Bell Work...Bell Work The photo above is supposeto depict mitosis/cell division however there might be something wrong in the picture. Do you think there is? If so, what is wrong in

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

© Kesler Science, LLC

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


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


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


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


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


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


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?


MitosisMitosis is also used for asexual reproduction:

1. budding2. vegetative

reproduction3. binary fission 4. fragmentation

(Examples: some types of jellyfish, worms, and plants)


Mitosis

• Four basic phases1. Prophase2. Metaphase3. Anaphase4. Telophase/Cytokinesis

By

Ali

Zifa

nCC B

Y-SA 4

.0 c

omm

ons.

wik

imed

ia.o

rg

• Occurs in a strict sequential order called the cell cycle

• Produces diploid cells (2) with the same genetic makeup as parent cell


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

By

Ali

Zifa

nCC B

Y-SA 4

.0 c

omm

ons.

wik

imed

ia.o

rg

nucleus

Where is the chromatin during

interphase?


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


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

By

Ali

Zifa

nC

C B

Y-SA 4

.0 c

omm

ons.

wik

imed

ia.o

rg

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


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


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

Documents

Bell Work...Bell Work The photo above is supposeto depict mitosis/cell division however there might be something wrong in the picture. Do you think there is? If so, what is wrong in