ANATOMY: CELLS

plasma membrane (cellular structures)

• Definition : the membrane that surrounds the cell

• Function: control what enters/leaves a cell. Interacts with other cells in the environment.

• Structure: phospholipid bilayer; separates the cell from the extra cellular fluid; cholesterol: stabilizes membrane fluidity

  Proteins: membrane proteins, allow material to enter/exit the cell. Also allows for communication between cells

Organelles (cellular structures)

definition: membranous (membrane bound) structures within a cell of that carry out particular functions

Cytosol (cellular structures)

• Definition: the liquid portion; gel like, toothpaste consistency. Mostly made of water with dissolved ions, nutrients, etc..

• Allows organelles to move around

Cytoplasm (cellular structures)

• Definition: everything between the plasma membrane and the nucleus. Includes cytosol and all organelles.

Nucleus (organelle)

• The largest organelle, that stores, DNA and makes RNA (RNA is used to make proteins)

Nucleolus (organelle)

• a region within the nucleus that makes ribosomes

Mitochondrion, mitochondria pl. (organelle)

Makes ATP (energy for the cell) from glucose and oxygen

Rough endoplasmic reticulum (organelle)

• a network found within the cytoplasm that has ribosomes imbedded in its membrane that makes proteins, destined to become membrane, secretory, and organelle proteins

Golgi apparatus/body/complex (organelle)

• Modifies and packages proteins into vesicles to send them to the proper destination

Lysosome (organelle)

• A storage vesicle that holds a lot of digestive enzymes.


• Function: Breaks down useless or old organelles, provides protection, and gets rid of unneeded substances.

Apoptosis

• Programmed cell death ("cell suicide").


• Importance: Necessary to eliminate cancerous, infected, old, or excess cells (which could form a tumor), helping to maintain homeostasis.


• Example: Every day, our bodies make about 12 cells that can become cancerous; apoptosis helps eliminate them.

Tay-Sachs’s disease

• Caused by a missing or non-functional digestive enzyme in lysosomes, preventing proper brain development, leading to seizures, intellectual disability, blindness, and often death by age 5.

Smooth endoplasmic reticulum (organelle)

Function:


• Metabolizes and makes lipids and carbohydrates

• Stores calcium

• Helps with detoxification of a cell ("the cell's liver").

Free ribosomes (structures in cytosol)

• structures that are used to read RNA and make proteins that stay in the cytosol

Cytoskeleton (structures in the cytosol)

• Definition : Protein fibers that maintain cell shape and are responsible for all movement

  1. Microtubules: maintain cells shape and allow organelles to move within the cell

  2. Intermediate filaments: provide physical strength to the cell; Helps cells resist pulling forces (e.g., keratin in hair and skin). made of keratin

  3. microfilaments: allow allows a cell to move or change shape; made of actin and myosin

Cell cycle

• A series of events that take place in a cell leading to its division and duplication.

Stem cell

• Undifferentiated cells (not fully matured).


• Their shape can change.

• Can replicate themselves or differentiate into many different cell types.

  
  

Types of Stem Cells:


• Totipotent stem cell: Capable of differentiating into any type of cell (e.g., zygote).

• Pluripotent stem cell: Capable of differentiating into many types of cells, but not all (e.g., embryonic stem cells).


• Unipotent stem cell: Capable of turning into one particular cell type (e.g., some tissue-specific stem cells).

-blast

-blast: Suffix indicating a stem cell (e.g., osteoblast - bone stem cell).

-cyte

-cyte: Suffix indicating a mature cell (e.g., osteocyte - mature bone cell).