Chapter 10 Review Sheet
**Make sure you can identify what a cell looks like in each stage of its life cycle, and what the identifying
characteristic is for each stage (see page 285). Also be able to relate the minor differences between plant and
animal cell division
1.
Why is the surface area-to-volume ratio so important to cells? A cell needs to be able to keep itself
nourished and to get rid of wastes quickly so the cytoplasm does not become toxic. The cell membrane
determines the rate at which these things can move in and out, but the volume determines how much is
needed (nutrients) or tolerable (wastes).
2.
If the surface area of a cube-shaped cell increased 10 times, how much would its volume have increased
by? 100 times
3.
Which is better for a cell: a high surface area to volume ratio, or a low one? A high ratio
4.
After asexual reproduction, how do the daughter cells compare to the parent cell? The daughter cells
are smaller initially, so they have a higher surface area to volume ratio compared to the parent; they do have
the exact same number of chromsomes and identical traits as the parent, unless there was a mutation.
5.
Name at least 3 different types of asexual reproduction. Binary fission, sporulation, budding, vegetative
propagation, mitosis
6.
Describe (in detail) the structure of a chromosome throughout the life cycle of a cell. Use the following
terms: chromosome, nucleosome, double helix, coil, supercoil. A chromosome is usually not visible except as
a threadlike substance in the nucleus. A chromosome is a single strand of DNA, which is actually made up of
sugars, phosphate and nitrogenous bases (we will study these later). The way the DNA strands are joined
makes them look like a ladder, which is twisted into a double helix. This helix is coiled around histone
proteins to form nucleosomes (beadlike structures), then supercoiled to form a single chromosome molecule.
The chromosomes are only visible during prophase, metaphase and anaphase, three stages on mitosis
7.
Why is it NOT appropriate to refer to interphase as “the resting phase” of the cell cycle? Interphase is
actually the phase of the cycle where the cell spends most of its time. It is actually subdivided into 3 stages,
designated by what is going on with the cell at that time. G1 is the stage of interphase where the cell spends
most of its time, doing whatever its specialized job is (being a lung cell, liver cell, etc). When it receives a
signal to divide, in synthesizes (copies) all of its DNA, during what is referred to as the S stage of interphase.
G2 follows, a short period in which the cell prepares for mitosis. All in all, there is a lot happening, and if
there could be said to be ANY period of rest at all, it would be a very brief on following the synthesis of DNA
8.
What are the centrioles made of? What is their function in cell division. Centrioles are made up of
microtubules, and their function is to organize the spindle and ensure the chromosomes separate properly
during anaphase
9.
What is a centromere? The protein disk where two sister chromatids are joined after replication
10.
During which stage(s) of a cell’s life cycle would the chromosomes be visible? Prophase, metaphase and
anaphase. After they are separated, they begin their unraveling returning to the chromatin state
11.
How many chromosomes are in a diploid human cell? A haploid cell? Where in the human body would
we find haploid cells? A diploid human cell contains 46 chromosomes; a haploid cell contains 23, and would be
found only in the ovaries and testes
12.
Name 2 things that control when a cell divides? Proteins such as cyclins and growth factors, and the
surface area-to-volume ratio
13.
What is cancer? In which kind of organisms can it occur? Cancer cells are just regular cells that begin to
divide out of control, ignoring the signal in the DNA that tells it to stop dividing and start doing its job again.
Cancer can occur in any multicellular organism
14.
What happens after plant cell division that DOESN’T occur in animal cells? A new cell plate (wall) has to
form between the new daughter cells.
15.
Which is the longest stage of mitosis? Prophase, because there are so many things that are required
before the chromosomes can separate
16.
What are your views on stem cell research? Be able to recognize at least one definite benefit that could
result. Answers will vary, but obviously, you should put some thought into this! Use scientific arguments, not
“emotional” ones
17.
Differentiate between: chromatin, chromatid, chromosome. They are all the different forms that DNA
is found in, at various times in the cell’s life cycle. During most of it (in the G1 stage of interphase), it is
represented as chromatin, a thin and thread-like form. After the S stage when the DNA is replicated (during
prophase), the chromosomes begins to shorten and condense, and when they finally become visible, the
chromosome is now composed of two sister chromatids—one is the original, the other is an identical copy.
When they separate, they are now called chromosomes again, and are individual DNA molecules again, no
longer joined
18..
What is the function of the spindle? To organize the chromosomes at the cell’s equator during
metaphase and to make sure they separate properly during anaphase