Science9 5.0

-How much percent of skin cells makes up the dustball? -Each day, you shed how many skin cells per hour? -When do you completely replace the outer layer of your skin?

-70% -Millions of skin cells -Each month, you completely replace the epidermis(outermost layer of skin)

Grafting's advantage

-Help the scion benefit from a more vigorous root system -Produces fruit within two to three years(trees grown from seeds take 5-10 yrs) -Can control the eventual size of plants

Why is human assisted cloning important?

-It can be used to save the genetic info of endangered animal species or to mass produce an organism with a desired trait -Pigs are cloned so that their organs can be used for human transplants

Advantages of asexual reproduction

-Large number of offspring are produced very quickly from only one parent when conditions are favourable -Energy is not required to find a mate -Large colonies can form, out competing other organisms for nutrients and water -Large number of organisms mean that species may survie when conditions or predators change

Vegetative reproduction

-Many plants reproduce this way. -Occurs when special cells in plant stems and plant roots divide repeatedly to form structures that will develop into a plant identical to the parent. -The plant BREAKS OFF

Disadvantages of asexual reproduction

-Offspring are genetic clones. Negative mutation can make organism susceptible to disease and destroy large number of offspring -Offspring are close together are fight for resources -Unfavourable conditions can wipe our entire colonies

Amoeba

-One celled, small, eukaryotic. -Has between 30-40 chromosomes. Some have hundreds.

Benefits to humans of vegetative reproduction ~ Human interference and its benefits

-Potatoes are the number one tuber crop in the world -Common camas provide a staple, starchy food for First Nations. ~ -Plants can reproduce at great distances with no competition -Plants can be introduced to areas you want the plant to grow

Binary fission

-Similar to mitosis, yet only occurs in single celled organisms. -A single parent cell replicates its genetic material and divide into two equal parts. -The chromosomes must be replicated and attached to the spindle fibres in mitosis to ensure that the exact number of chromosmes end up in the daughter cells.

Examples of checkpoints

-Stop!Some of the chromosomes have not attached themselves to spindle fibres in metaphase! Some of the chromosomes have not moved to the poles in anaphase. The cell must be repaired or destroyed! -Stop! The DNA is damaged. The cell must be destroyed!

What does cancer researchers do?

-Study how cancer disrupts the cell cycle -Look for mutated genes that produce the cancer -Identify treatments

When will the cell NOT divide?

-There are not enough nutrients to support cell growth -DNA is damaged -DNA within the nucleus has not been replicated.

Reproductive cloning

-a.k.a adult DNA cloning -Purpose: To produce a genetic duplicate with desirable qualities. Ex. A cow that produces lots of milk.

Lifespan of red blood cells

120 days

Lifespan of skin cells

20 days

Lifespan of stomach lining cells

20 days

If the environmental conditions are good, a baterium can reproduce every ________ by _______

20 minutes;binary fission

Lifespan of liver cells

200 days

Lifespan of intestinal lining cells

3 days

Lifespan of brain cells

30-50 years

Every minute your body produces ______ new cells

300 million

How many cells are in ones body?

50-100 million trillion

Dolly

A cloned sheep. She only lived for six years and dyed of a lung disease common in sheep. Before she died, she aged faster than normal

Clone bank

A collection of clones that make up the genome of a species. Clone banks enable biologists to preserve genetic info and conduct research.

Grafting-Budding

A scion bud is removed and placed in a slit in a rooted stock. It is used to grow apple trees

Cutting

A section of stem, root, or leaf is removed and then planted in a special growing medium. More than 45 different types of house plants such as African violet can be reproduced by this method. Plant hormones are often applied to the cut stem, which simulates cell division and growth, and makes the cutting grow roots

How does a tumor form? What does it cause?

A tumor forms when cancer cells divide uncontrollabl. Nearby blood vessels provide nutrients for the tumour and carry cancer cells to new locations, thus spreading cancer.

Examples of binary fission

ALL PROKARYOTES, and some organelles within eukaryotes(ex. mitochondria) and some eukaryotes. Amoeba, bacteria, blue-green algae, paramecium

Result of cancer---produces abnormal cells. How are they abnormal?

Abnormal in size, shape, or non-functional

Interphase:Continued growth and preparation

After DNA replicates, the cell continues to grow and makes proteins for the daughter cells that will be formed after cytokinesis. Organelles such as mitochondria and chloroplasts will be duplicated.

Artificial clones are made in:

Agricultural or horticultural industries and biomedical laboratories.

Why is it important for amoeba and many other one celled organisms to reproduce asexually?

Amoeba and those organismas are part of the food chain for more complex, multicellular organisms. In order to survive, they must produce in large numbers.

Difference between animal cell and plant cell during prophase

Animal cell: Has centrosome which contaisn centrioles Plant cell: No centriole, but spindle fibres still appear

What is grafting often used to produce?

Apple trees and rose plants.

