CELL GENERALITIES Flashcards
Lacks the membrane-bound structures
Prokaryotic cell
Possesses membrane surrounding the cell nucleus and organelle
Eukaryotic cell
● Stores and transmits genetic information DNA
Nucleus
● Responsible for transcription of mRNA
Nucleoulus
- ATP source
- Krebs cycle
- O2 phosphorylation
Mitochondria
Network of membranes
Endoplasmic Reticulum
- Protein synthesized by ribosomes is processed (in Golgi apparatus)
- Responsible for the translation of proteins
Rough Endoplasmic Reticulum
sites of protein synthesis
Ribosomes
- Enzymes for fatty acids and steroid synthesis
- Stores and releases calcium (more on muscle and cardiac
physiology)
Smooth Endoplasmic Reticulum
- Series of closely apposed flattened sacs
- Concentrates, modifies, and sorts proteins arriving from the rER
prior to their distribution.
Golgi Apparatus
Contains enzymes that are capable of digesting proteins, carbohydrates, lipids, nucleic acids, and other biological material
Lysosomes
- Provides structural support
- Gives structural strength to resist stretch
- Structural supporters and transport pathways
Cytoskeleton
Controls: location and communications of intracellular elements
Cytoskeleton
Mechanism: changing/maintaining shape and movement of the
Cytoskeleton
Separates the internal and extracellular environments
Plasma Membrane
- Composed of a bilayer of amphipathic lipids
- Physical barrier
Plasma Membrane
○ Monolayer structure containing a head and a tail
Micelles
○ Has a tail to tail arrangement
Liposomes
○ Acts as a protective barrier
Lipid bilayer
-The barrier becomes a regulator because:
■ Has a polar surface (has charges)
■ Has specialized membrane components
-Formed by the tail to tail arrangement of the phospholipid
molecules
inside layer and is soluble to fats(tail)
Hydrophobic
outside layer and soluble to water(head)
Hydrophilic
Other phospholipids Bilayer components:
- Cholesterol - stabilize the fluidity of the membrane at normal
temperature. - Sphingolipids
- Membrane proteins - help move large molecules from inside
to outside of the cell or vice versa. - Glycoconjugates - glucose conjugated to a protein.
FUNCTIONS OF PLASMA MEMBRANE
- Regulate the passage of substances into and out of the cell
● Detect chemical messengers arriving at the cell surface
● Link adjacent cells by membrane junctions
● Anchors cell to extracellular matrix
Protrude all the way through the membrane.
Integral proteins
Spans the cell membrane and provides cell communication
Integral proteins
- Provides structural CHANNELS (pores)
- Act as CARRIER proteins for transporting substances that could not penetrate the lipid bilayer
- Serves as RECEPTORS to H2O soluble chemicals such as peptide hormones
Integral proteins
Amphipathic
Integral proteins
Only to the surface and do not penetrate all the way through
Peripheral proteins
Primarily in the cytosolic (inner) side, attached to cytoskeleton elements that influence the cell shape and motility
Peripheral protein
Non-amphipathic
Peripheral protein
● Enable the cell to identify and interact with each other
● Usually extends to the extracellular fluid to form glycocalyx
Carbohydrates
TYPES AND ROLES OF MEMBRANE JUNCTIONS
● Desmosomes
○ Firm physical connections that hold adjacent cells
○ Example: Epithelial cells in the digestive tract
● Tight Junctions
○ Fuses adjacent plasma membranes (no space in between)
○ Well-developed in epithelial cells
○ Histologically basis: lumen to the blood vessels transport
○ Impermeable junctions that prevent molecules from passing
through intercellular space
○ Example: Tissues subjected to stress such as skin, heart, and
muscle
● Gap Junctions
○ Protein channels that link cytosol to facilitate electrical transmission
○ Communicating junction that allows ions and small molecules to pass for intercellular communication
○ Present in electrically excitable tissues such as smooth muscle and heart
Type of cell that generate mechanical force that produces movement
Muscle cell
Type of cell that Initiate and conduct electrical signals
Nerve cell
Connect, anchor, and support the structures of the body
Connective tissue cell
Create a protective barrier that selectively secretes and absorbs ions and organic molecules
Epithelial cell
Organs in the Nervous System
Brain, spinal cord, peripheral nerves and ganglia, special sense organs
Organs in the Musculoskeletal System
Cartilage, ligaments, bones, tendons, joints, skeletal muscle
Organs in the Digestive System
Mouth, pharynx, esophagus, stomach, intestines, salivary glands, pancreas, liver, gallbladder, pancreas
Organs in the Immune System
White blood cells, lymph vessels & nodes, spleen, thymus, and other lymphoid tissue
Circulatory System consists of:
Blood, heart, blood vessels
Defense against foreign invaders
Immune System
System responsible for Transport of blood
Circulatory system
Digestion and absorption of organic nutrients, salts, and water; excretion of waste materials
Digestive System