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Cell Anatomy
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53
Anatomy
Undergraduate 3
08/24/2012

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Term
What is a cell? How many different kinds?
Definition
smallest living units in our bodies
-252
Term
Three main components in a cell?
Definition
1. Plasma membrane- plasmalemma; forms the boundary of each cell
2. Cytoplasm- cytosol+organelles. "little organs" carry out essential functions of cells
3. Nucleus
Term
what is the structure of the plasma membrane model?
Definition
Fluid Mosaic model; phospholipid bilayer interspersed with protein and cholesterol- some carbohydrate.
Term
What component is the most abundent in the plasma membrane?
Definition
phospholipid
Term
types of membrane proteins:
Definition
integral and peripheral proteins
Term
What is an integral protein?
Definition
firmly imbedded in or attached to lipid bilayer
Term
Examples of integral proteins:
Definition
ion channels, carrier proteins, enzymes, receptors.
Term
What is a peripheral protein?
Definition
attach to membrane surface (most on inner portion of bilayer- most attaching to cytoskeletal filaments).
Term
Whats the function of the plasma membrane?
Definition
barrier between cell and extracellular environment (provides barrier against substances outside the cell).
Forms two body fluid compartments
Term
what two body fluid compartments does teh plasma membrane form?
Definition
intracellular- inside of cell (65% of total body water, TBW)
extracellular fluid outside cell (35% TBW)
Term
What are the type extracellular fluid?
Definition
interstitial fluid-surrounds cells
plasma-fluid portion of blood
other- fluid in joing capsules, eye
Term
What determines which substances enter or leave the cell? How?
Definition
Plasma Membrane is selectively permeable
Term
How is the membrane selectiveity permeable?
Definition
transport proteins
endocytosis/exocytosis
simple diffusion
osmosis
Term
What is a phospholipid?
Definition
Phosphate+ 2 long chains of fatty acids orientated in opposite directions (Heads facing out-hydrophillic, tails in-hydrophobic)
Term
How do transport proteins aid in the selective permeable membrane?
Definition
small lipid insoluble molecules are dependent on integral membrane proteins for movement.
Term
What is the movement of larger molecules called?
Definition
endocytosis/exocytosis
Term
What is simple difusion?
Definition
lipid soluble molecules pass directly through lipid bilayer of membrane
Term
What is osmosis
Definition
diffusion of water across a membrane
Term
Whats endocytosis?
Definition
mechanism by which molecules or particles not able to pass through membrane enter cells.
Term
Types of endocytosis:
Definition
phagocytosis-cell eats large particles
pinocytosis- cell drinks
receptor mediated endocytosis
Term
receptor-mediated endocytosis-
Definition
receptor-mediated endocytosis- substance binds to ceratin molecules on membrane, invaginates and forms a coated pit, pinches off to become a coated vesicle
Term
pinocytosis-
Definition
pinocytosis- cell drinks
Term
phagocytosis-
Definition
phagocytosis-cell eats large particles
Term
What is exocytosis?
Definition
mechanism that moves substances out of the cell
Term
How does exocytosis occur?
Definition
substance is enclosed in a secretory vesicle. The vesicle migrates to the plasma membrane. Proteins from the vesicles (v-snares) bind with membrane proteins (t-snares)
The lipid layers from both membranes bind, and the vesicle releases its contents to the outside of the cell.
Term
What lies internal to the plasma membrane?
Definition
cytoplasm
Term
what does the cytoplasm consist of?
Definition
cytosol, organelles, inclusions
Term
What is 50% of the cell volume?
Definition
cytosol- jelly like fluid in which other cellular elements are suspended. Consists of water ions enzymes
Term
How many categories of organelles are there? what are they?
Definition
2- membrane bound and non membrane bound.
Term
What are 5 membrane bound cytoplasmic organelles?
Definition
Endoplasmic reticulum
golgi apparatus
mitochondria
lysosomes
peroxisomes
Term
What is the ER?
Definition
network w/in the cytoplasm. Flattened envelopes(=cisterns)
Term
Types and functions of different ER?
Definition
rough ER- ribosomes stud the external surfaces- synthesis of proteins to be secreted out of the cell.
Smooth ER- consists of tubules in a branching network. No ribosomes are attached therefore no protein synthesis. Lipid (fat) synthesis, detoxifying enzymes, calcium storage.
Term
What is the golgi apparatus?
Definition
stack of three to ten disck shaped envelopes, receives transport vesicles from ER
- post translational processing of proteins
-sorts products of rough ER and sends them to proper destination
Term
3 locations golgi apparatus can send products of rough ER?
Definition
secretory vesicles to plasma membranes, lysosomes, transport vesicles to replace/insert "new" plasma membrane
Term
What is the mitochondria?
Definition
two membranes (inner/outer) and matrix (inner folded into cristae)
Power house of cells- generates metabolic energy=ATP)
enzymes of citric acid cycle (kreb's cycle) in matrix.
electron transport chain on cristae of inner membrane (proteins involved w/ATP production
Term
What are lysosomes?
Definition
membrane walled sacs constaing acid hydrolase (enzyme)
-digests unwanted substances (both intracellular substances plus substances brought into cells)
Term
What are peroxisomes?
Definition
membrane walled sacs of oxidase enzymes
-catalase (enzyme) neutralizes hydrogen peroxide, protects cell
-break down long chains of fatty acids, amino acids, and toxins
-numberous in the liver and kidneys
Term
What are three Non membrane bound cytoplasmic organelles?
Definition
ribosomes
cytoskeleton
centrioles
Centrosomes
Term
what are ribosomes?
Definition
constructed of proteins and ribosomal RNA. It is the site of protein synthesis
Term
Types of ribosomes?
Definition
fixed- attached to ER to synthesis proteins to be secreted by cell
free- loose in cytosol- synthesize non secreted proteins to remain in cell.
Term
what is the cytoskeleton?
Definition
"cell skeleton" an elaborate network of rod like structures.
Term
functions of the cytoskeleton?
Definition
cell movement, mechanical support, contraction, suspension/movement of organelles
Term
3 types of cytoskeleton?
Definition
microtubules cylindrical structures made of proteins (tubuin) hollow
microfilaments- contractile protein actin
intermediate filamets- protein fibers
Term
what are centrioles?
Definition
paied cylindrical bodies that consist of 27 short microtubules (9triplets) act in forming cilia mitotic spindle
Term
what are centrosomes?
Definition
composed of centrosome matrix (proteins) and centrioles
Term
What are temporary structure, not present in all cell types? What do this consist of?
Definition
cytoplasmic inclusions
-pigments, crystals of protein, food stores (lipid droplets found in liver and glycososomes store sugar as glycogen)
Term
What is the nucleous?
Definition
central core or kernel. control center of cell. contains dna.
Term
What does DNA do to the cell?
Definition
directs cells activities
Term
How big is nucleus?
Definition
5 micro meters in diameter
Term
Whats the nuclear envelope?
Definition
two parallel membrane seperated by fluid-filled space, contains pores.
Term
What is chromatin?
Definition
DNA with histone proteins.
-Condensed chromatin, high coiled strands of DNA.
-exteneded chromatin- contains uncoiled strands of DNA, code can be copied into mRNA
Term
Whats the highest level of organization of chromatin?
Definition
chromosomes- containing a long molecule of DNA
Term
What is the center or the nucleus? the little nuclueus?
Definition
nucleolus- contains parts of several chromosomes, site of ribosomes subunit manufacture.
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