Bio Exam UPDATED QUESTIONS AND
CORRECT ANSWERS
For what reason(s) do cells of single celled organisms divide? How about multicellular
organisms? What type of cell division is involved in each case? - CORRECT
ANSWER 1.) growth and development (Eurkaroytic cell-meiosis and mitosis)
2) regeneration / repair (eurkarotyic cells-mitosis )
3)reproduction - only for single celled organisms (prokaryotic binary fission)
Summarize what occurs during each of the 4 phases of the cell cycle. What is G0 phase? At
what point of the cycle can cells 'decide' to enter G0? - CORRECT ANSWER 4 phases
of Cell cycle: (Interphase)
1) G1- longest of all phases, includes normal cell growth, inspect DNA
2)G2- Extra cell growth, Inspects DNA ( if not can lead to mutations.)
3)S- DNA synthesis, Chromosome Duplication, DNA replication
4)M- Mitotic/ where cytokinesis occurs.
G0 phase-
where the cell exits the cell cycle usually occurring at the end of G1 (only for those who do
not replicate, neurons, muscle cells) none dividing the state, cells can re-enter G1.
Explain how the frequency of cell division varies in the tissues of an adult multicellular
organism. How does G0 phase fit in? Give examples of human cell types from lecture -
CORRECT ANSWER 1.) Continuous- red blood cells, GI tract cells, skin cells.
2) Based on need- liver cells.
3.) Rare/Never- muscle and brain cells.
G0 phase 1&2 can come back into the cycle 2&3 can enter prem in G0 (most human cells are
in G0)
The terms gene, genome, DNA, chromosome, replicated chromosome, sister chromatids, and
chromatin are distinct ways of referring to genetic material. What does each term mean? How
do terms relate to one another other? Compose sentences such as "_____ is made out of
, _____," or "_____ is composed of _____(a number) _____." - CORRECT
ANSWER Gene- a region of DNA encoding either a polypeptide or an RNA
Genome- total genetic info possessed by an organism (contained in every cell)
DNA- polynucleotide chain that contains protein (histone protein) making information.
Chromosome- packed together chromatin
Chromatin- DNA + Protein mixed together
Replicated chromosome- are two sister chromatids.
Sister chromatids- contains one identical DNA, each has a centromere base.
What are the two basic functions of histones? - CORRECT ANSWER 1.) Keep DNA
from getting tangled
2.)help regulate genes by condensing it - turning it off and on.
Comment on chromosomal structure and how it changes over the course of the cell cycle—
particularly between interphase and M phase—and why. - CORRECT
ANSWER Chromosomes are not visible during interphase, only chromatin because it's
still has to grow and replicate. M phase they become more visible as they condense and are
rearranged in the center of the cell to be pulled apart and split.
Describe the appearance and the location of the chromosomes, the nuclear envelope, and the
mitotic spindle during the five stages of mitotic cell division, as pictured in Figure 12.6. -
CORRECT ANSWER In prophase the chromosomes start to condense, centrosome
begin moving to opposite ends, and the spindle begins to form.
In pro-metaphase the nuclear envelope start to disintegrates, microtublus starts to grab the
chromosomes by their centromeres.
In metaphase chromosomes start to line up and kinetochore microtublues connect to the
ketochores on centromeres,
In Anaphase chromatides pulled apart and the cell elgonated dye to non kinetochore
microtubules.
In telephase is the last phase the nuclear envelope reintegrates for each set of chromosome
and the chromosomes decondense
CORRECT ANSWERS
For what reason(s) do cells of single celled organisms divide? How about multicellular
organisms? What type of cell division is involved in each case? - CORRECT
ANSWER 1.) growth and development (Eurkaroytic cell-meiosis and mitosis)
2) regeneration / repair (eurkarotyic cells-mitosis )
3)reproduction - only for single celled organisms (prokaryotic binary fission)
Summarize what occurs during each of the 4 phases of the cell cycle. What is G0 phase? At
what point of the cycle can cells 'decide' to enter G0? - CORRECT ANSWER 4 phases
of Cell cycle: (Interphase)
1) G1- longest of all phases, includes normal cell growth, inspect DNA
2)G2- Extra cell growth, Inspects DNA ( if not can lead to mutations.)
3)S- DNA synthesis, Chromosome Duplication, DNA replication
4)M- Mitotic/ where cytokinesis occurs.
G0 phase-
where the cell exits the cell cycle usually occurring at the end of G1 (only for those who do
not replicate, neurons, muscle cells) none dividing the state, cells can re-enter G1.
Explain how the frequency of cell division varies in the tissues of an adult multicellular
organism. How does G0 phase fit in? Give examples of human cell types from lecture -
CORRECT ANSWER 1.) Continuous- red blood cells, GI tract cells, skin cells.
2) Based on need- liver cells.
3.) Rare/Never- muscle and brain cells.
G0 phase 1&2 can come back into the cycle 2&3 can enter prem in G0 (most human cells are
in G0)
The terms gene, genome, DNA, chromosome, replicated chromosome, sister chromatids, and
chromatin are distinct ways of referring to genetic material. What does each term mean? How
do terms relate to one another other? Compose sentences such as "_____ is made out of
, _____," or "_____ is composed of _____(a number) _____." - CORRECT
ANSWER Gene- a region of DNA encoding either a polypeptide or an RNA
Genome- total genetic info possessed by an organism (contained in every cell)
DNA- polynucleotide chain that contains protein (histone protein) making information.
Chromosome- packed together chromatin
Chromatin- DNA + Protein mixed together
Replicated chromosome- are two sister chromatids.
Sister chromatids- contains one identical DNA, each has a centromere base.
What are the two basic functions of histones? - CORRECT ANSWER 1.) Keep DNA
from getting tangled
2.)help regulate genes by condensing it - turning it off and on.
Comment on chromosomal structure and how it changes over the course of the cell cycle—
particularly between interphase and M phase—and why. - CORRECT
ANSWER Chromosomes are not visible during interphase, only chromatin because it's
still has to grow and replicate. M phase they become more visible as they condense and are
rearranged in the center of the cell to be pulled apart and split.
Describe the appearance and the location of the chromosomes, the nuclear envelope, and the
mitotic spindle during the five stages of mitotic cell division, as pictured in Figure 12.6. -
CORRECT ANSWER In prophase the chromosomes start to condense, centrosome
begin moving to opposite ends, and the spindle begins to form.
In pro-metaphase the nuclear envelope start to disintegrates, microtublus starts to grab the
chromosomes by their centromeres.
In metaphase chromosomes start to line up and kinetochore microtublues connect to the
ketochores on centromeres,
In Anaphase chromatides pulled apart and the cell elgonated dye to non kinetochore
microtubules.
In telephase is the last phase the nuclear envelope reintegrates for each set of chromosome
and the chromosomes decondense
