Lectures 2-3: Cytology I And II Flashcards
Cytology definition
Study of the cell
Cytoplasm historically known as
Protoplasm
Function of plasma membrane
Surround nuclear envelope and cytoplasm
Nuclear envelope contains
DNA
Cytoplasm contains (3)
-cytosol
-suspended organelles
-cytoskeleton
What is cytosol
Matrix of H20 and solutes contained in cytoplasm
Unit membrane definition
Selective barrier around some cells and organelles
What is the difference between a plasma membrane and a unit membrane
No difference
Components of phospholipid
-hydrophobic tails
-hydrophilic heads
2 faces of plasma membrane
-E face
-P face
Orientation of phospholipids in bilayer
-hydrophilic heads face towards ECF/cytoplasm, hydrophobic tails face inwards on each other
-E face: faces ECF
-P face: faces cytoplasm
Other components found in plasma membrane (2)
-peripheral and integral proteins
-glycocalyx
Glycocalyx
Sugar coat on E face
2 main types of cellular transport
-passive
-active
Passive transport definition
No energy required
Diffusion
-gradient dependent
-passive
Membrane transport
-requires membrane transport proteins
-may be active or passive
Vesicular transport definition
Transportation of material into or out of cell by membrane bound vesicles
Is vesicular transport active or passive
Active because need to make membrane
2 types of vesicular transport
-endocytosis
-exocytosis
Endocytosis aka
Absorption
Exocytosis aka
Secretion
Exocytosis process: general (3)
-material packaged into secretory vesicles by Golgi apparatus
-transported to plasma membrane
-fuse with plasma membrane and released into ECF
2 types of exocytosis
-regulated
-constitutive
Regulated exocytosis process (4)
-vesicles congregate near plasma membrane
-secretory granules, vesicles waiting for signal will concentrate product
-secretions condense
-signaled release into ECF
Example of cells that use regulated exocytosis
-goblet cell
-cells that secrete mucous
Constitutive exocytosis
-continuous secretion into ECF (immediate)
-no accumulation of vesicles
-no signaling
Examples of cells that use constitutive exocytosis
-fibroblasts
-plasma cells
3 types of endocytosis
-pinocytosis
-phagocytosis
-receptor mediated endocytosis
Endocytosis process (2)
-plasma membrane in folds to form vesicle containing inbound material
-vesicles fuse with lysosomes
pinocytosis aka
cellular drinking
main function of pinocytosis
-membrane trafficking: recycling plasma membrane to maintain size of cell
what is taken up during pinocytosis
water, small dissolved solutes
pinocytotic vesicles aka
caveolae
phagocytosis aka
cellular eating
phagocytosis definition/what is consumed
engulfing large particles, cell debris, bacteria
what is a unique feature of phagocytosis (what do they use to consume things)
pseudopodia
phagocytosis process (4)
-pseudopodia extend/surround material
-phagosomes (vesicles) are formed
-phagosomes fuse with lysosomes
-lysosomes process/degrade/recycle material
example of a phagocytic cell
macrophage
characteristics of phagocytic cell (2)
-pseudopodia
-phagosomes, lysosomes, phagolysosomes
main function of phagocytosis
host defense and cleanup after injury
membrane trafficking during endocytosis vs exocytosis
-endocytosis: portions of cell membrane become endocytotic vesicles
-exocytosis: cell membrane returned to cell surface
organelle definition
intracellular structure that performs specific cellular function
how many organelles are found in animal cell
7
what are the 7 organelles found in animal cell
-nucleus
-ribosomes
-rough ER
-golgi apparatus
-lysosomes
-mitochondria
-smooth ER
4 components of nucleus
-nuclear envelope/plasma membrane
-nuclear pores
-chromatin/DNA
-nucleolus
function of nuclear pores
let DNA/RNA out of cell
function of nucleolus
assemble rRNA/ribosomes
chromatin definition
strands of DNA
2 types of chromatin
-euchromatin
-heterochromatin
euchromatin
-uncoiled DNA because busy with active transcription
-more electron lucent so appears pale
heterochromatin
