Artifact 2:

Levels of

Organization

1. Thibodeau, Gary. Anthon'ys Textbook of

Anatomy and Physiology. Seventeenth. St. Lou-

is, Missouri 63146: Mosby, 2003. Print.

2. N.d. Photograph. n.p. Web. 17 Sep 2012.

<http://www.glogster.com/

heyheyhey12345678/organelles-of-cells/g-

6nhse2jnscand9i2bv7m0vt?

old_view=True>.

3. N.d. Photograph. n.p. Web. 18 Sep 2012.

<http://www.universetoday.com/wp-content/

uploads/2010/02/c-atom_e.gif>.

4. N.d. Photograph. n.p. Web. 18 Sep 2012.

<http://www.lenntech.com/water-chemistry-

faq.htm >.

WORK CITED

ORGANIC MOLECULES

Most of the molecules in living things are organic mole-

cules, meaning that they contain carbon. The fact that car-

bon has four electrons in its outermost shell means that it is

capable of covalently bonding with other atoms to fill its

outermost shell. Organic molecules typically involve carbon

bonded to hydrogen, oxygen, nitrogen, and other carbon

atoms. (source 1)

Polymer: Monomer:

Polysaccharide Monosaccharide

Lipid Glycerol/Fatty Acid

Protein Amino Acids

Nucleic Acid Nucleotide

There are four major kinds of organic molecules: carbohy-

drates, lipids, proteins, and nucleic acids. Each of these

exists as a polymer, composed of monomers. (Source 1)

Monomers are joined together by dehydration synthesis

(condensation), which forms water molecules in the pro-

cess.

Polymers can also be broken into monomers by hydrolysis

reactions, which use water molecules in the process (source

1)

(Sourrce

3)

Inorganic molecules include water, oxygen and car-

bon dioxide, as well as acids, bases and salts

(electrolytes). These molecules are just as vital to life

as organic molecules because for example every

living being needs water to survive. While organic

compounds require carbon covalent bonds, inorganic

compounds do not. (source 1)

Cell membrane

Its function is to be the boundary between the extracel-

lular fluid and the intracellular fluid.

It is made up of phospholipids; it is arranged into two

layers called the phospholipid bi-layer. The hydropho-

bic fatty acid tails are facing towards the inside of the

membrane, while its hydrophilic polar heads are toward

the exterior of the membrane.

There are two types of proteins that are important to the

membrane: integral proteins and peripheral proteins.

Carbohydrates, glycolipids, glycoproteins, and choles-

terol are found in the membrane.

A phospholipid consists of a polar portion, called the

head, and two longer fatty acids, called the tail. Thus a

phospholipid molecule is represented as a sphere with

two long projections. When mixed with water, the

heads are attracted to the polar water molecules. The

nonpolar tails move as far from water as possible, and a

double layer of phospholipids with tails to the interior

results.

Functions: 1) They can provide receptor sites for chem-

ical messengers such as hormones and neurotransmit-

ters. 2) Enzymes catalyze reactions near the membrane.

3) Channel proteins are constantly open to allow pas-

sage of various solutes all the time. 4) Gated channels

open and close to regulate the passage of various so-

lutes. 5) Motor molecules are proteins that pull mem-

brane proteins and cause cellular movement. They tend

to be peripheral proteins. 6) Glycoproteins function in

cellular identification. 7) Cell adhesion molecules

(CAMs) bind one cell to another.

Cont.

There are also carrier proteins (not shown). Carriers

are integral proteins that bind to specific molecules

and transport them to the other side of the membrane.

Membrane proteins are also important in activating

second messenger systems. A messenger such as a

hormone or neurotransmitter binds to its receptor site.

The receptor releases a G protein, which may bind to a

membrane-bound enzyme such as adenylatecyclase.

Adenylatecyclase converts ATP to cyclic AMP

(cAMP). cAMP is the second messenger. cAMP acti-

vates a kinase, an enzyme that adds phosphate groups

to other cytosolic enzymes, thus activating some and

deactivating others. This leads to an alteration in vari-

ous metabolic activities. (source 1)

(source 2)

ALL ORGANELLES ON PAGE 69

Golgi Complex: modifies, packs, and distributes

proteins.

Mitochondria: Extracts Energy

Lysosomes: contains digestive enzymes.

Centrioles: Important in Mitosis

Plasma Membrane: separates the fluids

Nucleus: Contains DNA

Ribosomes: Assemble Amino Acids (protein)

Smooth Endoplasmic Reticulum: Stores calcium

in the bones.

Vesicles: carries lipids and proteins to cell sur-

face

Rough Endoplasmic reticulum: studded with

ribosomes and functions in protein synthesis.

Centrosomes: breaking of microtubules in the

cell.

Cytoplasm: internal substance that contains tiny

suspended structures

Peroxisomes: Contains enzymes the detoxify

harmful substances (source 1)