functional anatomy of cells Flashcards
4 major cell structures of eukaryotic cells
- Plasma membrane
- Cytoplasm
- Nucleus
organelles
cell membrane structure
Contain a variety of membranes:
1. PLASMA MEMBRANE: encloses the cell 2. ORGANELLE MEMBRANES: sacs and canals made of the same material as the plasma membrane that enclose organelles such as the ER and Golgi 3. Membrane structure-lipid bilayer of phospholipid molecules
how do membranes function in physiology
- Control transport in and out of cell-urinary system ex: wtaer channels
- Allow selective receptivity and signaling via transmembrane receptors-endocrine
- Surface glycoproteins-immune system
- Anchor for cytoskeleton or ECM. Imp for movement, tissue structure
- Cell signalling provides sites for the binding and catalysis of enzymes
Provide a passageway across the membrane for certain molecules, such as in gap junctions. Cell-cell communication-intrinsic control
surface glycoprotein and immune surveillance
- Self markers (MHC) - molecules on the surface of human cells that are unique to an individual, thus identifying the cell as self to immune system
- SELF-TOLERANCE: the ability of our immune system to attack abnormal or foreign cells bt spare our own normal cells
NON-SELF MARKERS: molecules on the surface of foreign or abnormal cells or particules act as flags to the immune system as non-self
- SELF-TOLERANCE: the ability of our immune system to attack abnormal or foreign cells bt spare our own normal cells
endocrine system: structure + functions
Structure: membrane receptor
Functions: when bound by a ligand triggers an intracellular signaling cascade that will alter intracellular activities ex: FSH hormone receptor
functions of proteins in cell membrane in cell adhesion
1.
STRUCTURE: integral (span entire membrane) membrane proteins
FUNCTIONS: binds other integral membrane proteins to form cell-cell connections
2.
STRUCTURE: integral membrane proteins
FUNCTIONS: binds ECM to give structure to tissues
integrins: an example of structural adhesin protein
- Function in cell adhesion
- Join cell-to-cell or cell to ECM
- Heterodimer made of an alpha or Beta subunits
- Integral proteins
- Involved in:
1. Wound healing
2. Angiogenesis
3. Development
4. Embryo attachment
Cancer invasion
cytoplasm
Gel-like internal substance of cells that includes many organelles suspended in watery intracellular fluid called cytosol
2 major groups of organelles
- MEMBRANOUS ORGANELLES are specialized sacos or canal made of cell membrane
Ex: golgi, ER, plasma membrane, lysosomes, proteosomes- NONMEMBRANOUS ORGANELLES are made of microscopic filaments or other nonmembranous materials
Ex: cytoskeleton, ribosomes, cilia and flagella, nucleolus (important for formation of ribosomes)
- NONMEMBRANOUS ORGANELLES are made of microscopic filaments or other nonmembranous materials
endoplasmic reticulum
- STRUCTURE: made of canals with MEMBRANOUS WALLS present throughout the cytoplasm; extend from the nucleus to the plasma membrane
- FUNCTIONS: think of the ER like a river circulating through the cell for protein transport to get from the cucleus to the cytoplasm to the cell surface for release. Protein move throught the canals
2 types of endoplasmic reticulum
- Rough endoplasmic reitculum:
- RIBOSOMES found on the outer surface of the membranous walls
- Ribosomes synthesize proteins
- Function in proteins synthesis and intracellular transportation
- Transports protein to Golgi
- Smooth endoplasmic reticulum
- DOES NOT HAVE RIBOSOMES on the membranous wall
- Synthesizes certain lipids and carbohydrates
- Makes membrane for use throughout the cell
- Removes and stores CA+ from cells interior. ** important for muscle contraction, and in hormone production
route of protein transport
- Ribosomes on ER synthesize proteins and these ones move through the canals of the ER and are folded and assemble into macromolecular groups
- Proteins destined for cell export or cell membrane (RER)
The proteins then go to the golgi complex to be modified
- Proteins destined for cell export or cell membrane (RER)
5 steps: 1. Proteins made on ribosomes on ER 2. Travel through ER 3. Leave ER in vesicle fuse with Golgi 4. Modified in golgi Vesicle fuses with plasma membrane for release of protein outside the cell
ribosomes-protein factories
- Ribosomes (non-membranous)
- Many are attached to the rough endoplasmic reticulum and many lie free, scattered through the cytoplasm
- Each ribosome is a NON-MEMBRANOUS structure made of 2 pieces, a large subunit and a small subunit; each one is composed of rRNA (ribosomal RNA)
- Free ribosomes make proteins for the cells domestic use
- Those attached to the ER make protein for export
Working ribosomes form groups known as polyribosomes
Golgi
Gogli apparatus:
STRUCTURE: MEMBRANOUS organell consisting of cisternae stacked on one another and located near the nucleus
FUNCTIONS: processes and packages PROTEIN MOLECULES from th endoplasmic reticulum. Proteins are modified by enzymes residing in the golgi. For ex: attachment of a carbohydrate group
- Processed proteins leave the final cisternae in a vesicle; contents may then be secreted to outside the cell
lysosomes
STRUCTURE: made of microscopic MEMBRANOUS SACS that have pinched off from gogli apparatus
FUNCTIONS:
1. cell digestive/recycling system performed by enzymes
2. Break down proteins, food molecules, foreign particules (neutrophils) suc as bacteria, old organelles
3. Amino acids are recycled
** TAY-SACHS DISEASE caused by a failure to produce an enzyme needed to break down LIPIDS-GANGLIOSIDES (FA derivatoves found in all cell membranes)