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Pathophys lecture 1

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Why is cell biology important?
- all body functions depend on the integrity of cells
- understanding of cellular biology is intrinsically necessary for an understanding of the disease
- an overwhelming amount of information reveals how cells are multicellular "social" organism
(cellular communication "cellular crosstalk" is at the heart of heart of cellular biology
What organisms are without a cell nucleus?
Prokaryotes
whose cells are organizes into complex structures by internal membranes and a cytoskeleton?
eukaryotes
who has no membrane-bound organelles?
prokaryotes
who has a single chromosome that is of circular form?
prokaryotes
who has a well defined nucleus?
eukaryotes
bacteria is an example of what type of organism?
prokaryotes
Nucleus is absent
prokaryotic
has more than one chromosome
eukaryotes
meiosis and the fusion of gametes
eukaryotic
partial, undirectional transfers
prokaryotic
lysosomes and peroxisomes
eukaryotic
microtubules are present in what cell
eukaryotic
(rare in prokaryotic cells)
endoplasmic reticulum is present in what cell
eukaryotic
mitochondria is absent in what cell
prokaryotic
what cell has a cytoskeleton
eukaryotic cells
(may be absent in prokaryotic cells)
describe the dna wrapping on proteins for eukaryotic cells
they wrap their DNA around proteins called histones
describe the dna wrapping on proteins for prokaryotic cells
multiple proteins act together to fold and condense prokaryotic dna. Folded dna is then organized into a variety of conformations that are supercoiled and wound around tetramers of the HU protein
which cell has the larger ribosomes
eukaryotic
the golgi apparatus is absent in what cell
prokaryotic
chloroplasts are present in what cell
eukaryotic cells (in plants)
where is chlorophyll located in prokaryotic cells
in the cytoplasm
what is microscopic in size, membrane bound, and is usually arranged as nine doublets surrounding two singlets
eukaryotic flagella
what is submicroscopic in size and is composed of only one fiber
prokaryotic flagella
what is the permeability of a eukaryotic nuclear membrane
it is selective
do prokaryotic cells have steroids in their plasma membrane
usually no
describe the cell wall of a eukaryotic cell
chemically simpler, only in plant cells and fungi
describe the cell wall of a prokaryotic cell
usually chemically complexed
this cell is 1-10um
prokaryotic cell
this cell is 10-100um
eukaryotic cell
cells differentiate or mature to perform various functions
1. movement
2. conductivity
3. metabolic absorption
4. secretions
5. excretion
6. respiration
7. reproduction
8. communication
three general components of eukaryotic cell
- plasma membrane
- cytoplasm
- intracellular organelles
what is located in the center of the eukaryotic cell
nucleus
is the nucleus the largest or smallest membrane bound organelle
largest
what membrane surrounds the nucleus
nuclear envelope
this is a small dense structure and is composed largely of RNA
nucleolus
chemical blueprints of life
DNA
this binds outside of DNA double helix and protects DNA as well as control what genes are expressed at what time
Histone proteins
which organelle functions in cell division and has control of genetic information
nucleus
the cytoplasm is the aqueous solution (cytosol) fills the space between what structures
nucleus and the plasma membrane
the cytoplasm is half or a third of the volume of an eukaryotic cell
HALF
what is the structure of cytoplasm
cytosol + cytoplasmic matrix + cytoplasmic organelles
does the cytoplasm participate in the synthesis of hormones and proteins and transport
yes
does the cytoplasm assist in the elimination of wastes and metabolic processes
yes
how does the cytoplasm contribute to the cell structure
it maintains the cell structure
does the cytoplasm store fat and carbohydrates
yes
cytoplasmic organelles
- ribosomes
- endoplasmic reticulum
- golgi complex
- lysosomes
- peroxisomes
- mitochondria
- vaults
- cytoskeleton
- plasma membrane
what are ribosomes
ribonucleic acid (RNA)-protein complexes
where are ribosomes synthesized
in the nucleolus
where are ribosomes secreted into
into the cytoplasm
where are the ribosomes located
can FLOAT free in the cytoplasm or is ATTACHED to the outer membrane of the endoplasmic reticulum (ER)
ribosomes are the site for what
protein synthesis
what is the membrane factory for the synthesis and transport of proteins and lipid components of cell organelles
endoplasmic reticulum
endo means..
within
reticulum means..
network
describe the structure of the endoplasmic reticulum
it is a network of tubular or saclike channels
is the endoplasmic reticulum continuous or non-continuous with the outer membrane
continuous
what type of ER is attached with ribosomes and RNA particles and are granular
Rough ER
what type of ER is agranular and has no attachments
Smooth ER
Messages sent through the endoplasmic reticulum is brought to what other structure
golgi bodies
final processing site for proteins (post office of cell)
golgi complex
is the golgi complex a network of bulky, rough membranes and vesicles?
no.. network of flattened, smooth membranes and vesicles
small membrane bound sacs where proteins from the ER are packaged into
transport vesicles
what are the vesicles collected by golgi bodies
cisternae
proteins are processed, packed and released as..
secretory vesicles
they are attached with plasma membrane and RELEASE contents (lipids ,proteins) from the cell
secretory vesicles
lyso means..
dissolution
soma means..
body
this originates from the golgi and contains digestive enyzmes (HYDROLASE)
lysosomes
what is the function of lysosomes
catalyze and breakdown proteins, lipids, mucleic acids, and carbohydrates
- recycling center
what do lysosomes fuse with and dispense their enzymes into in order to digest their contents
autophagic vacuoles
due to the lysosomes autolysis, what are they termed as
suicide bags
the lysosome MEMBRANE prevents the release and auto digestions of what?
