MCB 150 EXAM 3 UIUC | 2025/2026 UPDATE |
QUESTIONS AND ANSWERS | GRADED A+!!
Nucleoplasm Answer - substance of a cell nucleus
Chromatin Fibers Answer - DNA and protein
Nucleolus Answer - site for rRNA synthesis and processing assembly of
subunits
Nuclear Pore Complex Answer - particles can pass through this
Nuclear Lamina Answer - Network of proteins that provide attachement for
heterochromatin and give the nucleus shape
Who proposed that there were functional domains of nucleus? Answer - Rabl
What can visualize and identify chromosomes? Answer - Flourescence
Functional Domains of Nucleus Answer - each chromosome occupies a distinct
territory within the nucleus and is arranged in an organized fashion. nuclei are
divided into discrete funtional domains that play an important role in
regulating gene expression and in replication
,How many focis of replication are in the human nucleus? Answer - greater
than 100
The cell cycle consists of what? Answer - M phase and interphase (G1, S phase,
G2)
G1 Phase Answer - cell is growing and preparing for s phase
S phase Answer - when DNA synthesis occurs (replication), longest interphase
cycle
G2 phase Answer - make sure you are ready to go through next round of m
phase
M phase Answer - mitosis and cytokinesis (division of mother cell into two
identical daughter cells)
Early replication has what gene density? Answer - high gene density,
euchromatin
Late replication has what gene density? Answer - low gene density,
heterochromatin
Nucleolus Answer - ribosome production facility, site for rRNA synthesis, rRNA
processing, assembly of ribosomal subunits
what are the 4 types of rRNA? Answer - 5s, 5.8s, 18s, 28s
, How many copies does the human cell have of 5.8s, 18s, and 28s rRNA genes?
Answer - about 280
how many copies does the human cell have of 5s rRNA genes? Answer - about
2000
Tandem arrays Answer - when 5.8s, 18s, and 28s rRNAS are transcribed by
polymerase 1 into pre rRNA
45S GENES Answer - processed into 5.8s, 18s, and 28s rRNAS are found on
human chromosomes 13, 14, 15, 21, and 22
Where are 5s rRNA genes found in huge array? Answer - chromosome 1
Nucleolar organizing regions Answer - arrays of 45s rRNA genes, nucleolus
forms around these NOR, so if cell is not actively transcribing 45s rRNA genes,
there will be no nucleus
3 distinct regions of nucleolus Answer - fibrillar region or center
dense fibrillar region
granular zone
mutations Answer - heritable changes in the DNA
What mutations are in single cell organisms? Answer - all daughter cells have
the same mutation
What mutations are in multi cell organisms? Answer - Either somatic of germ-
line
QUESTIONS AND ANSWERS | GRADED A+!!
Nucleoplasm Answer - substance of a cell nucleus
Chromatin Fibers Answer - DNA and protein
Nucleolus Answer - site for rRNA synthesis and processing assembly of
subunits
Nuclear Pore Complex Answer - particles can pass through this
Nuclear Lamina Answer - Network of proteins that provide attachement for
heterochromatin and give the nucleus shape
Who proposed that there were functional domains of nucleus? Answer - Rabl
What can visualize and identify chromosomes? Answer - Flourescence
Functional Domains of Nucleus Answer - each chromosome occupies a distinct
territory within the nucleus and is arranged in an organized fashion. nuclei are
divided into discrete funtional domains that play an important role in
regulating gene expression and in replication
,How many focis of replication are in the human nucleus? Answer - greater
than 100
The cell cycle consists of what? Answer - M phase and interphase (G1, S phase,
G2)
G1 Phase Answer - cell is growing and preparing for s phase
S phase Answer - when DNA synthesis occurs (replication), longest interphase
cycle
G2 phase Answer - make sure you are ready to go through next round of m
phase
M phase Answer - mitosis and cytokinesis (division of mother cell into two
identical daughter cells)
Early replication has what gene density? Answer - high gene density,
euchromatin
Late replication has what gene density? Answer - low gene density,
heterochromatin
Nucleolus Answer - ribosome production facility, site for rRNA synthesis, rRNA
processing, assembly of ribosomal subunits
what are the 4 types of rRNA? Answer - 5s, 5.8s, 18s, 28s
, How many copies does the human cell have of 5.8s, 18s, and 28s rRNA genes?
Answer - about 280
how many copies does the human cell have of 5s rRNA genes? Answer - about
2000
Tandem arrays Answer - when 5.8s, 18s, and 28s rRNAS are transcribed by
polymerase 1 into pre rRNA
45S GENES Answer - processed into 5.8s, 18s, and 28s rRNAS are found on
human chromosomes 13, 14, 15, 21, and 22
Where are 5s rRNA genes found in huge array? Answer - chromosome 1
Nucleolar organizing regions Answer - arrays of 45s rRNA genes, nucleolus
forms around these NOR, so if cell is not actively transcribing 45s rRNA genes,
there will be no nucleus
3 distinct regions of nucleolus Answer - fibrillar region or center
dense fibrillar region
granular zone
mutations Answer - heritable changes in the DNA
What mutations are in single cell organisms? Answer - all daughter cells have
the same mutation
What mutations are in multi cell organisms? Answer - Either somatic of germ-
line
