Thursday, February 14, 2008

Cellular Compendium 1-4



"Homeostasis is, by definition, “a condition of dynamic equilibrium within any biological or social system. It is achieved through a variety of automatic mechanisms that compensate for internal and external changes.” In Greek terms, homeo, means “the same” and stasis, means “standing.” An example of homeostasis is the body being able to maintain a body temperature of about 98.6 F." Despite exercising where the temperature rises and sleeping where the temperature lowers the body basically stays the same. This happens because of the internal and external changes and mechanisms that occur in the body. Human and organisms have similar characteristics. There are eight commonalities when that can be thought of when comparing humans and organisms. See PIC # 1
There are five major groups or kingdoms that are in existence.
It is broke down like this: The first prokaryotic cells were around about 3.5 billion years ago and the first eukaryotic cells were about 1.2 billion years ago.
1st cells bacteria like organisms monerans>>>1st nucleated cells protists>>>fungi>>>plants>>>animals
Characteristics of life, living things, and organisms:
1.) All organisms including humans are made of cells. All cells consist of molecules. All molecules are made of atoms which are nonliving particles.
2.) All can maintain themselves by using molecules and energy from their environment.
3.) All living things have a metabolism. These are chemical reactions in the organism’s cells and tissues. There are two types of reactions that occur called anabolic and catabolic reactions take place and this happens at a rate of about a million a second.
4.) Is homoestasis.
5.) All can go with the flow. Meaning whatever life throws at them they can adapt and overcome. 6.) All can reproduce and grow
7.) They all evolve. Adapt, grow and go.
8.) All are part of the Earth’s ecosystem
The scientific method is a scientific approach finding and obtaining information to prove or disprove something through experiments. It starts with a hypothesis which is an educated guess as to what you think might happen. Next is the experimenting. Testing the idea and then recording the data. Ending it up with a theory, based on scientific facts, or conclusions.
In order to better understand the inter-workings of a cell then I think it is important to look at the chemical make up of a cell. Matter is anything that has weight and takes up space. Matter if made of tiny particles called atoms. See PIC #2 There are three subatomic particles that make up an atom. In the center of the atom, which is the nucleus, are positive protons and neutral neutrons. Floating around the outside of the atom are the electrons, which are negative in charge, in the electron cloud. Elements are made of atoms. All elements are listed on a chart called the periodic table. The periodic table has all the elements broken down into 7 groups for classification: alkali metals, alkali earth metals, main groups, transition metals, intertransition, halogens, and nobel gases. The elements categorized by being metals, nonmetals, or metalloids. On the table there are numbers. The atomic number consists of the number of protons. The mass number consists of the number of protons and neutrons in the nucleus. The atomic weight consists of the weighted number of its isotopes found on Earth.
Matter can be divided into two categories: pure substances & mixtures
Pure substances
are divided into two categories: elements & compounds
Mixtures are divided into two categories: homogeneous & heterogeneous matter
All mixtures can be physically separated into pure substances
All elements can be combined chemically to form compounds
When atoms combine they form molecules and a compound is a substance that is made up of two or more substances. Chemical bonds are occurring when the molecules in an atom join. One kind of bond is an ionic bond. This is when one atom gains an electron and the other atom loses one. Sodium chloride is an example of this type of bond. The other kind of chemical bond is called a covalent bond. This is when an atom shares an electron with another atom. There are other types of covalent bonds such as the polar covalent and hydrogen bonds. The polar covalent bond is when atoms are sharing an electron but it is not balanced out. A hydrogen bond is a bond that forms between slightly charged atoms usually on different molecules like water molecules between the hydrogen and oxygen bonds.


