Download - 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.