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=**Dividing Cells**=

Save this document to your Chemistry folder as “2.Dividing Cells”
 * You will be in a group of 5 or 6 and you are going to produce a wiki about this topic. Each group will have a wiki that you will share with your partners. The wiki will have all of the answers to the questions below with any relevant images and website links. You can spice up your wiki by turning it into storybook with characters – you could use The Simpsons or Dr. Seuss for example. If you have a different idea that is visual and fun, check with me. **


 * You will: **
 * 1) ** 1. **** answer the 2 sets of questions below using all of the vocabulary words **
 * 2) ** 2. **** have 4-5 relevant diagrams with captions or comments to help with understanding the concepts you are learning. **


 * 1) ** 3. **** have 2-3 relevant URLs (or hyperlinked) of interactive websites that demonstrate concepts. You need to refer to the website in your text saying how it helps explain a concept and/or how to get the most out of the site. **

** Essential Question ** ** What is the fact and fiction of the statement "DNA is like a tightly wound rubber band **   ** doing the same job as a hard drive in your computer" **

** 1. What is DNA and where is it found? **
 * information about information about organism and is passed from parents to offspring. It is found in the chromatin in the nucleus. RNA is also found in the same place as the DNA **

** 2. What does it look like (its structure) and what is it made from? **  ** DNA comes in the form of a twisted ladder shape scientist called a Double Helix. Made from the letter A,C,T and G. **

** 3. How and why does it copy itself? **
 * The first step is for a DNA molecule to “unzip” between its base pairs. Then one of the strands of DNA directs the production of a strand of messenger RNA. To form the RNA strand, RNA bases pair up with the DNA bases. The process is similar to the process in which DNA replicates. Cytosine always pairs with guanine. However, uracil not thymine pairs with adenine. **

** 4. What are genes and where are genes found? **  ** Genes are something that have information, code for a certain protein, and made out of a series of base in a row. The bases in a gene are arranged in a specific order. **

**__ Vocabulary For DNA __** Vocabulary for Genetics
 * nucleus chromosome guanine DNA thymine nucleic acids cytosine RNA DNA replication gene double helix twisted ladder nitrogen bases base pairs backbone hydrogen bond adenine cell division trait **

Nitrogen bases – Type of molecule that forms an important part of nucleus acid, and contraining nitrogen-containing ring structure. Cell division – It is a process where cell divides himself into two or more daughter cells. Guanine – Nitrogen bases in DNA RNA – RNA stands for Ribonucleic acid, and it is one of the three most important large molecules (with DNA) that are essential for all known forms of life. RNA are similar to DNA except for some major parts like RNA are usually single stranded but DNA are double standed. Base pairs – Bases pairs are the pairs of nucleotide joined with a Hydrogen Bond. Nucleotides are molecules that when joined, they form DNA or RNA. Trait – Characteristics ________________________________________________________________________________________________________________________________________ DNA— A genetic material that carries out information that is passed from your parents. Gene— A characteristic trait that is created from the heredity of your parents. Backbone—It is one of units that DNA consists, made out of sugars and phosphate. thymine—One of the nucleobases found in DNA. It binds with the other bases, adenine to stabilize the nucleic acid structure. double helix— It is a structure formed by a double stranded nucleic acid, RNA and DNA. hydrogen bond— It is a interaction between the hydrogen atom and electronegative atom ________________________________________________________________________________________________________________________________________ Nucleus: A cell part that controls the one cell that it’s located in. Nucleic Acids: natural molecule made up of carbon, oxygen, hydrogen, and nitrogen that contain instructor cells. Twisted Ladder: form of what DNA looks like. Adenine: A compound that is one part of the bases of nucleic acid. Chromosome: compressed chromatin that contains DNA. Cytosine: Compound found in tissue as a base of nucleic acid

Meiosis is the process that occurs in the formation of sex cells (sperm and egg) by which the number of chromosomes is reduced by half. Number of cells? (4 cells)

Chromosomes are two rod of condensed chromatin contains DNA that carries genetic information.

Chromatids are two strands of the same DNA

Centromeres are structures that holds the chromatids.

Chromatins are inside chromosomes.

Before meiosis begins, every chromosome in the parent cell is copied. Chromosomes can hold two chromatids together. Two chromatids then form one chromosome. The chromosomes line up across the middle of the cell. Each chromosome attaches to a spindle fiber at its centromere The two chromatids from a chromosome then split and become two chromosomes in total, they then goto opposite ends of the cell Each cell has only half the number of chromosomes that the parent cell had at the beginning of meiosis. Each cell has only one chromosome from each original pair.

