate?
|
walnut/squash ball
|
|
What is the benefit of Intensity Modulated Radiation Therapy (IMRT)?
|
you can avoid radiating places you don't want to treat
|
|
What are STRs? What types are there?
|
- simple tandem repeats
- small sequences repeated down the length of a chromosome - microsatellites/simple sequence repeats: repeat 1-5 bases - minisatellites/VNTRs: about 6-500 bases |
|
Why are micro and minisatellites used as markers for DNA fingerprinting?
|
high variation among individuals
|
|
What percetage of forensic DNA case work consists of direct indentification?
|
>75%
|
|
What are the three main types of forensic DNA markers?
|
autosomal, mitochondrial, Y-chromosome
|
|
What are the autosomal DNA markers?
|
- VNTRs
- SNPs - STRs |
|
Describe the process used when VNTRs are being analyzed?
|
- DNA digested
- analyzed by Southern hybridization |
|
Which process is used when STRs are being analyzed?
|
PCR
|
|
Which genes are analyzed by codis?
|
3 4 5 7 8 13 18 21
|
|
What does CODIS stand for?
|
Combined DNA Index System
|
|
What does COI stand for?
|
convicted offender index
|
|
What does CSI stand for?
|
Crime Scene Index
|
|
What percentage of conceptions have serious genetic errors?
|
>70%
|
|
Who makes more errors, mother or father? Who more molecular errors?
|
mother, father
|
|
What percentage of eggs have a chromosomal error/sperm are abnormal?
|
~ 20%
|
|
What are 3 significant changes affecting human reproduction due to medical advances?
|
- increased reproductive fitness
- increase in genetic disease treatment - prenatal identification and replacement of affected conceptions |
|
Name 5 methods of prenatal diagosis.
|
serum screening, ultrasonography, chorionic villus sampling (CVS), amniocentesis, cordoncentesis
|
|
What percentage of pregnancies are lost?
|
over 60%
|
|
How are Belgian Blue cows created?
|
myostatin gene modification
|
|
What are the 3 types of DNA repair?
|
error free, apoptosis, error prone
|
|
How does information flow in a cell?
|
DNA-->mRNA--> Proteins
|
|
Which proteins regulate apoptosis?
|
BcH2 and BAX
|
|
What causes an XY female?
|
SRY gene is missing
|