Cell Divison + ASR Unit 7

A regular pattern of ______, _____ _________, and cell division

• growth

• DNA duplication

The cell cycle is mostly composed of ______, which included _ parts

• interphase

• 3

interphase consists of:

• gap 1 (G1)

• Synthesis (S)

• Gap 2 (G2)

After finishing interphase the cell enters into _____

Mitosis

• cell grows and organelles replicate (make copies of themselves)

• Includes a CHECKPOINT

Gap 1 (G1)

cell makes a copy of its DNA

Synthesis (S)

• cell grows some more

• Includes another CHECKPOINT

Gap 2 (G2)

After interphase, a cell then enters into _____, and finally ends with _________

• mitosis

• Cytokinesis

division of the nucleus

Mitosis

division of the cytoplasm (the whole thing)

Cytokinesis

What is the result of cytokinesis and mitosis?

Two “daughter” cells that are genetically identical to the original cell

What is the order of cell division

• interphase

• Mitosis

• Cytokinesis

The S, G2, and Mitosis stages take about __ _____

12 hours

The __ _____ can be anywhere from a few hours, to years and years - it all depends on the ____ _____

• G1 stage

• Cell type

The amount of time a cell lives is dependent on how much “_____ __ _____” we put on them.

“wear and tear”

skin cell approximate life span:

2 weeks

Red blood cell approximate life span:

4 months

Liver cell approximate life span:

1 year

Intestines approximate life span:

5 days

White blood cells approximate life span:

10 hours

Brain cells approximate life span:

Whole life

Heart cells approximate life span:

Whole life

Cells must remain the perfect ____ to function

ex: surface area to _____ ratio

• size

• Volume

What would happen in your heart was too small or too big?

Many things could happen because your cells have to be a perfect size from surface to volume ratio

A long thread of DNA that holds all of your bodies genes

Chromosome

Your body cells each have __ chromosomes

46

If you laid the DNA from just one cell out in a straight line, it would measure __ ____ long

10 feet

During interphase, chromosomes are in a form known as _____

Chromatin (tangled DNA)

During the S phase, chromosomes replicate, forming what?

Chromatids (identical sides)

Chromatids joined by a ______ (center of the chromosome)

Centromere

During interphase, the cell ____ its DNA and grows ______

• copies

• Larger

By the end of interphase, the cell has ___ sets of chromosomes (DNA) and is large enough to _____

• two

• Divide

Mitosis divides the nucleus into two ______ _____

Identical nuclei

What happens in prophase?

• centriole forms: like a magnet that pulls chromosomes apart

• Mitotic spindle stretches out from centriole

• Nuclear envelope breaks down

What happens in metaphase

Chromosomes line up in the MIDDLE of the cell

What happens in Anaphase?

• chromatids separate

• Chromatids are pulled APART toward opposite ends

What happens in telophase?

• a complete set of identical nuclei are at each end of the cell

• Nuclear envelope reforms

What happens during cytokinesis?

• cytoplasm divides into two identical cells

• Cell cycle starts all over again

Cancer is when what happens?

Cells divide at an uncontrollable rate

Cancer cells divide much quicker than healthy cells

An unorganized clump of cancer cells

Tumor

Cells cells are bad because they don't work properly including what?

• they take away food, energy, and oxygen from the good cells

• They take up too much space, so there is no room for the good cells to divide

What is the benign tumor?

• cells stay close together

• Usually not as harmful

• The tumor can usually be cured by removing it

What is the malignant tumor?

• always harmful - some of the tumor breaks away (metasizes)

• These break-away pieces are then carries through the bloodstream to other parts of the body where they will form new tumors

What is a way of cancer treatment?

• if possible the ideal way to remove tumors is through surgery

• This may not always he possible however if the tumor has already started spreading

What is the radiation cancer treatment?

• localized - given directly to the cancer cells

• Kills cancer cells and shrinks tumors

• Damages the cell’s DNA so that it can not divide

What is the chemotherapy cancer treatment?

• systemic - given to the entire body

• Kills both healthy cells and cancer cells

• Given through an IV (intravenous needle)

Many times cancer is a combination of what?

The three methods

What is the pituitary gland?

• a pea-sized gland attached to the brain

• It is important in controlling growth and development

The pituitary gland really kicks in during growth spurts and releases something called what?

“The growth hormone” - should stop being produced after puberty

What is acromegaly?

• gigantism

• The pituitary gland released the growth hormone continually

• Results in a growth spurt that never ends

Who is the tallest woman and man?

• Yao Defen (1972-2008ish) - 7’9” when she died

• Robert Wallow (1918-1940) - 8’11” when he died

What is primordial dwarfism?

• the pituitary gland fails to release growth hormone

• Result is abnormal growth - never getting bigger

In the case of primordial dwarfism, all body parts are like what?

• proportional but really small

In the more common form of dwarfism, the head and torso are normal size bur the limbs are what?

• short

• unproportional

Who is the world’s shortest person?

He PingPing (1988-2010) - 2’1”

In mitosis the nucleus divides. Would that be eukaryotic or prokaryotic cell?

Eukaryotic- cells with a nucleus

The process of cell division in prokaryotic cells is called this

Binary fission

when a cell just grows and grows and then is pinched in half

Binary fission

Do binary fission and mitosis both end the same way?

Yes - “daughter calls” (offspring) that are genetically identical to the parent cell

two organisms

Sexual reproduction

Asexual reproduction

One organism

what would mitosis snd binary fission be? A or S

Asexual

Sexual reproduction results in diversity meaning what?

Some genes from mom and some from dad

Asexual reproduction results in exact ____ or clones of ___ parent

• copies

• One

sometimes asexual reproduction can be ____ but sometimes ___

• good

• Bad

what are advantages of asexual reproduction?

• a large number of offspring are produces very quickly

  fun fact: Bacteria cells can make over 1000 new bacteria cells in only 10 hours

What is another advantage for AS reproduction?

• all offspring can have offspring - in humans, only females can have babies and that is only if they find a mate

What is the disadvantages of AS reproduction?

• if the environment is changing, the offspring may not be able to adapt

  • If everyone had the same traits as me, how might that be a disadvantage if the ozone layer continues to deplete?

The more genetic diversity there is what?

The better we are able to adapt and survive

Regeneration

• Growing back missing body parts

  • ex: regenerating a limb

What is the process of cell division?

Mitosis

What is coiled up DNA called?

Chromatin

What does the nuclear envelope do?

It keeps the chromatin from entering the cytoplasm

How many daughter cells are made during mitosis?

2 daughter cells

Which to processes are involved in mitotic cells division?

Nuclear duplication and cytoplasmic division

How many chromosomes will be found in each of the two new cells formed as a result of mitotic cell division?

The same number of chromosomes as the parent cell

List the order of the phases of mitosis from left to right by letter:

First:

____; then:

_______; then:

_________, and last:

_________

A. attachment of double stranded chromosomes to the spindle apparatus

B. formation of single stranded chromosomes, which are moved to the opposite ends of the

cell

C. disintegration of the nuclear membrane

D. nuclear membrane formation around each set of chromosomes, forming 2 nucle

C, A, B, D

What is the main function of

the centromere during

metaphase?

The centromere is the site where the spindle fobers attach to the chromosomes

What is the significance of the chromosomes lining up in the middle of the cell during metaphase?

It ensures that each daughter cell receives a complete set of chromosomes

What happens to the sister chromatids during anaphase?

They are pulled apart and move to opposite poles of the cell

During which phase of the cell cycle does DNA replication occur?

Synthesis (S phase)

What is the role of checkpoints during mitosis?

To make sure everything is going smoothly before moving on to the next phase