-coiled DNA because inactive (so DNA is condensed)
-more electron dense so appears dark
a large, open/vesicular nucleus with more euchromatin is indicative of a more _______ cell
active
ribosomes main function
make proteins
2 types of ribosomes
-free ribosomes (polyribosomes)
-ER bound ribosomes
free ribosomes (polyribosomes) create what kind of proteins
cytoplasmic –> stay in cytoplasm
ER bound ribosomes create what kind of proteins/enzymes
membrane and secretory proteins, lysosomal enzymes
ER bound ribosomes must be attached to __________ in order to leave the cell
golgi apparatus
rough ER definition
interconnected, flattened membranous sacs for protein synthesis
outer surface of rough ER contains:
ER bound ribosomes
inner lumen of rough ER contains
cisterna
cisterna: function
where proteins are synthesized
a cell containing a lot of rough ER most likely functions in ___________
secretion
golgi apparatus definition/function
interconnected, flattened sacs where proteins from rough ER are processed, sorted, packaged within cisterna
rough ER vs smooth ER
smooth ER does not have ribosomes
rough ER to golgi apparatus: 3 destinations
-unit membranes
-secretion (secretory vesicles)
-lysosomes
lysosomes structure
-spherical
-membrane enclosed
lysosome digestive compartments
enzymes (acid hydrolases) that process/degrade lysosomal contents
why do lysosomes have varied electron densities
because concentration of digestive compartments vary according to specific function
what do lysosomes fuse with (3)
-autophagosomes
-endocytotic vesicles
-phagosomes in specialized cells
mitochondria function
ATP synthesis
mitochondria shape
rod shaped
how many membranes do mitochondria have
2
mitochondria: 2 unit membranes structure
-outer is smooth
-inner is folded and forms cristae
what indicates the energy requirements of the cell
number of mitochondria
what are cristae
-folds of inner membrane of mitochondria that provide greater surface area
-extend into matrix
most common place where vesicular mitochondria are found
steroid hormone producing cells
smooth ER structure
interconnected membrane enclosed tubules (not sacs)
smooth ER is abundant in what kind of cells (2)
-cells that detoxify (liver)
-cells that secrete steroid hormones
is smooth ER present in all cells
yes
main functions of smooth ER (3)
-autophagy
-synthesize lipids, cholesterol, and triglycerides
-metabolism
3 cytoskeletal elements found in animal cells
-actin
-intermediate filaments
-microtubules
3 functions of cytoskeleton
-cell morphology/shape
-cell mobility
-interact with extracellular matrix
actin are what kind of filaments
thin
which filament has the smallest diameter
actin
functions of actin (4)
-anchor cells to each other and extracellular matrix
-form structural core of microvilli, stereocilia
-movement (contraction, extending)
functions of intermediate filaments (2)
-cell to cell adhesion
-cell to extracellular matrix adhesion
features of intermediate filaments (2)
-high tensile strength
-constructed of different substances in different cells
what is the largest cytoskeletal component
microtubules
functions of microtubules (3)
-provide rigidity to cell shape
-aid intercellular transport
-movement of cell, cilia, flagella
how do we differentiate actin from microtubules
-microtubules have a lumen
microtubules are a structural component of: (3)
-centrioles
-basal bodies
-cilia
inclusions: definition
substances in cytoplasm not dissolved and not membrane bound
examples of inclusions
-glycogen
-pigment
-lipids
2 functional faces of golgi apparatus
-cis face
-trans face
where does cis face of golgi face
rough ER
where does trans face of golgi complex face
plasma membrane
2 ways cristae extend into matrix
-as broad flattened folds of inner membrane
-as tubular folds of flattened membrane
in vesicular mitochondria, how do cristae extend into matrix (shape)
tubular folds
rough ER vs smooth ER shape
-rough ER is membranous sacs
-smooth ER is membrane enclosed tubules
