stuff to know for 3rd quiz biology
what are the steps of interphase
1). G1 2). S 3). G2
what are the steps of the miotic phase
1). mitosis 2). cytokenisis
what happens in Telophase
1. chromosomes disapear 2. nuclear membrane appear 3. centrioles stop moving 4. clevage furrow forms
what happens in prophase
1. cromosomes start to appear 2. nuclear membrane disapears 3. centrioles migrate to opposite ends of the cell as they migrate they create spindel fibers that attach to the centromere of the chromosomes
what percentage of DNA does the zygote have from the parents
50 50
what is a chromosome and why is it important
A chromosome is made of DNA wrapped around proteins and contains all the genetic information for the organism
what happens in the S phase
DNA synthesis
most normal cells in an adult organism are in which phase of the cell cycle
G1
which stage of the cell cycle takes the longest
G1
during which phase does the size of the cell increase
G1 and G2
caner, the uncontrolled growth of cells, often results in a tumor, or mass of abnormal cells. Some cancerous tumors consist of many cells that are much smaller than normal. What part or parts of the cell cycle are most likely being affected
G1 may be affected, not allowing the cells to fully grow
If a starfish sustains damage to a limb, it often grows a new one. If a human adult sustains damage to his or her spinal cord, mobility is often impaired. If a gecko lises its tail, it may grow a new one. Whcih type of cell is less likely to go through the cell cycle after being damaged; a starfish limb, human spicnal cord, or gecko tail.
Human spinal cord cells, because that injury can't be repaired
what are the steps of mitosis
Prophase Metaphase Anaphase Telophase
what are the four phases in the mitosis process
Prophase, metaphase, anaphase, and telophase
Occasionally cells stop dividing and enter another phase, G0. If you damage your liver, new liver cells can be produced to replace up to 75% of the liber. However, if you sustain brain damage your body does not produce new brain cells. explain this observation using what you have learned about the cell cycle
The brain cells are in G0 and do not reproduce, but the liver cells will reproduce to make new ones.
what could happen, after several cell cycles, to an organism whose damaged cells did not go through apoptosis? In other words, what if a damaged cell that is supposed to die does not.
a tumor (cancer) may develop when cells keep dividing when they're not supposed to
what is formed when the ova is fertilized by the sperm
a zygote
what is when only one organism is needed to reproduce offspring that are genetically identical
asexual reproduction
what happens in G2
cell growth and cell prepares to divide
what is the G1 phase of interphase
cell growth, and the cell prepares to divide
what happens in metaphase
chromosomes line up in the middle of the cell
what happens in cytoplasm
cytoplasm divides
if a culture in the lab starts with one human cell, how many cells will be there after 48 hours
four cells
identify two ways that the growth of an organism can be accomplished through the events of the cell cycle
growth can happen when cells increase in size or when the number of cells in an organism increases (this takes place during G1 and M respectively)
how might targeting rapidly growing cells explain common chemotherapy side effects such as hair loss and nausea
hair follicle cells and stomach lining cells are both examples of normally fast-growing cells. These would be affected along with the cancer cells. As the chemo targets rapidly dividing cells.
Describe one way cancer might arise rom problems with the cell cycle
if cells divide out of control, cancer is present. If any of the time for G1 or G2 is eliminated, cells would divide prematuraley
what are the two steps of the cell cycle
interphase and miotic
imagine 100 cells were chosen randomly from a tissue sample and examined under a microscope. In which phase of the cell cycle would you expect to find the largest number of cells.
more cells would be in the longer lasting gap1 phase, because if cells don't spend much time in a phase, they are less likely to be in at any given time
is more time spent in in gap1 or mitosis
more time is spent in gap1
is the original cell dead or does it disappear after mitosis
no, the orignal cell is divided into two new cells. Each cell has exactly the same DNA as the original cell, which duplicated its DNA before it divided. Therefore, each new cell has a complete set of chromosomes (DNA) as well as half the organelles from the original parent cell.
what are somatic cells
nonreproductive cells and they have two sets of chromosomes
other than cytokinesis what else occurs during the mitosis phase? Hint: Consider the sets of DNA in each cell
nuclear division; the DNA is evenly divided, creating two separate nuclei
what are gametes
reproductive cells, sperm and eggs, have one set of chromosomes, ova is female and sperm is male
what happens in anaphase
sister chromatids get pulled apart
some types of cancers are treated with radiation, similar to ultraviolet light. Why might it be beneficial to irradiate cancer cells
the caner cells will be damaged so that they will no longer function as normal cells, they will not divide or may be induced to undergo apoptosis
cyto = cell, kinesis = cutting. What do you think takes place during cytokinesis
the cell (cytoplasm) is split in two
how might the DNA damage go on to affect the rest of the cell cycle isf apoptosis did not occur
the cell has mutations so it might not go through the cycle correctly or two cells might be formed that each contain the mutation
compare the amount of DNA at the beginning and end of synthesis. Why did the amound of DNA change
the cell is preparing to divide, so there is double the amount of DNA at the end of synthesis than at the beginning
why might it be beneficial to an organism for the damaged cell to enter G0 instead of deciding once they exist
the cells will not duplicate and pass on their harmful mutations
ultraviolet light affects the cell in G1. The ultraviolet light may cause DNA damage, which is known as a mutation. How might such damage affect events taking place during the synthesis phase
the damaged DNA is copied so both new cells would have the mutation
apoptosis
the process of kiling the damaged cell before it passes on the problem to its daughter cells
what is the centromere
the region on the chromosomes where the fibers attach
for those cancerous cells, what happens to the time that is necessary for the cell cycle? What implication might this have for doctors who are treating cancer patients
the time decreases bc the time necessary for G1 is reduced. Doctors need to start treatment quickly and use a drug that is absorbed by the system rapidly since the cancer cells reproduce at a faster rate than normal cells.
true or false you only see chromosomes when cell is about to divide and the rest of the time is seen as chromatin
true
if a culture in the lab starts with one human cell, how many cells will be there after 24 hours
two cells
how many chromatids are in each replicated chromosome
two chromatids per replicated chromosome
is the a amoebe aesexual
yepppppppppp