Bio-Phys 10.1-10.4, 11.4 Flashcards
How does getting too big affect the cells ability to bring in needed supplies across the cell membrane?
It affects the cells ability because the surface area is were supplied pass-through and the ratio of surface area to volume decreases. The cell gets too busy
How does getting too big affect the cells ability to use its DNA efficiently?
It doesn’t have enough to meet the needs of the entire cell
How does getting too big affect the cells ability to dump waste out of the cell membrane?
The same reason it’s hard to get stuff in. It’s less efficient because the ratio of surface area to volume decreases.
If a cell doubles in size, what happens to it’s ratio of surface area to volume?
It decreases
What happens if the cell gets too big?
It divides forming two daughter cells, in a process called cell division.
Describe how cell division solves the problem of cell growth?
The cell divides forming two daughter cells with replicated, identical DNA. Each daughter cell has an increased ratio of surface area to volume, which allows for efficient exchange of materials
Cell cycle
Four phases in the cell cycle. First three phases are part of interphase. The G1 phase, S-phase, G2 phase. Last phase is the M phase, or mitosis.
G1 phase
Cells do most of their growing, increase in size.
S-phase
After the G1 phase. Chromosomes are replicated and synthesis of DNA molecules occur
G2 phase.
Followed buddy S-phase. Shortest the phases during interphase. Many of the organelles required for cell division are produced
Prophase
First step of mitosis. DNA becomes visible. Becomes clumped up and clumpy. Four steps in prophase. 1.copied chromosome coil up to form sister chromatids. 2.Nucleolus and nucleus disappear. 3.centrioles form and move to opposite ends of the cell. 4.spindle fibers form and attached to centromere (middle of sister chromatid)
Metaphase
Second step in mitosis. Spindle fibers get the sister chromatids to line up down the middle of the cell, looks like spiders crawling in a line
Anaphase
Sister chromatids come apart. Spindle fibers contract at the same time an enzyme dissolves the centromere
Telophase
Nucleus and Nucleolus reappear. DNA unwinds(in both cells). Organelles move to the two cells. As soon as the splitting starts, telophase is over
Cytokinesis
The splitting of the cell into two identical cells.
Centromeres
Usually located near the middle of the chromatids although some line near the end.
Mitosis
The first stage, division of the cell nucleus
Cytokinesis
The second stage, division of the cytoplasm.
Chromatid
Identical chromatids make up chromosomes
Interphase
And in between period Of growth called Interphase
Cell cycle
A series of events that cells go through as they grow and divide
Factors that control the cell starting of mitosis or not
If cells are touching on all sides there is no mitosis but if a cell is missing it goes into mitosis
Cyclin
Regulate the timing of the cell cycle in eukaryotic cells.
Cancer
A disorder in which some of the body’s own cells lose the ability to control growth, is one such example
How cancer cells are different from regular cells
They don’t respond to signals that regulate growth
Ways to prevent cancer
Eat healthy foods, stay active, don’t smoke, avoid radiation.
Homologous chromosomes
Two sets of chromosomes ie. fruit fly has 8, 4 from make parent 4 from female parent
Haploid cell
One the single set of chromosomes and therefore only a single set of genes.
Diploid cell
Containing both sets of homologous chromosomes. Two sets.
Tetrad
One chromosome pairs with its corresponding homologous chromosome to form a structure it’s called a tetrad. There are four chromatids in the tetrad
Prophase one
Most important step out of miosos. Crossing over is absolutely key to the dominance of sexually reproducing organisms over critters that done.
Metaphase one
Spindle fibers lineup the tetrads at the middle of the cell, centromere’s don’t dissolve this time
Anaphase one
The tetradS separate, but NOT the sister chromatids. Introduces more genetic variation
Telophase one
one cell splits. Now you have two cells with sister chromatids in the middle instead of the DNA
Prophase two
Spindles form, chromosomes coil up again.
Metaphase two
The sister chromatids lineup along the center of each cell, the spindle fibers attached to the centromere’s.
Anaphase two
Centromere’s dissolve, sister chromatids pull apart.
Telophase two
Cells splits. You now have four haploid cells that are genetically unique.
Crossing over
Homologous chromosomes pair up and form tetrads in meiosis one exchange portions of their chromatids and process called crossing over
Why is crossing over important
Because we need genetic variability
What is the difference between sister chromatids and tetrads?
Sister chromatids occur in mitosis and tetrad occur in meiosis and tetrads cross together, exchanging portions of their chromatids.
How many cells are produced by meiosis?
4
How does this all go from being a diploid to haploid
Meiosis
What are the two stages of the cell cycle?
Mitosis and cytokinesis
Why does a cell copy it’s genetic information before it splits?
So each daughter has the genetic info needed
Without spindles what would happen to the replicated DNA in the cell
It would stay condensed and would not replicate????
What would happen if the cell never split?
The genetic information needed would not be passed on.
What is the difference between animals cells and plant cells when cytokinesis occurs?
In plant cells structure known as the cell plate forms midway between the divided nuclei and in animal cells the cell name membrane draws inward until the cytoplasm is pinched
The difference between an internal regulator and external regulator
Iregular has proteins that respond to the events within the cell whereas external regulators have proteins that respond to events outside the cell
What does a tumor do
Damages surrounding tissue
