physiology - cellular Flashcards
types of muscle tissue (3)
striated
smooth
cardiac
primary tissues (4)
muscle
epithelial (forms membranes or glands)
nervous
connective
types of connective tissue (4)
connective tissue proper
cartilage
bone
blood
functions of plasma membrane (4)
- physical isolation - maintain homeostasis
- exchange of things with the outside
- sensitive to environmental changes
- structural support to other membranes
what is the plasma membrane?
phospholipid bilayer. Fluid mosaic model.
contains lipids, proteins (channels), cholesterol, carbohydrates.
phospholipids have hydrophilic heads and hydrophobic tails
Proteins types in membrane (2)
Integral (transmembrane proteins)
Peripheral proteins
glucose requires trans-membrane transporters in order to enter the cell. called GLUT (GLUcose Transporter), GLUT4 is the most common, found in muscle and adipose cells.
Functions of membrane proteins (5)
Receptor - binds to ligands that can trigger changes in the cell.
Enzyme (integral or peripheral proteins). Catalyse reactions in cytosol or extracellular fluid
Channel
Gate
Cell-identity marker (glycoproteins)
Anchoring proteins
Inside cell - bound to the cytoplasm via filaments to give structure
Outside cell - bound to other membranes/ cells to create tissues.
Carrier proteins
Diffusion (passive) or requires ATP (active)
Glucose enters passively, Sodium (Na) and Calcium require ATP to exit into extracellular fluid.
May just be a Gate.
Fluid mosaic model
Some proteins have fixed location (rafts)
Some integral proteins drift across the cell membrane.
Constant remodelling of plasma membrane
Role of carbohydrates (3%) in plasma membrane
Carbohyrates extend out of cell membrane (called glycocalyx). Used for : Lubrication and protection anchoring and locomotion Specificity in binding. Recognition.
sodium/ potassium pump
active transport of sodium and potassium
Large molecule transportation
vesicles; endocytosis and exocytosis
Eg. polypeptides
non-membraneous organelles (5)
cytoskeleton, microvilli, centrioles, cilia, ribosomes
membraneous organelles
endoplasmic reticulum, golgi apparatus, lysosomes, mitochrondria
cytoskeleton
Internal network of proteins to give strength and flexibility.
Ribosomes (two subunits)
produce proteins from messenger RNA. Located in cytoplasm and endoplasmic reticulum.
Ribosomal RNA molecules serve as enzymes for protein synthesis, and proteins.
Smooth E R
site for enzyme reactions, storage and synthesis
Lysosomes
cleanup and recycling of cell. Lack of a specific lysosomal enzyme can cause build up of waste products.
Mitochondria
produce ATP - adenosine triphosphate
Contains their own DNA - therefore originally a separate organism?
Trans-membrane protein transporters and glucose uptake
GLUT4 is the most common and found in muscle and adipose tissue. Insulin binds to insulin receptors on the cell surface and this increases the number of GLUT proteins (glucose transporters)
