bell work...bell work the photo above is supposeto depict mitosis/cell division however there might...
TRANSCRIPT
Vers. 07/2020 © Kesler Science, LLC
Bell Work
The photo above is suppose to depict mitosis/cell division however there might be something wrong in the picture. Do you think there
is? If so, what is wrong in this picture? If there is nothing wrong then can you explain how it is correct?
** Take a GUESS, you do not need to know anything about this to create a possible answer.
Vers. 07/2020 © Kesler Science, LLC
Exploration... (will be turned in)1. Put the images below in the order you think it correct. 2. Between each image explain WHY they should go before/after one another
A B C D E
3. Now, describe what would happen to the rest of the images if you removed the second cell in the order you created
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Mitosis and MeiosisVocabulary cell: Smallest structural and functional unit of an
organism. Our bodies are made of them.cell division: How cells reproduce by splitting apart
somatic cell: All cells in the body, except for germ cellsmitosis: The way in which somatic cells divide
germ cell: Only found in the ovaries and testes (reproductive organs)
meiosis: The ways in which germ cells divide
Type of Cell: somatic germ
Divides by: mitosis meiosis I&II
# of Chromosomes:
46 (in humans) 23
Location in body:
Found all over the
body
Reproductive system
(testes and ovaries)
What is a cell?
Differences in Cell Division
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Mitosis and MeiosisVocabulary
chromatin – unwound DNA found in the nucleus
chromosome – tightly packed DNA, found onlyduring cell division. Can be seen with a microscope
What is the difference between chromatin and chromosomes? chromatin chromosome
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Mitosis and Meiosis Vocabulary
chromatid – each of two thread-like strands into which a chromosome divides during mitosis
sister chromatids –two identical copies of a chromatid
centromere – a structure in a chromosome that holds the two chromatids together
What does a centromere hold
together?
Image by bioninja: Cornell, B. 2016. http://ib.bioninja.com.au
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Mitosis and MeiosisVocabulary
spindle fibers – controls the movement and separation of chromosomes during division
centriole – helps in the formation of spindle fibers
nuclear envelope – a membrane that separates the nucleus from the cytoplasm in eukaryotic cells
centrioles
nuclear envelope is breaking down spindle fibers
nuclear envelope is broken down
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MitosisSomatic cells
• Any cells that are not germ cells
• Contains 46 chromosomes in humans
• Divides by mitosis• Found throughout the body:
Blood vesselsBlood cellsBone MarrowBrainMusclesSkinTeethIntestines and other internal organs
Image credits: commons.wikimedia.org: Cardiac muscle by OpenStax College -Anatomy & Physiology, Connexionshttp://cnx.org/content/col11496/1.6/, Jun 19, 2013., CC BY 3.0 Spinal Cord motor neuron and red blood cells by Fayette A Reynolds M.S, Berkshire Community College Bioscience Image Library
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Mitosis
Credits: David O Morgan-The Cell Cycle. Principles of Control. commons.wikimedia.org. TheAlphaWolf - CC BY-SA 3.0, commons.wikimedia.org
Stages of early mitosis in a vertebrate cell with micrographs of chromatids
Cell Division by MitosisMitosis in somatic cells results in two cells exactly the same as the parent cellThe two new cells are diploid cellsMitosis involves one “set” of division stages
Mitosis results in diploid (2) cells
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MitosisMitosis creates new cells for growth and repair.
This image shows a recent cell division and the resulting two daughter cells, including two nuclei and unwinding chromosomes.
After a cell goes through mitosis, how many cells are there?
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MitosisMitosis is also used for asexual reproduction:
1. budding2. vegetative
reproduction3. binary fission 4. fragmentation
(Examples: some types of jellyfish, worms, and plants)
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Mitosis
• Four basic phases1. Prophase2. Metaphase3. Anaphase4. Telophase/Cytokinesis
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• Occurs in a strict sequential order called the cell cycle
• Produces diploid cells (2) with the same genetic makeup as parent cell
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Mitosis InterphaseOccurs between mitosis cycles• Chromatin is unwound • The cell grows in
preparation for cell division
• Note the position of the centrioles
• Just before mitosis starts, single chromosomes replicate to make a pair of long, stringy sister chromatids
centrioles
unwound chromatin
nucleolus
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nucleus
Where is the chromatin during
interphase?
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MitosisProphaseFirst phase of mitosis • Chromosomes condense and
become visible through a microscope
• Spindles begin to form• The nuclear membrane
breaks down• Centrioles begin moving
toward the poles
The nuclear membrane breaks apart to allow the contents to be used in mitosis. What is stored
in the nucleus? chromosomes
spindles
nuclear membrane
centrioles
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MitosisMetaphase Second phase of mitosis• The chromosomes, guided by the spindle
(microtubule) fibers, line up in the middle of the dividing cell
• The centrosomes are at opposite ends (spindle poles) of the cell
centrosome
spindle fibers
chromosomes
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centrosome - an organelle near the nucleus of a cell that contains the centrioles (in animal cells) and from which the spindle fibers develop in cell division
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MitosisAnaphaseThird phase of mitosis• The two sister chromatids of each chromosome are
pulled apart by the spindle fibers• Chromatids move away from each other toward the
poles; now each one is called a chromosome• The cell elongates so that the poles are farther
apart
Why does the cell get longer during anaphase??
chromosomes
spindle fibers
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MitosisTelophase (and cytokinesis)
The last phase of mitosis• The chromosomes have reached
the poles and begin to unwind• Two new nuclear envelopes form
around each of the two separated sets of chromosomes (forming two nuclei in one cell)
cleavage furrow at midbody
new nuclear envelopes forming
By Ali Zifan CC BY-SA 4.0 commons.wikimedia.org
Fluorescent scan of final stage of mitosis
• The cleavage furrow begins separating the cytoplasm into two cells, each with a nucleus (this is cytokinesis)
• When complete, the cell has divided into two daughter cells exactly like the parent cell