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**//__Mitosis__//** is the second stage of a cell cycle, the stage where the cell's nucleus is divided into two nuclei. During the process of Mitosis, mitosis copies the DNA (information) of the original cells to the new daughter cells. At the end of the Cell cycle, there are two daughter cells same as the original cell, with all the same DNA. =====

During ** __//cytokinesis,//__ ** the cytoplasm divides, and the organelles of the original cell are split in half, then distributed into the two daughter cells evenly, so both daughter cells have everything it needs to exist.

Definitions Meiosis: The process that occurs in the formation of sex cells (sperm, Egg) by which the number of chromosomes is reduced by half.

-Chromatids: Process of chromosome dividing(two chromatids make one chromosome)

- Chromosome: A doubled rod of condensed chromatin contains DNA that carries genetic information. How do cells divide. Well, people don't grow by making their body cells larger. Instead, cells divide, making two cells from one. And Luckily, cell division is a lot more precise as how you cut a sandwich sandwich_dividing skills. When a cell divides, the nucleus leads the way. We call it Mitosis when the nucleus divides into two identical nuclei. Mitosis ensures that each cell offspring will have a complete set of chromosomes just like the parent cell. Chromosomes are two DNA molecules held together by a cellular structure known as a centromere. Every human cell has 46 chromosomes in all. Mitosis has four steps: prophase, metaphase, anaphase and telophase. After mitosis, the cell membrane splits and two whole new cells are formed. Both plant and animal cells undergo mitosis, but plant cells don't have centrioles and they have a rigid cell wall. Living organisms groom by cell division, so mitosis is pretty important. Information:

DNA is a nucleic acid that is found in the nucleus of a cell. It is a molecule that has information about everything that happens in the cell. Another nucleic acid is RNA. Chromosomes are made form DNA and are found in the nucleus of a cell.

It has the shape/structure of a double helix. It looks like a ladder that has been twisted, so its shape is often described as that of a twisted ladder.

DNA is made from the nitrogen bases ( adenine,theymine,guanine, and cytosine) that from the rungs of the twisted ladder and also phosphate and deoxyribose sugar that make up the legs (or backbone) of the ladder. The base pairs make up the rungs of the ladder. Adenine always forms hydrogen bonds with Thymine to make a rung of a ladder. Guanine always forms hydrogen bonds with Cytosine to make a rung of the ladder.

DNA is all coiled up inside chromosomes. It first has to unwind, and then unzip itself. Unzipping exposes the nitrogen bases on both sides of the DNA molecule. New nitrogen bases in the nucleus attach themselves to the exposed nitrogen bases and you end up with two completely new strands of identical DNA that then rewind themselves (coil up).

DNA replication occurs during interphase when the cell is getting ready to undergo cell division (to make new cells). Those new cells each need a complete set of DNA so they have all the necessary information to carry out the processes they need to do.

Genes are things that have the information for one particular trait or protein. One henna for one trait.

Chromosomes are made of hone huge, long DNA molecule all coiled up. There are thousands of genes on one chromosome. A piece of a chromosome (and therefore a piece of that long DNA molecule) that has information for one treat,is a gene.

Asexual reproduction is faster than sexual reproduction so and organism (such as bacteria) that reproduces asexually by binary fission, can produce very large numbers in a very short time. The bacteria cells that are produced are identical.

Since only one cell is needed to reproduce (there is no need to search for a mate), it is much simpler and does not waste as many resources.

Organisms that are able to carry out meiosis are able to produce offspring that are different there is variation in the population. This means that there is a change for some organisms to survive if a disease affects the population. It also means that some organisms might have something special that gives them a greater chance to survive and then later, reproduce. This is the idea behind evolution.

Organisms that only use asexual reproduction are all genetically identical. If a disease affects the population, every organism could potentially be affected by that disease. If there is defect in the original cell, all cells will have the defect since they are all identical.

Cell Cycle (with Mitosis as a part) and Meiosis are both forms of cell division. There is no relationship between the cell cycle and meiosis.

__//Genes-//__are made from strands of DNA.
 * End of meiosis- Four sex cells have been produced. Each cell has only half the number of chromosomes that the parent cell had at the beginning of meiosis ||  ||

__//DNA(a molecule)//__- DNA is like a blue print for building different parts of the cell. The DNA molecule looks like a twisted ladder called "Double Helix". The ladder's rungs are built by 4 letters from the alphabet, A,C,G, and T. A always pair with T, C always pair with G. Combinations of the letters create a gene, which commands other cells to create proteins.


 * //__Chromosome & Chromatids__//**

[|**http://learn.genetics.utah.edu/index.html**] [|**http://www.cellsalive.com/meiosis.htm**] This website includes information about reproduction. It illustrates each step in the cycle. It animates and tells specific detail about each step. To make it automatically change image you click play and it will explain in detail.