Eurasian milfoil

Aquatic weed that is not native to North America and accidentally introduced by boat propellers that trasnport plant fragments into BC. It causes great harm to lake ecosystems.

Budding

Areas of an individual undergoes repeated mitosis and cell division, developing into an outgrowth. The bud may stay attached or detach and become a new individual. The bud is smaller than its parent

Why does cancer cells have large, abnormal nuclei?

Because cell division checkpoints doesn't function and chromosomes don't divide correctly.

How can some multicelluar organisms reproduce by budding?

Because they (ex:Hydra and sponge) only have a few different cell types.

Why do bioengineers clone animals and plants?

Because they want to improve livestock breeds and improve plant production.

The methods of asexual reproduction becomes more and more complex. List them in the order of least to greatest.

Binary fission, budding, fragmentation, vegetative reporoduction and spore formation

What are the five types of asexual reproduction?

Binary fission, budding, fragmentation, vegetative reproduction, and spore formation.

For some type of bacteria, _____ is the only method of reproduction

Binary fission: Bacteria don't have nucleus n do not undergo mitosis. Only the ring of DNA replicates.

Mutagens

Can cause mutations in a cell and may harm the organism. Includes viruses, X rays, ultraviolet light, and chemicals. Can cause change in base sequence in a gene

How do cancer cells spread?

Cancer cells release chemicals to attract small nearby blood vessels. Blood vessels branch into the tumor and deliver nutrients which feed the growing tumor, making it divde more rapidly. If some tumor cells break away and are carried by the blood vessel to a new location, they might divide and form a new tumor.

Interphase:Growth and Preparation

Cell increases in size and makes the proteins n molecuoles necessary for functioning. Some organelles begin to duplicate

What evidence does researcher has regarding checkpoints and cancer?

Certain types of inherited colon cancer and breast cancer is linked with gene mutations in checkpoint proteins.

What is cell division controlled by?

Checkpoints, or specialized proteins in the nucleus

How do humans participate in vegetative reproduction

Cuttings and grafts

Interphase:Replication

DNA copies the 3 million base pairs of DNA info: DNA unwinds the steps of the ladder and two new sides form based on the two old sides.

Why is bacteria very resistant to antibiotics?

DNA inside bacteria mutates too quickly.

Sister chromatids

DNA molecuoles that were replicated during Interphase join together to form sister chromatids of a chromosome.

When does the nucleolus and nuclear membrane disappear and reappear?

Disappear---prophase; reappear---telophase

When does the cell temporarily has two copies of DNA?

During Interphase, when DNA finishes replication.

What controlls the process of DNA replication?

Enzymes. They help to unzip the DNA ladder

T/F:During Interphase, a cell triples everything in its cytoplasm

False: The cell DOUBLES everything in its cytoplasm

Grafting

For plants that cannot grow root from cuttings, parts of a desirable plant is removed and attached to another plant Stems called scions are attached to the rooted stock of a similar plant species.

B.Taitanus-Found in Africa

Hatchlings are born with specialized teeth for eating mother's skin(up to four weeks) -Special teeth---spoon shaped for scraping, spiked for piercing, and grapple hook for staying attched to mother.

Sea star

If one of its arms break off(has to contain a central piece), if it contains enough genetic info, it can develop into another sea star. They have an impact on the shellfish industry because they feed on oyster and clams.

When does chromosomes become visible under a microscope?

In Early prophase, when chromosomes coil up into X-shape.

When, during the cell cycle, is the chromatin in its loosely coiled form? Why?

In the Interphase stage, after DNA replicates. In its loosely coiled form, DNA can be copied into RNA so that proteins can be made in preparation for cell division.

How are burn victims treated?

Individual skin cells are cloned to grow new tissue for burn victims.

What are the three stages in the cell cycle?

Interphase, Mitosis(which includes 4 stages) and Cytokinesis.

How does a cell divide uncontrollably? What is the name of the disease that results from uncontrolled cell division?

It happens when a mutation occurs in a gene producing the instructions for a checkpoint protein. Cancer.

In order for a cell to become cancerous it must...

It must have several mutations in its checkpoint proteins. This explains why the risk of cancer increases as you get older.

Why is budding advantageous?

It's advantageous to animals such as sponges because they attach to rocks and move very little. Colonies can be maintained in the same place, and new ones can be established when buds break away.

Centromere

Joins the sister chromatids together.

Aspen trees

Most widely distributed trees in North America. Many of these trees grow in multistemmed groups of clones.

Which two cells usually do not continue to divide in an adult?

Nerve cells and muscle cells, though they do continue to carry out functions necessary for survival.

Disadvantage of vegetative reproduction

New plant will grow very close to each other and the parent. This leads to competition for soil, nutrients and light.

Are cancer cells specialized?

No. They do not function as part of your body. A cancer cell formed in the lungs does not make the proteins for a lung cell and thus does not function as a lung cell.

