Bio 1A03 Test 3 Questions and Answers
Verified 100% Correct
What are telomeres? - ANSWER -ends of chromosomes designed to protect from
DNA shortening. Made of of 100s-1000s of TTAGGG tandem repeats. get
increasingly short with each division especially in somatic cells
telomere shortening does not occur in which types of cell? - ANSWER -gametes
and stem cells. they contain telomerase, a reverse transcriptase that binds to the
ends of the tails and adds repeats. potentially useful for aging/cancer
karyotype - ANSWER -A display of the chromosome pairs of a cell arranged by
size and shape.
ploidy - ANSWER -number of sets of chromosomes in a cell
haploid vs diploid - ANSWER -one set of chromosomes vs two sets of
chromosomes
mitotic spindle - ANSWER -a structure made of microtubules that controls
chromosome movement during mitosis
unlike animals, during cell division, plant cells do not contain ____ - ANSWER -
centrosomes (though they do have mitotic spindle). final location defines the poles.
phragmoplast - ANSWER -In dividing plant cells, a structure formed by
overlapping microtubules that guide vesicles containing cell wall components to
the middle of the cell.
cyclin A - ANSWER -helps activate DNA synth
cyclin B - ANSWER -helps prepare for mitosis
,Cyclin D & E - ANSWER -helps prepare for DNA replication (before A)
If one DNA strand is damaged during replication, what occurs in the other strand?
- ANSWER -It slows down. DNA replication occurs simultaneously and the DNA
polymerases interact together.
Amount of nucleotides lost per division - ANSWER -About 100. Adult cells can
only divide under 50 times on average because of this, telomerase is inactive
almost everywhere. Cells typically stop dividing when under 100 TTAGGG
repeats are left. Telomerase reactivation has been associated with cancer.
Components needed for PCR (in vitro replication) - ANSWER --Pair of primers to
bind to specific point of DNA
-DNA polymerase (usually Taq)
-Template DNA
-essential ions and salts (buffered solution)
-free deoxyribonucleotides (dNTPs): dATP, dGTP, dCTP, dTTP
-topoisomerase and helicase not required due to thermocycler
Taq polymerase - ANSWER -heat-tolerant up to 95°C comes from thermus
aquaticus
Stages of PCR with explanation - ANSWER --Denaturation: unwinds DNA
through heating
-Annealing: primers bind to DNA strands
-extension: DNA polymerase and dNTPS extends (/amplifies) DNA
gel electrophoresis - ANSWER -visualize DNA fragments, separate and compare
lengths
, shot gun sequencing phases - ANSWER -1. Random sequencing of DNA in each
fragment (10-50 copies of each region)
2. Identifying the regions of *overlap* and inferring / assembling each
chromosome
3. annotating the sequences to best identify regions of coding/regulatory/non
coding regions
sanger sequencing (dideoxy chain termination method) - ANSWER --Same
requirements as PCR
-work on the basis of modified fluorescent dNTPs missing 3' hydroxyl (ddNTPs)
which stop elongation of DNA strand. DNA added to tubes with different ddNTPs
leading to series of interrupted daughter strands with varying lengths.
-Only works on small fragments (few hundred nucleotides)
spectogram trace - ANSWER -compiles fragments from sanger sequencing into
*complimentary* (because of the binding) sequence to be read left to right
contigs - ANSWER -Overlapping DNA segments that share the same sequence.
consensus regions - ANSWER -Regions of DNA having similar structure and
function in different organisms.
Created from overlapping sequences/contigs
How many reading frames are there in a double stranded DNA and how do you
decide which to use? - ANSWER -6 possible reading frames.
