Basic Science Flashcards
The cell is the basic ____ building block of life
metabolic
Most mammalian cells are ___um in size vs bacterial cells that are ___um
10-100um; 1um
T/F: larger organisms contain larger cells
FALSE: they contain more cells
how many modes of specialization do vertebrate cells have?
400
What is a cell?
complex membrane-bounded aqueous gel
How are eukaryotic cells distinguished?
well-developed membrane system that envelopes the nucleus and partitions many cellular compartments
What else does the body contain in substantial amount other than cells? (2)
- intercellular material (insoluble, fibrous)
- intercellular fluid
T/F: tissues are made up of only one type of cell
FALSE: most contain mixture
what are the 4 primary tissues?
- epithelium
- connective tissue
- muscle tissue
- nervous tissue
T/F: all 4 types of tissue are present in a single organ
yes (often)
What are organ systems?
multiple organs that collectively perform an associated function
the organized patterns of cells to form tissues relies on cell ____ and _____
adhesion; cohesion
what are the smaller subunits found in cells called?
organelles
- T/F: organelles are in the sub-micrometer range
- T/F: organelles can be visualize with light microscopes
- TRUE
- FALSE: only seen by electron microscope
Organelles are found within what part of the cell? What does it look like?
protoplasm; gel-like substance
what can the protoplasm be subdivided into?
karyoplasm and cytoplasm
place the term with the correct definition: (cytoplasm/karyoplasm)
- found between the cell membrane (plasma membrane) and nucleus
- nucleus that surrounds the DNA
- cytoplasm
- karyoplasm
what’s the difference between cytosol and organelles?
cytosol = fluid component of the cytoplasm
organelles = insoluble, structural and functional components found in it
phospholipid bilayer membranes contain the ____
protoplasm
T/F: all organelles are membrane-bound
FALSE
which organelles are membrane-bound? (9)
- cell/plasma membrane
- cell membrane lipids
- cell membrane proteins
- endoplasmic reticulum
- Golgi apparatus
- secretory granules
- lysosomes
- endosomes
- peroxisomes
Phospholipid bilayers are __ based on the amount of ___ they contain. More cholesterol makes them ___ fluid
fluid; cholesterol; less
Cell membranes are visible in the (light/electron) microscope
electron
how do leaflets and polarity relate to cell membranes?
lipid bilayers contain inner and outer leaflets and each have hydrophilic heads with hydrophobic tails
what is the most common molecule in membranes? what does it contain?
phospholipids
1. polar head group of glycerol
2. 2 hydrophobic hydrocarbon tails (FATTY ACIDS)
membrane proteins extend from the (inner/outer) leaflet into the ____ space
outer; extracellular
the abundance of cell membrane proteins is known as?
glycocalyx (cell coat)
What’s the difference between transmembrane (integral) proteins and peripheral membrane proteins?
transmembrane proteins span the entirety of the lipid bilayer
peripheral membrane proteins are only at the inner or outer leaflets
what are the characteristics of the rough ER?
- ribosomes (seen in electron microscope)
- flattened saccules (rER cisternae)
where are cell membrane proteins and proteins destined for secretion assembled initially?
rER
the sER is (more/less) abundant than the rER in cells
less
what are the characteristics of the sER and what is its function?
devoid of ribosomes and continuous with the rER
function in detoxification of toxic materials, lipid metabolism and synthesis of steroids, cholesterol, triglycerides (in muscle cells –> stores Ca ions)
what is the Golgi apparatus made of?
Golgi cisternae (saccules)
what are the functions of the Golgi apparatus? (2)
- receives lipids and proteins from ER and dispatches them
- synthesizes carbohydrates
what do the saccules of the Golgi look like? what are the different faces of the saccules?
stacked and slightly curved with (like kitchen bowls), with the bowls facing outwards
convex bottom = cis/proximal face
concave open = trans/distal
how can sacculues change?
perforated (fenestrated) to form net-like structure
at periphery gives rise to secretory granules
what do the cis/trans Golgi networks do?
secretory granules are released from the trans Golgi face, passing through the trans Golgi network
what are lysosomes and what do they do?
membranous vesicles of hydrolytic enzymes (ACID HYDROLASES)
degradation of macromolecules
how do lysosomes and endosomes work together?
lysosomes receive material by the endosomes via the endocytic pathway
what are peroxisomes and what do they contain?
rich in oxidative enzymes, notable CATALASE and URATE OXIDASE
what is the function of peroxisomes?
produce hydrogen peroxide and use it to oxidize toxic molecules from the bloodstream (i.e., alcohol)
what happens when the oxidative enzymes in peroxisomes have very high concentrations?
they form a protein crystal (crystalloid core)
the nucleus is separated from the ___ by the ___
cytosol; nuclear envelope
what structure is the nuclear envelope similar to and how is it different?
endoplasmic reticulum; only posses ribosomes on outer surface
why is the nuclear envelope perforated by nuclear pores?
selective exchange of material btw the nucleoplasm and cytoplasm
what 3 structures are found in the nucleus?
