II.  Cytoplasm – the substance between the plasma membrane and the nuclear membrane.  The matrix is where the organelles are found:

-         Thick, semitransparent

-         Elastic fluid containing suspended particles and a series of microtubules and filaments

-         Cytoskeleton – gives the cell its shape and support

-         Cell is 75% - 90% water

-         Proteins, carbs, lipids, and inorganic substances make up the solids

-         Some chemical rxn’s take place

-         Raw materials that are unusable

-         Decomposition rxn’s – H₂O  à  H₂ + O₂

A. Organelles: structure and physiology

·        Cell contains compartmentalized structures called organelles

·        They have specific shapes and specific roles in growth, maintenance, repair, and control.

·        Types of organelles:

1.   Nucleus – spherical or oval

·        largest organelle

·        contains hereditary information

·        most cells only have one

·        RBC’s do not have one

·        seperated from cytoplasm by a double membrane (nuclear envelope)

·        perinuclear cisternae – has tiny pores for communication           

Inside is gel-like substance called Karyolymph (nucleoplasm)

·        nucleolus is found inside the nucleus and is non-membrane bound

·        breaks apart during cell division, and it makes RNA and proteins

·        DNA is not seen when spread out in the thread-like form called chromatin and is the only time that it can replicate itself for cell division.

·        Proteins are called Histones

·        see diagram from class for coiling methods.

2.  Ribosome – made of 2 subunits a large and a small

•           main purpose is to make proteins

•           Amino Acids join them one at a time to make a chain

•           some are free (proteins for inside)

•           some attached to organelles (outside)

3.  Endoplasmic Reticulum –

•           Double membrane channels called cisternae

•           channels are external of nuclear membrane

2 Types of ER 

a. Granular (Rough) ER

b. Agranular (Smooth) ER

•           maintain stability and distribution of cytoplasm

•           it is the transportation system of cell

•           storage area for synthesized molecules

•           Rough ER –synthesize proteins

•           Smooth ER – synthesize lipids and release of Ca²⁺ for muscle contraction

4.  Golgi Complex – principle function is to process, sort, package, and deliver proteins to various parts of the cell.

•           its near the nucleus

•           consists of 4-8 flattened sacs with expanded areas at the ends (cisternae – divided into cis, middle, and trans)

•           fuses with cis

•           golgi puts proteins in its vesicles

•           goes from cis à middle à trans its transfored into specific functions (see diagram from class)

•           2 types of vesicles for secretory granules and lipid secretion

5.  Mitochondria – small, spherical, rod-shaped, and filamentous

•           is the powerhouse of the cell

•           energy made from glucose à ATP (Adensosin triphosphate)

•           consists of 2 membranes (like plasma membrane)

•           outer membrane smooth (shorter)

•           inner made of a series of folds called cristae (longer)

•           center space is the matrix

•           have ability to self replicate

•           inner membrane (see diagram from class)

6.  Lysosomes (lysis-dissolution; soma – body)

•           made by golgi with single membrane

•           powerful digestive enzymes

•           Ty-Sacchs – deficiency of lysosomes

•           WBC’s destroy harmful substances

•           primary lysosome is inactive until fusion with vacuole

•           vacuole temporary storage area

•           engulf, digest it until small enough to go thru membrane

•           engulf worn out organelles and those materials are put back into cytoplasm for reuse (autophagy)

•           Autolysis (self-distruction) (suicide packets)

7.  Peroxisomes – similar to lysosomes

•           abundant in liver

•           rid of peroxides that are toxic to us

•           2H₂O   à  2H₂O  +  2O₂

8.  Cytoskeleton – network of microfilaments that give cells support and structure

•           microfilaments – made up of protein called actin

•           microtubules – made of protein called tubulin

•           contain channels for movement

•           assist in movement of pseudopodia

•           forms flagella and cilia, centrioles, and mitotic spindles

9. Centrosome and Centrioles

•           located by nucleus

•           made of a pair of centrioles

•           each centriole is made up of 9 triplet cluster of microtubules (see diagram from class)

10.  Flagella and Cilia – used for locomotion

•           flagella – usually few of them and long

•           contain cytoplasm connected to membrane       

•           cilia – usually many and short