BIOL 3110 Final Exam Questions and
Answers (Solved Papers)
dna-histone complex is called a ______________________. & is
defined as the: - Correct Answers ✅-nucleosome
-repeating unit of chromatin
each nucleosome contains how many bp of dna? how many
turns of dna is this? what specific histones is dna wrapped
around? (Lec 15 - Fig 1) - Correct Answers ✅-147 bp, 1.7
turns
-wraps around 2 copies each of H2A, H2B, H3, H4 (the
octamer)
-H1 helps hold this entire unit together
In what manner does dna wrap around histones? - Correct
Answers ✅-dna wraps around histones to create left handed
nucleosomes
what is the role of H1 histone in helping dna being packed
into a chromosome? - Correct Answers ✅-H1 histone helps
form 11nm fibers, then 30 nm fibers, then 300nm fibers
(known as chromatin domain), then 700nm fibers
(q: why is the size getting bigger and not smaller?)
H2A, H2B, H3, & H4 are all similar in size. are they larger or
smaller than H1? - Correct Answers ✅smaller
,BIOL 3110 Final Exam Questions and
Answers (Solved Papers)
what component of histones allows them to tightly wrap
around dna? - Correct Answers ✅-they're basic (composed
of Lys + Arg)
-this wraps around the -'ve charged P of minor grooved dna
-this stabilizes the charge
histones are very conserved proteins. what does this mean? -
Correct Answers ✅antibodies that recognize human
histones can also recognize histones from other organisms
eg. mice
all histones have similar domain structures from n to c
terminus. explain why. - Correct Answers ✅-unstructured n
terminus & highly structured histone folds (middle region)
-H2A & H2B have longer C terminal tails
-H3 & H4 have longer n terminal tails
how does H2A form a unit with H2B, & H3 forms a unit with
H4? (Lec 15 - Fig 2) - Correct Answers ✅histone folds come
together to form "hand-shake motifs" which allow for both
dimerizations
How is octamer formed? (Lec 15 - Fig 3) - Correct Answers
✅-2 H3-H4 dimers interact to form a tetramer, which forms
the central disc of the octamer
,BIOL 3110 Final Exam Questions and
Answers (Solved Papers)
-then both individual H2A-H2B dimers are added 1 by 1 to the
disc
-octamer is formed
what 2 proteins are required for the assembly (& removal) of
histones on dna? - Correct Answers ✅1) histone
chaperones
2)ATP-dependent chromatin remodelling complex
nucleosomes are linked together by ____________________.
what is 1 downside of this? (Lec 15 - Fig 4) - Correct
Answers ✅-linker dna
-since the linker dna isn't wrapped by histones, its more
exposed to MNase (nucleosome) digestion
what 2 factors allow for the stabilization of the condensed 30
nm fiber? - Correct Answers ✅1) addition of H1
2) increased ionic strength (high salt mimizes repulsion of
phosphate groups)
when do we see the highest compacted state of chromatin? -
Correct Answers ✅metaphase
centromere/kinetochore is where: - Correct Answers
✅sister chromatids are attached together
, BIOL 3110 Final Exam Questions and
Answers (Solved Papers)
how many telomeres are there on one metaphase
chromosome? how many centromeres/kinetochores? -
Correct Answers ✅4, 1
cytogenetics - Correct Answers ✅the study of
chromosomes & their abnormalities
what is the importance of metaphase chromosomes in lab? -
Correct Answers ✅-clinical tests are done on them
(cytogenetics)
-can be used to diagnose diseases
chromosomes are divided into what 2 arms? - Correct
Answers ✅p arm + q arm
metaphase chromosomes are classified into what 4 diff
types? explain the lengths of p and q arm for each. (Lec 15 -
Fig 6) - Correct Answers ✅"msat"
1) metacentric = centromere is in middle of chromosome
-p and q arm are the same length
2)submetacentric = centromere is in btw the mid and end of
chromosome
Answers (Solved Papers)
dna-histone complex is called a ______________________. & is
defined as the: - Correct Answers ✅-nucleosome
-repeating unit of chromatin
each nucleosome contains how many bp of dna? how many
turns of dna is this? what specific histones is dna wrapped
around? (Lec 15 - Fig 1) - Correct Answers ✅-147 bp, 1.7
turns
-wraps around 2 copies each of H2A, H2B, H3, H4 (the
octamer)
-H1 helps hold this entire unit together
In what manner does dna wrap around histones? - Correct
Answers ✅-dna wraps around histones to create left handed
nucleosomes
what is the role of H1 histone in helping dna being packed
into a chromosome? - Correct Answers ✅-H1 histone helps
form 11nm fibers, then 30 nm fibers, then 300nm fibers
(known as chromatin domain), then 700nm fibers
(q: why is the size getting bigger and not smaller?)
