[Exercise 1-6] (COMPILATION)

8/20/2019 [Exercise 1-6] (COMPILATION)

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Frisco_Bio22Lab_0809Summer

BIOLOGY 22POST-LABORATORY DISCUSSION

Ms. Heidie L. Frisco

21 April 2009

(1st Departmental Exam)


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Exercise 4:

Cell Division Mitosis

Objectives:

1. Define and differentiate the two types of cellular

reproduction/division: mitosis and meiosis2. Describe the different phases of the cell cycle and

the importance of each phase in the life of a

dividing cell

3. Enumerate the different stages of mitosis anddescribe in detail the events that occur in each

stage, with emphasis on the events that occur in

the nucleus, such as chromosome condensation,

duplication, and separation


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Cells are diverse.


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Cells are diverse.


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Cells have different life spans and life cycles.

The Young and Restless

• Skin cells live for about a month.Thus, they must be replaced.

• If you get a cut, new cells are

needed for the wound to heal.

• If you fracture your leg, new cells

in the bone will be needed torepair the injury.

The Wise and Mature

• You are born with most of the

brain cells that you will everhave.

• Woman are born with all of the

eggs cells that they will ever

carry.


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Cells have different life spans and life cycles.

The Young and Restless

• Skin cells live for about a month.Thus, they must be replaced.

• If you get a cut, new cells are

needed for the wound to heal.

• If you fracture your leg, new cells

in the bone will be needed torepair the injury.

The Wise and Mature

• Your brain cells are not

replicating at the same ratethroughout your life, so hold on to

what you’ve got.

• Woman are born with all of the

eggs cells that they will ever

carry.

The Cellular Life Cycle

Cell is

doing it’s job

Cell is dividing

to generate

new cells.


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Mitosis• Makes an exact copy of a cell through cell division.

• The new cells (daughter cells), have the sameamount of DNA as the old (mother) cell.

• This occurs all over your body.

Meiosis

• Creates cell with only half the amount of DNA

• Why would you want to do this?

There are two types of cell division.


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The Human life cycle requires both mitosis and meiosis.

SexualReproduction

Development

And Growth

Fusion of egg

and spermrestores the

number of

chromosomes.

MEIOSIS FERTILIZATION

Egg cell

Sperm cell

diploid (2n)

haploid (n)

Figure 8.13

Lots of MITOSIS


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Mitosis to form a human skin cell (for example).

• A skin cell with 46 chromosomes divides, producing twocells that each still have 46 chromosomes.

• These cells are said to be diploid (they have the normalnumber of chromosomes).

Meiosis to form a human egg or sperm.

• A cell with 46 chromosome divides in such a way as toproduce an egg or sperm with 23 chromosomes.

• These eggs and sperm are said to be haploid (they havehalf the normal of number of chromosomes.

There are two types of cell replication in the

normal human life cycle.


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Interphase

The cell is doing its

normal activities and, for

a time (S), uses energyto replicate its DNA.

The Mitotic Phase

Over several stages, the

cell divides.



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The Mitotic Phase

Over several stages, the

cell divides.


Figure 8.1A


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Figure 8.1A

The goal of Mitosis is two make two cells

that are diploid (each has two copies of

every chromosome) and that have all the

organelles to function.


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The S phase

In order for each cell

to have the same

DNA, the DNA must

replicate.



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All of the chromosomes replicate.

Each of the original

chromosomes is

attached to its copy atthe centromere. The

two identical

chromsomes are called

sister chromatids.


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Mitotic Phase (M)

Once the cell has two

copies of all the

chromosomes, then it

can divide. This

occurs in specific

stages.



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Prophase and PrometaphaseMetaphase

Anaphase

Telophase and Cytokinesis

One blends into another.

The Stages of the Mitotic Phase


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Prophase and Prometaphase• The DNA compacts (supercoils).

• Duplicated centrosomes head to each pole and spindles begin to

form.

• The nuclear membrane and nucleolus breakdown.



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Metaphase• The spindle fibers attached to the duplicated chromsomes and drag

them to the center of the cell (the equator).



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Anaphase• The sister chromatids separate and are pulled to opposite sides of the

cell as the spindles shorten. Each side now has the exact same set of

chromosomes.



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Telophase and Cytokinesis• New nuclear membranes and nucleoli form around the two sets of

chromosomes.

• The cytoplasm begins to divide and the cells pinch off into two.



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During all ofinterphase, the cell

looks like what we

are used to seeing.The DNA is in the

nucleus. There is a

clear boundarybetween the nucleus

and the cytoplasm.

After the mitotic phase, the cell reenters

interphase.


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Animal Vs. Plant Mitosis

CRITERIA ANIMAL PLANT


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Exercise 5:

TissuesObjectives:

1. Define tissues.

2. Differentiate the 5 principal kinds of tissue and their

respective functions.3. Describe the main types of epithelial tissue andlocate those in the body.

4. Describe the main types of connective tissue andgive their functions.

5. Compare the 3 types of muscle tissue and theirfunctions

6. Give the function of nervous tissue and distinguishbetween neurons and glial cells.

7. Describe the 2 reproductive tissues and their

functions


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[Exercise 1-6] (COMPILATION)

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