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with some of the latest science discoveries and inventions.
Times they are a changing - and science is the engine of that change.
I am in grade 10 science and we are almost finished the biology unit.
We have a big unit exam tomorrow and I need some help. In the animal
cell (not sure if it's in the plant cell or not) there is a thing called
the "centrosome" I was wondering if you could tell me what it's function
is in the cell. I have no idea, and probably should know.
Thanx a lot. Lesia
A centrosome is the system of microtubules and centrioles that pull the
pairs of chromosomes apart when plant and animan cells divide. The
centromere is a very important reason why all daughter cells have the same
chromosomes and genes as the parent cell.
Think of the difficulty in making cell division work perfectly each and
every time. You must figure out a way to duplicate, exactly, 5 feet of
DNA, wind it into chromosomes and last but not least, make sure that each
daughter cell gets one copy of each chromosome. The centromeres are
invaluable in that last step.
The centromere is usually somewhat near the middle of the chromosome,
although its exact position varies from chromosome to chromosome. Once you
complete the duplication of the DNA, the two identical DNA duplexes are
held together by the centromere. The DNA winds up into a chromosome that
has two 'sister chromotids' which are the two identical chromosomes. The
centrosome hooks up with the centromere, pulling the sister chromotids to
the center of the cell. The centromere duplicates itself and, finally, the
centrosome pulls the two sister centromeres apart and the chromatids (new
chromosomes) apart with it. The sisters move into different ends of the
cell and the cell pinches down in the middle to create the two new cells.
I hope this helps. Good luck. I just know you will do a great job on
Thanks for asking,
You have a great site with wonderful information. But I have a
question. I have to make a cell model and I was wondering what kind of
things that I can use to represent things in the cell like, cell membrane,
cytoplasm, nucleus, etc. It has to be things from our home and creative
and also different. Can you help me?
I can only pass on some ideas I have seen used by students such as yourself.
One young lady wrote that they had to make a model of a cell used things
that suggested the function of the cell part. For instance, a battery for a
I have seen kids use only pieces of candy that reflect the shape of the cell
part. Such as, a gum ball for the nucleus.
I have also seen models made of pasta and others of small toys, such as one
of those balls with the long, flexible rays of plastic (squish or kwish or
something ball) for the nucleus.
Here are some alternative ways to think of the functions of the various
organelles. These descriptions may lead you to think of some cell model that
is creative and new. Lets begin with the organelles (parts of the eukaryotic
cell) that both plant and animal cells have. Nucleus: brain or library.
Mitochondrion: battery or power plant. Golgi Apparatus: mail sorting room.
Granules: special equipment closet. All membranes: import/export customs
office. Endoplasmic Reticulum: kitchen or construction site. In plants only,
we have the Chloroplast: sugar factory or transformer and the vacuole:
Hope this is enough to get you started. I know you will come up with
my name is Phillip and I am in the sixth grade and I am doing a
project on fingerprints and I was wondering if you were cloned wouldn't your
clone have the same fingerprints as you?
Twins and triplets are natural clones of human beings. The fertilized egg
splits all the way in two by accident, when it divides. When you look at
human twin, you see that, although they have identical DNA sequences, there
are many things that are different. That is because not every detail about a
person is determined by their genes. For instance, the personality of two
twins is often very different. So, too, are their fingerprints. The DNA
determines that you will have fingerprints on the tips of your fingers, to
help with touch and picking up things. But the DNA does not determine
exactly what that pattern will be.
This is an excellent question to pose. You are obviously very bright and
could easily be a scientist when you grow up. Keep thinking and asking.
this page I was able to learn a lot more about Bacteria Cells. This page
also helped me in a small presentation on Bacteria Cells, and how to
describe them to the class so they would understand. Thanks a lot.
Thank you so much for
your kind e-mail. We are very pleased that our information on Bacterial
cells was of interest and of use to you. Science is full of fun stuff just
like that. Maybe some day you will discover something in science that school
kids the world over will have to learn about.
Enjoy your school year. And, again, thank you.
What are genes made of?
What an excellent question! Genes are made of DNA. A gene is small strand of
DNA. A long strand of many genes (like a necklace with many beads strung
together) is called a chromosome. DNA is made by linking many thousands of
'nucleotides' together to make a string of DNA. A nucleotide is made of
sugar, phosphate, and a base. These are all made of carbon, hydrogen,
oxygen, phosphate, and nitrogen atoms. This is all shown in the web pages:
Learn more! Google:
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