Look for long periods without stop codons, a start codon, possibly promoter or
other regulatory site (usually done by a computer). easier in prokaryotes
sequence motif - ANSWER -A pattern of nucleotides or amino acids shared by
different genes or proteins that often have related functions. (ex transcription
factors, hairpin loops, ORFs)
____ % of eukaryotic genome is non coding - ANSWER -50%
Verified 100% Correct
What are telomeres? - ANSWER -ends of chromosomes designed to protect from
DNA shortening. Made of of 100s-1000s of TTAGGG tandem repeats. get
increasingly short with each division especially in somatic cells
telomere shortening does not occur in which types of cell? - ANSWER -gametes
and stem cells. they contain telomerase, a reverse transcriptase that binds to the
ends of the tails and adds repeats. potentially useful for aging/cancer
karyotype - ANSWER -A display of the chromosome pairs of a cell arranged by
size and shape.
ploidy - ANSWER -number of sets of chromosomes in a cell
haploid vs diploid - ANSWER -one set of chromosomes vs two sets of
chromosomes
mitotic spindle - ANSWER -a structure made of microtubules that controls
chromosome movement during mitosis
unlike animals, during cell division, plant cells do not contain ____ - ANSWER -
centrosomes (though they do have mitotic spindle). final location defines the poles.
phragmoplast - ANSWER -In dividing plant cells, a structure formed by
overlapping microtubules that guide vesicles containing cell wall components to
the middle of the cell.
cyclin A - ANSWER -helps activate DNA synth
cyclin B - ANSWER -helps prepare for mitosis
,Cyclin D & E - ANSWER -helps prepare for DNA replication (before A)
If one DNA strand is damaged during replication, what occurs in the other strand?
- ANSWER -It slows down. DNA replication occurs simultaneously and the DNA
polymerases interact together.
Amount of nucleotides lost per division - ANSWER -About 100. Adult cells can
only divide under 50 times on average because of this, telomerase is inactive
almost everywhere. Cells typically stop dividing when under 100 TTAGGG
repeats are left. Telomerase reactivation has been associated with cancer.
Components needed for PCR (in vitro replication) - ANSWER --Pair of primers to
bind to specific point of DNA
-DNA polymerase (usually Taq)
-Template DNA
-essential ions and salts (buffered solution)
-free deoxyribonucleotides (dNTPs): dATP, dGTP, dCTP, dTTP
-topoisomerase and helicase not required due to thermocycler
Taq polymerase - ANSWER -heat-tolerant up to 95°C comes from thermus
aquaticus
Stages of PCR with explanation - ANSWER --Denaturation: unwinds DNA
through heating
-Annealing: primers bind to DNA strands
-extension: DNA polymerase and dNTPS extends (/amplifies) DNA
gel electrophoresis - ANSWER -visualize DNA fragments, separate and compare
lengths
, shot gun sequencing phases - ANSWER -1. Random sequencing of DNA in each
fragment (10-50 copies of each region)
2. Identifying the regions of *overlap* and inferring / assembling each
chromosome
3. annotating the sequences to best identify regions of coding/regulatory/non
coding regions
sanger sequencing (dideoxy chain termination method) - ANSWER --Same
requirements as PCR
-work on the basis of modified fluorescent dNTPs missing 3' hydroxyl (ddNTPs)
which stop elongation of DNA strand. DNA added to tubes with different ddNTPs
leading to series of interrupted daughter strands with varying lengths.
-Only works on small fragments (few hundred nucleotides)
spectogram trace - ANSWER -compiles fragments from sanger sequencing into
*complimentary* (because of the binding) sequence to be read left to right
contigs - ANSWER -Overlapping DNA segments that share the same sequence.
consensus regions - ANSWER -Regions of DNA having similar structure and
function in different organisms.
Created from overlapping sequences/contigs
How many reading frames are there in a double stranded DNA and how do you
decide which to use? - ANSWER -6 possible reading frames.
Look for long periods without stop codons, a start codon, possibly promoter or
other regulatory site (usually done by a computer). easier in prokaryotes
sequence motif - ANSWER -A pattern of nucleotides or amino acids shared by
different genes or proteins that often have related functions. (ex transcription
factors, hairpin loops, ORFs)
____ % of eukaryotic genome is non coding - ANSWER -50%
