Test 1 Flashcards
3 Main Parts of Cell
1) Plasma membrane
2) Nucleus
3) Cytoplasm (Cytosol is the liquid portion of the cytoplasm)
Plasma Membrane Function
- Flexible outer surface
- separates outside and inside of cell
- cellular communication
- regulates what goes in and out of a cell
- selectively permeability
Fluid Mosaic Model
- most lipids easily rotate and move sideways in their own 1/2 of the bilayer
- lipids change places
- membrane fluidity allows the assembly of membrane proteins, movement of membrane components, self-sealing
Function of Membrane Proteins (Peripheral and Integral)
- cell to cell communication
- channels/carriers
Passive Transport
1) Simple diffusion - area of high concentration > lower concentration
2) Facilitated diffusion - channel/carrier mediated w/o expenditure of energy
Osmosis
- net movement of water across plasma membrane
- simple diffusion + water channels (aquaporins)
Primary Active Transport
- uses energy from ATP
- carriers called pumps
- most common: Na+/K+ ATPase
- Function: maintains Na+ and K+ inside the cell
Secondary Active Transport
- energy stored in the Na+ and H+ concentration gradient is used to drive other substances cross the membrane
- symporters & antiporters
Tonicity of Cells
- shrivelled if placed in hypertonic solution
- normal in isotonic
- swollen in hypotonic
Vesicles Transport
- Active transport requires the use of energy in the form of ATP to move molecules in & out of the cell
- Molecules move against their concentration gradient
- Uses integral proteins
Endocytosis
- substances brought into cell
- phagocytosis
- receptor-mediated endocytosis
- pinocytosis
Exocytosis
- cells release materials to surroundings
- all cell carry out exocytosis
- neurons release neurotransmitters, etc.
Cytoskeleton
- Network of protein filaments
- provide structure to the cells and organizes cell content
- help with movement of organelles, chromosomes, and whole cell
- microfilaments (actin), intermediate filaments, microtubules
Mitochondria
•Contains DNA and many enzymes
•Power house of the cells = Produces ATP
•Regular exercise increases the number of mitochondria in
muscle cells, increasing efficiency
Endoplasmic Reticulum
1) Smooth ER - no ribosomes, makes phospholipids for membrane, detoxification, stores calcium
2) Rough ER - contains ribosomes, synthesizes proteins to be exported, modifes new proteins
Ribosome
- organelles composed of proteins and rRNA
- free floating site of protein synthesis
- small and large subunit
Golgi apparatus
- modifies, packages, sorts and transports proteins, synthesizes lysosomes
- proteins comes from ribosome on ER, then to Golgi, then to designated area
Lysosome
-Vesicles with powerful digestive enzymes
Proteasomes
- barrel shaped organelle
- breaks down damaged, unneeded and abnormal proteins
Nucleus
- directs cellular activity
- surrounded by nuclear envelope
- genes, composed of DNA are found here
- nucleolus (produces ribosomes)
Cell Cycle
1) Interphase - G1 phase, S phase, G2 phase
2) Mitotic Phase (prophase, metaphase, anaphase, telophase)
Transcription
- DNA > RNA
- mRNA makes copy of the DNA instructions
- goes to ribosomes, site of protein synthesis
Translation
- RNA > protein
- mRNA goes to ribosome, tRNA brings a.a. to ribosomes
- forms polypeptide chain
Epithelial Tissue Characteristics
- covers all body surfaces
- lines internal passageways
- forms glands, main glandular tissue
- attached to basement membrane
- polar - apical and basal surfaces
- has nerve endings
- cells reproduce rapidly
- avascular
- tightly packed together
Epithelial Tissue Functions
- Physical protection - against abrasions
- Selective permeability - into and out of body
- Secretions - forms glands, secrete mucus
- Sensations - sends stimulus to CNS
Simple squamous
- single layered, most delicate
- absorption/diffusion
- respiratory system, ventral body cavities, circulatory system
Simple cuboidal
- single-layered cube shaped
- provides limited protection, absorption, secretion
Stratified squamous
S K I N
Stratified cuboidal
-fouund along ducts of sweat and mammary glands
Simple columnar
-small intestine, secretion