chapter four

CHAPTER FOURCHAPTER FOUR““CELL REPRODUCTION”CELL REPRODUCTION”

(p.96)(p.96)

- is also known as cell division

- or mitosis or fission.

Cell Reproduction

REASONS FOR MITOSISREASONS FOR MITOSIS

GrowthGrowth-adding cells to the body.-adding cells to the body.ReplaceReplace- worn-out or dying cells.worn-out or dying cells. Ex. Red blood cells (2-3 Ex. Red blood cells (2-3

million per second).million per second).RepairRepair- bruises and cuts.bruises and cuts.Reproduction *Reproduction *- one celled organisms.- one celled organisms.

------------------------------------------------Parent cell- the original cell.Daughter cells- the two new cells that are formed

Parent CellParent Cell

Daughter CellDaughter Cell

Mitosis

New cells must have the same number of chromosomes. The DNA must be duplicated.

Humans: 46Fruit Flies: 8Cat: 32Potato and Chimp: 48

- a type of cell division which produces daughter cells exactly like the parent.

MITOSIS is a series of changes MITOSIS is a series of changes or phasesor phases

1) 1) INTERPHASEINTERPHASE

WHEN THE CELL IS NOT DUPLICATING.

NORMAL CELL ACTIVITIES.

MOST OF A CELL’S LIFE IS SPENT IN INTERPHASE.

Time spent in the Cell Time spent in the Cell CycleCycle

Growth andDNA Synthesis

Growth andPreparation forDivison

Mitosis

Rapid Growth

10 hours

4 hours

2 hours

4 hours

2) 2) PROPHASEPROPHASE- - first first realreal stage of stage of mitosis. mitosis.

Nucleus breaks Nucleus breaks apart.apart.

-nuclear -nuclear membrane membrane disadisappppearsears

Tube-like Tube-like structures called structures called spindle fibersspindle fibers aappppear and attach ear and attach to the centrioles.to the centrioles.

3) 3) METAPHASEMETAPHASE

Spindle fibers Spindle fibers attach to the attach to the chromosome at chromosome at their middle their middle point.point.

- called a - called a centromerecentromere..

4) 4) ANAPHASEANAPHASE

Centrioles and Centrioles and spindle fibers pull spindle fibers pull aapart the part the chromosomes to chromosomes to opposite sides of opposite sides of the cell.the cell.

5) 5) TELOPHASETELOPHASE Centriole and Centriole and

spindle fibers spindle fibers disappear.disappear.

Nucleus reforms.Nucleus reforms. Chromosomes have Chromosomes have

duplicated.duplicated. Cell membrane Cell membrane

pinches in to form pinches in to form two daughter cells.two daughter cells.

After telophase, cells enter After telophase, cells enter interphase again.interphase again.

INTERPHASE

PROPHASE

METAPHASE

ANAPHASE

TELOPHASE

IDENTIFY THIS STAGE IDENTIFY THIS STAGE OF MITOSIS OF MITOSIS

INTERPHASE

IDENTIFY THIS STAGE IDENTIFY THIS STAGE OF MITOSISOF MITOSIS

METAPHASE

IDENTIFY THIS STAGE IDENTIFY THIS STAGE OF MITOSISOF MITOSIS

IT’S A TOUGH ONE….

PROPHASE

IDENTIFY THIS STAGE IDENTIFY THIS STAGE OF MITOSISOF MITOSIS

ANAPHASE

IDENTIFY THIS STAGE IDENTIFY THIS STAGE OF MITOSISOF MITOSIS

TELOPHASE

In plants, a new cell wall - called a cell plate - forms between the daughter cells.

ASSIGNMENT:WORKSHEET “MITOSIS”

DNA - “deoxyribonucleic acid”

- a chemical which makes up the chromosomes.

- Key to heredity.- Duplicated during

mitosis.

It’s structure and how it works was a mystery until 1952.

James Watson and Francis Crick-proved the shape/structure of DNA was a double helix. (twisted ladder) p.111

The DNA molecule is made of four chemicals put into a certain order.

- the sequence forms the hereditary code.

- it controls eye color, height, allergies, etc.

Base pairs

Guanine --- Cytosine

Adenine --- Thymine

A section of the chromosome called a gene determines traits.

Ex. blonde hair, blue eyes, etc

DNA is duplicated during mitosis

- called replication.- sometimes an error

occurs (caused by pollution or x-rays) called a mutation.