Water is a very important aspect in our bodies and it is extremely important to cell growth and survival. The human body is made up of more then 2/3 water. Water is helpful in many ways. It aids in the breaking down of proteins, it is a lubricate, it helps in joint mobility, and transportation of wastes. See PIC #3
Acids and bases are another key component in the body. An acid is a substance that adds a hydrogen ion to a solution. A base is a substance that takes away a hydrogen ion from a solution. Both of these reactions help in regulating the body and making it chemically neutral. The PH scale is a scale that measures the acidity or basic substances and puts a rating on them. Another key component in helping to balance out things is called a buffer. It is usually found in things such as soil and water. If certain levels are high or low then the buffers will take hydrogen ions out or put them in where they are needed to help in balancing out the PH levels.
Some important molecules to think about thinking about biological molecules are carbohydrates, lipids, proteins, peptides, amino acids, and nucleic acids. Carbohydrates are considered to be starch and blood sugar glucose. Both of which are used to produce energy for the cells. Lipids are considered to be fats and steroids. When thinking about cholesterol think lipids. This is an important component in cells it is used as insulation and can be found in snack foods and nuts, meats, and fried foods. All the yummy stuff.
Proteins >>made of>>amino acids>>made of>>peptides and they can be found in many meats like chicken or fish and also dairy products. Next are the nucleic acids and these guys are made up of long chains called nucleotides. This is where the DNA and genetic material is found in the cells. It makes up who we are!


When talking about cells thinking about microscopes is like peanut butter and jelly it goes hand in hand. Without a microscope seeing cells, bacteria, DNA or anything that can’t be seen with the naked eye would not be known about today. The microscope is made of a combination of lenses and light and both of these are used to aid in the magnification of any particular object. Microscopes fall into either one of two categories. The light microscope (uses light) or the electron (uses a beam of electrons) microscope. Both of these microscopes take tiny images and magnify them to the point of understanding. Electron microscopes can magnify an object up to 100, 000 times its size and the electron scanning microscope can make it to where the ability is there to see the object under 3D. See “HISTORY OF A MICROSCOPE” and “Me & my microscope,” “Let’s talk Microscope,”and “Just Cheeky” for more information, who founded it, how it works, and all the important parts.
“Human cells are the product of millions of years of evolution.“ When thinking about cells two things should come to mind See PIC #4 for cell parts ;
the nuclear and the cytoplasmic compartments.
The nuclear compartment is better known as the nucleus. It is the brain of the cell. It aids in structure formation and function.
The cytoplasmic compartment is like the cheese between the bread. The pieces of bread being the nucleus and the plasma membrane.
The plasma membrane is the outside later of the cell. It controls who goes in and what comes out. It is like the front door to the house.
In the cytoplamic area is a watery fluid that is made up of molecules, food, vitamins, wastes, dissolved gases and water and this is called the cytoplasm.
The cell has many structures that have particular functions and those are called the organelles.
Organelles and a brief description:
Endoplasmic reticulum:
made up of tubes and bedazzled with ribosomes. It is where synthesis occurs in lysosomal enzymes and proteins for extracellular use.
Ribosomes: made of RNA and protein found in cytoplasm produces proteins and polysomes
Polysome: mRNA bound to ribosome where protein synthesis occurs.
Golgi complex: flattened sacs near the nucleus this sorts, packages and proteins produced on RER the grocery store of the cell.
Secretory vesicles: membrane- bound vesicles containing protein from RER repackaged by gogli complex the package contains protein hormones or enzymes and then it waits for the green light so he can release it.
Food vacuole: membrane bound vesicles containing yummy food for the cell and combines it with lysosomes.
Lysosome: round membrane bound structure holding enzymes for digestion It is like the stomach acid of the cell. Helping to break down the food vacuole materials.
Mitrochondria: round, long, or oval structures, it has a double membrane and the inner one has folds. Breaks down glucose
Cytoskeleton: it is a networking of microtubules and microfilaments in the cell. Supports the cell, moves molecules and organelles through the cell and bind enzymes.
Cilia: small projections in the cell membrane containing microtubules found only on certain cells not all and this helps to move certain materials along the surface of the cells.
Flagella: Microtubules found on only sperm cells to help move the sperms cells along
Centrioles: small cylindrical tubes arranged in 9 sets of 3. Not found in plants. Help organize spindles for cell division.
SEE PIC #5
The plasma membrane is made up of lipids, protein, and carbohydrates. The first part of the membrane in the plasma of cells is the phosopholipid. They look like lollipops with a charged head and an uncharged tail.
During membrane transport molecules are moved through the membrane in five different ways: Diffusion is the movement of molecules or ions in and out of the cell from high concentrations to low concentrations.
Simple diffusion: movement of lipid-soluble chemicals moving through the membrane without assistance.
Facilitated diffusion: is where carrier proteins move molecules across the membrane from high to low concentration area. It is like the “crossing guard” to these molecules.
Active transport: movement of molecules across the membrane by facilitated diffusion and that has energy supplied by a special molecule called ATP that stands for adenosine triphosphate. It is an energy transporter.
Endocytosis: it takes care of molecules going into the cell. The phagocytosis eats the large particles like viruses and bacteria and the pinocytosis drinks down the extracellular fluids and dissolved materials.
Exocytosis: this kicks stuff out of the cell. By stuff, I mean, large molecules like protein hormones from the endocrine glands.
Osmosis: this is the diffusion of water across the plasma membrane. This comes from the greek word meaning “to push.”
Cellular respiration is achieved through the breakdown of glucose and this can be chemically in four basic steps.
The glycolysis is the first phase of cellular respiration that occurs in the cytoplasm and it breaks down glucose into 2 pyruvate molecules. The transition reaction is the next phase in cellular respiration that occurs in the mitochondrian and one carbon atom is cleaved off the pyruvate. The citric acid cycle is the next phase of cellular respiration and this happens in the inner most layer of the mitochondrian compartment. In this compartment it completes the breakdown of glucose. In the last phase of cellular respiration is the electron transport. This also occurs in the innermost membrane of the mitochondrion and here electrons are given off during the citric acid cycle and glycolysis enters into the electron transport system. Enzymes are very important in the chemical reactions of all cells. Enzymes are controlled the cells and this helps speed up or slow down the metabolism.
Electron transport has to have oxygen to continue and without it it will stop working. When that happens cells have to have a back up. So they rely on fermentation and glycolysis to give them energy. Fermentation is a chemical reaction where pyruvate is changed into lactic acid. You can get lactic acid from different foods that you eat like yogurt, and cheese.
See PIC #6
Cells>>>combine to form>>>tissues>>>combine to form>>>organs

