For Chapters 1-4:
--Basic Characteristics of Life
--Molecules of Life
--Cell Structure & Function
--Cell Organelles
--Various Tissues
**The Basic Characteristics of Life**
Sylvia Mader lists the seven basic characteristics of living things (p.2) as follows:
1. They are organized, from atoms to the biosphere.
-----> All life is organized in some way. The most basic way, through atoms, is seen here. Atoms combine to form molecules (or compounds) which then combine to form an organelle. Those organelles make up cells from which tissues are made from. Organs make their way to the scene when the tissues join, yet when a series of organs come together, they create an organ system. Finally, when the organ systems collaborate, they create an organism.
2. They take materials and energy from the environment.
----->Living things need to EAT! Whether it be humans who eat they McDonalds or plants that consume energy from the sun, organisms need some form of "food" to help nourish themselves in some way. By taking materials from the enviroment, as humans, we too are converting this to energy to sustain life.
3. Living things reproduce, where they produce offspring that resemble themselves.
-----> Where would we be if reproduction didn't exist? We wouldn't exist. Life wouldn't be able to exist...for long. Reproduction allows organisms to live on and later evolve. "...[They] create a copy of themselves and ensure the continuance of thier own kind" (p.4). Genes make this possible. With these DNA molecules, genes carry codes with information for the directions of the organelles of a cell. DNA replicates itself making it so that these genes function in the same way.
4. Organisms grow and develop by undergoing various stages from fertilization to death.
-----> Growth and development is another factor of living things. Both are always fluctuating throughout the life cycle (ex. healing of a wound, weight changes, or giving birth.) All organisms maintain this characteristic.
5. They are homeostatic; internal conditions stay just about they same.
-----> Homeostasis provides the internal vs. external temperature balances. Human body temperature, for example, stays between 36.5 and 37.5 degrees Celsius throughout an average day. When these temperatures are too far below or above, sicknesses and even death are likely to occur. Homeostasis includes far more than just shivering or shaking, or sweating. It includes characteristics such as, exchanging gases with the environment and creating waste, or taking in and distributing important nutrients to the body.
6. They respond to stimuli; they react to external and internal changes.
-----> As the picture exemplifies, even YOU have the ability to scare this poor kitten. In other words, you were the stimuli and little kitten's response is his frightened expression. This is just an example of an external behavioral response. An internal response could include something as simple as a stomach ache from eating too much sugar-high foods. Your body may start to twitch and your stomach may cramp and your body may want to get it out of its system through one factor of waste management.
7. They have an evolutionary history and have adapted modifications to a particular way of life.
-----> I believe I once saw a television special on the evolution of human life (the History Channel). Now, I am not to be quoted but I believe they traced our history back to a fish. That's right, a fish! Whether that be accurate or not, human life did not just pop into the air. We evolved. DNA fluctuates ever so slightly for organisms to evolve to their environment. For instance, camels retain water to survive in their drastically dry climates. Though not all camels are the same. Some factors: hooves and humps, alter from each breed to adapt to their own unique climate.
**Molecules of Life**
In biology, there are four categories of organic molecules (molecules that have both carbon and hydrogen, usually found in living things) called carbohydrates, lipids, proteins and nucleic acids that are found in cells (Mader, 27).
-Carbohydrates function to provide quick and short-term energy for all living things. There are simple and complex carbohydrates. A carboxyl group is shown as C6H12O6.
-"Lipids contain more energy per gram than other biological molecules..." (Mader, 30) Lipids won't dissolve in water. Foods high in oil or fat contain lipids.
-Proteins aid in the functioning of cells. Different proteins (their shapes differ as functions differ) have different functions and are found in our hormones, plasma, and antibodies. Proteins help us move from place to place as well as chew our food and convert it to energy.
-Nucleic Acids (DNA & RNA) : DNA's function is the storage of all the genetic information of the cell of an organism. RNA's function differs in that it deals mainly with the 20 amino acids. DNA contains the bases adenine, thymine, guanine, and cytosine, while RNA contains uracil rather than thymine. DNA is a double strand (helix), unlike RNA. DNA is a deoxyribose sugar versus the ribose RNA is. (Mader, 35-36).
**Cell Structure & Function**
Structure-- The molecules of the main lipid, phospholipid form two layers called a phospholipid bilayer. This is formed because the ends of a lipid are opposites. One end is polar while the other is non-polar.
Function-- This creates the cell membrance which supports and retains the cytoplasm fencing it in, so to speak. Water is able to come in and out of the cell, non-polar molecules dissolve into the bilayer, but most polar compounds (amino acids, organic acids, inorganic salts) are not given that luxury. Instead they are moved through the use of proteins.
Cell Size is another issue. "As the volume of a cube increases from 1 mm3 to 2 mm3 the surface-area-to-volume ratio decreases." (Mader, 42). For instance, when the surface area increases from 1 mm2 to 2 mm2, the surface area decreases by half from 6 to 3.
**Cell Organelles**
A cell is very much like a city. Many different parts create such a tiny thing, yet the cell is very complex. Each organelle has its own unique and specific function to perform. A few include the ribosomes, which carry out protein synthesis; mitochondria, of which carries on cellular respiration; the golgi apparatus, which processes and directs cell production; nucleolus, produces subunits of ribosomes; chromatin, diffuses threads containing DNA and protein; and vesicles, which are membrane-bounded sacs that store and transport substances. Cells are, again, very complex, yet they maintain order and conduct their jobs right along one another, cell by cell.
**Various Tissues**
Tissues are made up of numerous cells that work together to complete a function. The four major tissues in humans include: connective tissues (bones, cartilage, gibrous tissues, and fluid tissues -->blood), epithelial tissues (skin), muscular tissues, and nervous tissues (made from nerve cells or neurons). Connective tissues bind and support body parts. Epithelial tissues vocer body surfaces and line body cavities, otherwise protecting the body. Muscular tissues enable us to move. Nervous tissue is what takes stimuli and directs your reaction.
*Work-Cited*
Mader, Sylvia S. “Human Biology” 10th ed. New York: McGraw-Hill, 2007.
Picture representing organization:
Picture representing materials and energy being taken from the environment:
Picture representing reproduction:
Picture representing growth and development:
Picture representing homeostasis:
Picture representing response to stimuli:
Picture representing evolutionary history:
Pictures representing molecules of life:
Picture representing cell structure and function:
Picture representing cell organelles:
Picture representing tissues:
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