- a permanent change in the gene.

- most are harmful.

ex. deformed frogs in Minnesota.

DNA ResearchRecombinant DNA- new DNA created

when DNA from one organism is combined with another organism.

- also called “gene splicing”.

This has created “new” organisms.

1. oil eating bacteria.

2. Disease resistant potatoes.

3. Insulin producing bacteria.

4. “Round-up ready” corn

What if we could replace the DNA strand which causes

cancer?

Many are against DNA research. We could create a very deadly disease.

Cloning

- a clone is genetically identical to its parent.

- The DNA comes from one parent - not two.

- Good? Bad?

Dolly 1996 -2003

ASSIGNMENT:

WORKSHEET “DNA”

CLASSIFICATION (P. 22-26)

- methods of grouping things according to similarities or differences.

Ex. by size, color, age, etc.

Classifying organisms is called taxonomy.- started by Aristotle

in 350 BC.

Many disagreements about the groupings:

-by air?

-by sea?

-by land?Where to put frogs? Geese?

Today’s system is called binomial nomenclature (two-name naming)

Ex. Canis lupus- created by

Carolus Linnaeus.

Ex. Canis familiaris

Latin was used by scientists and scholars in the 1700’s.

- used today to avoid the confusion of using many different languages.

Ex. Spanish moss- not Spanish- not moss

The Latin names are an organism’s genus species.

Canis familiaris

Genus grouping Species grouping

Always capitalized

Always lower case.

Most precise

“smallest”

Can produce offspring

Both italicized

Other examples:

Felis domesticus

Acer rubrum ‘red maple’

Homo sapiens sapiens

Bison bison

ASSIGNMENT:

READ PAGES 22 - 26.

CLASSIFICATION CATEGORIES

- there are seven different levels of scientific classifications.

- it becomes more exact/specific as you “move down”.

Ex. Bottlenose Dolphin

Tursiops truncatus

Kingdom Animal

Phylum Chordate

Class Mammal

Order Cetacea

Family Delphinadae

Genus Tursiops

Species truncatus

King Phillip cried out for goodness sake

Six Kingdom Classification

1) Kingdom Animal

- are multicellular.

- can move from place to place.

- cannot make their own food.

2) Kingdom Plant

- make their own food through photosynthesis.

- can be large (redwoods) or unicellular (plankton)

3) Kingdom Fungi

-can not move.

- can not make their own food.

- absorb food from dead material.

Ex. mushrooms, mold, yeast.

4) Kingdom Protist

-are unicellular.

- have traits of both plants and animals.

Ex. Euglena

- can move but it has chloroplasts.

5) Kingdom Eubacteria

Ex. strep.

6) Kingdom Archebacteria

Ex. stromatolites-both are prokaryotic.

- unicellular.

- Archebacteria are ‘older’ and more primitive and can live in harsh conditions.

The difference between them is their chemical make-up.

These kingdoms were formed when Kingdom Monera was split into two.

ASSIGNMENT:

WORKSHEET“CLASSIFICATION”

Asexual ReproductionAsexual Reproduction

New organisms are produced from one parent.New organisms are produced from one parent. DNA is identical to parent.DNA is identical to parent. ExamplesExamples

Potato from tuberPotato from tuber Strawberries from runnersStrawberries from runners Fission: one celled organism divides to form 2Fission: one celled organism divides to form 2 Budding: new organisms grow from one parent Budding: new organisms grow from one parent

(Hydras)(Hydras) Regeneration: grow back missing partsRegeneration: grow back missing parts

More organism grow from parts of one organismMore organism grow from parts of one organism Sponges, planaria, sea starsSponges, planaria, sea stars

DNADNA(DEOXYRIBONUCLEIC ACID)(DEOXYRIBONUCLEIC ACID)

The structure of DNA was discovered byWatson and Crick

The shape of DNA is called a Double Helix

DNA IS MADE UP OFDNA IS MADE UP OF BASE PAIRS BASE PAIRS

GUANINE - CYTOSINE

THYMINE - ADENINE

AN ORGANISM WHICH AN ORGANISM WHICH RECEIVES DNA FROM ONLY RECEIVES DNA FROM ONLY ONE PARENT IS CALLED AONE PARENT IS CALLED A

CLONE.CLONE.