Chapter 4 Life

Picture of mitosis above.

Chapter 4 section 3 Notes, Talon
Sexual Reproduction and Meiosis

Vocabulary:
Sexual Reproduction: two cells sometimes called an egg and a sperm come together (2 organisms)
Sperm: Formed in the male reproductive organs (testes)
Egg: Formed in the female reproductive organs (ovaries)
Fertilization: the joining of an egg and a sperm
Zygote: The cell that forms as a result of fertilization
Diploid: Containing 2 sets of chromosomes
Haploid: Containing 1 set of chromosomes
Meiosis: The process that produces haploid sex cells

Your body forms 2 types of cells- body cells and sex cells
Body cells are diploid… they have two sets of chromosomes.
In the human body diploid cells have 23 pairs of chromosomes, you get one pair from your mother and one pair from your father.

Sex cells are haploid… They have only one set of chromosomes. Instead of having 23 pairs, they have only 23 in humans.

Sometimes we say that haploid cells have 1n and diploid cells have 2n. (n would represent a set of chromosomes, 2*n would mean 2 sets)
How many chromosomes would be in an egg? How many would be in a sperm?

How do an egg and sperm make a zygote?





Look at the Pictures in your book on pages 106 and 107.

Meiosis produces haploid (1n) sex cells. This process is similar to mitosis but the resulting cells have only one set of chromosomes not 2.
During meiosis, two divisions of the nucleus occur. These are called meiosis I and meiosis II. Each step has names like those in mitosis.
Meiosis I- ( follow along on your diagram)
Prophase I- chromosomes visible, centrioles are at each end, spindle fibers are beginning to form.
Metaphase I- chromosomes line up in the middle of the cell and attach to a spindle fiber
Anaphase I- Two pairs of chromatids move away from each other toward opposite ends of the cell. The centromere (center piece of chromosome) is attached to the spindle so the chromatids do not separate like in mitosis.
Telophase I- cytoplasm divides and two new cells form. Each new cell has one duplicated chromosome from each similar pair.

What is different about the above steps from mitosis?
Meiosis II- The chromatids of each of the duplicated chromosomes will be separated in meiosis II. Meiosis II deals with the duplicated chromosomes. They will be separated and put into the sex cells.
Prophase II- duplicated chromosomes and spindle fibers reappear in each new cell with centrioles on each end of the cell and spindle fibers stretching along the cell.
Metaphase II- the duplicated chromosomes move to the center of the cell and line up. Each centromere attaches to 2 spindle fibers.
Anaphase II- The centromere divides and each chromatid moves to opposite ends of the cell. The chromatids are no longer in pairs so they are individual chromosomes.
Telophase II- spindle fibers disappear and a nuclear membrane forms around the chromosomes at each end of the cell. The cytoplasm then divides.

Summary- Meiosis I produces 2 cells. Both of these produce 2 cells. Two divisions of the nucleus result in 4 sex cells. Each of these sex cells has one-half the number of chromosomes. This process can make eggs or sperm.

Mistakes in Meiosis- Because this process happens so much in organisms mistakes can be made. Sex cells with too many or too little chromosomes can be produced. Sometimes these sex cells die. If they live the resulting organism will have more than the necessary number of chromosomes. Sometimes they will be unfertile (unable to have children). They may not grow normally. Downs syndrome.

Chapter 3 Life Study Guide

Chapter 3 Study Guide from your book (use this to study along with your homeworks and notes)
Section 1 Chemistry of Life

1. Matter is anything that has mass and takes up space

2. Energy in matter is in the chemical bonds that hold matter together

3. All organic compounds contain the elements hydrogen and carbon. The organic compounds in living things are:
Carbohydrates- for quick energy
Lipids- for energy stores and cell membranes, hydrophobic
Proteins- made of nucleic acids, building blocks of structures, enzymes are proteins that are the catalysts of the body
Nucleic acids- Make up DNA which eventually makes proteins

4. Organic and inorganic compounds are important to living things.

Section 2 Moving cellular materials

1. The selectively permeable cell membrane controls which molecules can pass into and out of the cell.

2. In diffusion, molecules spread out from an area of high concentration to an area of low concentration. They will do this till they reach equilibrium.