the cytoplasm
Primary or secondary lysosomes: they are FRESHLY synthesized by the golgi apparatus
primary
which lysosome contains lysosomal enzymes
primary
which lysosome is formed by the fusion of the primary lysosome and an endocytotic /phagocytotic vesicle
secondary
which lysosome DOES NOT release its contents out of the cell
primary
what can the secondary lysosome release?
it may release USEFUL PRODUCTS (which will serve as building blocks of new materials) into the cytoplasm of the cell, or release waste products/ products that cannot be digested out of the cell via exocytosis
what contains oxidative enzymes, such as catalase, and urate oxidase?
peroxisomes
what do oxidative enzymes do
remove hydrogen atoms from substrates to produce H2O2
this anti oxidant enzyme uses H2O2 to oxidize substrates like ethanol, phenols, formaldehyde
CATALASE
peroxisomes are the major sites of what
oxygen utilization
peroxisomes break down substances down into harmful or harmless products
harmless
peroxisomes are involved in the synthesis of what
phospholipids that are necessary for nerve cell myelination
mitochondrial DNA is inherited from which parent?
the mother
this is responsible for CELLULAR RESPIRATUION and ENERGY PRODUCTION
the mitochondria
the mitochondria participates in what type of phosphorylation
oxidative
what kind membrane is the mitochondria surrounded by
double lipid bilayer
is the outer membrane of the mitochondria smooth or rough
smooth
what does the cristae provide for the mitochondria?
increased inner membrane surface area
the inner membrane of the mitochondria contains enzymes of what cycle
krebs
where is ATP in the ETC produced?
the inner membrane of the mitochondria
does the mitochondria contain their own DNA
yes, their DNA codes for enzymes needed for oxidative phosphorylation
what are the ribonucleoproteins?
the vaults
vaults are the shape of?
octagonal barrels
what do the vaults carry?
they carry messenger RNA (mRNA)
what are the "bones and muscles" of the cell?
the cytoskeleton
the cytoskeleton maintains the cell's what?
the cell's shape and internal organization
what kind of movements does the cytoskeleton permit?
movement of substances within the cell and movement of external projections (cilia or flagella)
what is a component of the cytoskeleton?
microtubules
what forms the microtubules?
by the polymerization of a dimer of two globular proteins, ALPHA and BETA tubulin
microtubules are involved in what processes?
chromosome separation (mitosis and meiosis)
what are the cylindrical cell structure composed of microtubules
centriole
what are the actin filaments
microfilaments
are the microfilaments the thinnest or thickest filaments of the cytoskeleton?
the thinnest
are microfilaments strong or weak
they are flexible and strong
why are microfilaments important?
important in cell reproduction and movement
plasma membranes provide what?
-selective transport system (movement of substances in and out of cells)
-cell to cell recognition (receptors for hormones)
-cellular mobility and shape
what are the components of the plasma membrane
hydrophobic and hydrophilic
is the plasma membrane semi or im permeable
semi permeable and fluid like
what is the modern theory of the plasma membrane
lipid bilayer
hydrophobic
water fearing
hydrophilic
water loving
lipid bilayer model: cell membrane consists of ..
primarily of a thin layer of amphipathic phospholipids
randomly arranged in what ways..
- hydrophobic TAIL regions are isolated from the surrounding polar fluid
- hydrophilic HEAD regions associates with the intracellular (cytosolic) and extracellular faces of the resulting bilayer
cell membrane is impermeable to what
water soluble molecules (due to oily core)
cell membrane allows the diffusion of what
lipid soluble molecules, like O2 and CO2
plasma membrane structure that is for transport and exchange; cave like domains
caveolae
amphipathic lipids
- hydrophilic and hydrophobic
- phospholipids, glycolipids
proteins are made from
chain of amino acids known as polypeptides
proteins are major what of the cell
work horses
what do proteins include
integral, peripheral, and transmembrane
what are the functions of proteins
-receptors
- transporters
- enzymes
- catalysts
proteases
enzymes that breakdown proteins
ribosomes are nucleoproteins that are synthesized in ..
nucleolus
the plasma membrane of a cell is composed primarily of ..
amphipathic molecules
cellular receptors are protein molecules on the ..
plasma membrane, cytoplasm, or nucleus
proteins bind with ..
LIGANDS (smaller molecules, eg. hormones)
-must fit together - 'lock and key'
categories of cellular receptors
- channel linked receptors
- enzyme linked receptor
- g protein coupled receptors
- membrane permeant signaling molecules activate intracellular receptors
cellular communication maintains what
- homeostasis
- regulates growth and division
- coordinates various functions
contact dependent
paracrine
autocrine
hormonal (aka endocrine signal)
neurohormone secretion
neurotransmitter - diffuse across the synaptic cleft and act on postsynaptic cells
also known as cell signaling, the transmission of molecular signals from a cell's exterior to its interior is known as ..
signal transduction
first messengers
-EXTRACELLULAR MESSENGERS that convey instructions to the cell's interior
- transfer, amplify, distribute and modulate
- CHANNEL REGULATION
- opens and closes gate
second messengers
two pathways, Adenosine monophosphate (cAMP) and Ca++
...
...
...
...
cAMP is a what
intracellular second messenger
...
one sided communication - exterior to interior
Ca++ as a second messenger activates calmodulin
...
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