Structure of a Cell

Plasma membrane
The outer limiting boundary of the cell. It protects the cell and controls what enters and leaves. It is therefore semipermeable
*The center that regulates life aspects/all of the cell's activities;
*Stores DNA/Genetic material
*contains the nucleolis
production: produces ribosomal subunits in nucleolus and exports them into cytoplasm for assembly into ribosome
All cellular contents between plasma membrane & nucleus. Contains cytosol, a viscous fluid & inclusions & organelles
hollow cylinders of tubulin protein; able to lengthen and shorten
The cytoskeleton includes
1. Microtubules - hollow cylinders of tubulin protein; able to lengthen and shorten
2. Intermediate Filaments -
3. Microtubules - actin protein monomers found in filaments **thickest**
(or nuclei) Spherical, dark-staining, dense granular region in the nucleus; synthesizes rNA and assembles ribosomes in the nucleus
Nuclear pores
Openings through the nuclear envelope; allow for passage of materials between nucleus and cytoplasm
Nuclear membrane/envelope
Double membrane boundary between cytoplasm and nuclear content; bilayer of phospholipids with nuclear pores
filamentous association of DNA and histone proteins
Rough endoplasmic reticulum
flattened intracellular network of membrane sacs called cisternae; ribosomes are attached on cytoplasmic surface; synthesizes proteins for secretion, new proteins for the plasma membrane and lysosomal enzymes, transports and stores molecules
Smooth endoplasmic reticulum
interconnected network of tubes (membrane and tubules and vesicles); no ribosomes. Synthesizes lipids, metabolizes carbohydrates, detoxifies drugs and alcohol
Mitochondrion (x: mitochondria)
double membrane structures with cristae, fluid matrix contents at center; synthesizes most ATP [adenosine triphosphate] during cellular respiration
"powerhouse of the cell"
Dense cytoplasmic granules with two subunits (large and small); may be free in cytoplasm (free ribosomes) or bound to rough ER (fixed ribosomes)
golgi apparatus
"post office of the cell"; small tiny bags/scas called vesicles; modifies, packages and sorts newly synthesized proteins for secretion, inclusion in new plasma membrane or lysosomal sacs
membrane enclosed sacs usually containing large amounts of enzymes to break down harmful enzyme substances; convert hydrogen peroxide formed during metabolism to water
membrane sacs with digestive hydraulic enzymes; digest materials or microbes ingested by the cell and remove old/damaged organelles; self-destruct (autolyze)
organize microtubules during cell division for movement of chromosomes (mitosis)
whiplike locomotory organelle that arises from within the cell and extends outside of it
short membrane attached projections containing microtubules; occur in large numbers on exposed membrane surfaces; move fluids mucus and materials over the cell surface
closed cellular structure in the cytoplasm surrounded by a single membrane
the process through which a substance EXITS the cell
the process through which a substance ENTERS the cell
The cytoskeleton includes
1. Microfilaments
2. Intermediate filaments
3. Microtubules *thickest*
Cellular functions
-covering (i.e. skin)
-storage (i.e. space [lumen])
-movement (i.e. muscle cells)
-connection (i.e. connective tissue)
-defense (i.e. white blood cells)
-communication (i.e. nerve cells)
-reproduction (i.e. gametes)
3 Major Parts of a Cell
1. Nucleus
2. Cytoplasm
3. Plasma Membrane
phospholipid bilayer
contains proteins, cholesterol & carbohydrates.
cellular respiration/aerobic respiration
glycolysis by using oxygen
organizes microtubules, participates in spindle formation during cell division
goblet cell
mucin-secreting cell