3. Osmosis is just diffusion through a semi-permeable membrane.

4. Cells use energy to move molecules by active transport but do not use energy for passive transport.

Section 3 Energy for Life
1. Photosynthesis is the process by which some producers (plants) change light energy into chemical energy. Carbon dioxide plus water plus light yield glucose plus oxygen.

2. Some one-celled organisms and cells that lack oxygen use fermentation (done without oxygen) to release small amounts of energy from glucose. Wastes like alcohol, carbon dioxide, and lactic acid are produced.

Chapter 3 Notes

Talon
Chapter 3
The Chemistry of Life (from your text book)

See table on Page 69.

Elements that make up the Human Body -Highest percentage on top
Oxygen
65.0
Carbon
18.5
Hydrogen
9.5
Nitrogen
3.2
Calcium
1.5
Phosphorus
1.0
Potassium
0.4
Sulfur
0.3
Sodium
0.2
Chlorine
0.2
Magnesum
0.1

The study of chemistry plays a huge role in the study of biology.

Organic compounds: Contain carbon and hydrogen

Lipids- fats, oils, waxes, phospholipids, cholesterol- do not mix with water. (hydrophobic)

Carbohydrates- sugars, starch, cellulose, supply energy or serve to give structure to plant cells (cellulose)

Protiens- Enzymes, hormones, skin, hair, tissues, DNA codes for protein, made up of amino acids, muscle contains large amounts of protein. Enzymes regulate all chemical reactions in cells.

Nucleic Acids- DNA, the genetic material, RNA, used to make enzymes and other proteins.

Inorganic compounds- non-carbon compounds.

Water- VERY important, used in every process in the body (adult 60% water) 2/3rds are inside cells

Other important compounds-
Calcium phosphate- gives strength to bones
Hydrochloric acid- breaks down food in the stomach
Sodium bicarbonate- helps the digestion of food to occur
Salts, KCl, NaCl- important in sending messages along nerves.

What's the difference between a substance and a mixture?
A mixture can be seperated by ordinary processes. A mixture is made up from a combination of different substances.
Substances have only one property.

Ex. Mixture- iron filings and sand
Substance- Salt

Chapter 3 section 2-
Passive transport- movement of substances through the cell membrane without the use of energy
Active transport- Movement of substances through the cell membrane with energy

Diffusion- When molecules more from an area of higher concentration to an area of lower concentration (ex) when someone sprays axe in a corner of a room it will diffuse till all the molecules are spread evenly throughout the room

When molecules are spread evenly we call that "Equilibrium"

Osmosis- Diffusion through a membrane like a cell membrane. In a cell water or other materials may diffuse in or out through the membrane.

Cell membranes are called "Semi-permeable" because they let some things in but not all. You could think of this like a screen on a window; it lets air in but not bugs.

Endocytosis- When a cell takes in large particles by surrounding it with a membrane.

Exocytosis- When a cell gets rid of a large particle in the opposite way of endocytosis



Chapter 3 section 3
Energy for Life
How do we get energy? Ultimately- the sun
Directly- we eat food

Food must be changed into useable forms.

Metabolism- The total of all chemical reactions in an organism

Catalyst- substance that speeds up or causes a reaction to happen

Enzymes- Help reactions take place in the body. The “catalysts of the body”

Photosynthesis- Plants use water, sunlight, and carbon dioxide to produce their energy which is sugar. Oxygen is a byproduct of the reaction, this benefits us. This is very important in the reduction of greenhouse gases.

Light energy+ carbon dioxide+ water -> Sugar (glucose) + oxygen

Respiration- Chemical reactions that break down food into simpler substances we can use (enzymes involved) Takes place in the mitochondria

Breaking down Carbohydrates- respiration happens in the cytoplasm. Carbohydrates are broken down into glucose. Glucose is broken down into two simpler molecules….. See below.
Digestion Glycolisis fermentation Krebs cycle
Carbohydrate--> glucose->2 molecules of pyruvate-> 2 acetyl groups->2 molecules of ATP

The whole process uses energy and creates waste products of CO2 and water.

Fermentation- (in the cytoplasm)- release of energy anaerobically (without oxygen)
Examples: Running- burning buildup of lactic acid.
Bread dough rising- yeast ferments sugar in dough and excretes a gas
Alcohol- product of fermentation
Bacteria- breakdown sugar in milk to make yogurts and cheeses