Cell Compendium

Cells

Basic Characteristics of Life-

  Share common structure of organization 

  Take materials and energy from the environment

  Reproduce

  Growth and Development

  Interact with environment through stimuli

  Evolve

Molecules of Life 

Pairing of two or more atoms creates a molecule. When different atoms combine it creates a compound. There are 4 types of organic molecules: 

1. Proteins- Composed of amino acids they support structure and functioning of cells. It is within the skin hair and nails such as keratin and collagen. In enzymes they create specific chemical reactions. When in the plasma membrane they help to transport materials in and out of the cell. Hormones and antibodies also consist of proteins. Certain proteins also help in muscle contraction.

2. Carbohydrates- Are sugars that function in the storage and transport of short - term energy.They have a 2:1 ratio of hydrogen to oxygen similar to water. They are the main energy source for the human body. The process of metabolism releases energy. There are 2 types: Simple carbohyrates are called monosaccharides. Examples are fructose,

glucose, galactose. "When humans eat starch, glucose is absorbed into the bloodstream. Once absorbed, the human body distributes glucose to the areas where it is needed for energy".Complex carbohydrates are polysaccharrides consisting of long chain simple sugars. 

3. Lipids - Functions in storing of energy, signaling pathways, insulating the body, and forming of cell membrane. A high energy source not water soluble. It includes cholesterol, sterol, glycerides and fatty acids which are neutral and don't carry a charge. Phosholipids are different in molecular structure, having phosphate and nitrogen. They are polar and form the cell membranes. Steroids differ by having 4 fused carbon rings. Testosterone, estrogen, and cortisol are important to reproduction and metabolism.      

4. Nucleic Acid - There are 2 types DNA and RNA. DNA stores genetic info and is like a blueprint that contains instructions for the components of cells, proteins, and RNA molecules. The part of The DNA that carries the instruction is the genes. DNA is able to replicate and transmit the information when a cell reproduces. RNA is involved in protein synthesis. Both are polymers and macromolecules which are made of sugar, a base, and phosphate. Sugar deoxyribose is DNA and RNA contains the sugar ribose. DNA has a helix  and is double stranded and RNA is single stranded without a helix. ATP is a high energy molecule created when adenine and ribose are changed by a regrouping of three phosphates.

Cell Structure and Function

Cells form the structure of living organisms. The cell is the smallest unit of life capable of exhibiting the basic characteristics of life.

The Cell Theory states that all cells come from other cells, all of life is made of cells, and that cells are the basic unit of life. Cells can be different in shape and function. 

The outer shell of the cell is called the plasma membrane it is permeable and regulates what enters and exits the cell. The membrane contains proteins and lipids.Diffusion is a process of molecules equally distributing from high to low areas of concentration. It creates a means for molecules to enter and exit a cell. Osmosis moves water  and a solute across the membrane. Facilitated transport is when a protein is used as a carrier to cross the membrane. Diffusion, osmosis, and facilitated transport are "passive" they don't require energy to facilitate movement. Active transport requires cellular energy, a protein carrier and moves from low to high. Endocytosis is a process that takes in substances through the membrane by creating a "pouch" and exocytosis is the process when a "pouch" is formed to release a substance. Within the membrane is a fluid consisting largely of protein called the cytoplasm where various organelles reside. 

Cell Organelles and Metabolism

Membraned bodies within the cytoplasm with specific design and functions.

1.Endoplasmic reticulum- channels that connect the nucleus to the cell membrane. There are 2 types, rough and smooth. Rough contains ribosomes and smooth do not.

2.Ribosomes- are attached to the endoplasmic reticulum and where RNA synthesize proteins.

3.Gogli apparatus- flat stacked membranes where sugars are converted to starch or bonded to proteins and lipids.

4.Vesicle-a storage sac that can move between organelles by endocytosis or exocytosis.

5.Lysomes- are found in all cells, contain enzymes that break down macromolecules.

6.Mitochondria- where cellular metabolism occur. Converts glucose into ATP molecules in the process of cellular respiration. Cellular respiration is an important metabolic process that releases energy slowly. The process of converting glucose is called glycolysis. 

7.Nucleus-contains DNA information and contained in a double membrane. 

Cytoskeleton- its protein meshing maintains the cells shape and buffers organelles. There are 3 different tubules: microtubules,actin filaments, and intermediate filaments. The centrosome organize center of the microtubes. The cilia and flagella are have micotubes in the center. Their protein projections create movement.   

Tissue Types

Tissue comprises of cells that are specific to its function. There are 4 types:

Connective Tissue 

Fibrous connective tissue are made of fibroblasts that support the internal organs.

Adipose is another connective tissue that stores fat, protects, and insulates. 

Dense fibrous connective tissues is in tendins, ligaments and connect muscle to bone. 

Supportive connective tissue consisting of cartilage is called hyaline cartilage, elastic cartilage is found in the ear, and fibrocartilage is found in knee joints and vertebrae.

Fluid connective tissue include blood:white blood cells and platelets, and lymph that absorb fluids.   

Muscular Tissue

Contain actin and myosin proteins that enable movement.There are 3 types: skeletal muscle which are striated and voluntary with multiple nuclei, smooth muscle can be found along the walls of organs and is involuntary and has a single nuclei, and cardiac muscle which lines the heart is striated and involuntary. 

Nervous Tissue 

Form a communication network consisting of neurons and neuroglia. Neurons are made of dendrites which receive signals, the cell body, and axon which conducts impulses,

Epithelial Tissue

Forms along the body cavities consisting of tightly packed cells. It is exposed on one side and secured to connective tissue on the other.There are 5 types:

Simple Epithelia

Squamous epithelium has a single layer of cells, found in the lining of the lungs and blood vessels. Cuboidal epithelium also has a single layer and is found in the glands. Columnar epithilium line the digestive tract and oviducts and are columnar in structure. 

Pseudostratified Columnar Epithelium line the windpipe and.

Transitional Epithelium can be found lining the urinary bladder and urethra and can change according to tension.

Stratified Epithelium have layer of cells and can be found in the nose moth esophagus and cervix.

Glandular Epithelium secretes a substance to be move to the blood or ducts.