H2A, H2B, H3, & H4 are all similar in size. are they larger or
smaller than H1? - Correct Answers ✅smaller
,BIOL 3110 Final Exam Questions and
Answers (Solved Papers)
what component of histones allows them to tightly wrap
around dna? - Correct Answers ✅-they're basic (composed
of Lys + Arg)
-this wraps around the -'ve charged P of minor grooved dna
-this stabilizes the charge
histones are very conserved proteins. what does this mean? -
Correct Answers ✅antibodies that recognize human
histones can also recognize histones from other organisms
eg. mice
all histones have similar domain structures from n to c
terminus. explain why. - Correct Answers ✅-unstructured n
terminus & highly structured histone folds (middle region)
-H2A & H2B have longer C terminal tails
-H3 & H4 have longer n terminal tails
how does H2A form a unit with H2B, & H3 forms a unit with
H4? (Lec 15 - Fig 2) - Correct Answers ✅histone folds come
together to form "hand-shake motifs" which allow for both
dimerizations
How is octamer formed? (Lec 15 - Fig 3) - Correct Answers
✅-2 H3-H4 dimers interact to form a tetramer, which forms
the central disc of the octamer
,BIOL 3110 Final Exam Questions and
Answers (Solved Papers)
-then both individual H2A-H2B dimers are added 1 by 1 to the
disc
-octamer is formed
what 2 proteins are required for the assembly (& removal) of
histones on dna? - Correct Answers ✅1) histone
chaperones
2)ATP-dependent chromatin remodelling complex
nucleosomes are linked together by ____________________.
what is 1 downside of this? (Lec 15 - Fig 4) - Correct
Answers ✅-linker dna
-since the linker dna isn't wrapped by histones, its more
exposed to MNase (nucleosome) digestion
what 2 factors allow for the stabilization of the condensed 30
nm fiber? - Correct Answers ✅1) addition of H1
2) increased ionic strength (high salt mimizes repulsion of
phosphate groups)
when do we see the highest compacted state of chromatin? -
Correct Answers ✅metaphase
centromere/kinetochore is where: - Correct Answers
✅sister chromatids are attached together
, BIOL 3110 Final Exam Questions and
Answers (Solved Papers)
how many telomeres are there on one metaphase
chromosome? how many centromeres/kinetochores? -
Correct Answers ✅4, 1
cytogenetics - Correct Answers ✅the study of
chromosomes & their abnormalities
what is the importance of metaphase chromosomes in lab? -
Correct Answers ✅-clinical tests are done on them
(cytogenetics)
-can be used to diagnose diseases
chromosomes are divided into what 2 arms? - Correct
Answers ✅p arm + q arm
metaphase chromosomes are classified into what 4 diff
types? explain the lengths of p and q arm for each. (Lec 15 -
Fig 6) - Correct Answers ✅"msat"
1) metacentric = centromere is in middle of chromosome
-p and q arm are the same length
2)submetacentric = centromere is in btw the mid and end of
chromosome