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reproduce asexually. ||
 * [[image:Screen_shot_2011-12-01_at_1.49.53_PM.png]]Aphids reproduces asexually. ||  ||
 * [[image:Screen_shot_2011-12-01_at_1.42.55_PM.png]] || Paracium
 * [[image:Screen_shot_2011-12-01_at_1.35.57_PM.png]]Amobeas reproduce asexually. ||  ||

sexually || and cats are animals who reproduce sexually. ||
 * [[image:Tiger.jpeg width="400" height="315"]] || The tiger reproduces
 * [[image:Screen_shot_2011-12-01_at_1.36.28_PM.png width="400" height="283"]] || Dogs


 * Asexual Reproduction || Advantage of asexual reproduction of plants they can produce faster and spread faster. Disadvantage of sexual production is that it requires 2 organisms. And the disadvantage of asexual reproduction is that when they parent have a disease it will be completely spread to their offspring. Asexual reproduction is faster than sexual reproduction, do not need to find a mate. asexual reproduction does not produce difference, whereas sexual reproduction does. Offspring is different from the parents. Variation the offspring can be better than their parents. Yet another advantage to asexual reproduction is its reliability. || [[image:images-1.jpeg]] ||
 * Sexual Reproduction || For the reason that there are less stages than the sexual process of fertilization and production of gametes, the probability for error is decreased as opposed to the possibility of mistake during the fertilization and gamete production process. Plants sexual reproduction in plants are spreader by the insects or the wing. The Pollen grains can then fuse with the egg cells and seeds are produced. Then the seeds grow into new plants. || [[image:life.jpeg]] ||

__**Essential**____ **Questions** __ ** Compare and contrast a photocopier and a muscle cell? **   ** Compare and contrast chromosomes and playing cards? **   ** 1. What are the advantages + disadvantages of both sexual and asexual reproduction? **   ** 2. Name 3 organisms that reproduce sexually and 3 that reproduce asexually. **

** 3. What is the relationship between the cell cycle, mitosis and meiosis? **   ** 4. What are the cell cycle and meiosis used for? **   ** 5. What is similar about the cell cycle and meiosis? **   ** 6. What is different about cell cycle and meiosis? **   **__ Vocabulary For Cell Cycle, Mitosis and Meiosis __** ** Chromatid Nucleus DNA Cell Division Mitosis ** **__ Resources Available __**
 * Identical Replication Variation Chromosome Sex cells **
 * Cell cycle Cells produced Centromere DNA Replication **
 * Asexual Reproduction Sexual Reproduction Growth + Repair **

Foundation Science 2 – pp 48 – 53, 56 - 57
 * Textbook ** Prentice Hall – pp 18, 29, 55-62, and 92 - 98

"DNA, Genes, + Chromosomes" "Genes + Traits"
 * Videos ** Biology Essentials - "Genetics + Heredity: The Blueprint of Life"

Generations - "Mitosis and Meiosis" NeoSci - "Cell Division"

[|**www.brainpop.com**] ( saspuxi – 123456) – “Asexual Reproduction”, “DNA”, “Genes”, “Mitosis” [|**http://learn.genetics.utah.edu/index.html**] - do the “Tour of the Basics” – “What is DNA?” and “What is a Chromosome?” - do the “Build a DNA Molecule”
 * Websites **

[|**http://www.pbs.org/wgbh/aso/tryit/dna/shockwave.html**]** - ** try copying DNA [|**http://www.stolaf.edu/people/giannini/flashanimat/molgenetics/dna-rna2.swf**]** - use Firefox - ** copying DNA movie (don’t worry about the fancy names)

[|**http://www.pbs.org/wgbh/nova/baby/divi_flash.html**] - M&M compare + contrast [|**http://biologyinmotion.com/cell_division/**] - practice mitosis and meiosis [|**http://www.cellsalive.com/meiosis.htm**] - play movie or go frame by frame, use the magnifier [|**http://www.rothamsted.ac.uk/notebook/courses/guide/movie/meiosis.htm**]** - ** meiosis movie [|**www.explorelearning.com**] - (saspuxi – 123456) – “Building DNA” [|**http://activity.ntsec.gov.tw/lifeworld/english/genec_0.html**] - “Genetic Codes” then have a look at the different sections

[|**http://www.abpischools.org.uk/page/modules/genome/dna2.cfm?age=Age%20Range%2014-16&subject=Biology**] - Genes + DNA

[|**http://www.abpischools.org.uk/res/coResourceImport/resources04/cancer/index.cfm**] - Cell division and cancer

**__ Possibly Useful Images __**

Remember that when two DNA molecules are joined together, each molecule is called a chromatid and the two of the molecules are called a duplicated chromosome. When a DNA molecule(and proteins) is not attached to another one then that single molecule of DNA is not a chromatid but an unduplicated chromosome. ** Chromatid vs. Chromosome **