There are four major types of tissues that are found in humans.
The epithelium forms the lining or external coverin of the organs and also forms glands. The stomach is lined with epithelium. Glandular epithelia is made up of cells that all clump together to form the glands in the body. Epithelial tissues is a perfect example of biological principle that structure works with function. The skin is made up of several layers of cells. The top layer of skin is called the epidermis. This is one of our best barriers against disease, infection, and viruses. Connective tissue holds together organs and cells. There are specialized connective tissues in the body such as cartilage, bone, and blood. Next is the muscular tissues that are groups of cells that flex and contract when stimulated or necessary. There are three types of muscular tissues in the body. Skeletal muscles which are called this because it is often times connected to bones or the skeletal body. The cardiac muscle is a banded muscle that does not require voluntary control. An example of this type of muscle is the heart. It is not necessary to constantly think about the heart and its beating because it does it one its own. The smooth muscle is another muscular tissue and it is called this because it hasn’t any visible striations and it is involuntary. A place that you could fine these kinds of muscles would be in the intestines or uterus. The next tissue group to talk about is the nervous tissues. These are filled with cells that give move nerve impulses throughout the body. There are two types of nerve cells the conductive and nonconductive. The conductive nerve cells are also called neurons. This is what responds to different types of stimuli. If you touch a stove it is the nerve cells that respond that tell you that it is hot! Nonconductive cells are also known as neuroglia. These nerve cells are the watch dogs. They watch and guard our bodies against toxins.
The heath of humans is completely dependent of the daily maintence of homeostasis. Without it we would cease to exist. Many contributing factors can make or break the order of homeostasis. It is absolutely necessary for the survival that there be a healthy environment, manageable stress levels, as well as contributing factors in our atmosphere. Without cells there would not be a life as we see it now. The idea of everything in life is here for a reason is not far from the truth. From the smallest of organisms to the largest of animals they are all made up of one little thing called a cell. By which with the smallest disfunction can be easily disrupted and destroyed. The cycle of life is dependent on the circulation cellular functioning.
http://www.ncbi.nlm.nih.gov/About/primer/genetics_cell.html for the picture

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