Telophase

One complete set of chromosmes is now at each pole of the cell. Spindle fibres begin to disappear and nuclear membrane forms around the chromosomes. Nucleolus reappears and now there are two nuclei in one cell. The cell is ready to divide. Chromosmes begin to uncoil and go back to chromatin

What is the problem with Reproductive cloning?

Only 10 percent of the clones survive, and the survivers can be abnormally large and have higher rates of infection and cancer. Requires chemicals n electricity Cells are exposed to mutagens in the process

Why is precise control of the cell cycle important to an organism?

Otherwise, cancer will form

Early Prophase

Part of Mitosis: -Replicated chromosomes coil up into an X-shape. Nucleolus disappear and nuclear membrane starts to break down. -Spindle fibres(tiny, tube-like n made of protein) begin to form. They stretch across the cells that are moving towards opposite poles of the cell. -Centrioles organize the spindle fibres and begin to move apart(only in animal cells)

Marine algae

Reproduce by binary fission, cause red tide and paralytic shellfish poisoning

Spores

Reproductive cells that have a nucleus and cytoplasm

Cytokinesis-summary

SEPERATES the two nuclei and cell contents into two daughter cells

Examples of fragmentation

Sea star,Eurasian milfoil,lobster,crayfish,(human cell, hair, nail, skin)

Cytokinesis

Seperates the two nuclei into two daughter cells. Animal cell: Cell membrane pinches together to divide the cell's cytoplasm and organelles Plant cell: Cell plate(contains material to form a cell wall and membrane) forms along the center of the cell to divide the cell.

Snakes

Shed their skin, occurs several times a year and each shed takes several days

Spore formation

Single celled reproductive cell called spore is formed. It grows into a new individual by mitosis. Spores are very light and rely on water or wind to carry them away. They have a tough outer coating that allows them to survive until conditions become favorable If conditions are suitable----moisture, temperature, food source, a new individual will grow

-What makes up most of the grey dust ball in your house?

Skin cells.

Examples of spore formation

Some bacteria, penicillium, micro-organisms, and fungi such as bread mould and puffballs, some plants such as mosses and ferns

Inherited cnacer

Some forms can be inherited. E.g. breast, ovary, stomach, colon. This is because their gense havbe a higher chance of cancer

Runners n Rhizomes

Sometimes in vegetative reproduction, the part doesn't have to break. Runners: Runs along the surface of the ground(e.g.strawberries) Rhizomes:Underground stems like grass or ferns -Not applicable to flowering plants

Checkpoints

Special proteins monitor cell activities and send this information to the nucleus. The nucleus then instructs the cell whether or not to divide.

Anaphase

Spindle fibres begin to contract and shorten. This results in the centromeres to be pulled apart, and the sister chromatids then move to the opposite poles of the cell. Once they sepearte, each sister chromatid is considered to be a chromosome. Furrows or indentations appear on the equatorial plane(beginning of cytokinesis)

Late prophase

Spindle fibres complete forming. Chromosmes attach to spindle fibres at their centromeres and nuclear membrane disappears completely. Sister chromatids coil tightly and crossover may occur

Interphase-summary

The (longest) stage in which cells carry out functions necessary for surviving and PREPARE for cell divison

Why can't we just take any body cell from an animal(ex.cow) and make it into another individual? What can we do instead?

The cells have been specialized; we can only take the nucleus out and put it into an egg cell with the nucleus removed.

Metaphase

The spindle fibre tuggs and pulls the X shaped chromosomes into a singel line across the equator of the cell. Centromere divides and releases each chromatid from the other

Why can't more complex, multicellular organisms reproduce asexually? How do they clone?

Their cells become specialized; they clone with human assistance

What is 'special' about cancer cells?

They are often abnormal in shape(have a large, abnormal nuclei) and do not respond to messages from neighbouring cells. Thus, they don't stop dividing and grow in multiple layers that form a tumor

Since when did cells start dividing, and when do they stop/slow down?

They start at the fertilized egg stage and slow down after puberty. However, some cells that take a lot of wear and tear will still continue to divide.

Examples of vegetative reproduction

Tulip, daffodil, hyacinth bulbs, strawberry stem runners, potato sprouts, aspen, common camas, african violet

Mitosis-summary

Usually the shortest stage, divides the duplicated contents of the cell's NUCLEUS into two equal parts. Includes prophase, metaphase, anaphase, and telophase. Results in two daughter nuclei each with the same number of chromosomes as the parent. Occasionally mistakes are made, but the daughter cells are usually identical.

Fragmentation

When an organism breaks apart as a result of injury, the fragment develops into a clone of its parent.

When does mutations happen in binary fission?

When errors occur during DNA replication or when chromosomes fail to move into the two new cells.

Example of budding

Yeast cell, hydra, fungi, planarian, sponge

When you become ill very quickly, it's actually because...

ex: The streptococcus bacteria divides quickly and multiply into millions within two days.