chromatin, nucleolus and nucleoplasm
how do heterochromatin and euchromatin differ?
heterochromatin is condensed chromatin
euchromatin is dispersed chromatin
what is the nucleolus?
transient structure that only appears during interphase state of cell division
describe the structure of the mitochondria (3)
- large amounts of unfolded membrane, providing large surface area for electron-transport processes
- outer and inner mitochondrial membranes (phospholipid bilayer)
- matrix space and inner-membrane space
the enzymes of respiratory chain are embedded in the ___ of the mitochondria which are essential to the process of ____, generating ___ molecules of ATP
inner membrane; oxidative phosphorylation; 30
what is the major working part of the mitochondrion?
inner membrane and mitochondrial matrix
what happens to the highly unfolded inner membrane of the mitochondria?
form cristae (transport proteins)
compare large lipid droplets vs smaller lipid fat droplets
large droplet:
- called adipocytes
- fat/triglyceride (3 molecules of fatty acid + glycerol)
small droplet:
- adjacent to mitochondria
describe glycogen (3)
- found in the cytoplasm
- large, branched polymer of glucose
- forms granules and clusters called rossettes
what is the purpose of the cytoskeleton and what are its 3 types?
gives cell its shape, capacity to move, ability to arrange its organelles, transport
microtubules, intermediate filaments, microfilaments (actin)
T/F: most organelles are attached to the cytoskeleton and can be moved by cytoskeletal rearrangements
TRUE
match the term with its correct definition (microtubule, intermediate filament, microfilaments):
- primary organization of cytoskeleton
- movement
- mechanical strength
- microtubules
- microfilaments
- intermediate filament
what do the 3 types of cytoskeleton have in common?
exert their function by polymerization reactions (rapidly elongate)
describe microtubules (3)
- emanate from the centrosome which contains pair of complex micro tubular structures (CENTRIOLES)
- low hollow cylinders
- made of tubulin
describe intermediate filaments (3)
- ropelike fibers
- structural support
- transmit mechanical stresses across cells
describe microfilaments (2)
- double stranded, helical polymers of ACTIN
- flexible and dispersed throughout
what is the most abundant protein in many eukaryotic cells?
actin
T/F: all actin is in a polymerized, filamentous state
FALSE
what are the two forms of epithelial tissue?
sheet of cells and glands
what are the 3 derivation of epithelia?
- ectoderm
- endoderm
- mesoderm
what are the functions of epithelia? (6)
- protection
- thermoregulation
- transport
- secretion
- absorption
- sensation
T/F: the epithelia’s nucleus is stained pink and its cytoplasm is stained blue
FALSE: nucleus is stained blue and cytoplasm stained pink
what is the epithelia?
epithelium is a sheet of cells, making up a tissue that covers a surface
what two things do epithelium cover?
- borders surface or space
- borders basement membrane/basal lamina
what’s the difference between basement membrane and basal lamina?
basement membrane is the light microscopic term
basal lamina is the electron microscopic term
what does the basement membrane separate?
the epithelium from the connective tissue
what is the difference between simple epithelia and stratified epithelia?
simple: one cell thick
stratified: multiple layers thick
where do the epithelial names derive from?
shape of the surface cells (i.e., squamous, cuboidal or columnar)
what is connective tissue?
space between two epithelial linings made up of cells and extracellular material
give an example of:
1. cellular connective tissue
2. acellular connective tissue
- blood and marrow
- bone
why is connective tissue space important?
physiological background for diffusion of nutrients to the tissues and of waste products from tissues to blood
what are the functions of binding and connecting connective tissues? explain (3)
- connects tissues together and provides flexible support
- nutritive and excretory role: carries capillaries that supply nutrients to cells and remove metabolic products
- defence: swelling/edema and there is steady state btw plasma lost from blood and lymph collected by lymphatic vessels
what cells are found in the connective tissue? (6)
- mesenchyme
- fibroblast
- fibrocyte
- macrophage
- mast cell
- plasma cell
what do inter or extracellular substance consist of? (3)
secretion products of:
1. fibrous elements
2. amorphous ground substance
3. minerals of calcium phosphate
what are the fibrous elements of connective tissue?
- collagen
- elastic fibres/laminae (from elastin)
- reticular fibres (type 3 collagen with small fibril size)
T/F: elastin is selectively stained with Verhoff’s hematoxylin, giving a black color
TRUE
what are collagen and elastin synthesized and secreted by? (6)
- fibroblasts
- fibrocytes
- osteoblasts
- osteocytes
- odontoblasts
- cementoblasts
elastin is synthesized by two additional structures. which ones?
- chondrocytes (elastic cartilage)
- smooth muscle fibers
describe mesenchymal stem cells (3)
- embryonic cell of mesodermal origin (between outer/inner ectoderm)
- gives rise to endothelial cells of blood vessels, blood cells and fibroblasts
- abundant at early age and decreases throughout life
describe fibroblasts/fibrocytes (3)
- abundant in young forming tissue, decreases as connective tissues form
- participate in turning over the EM
produce collagen, elastin, noncallegnous proteins and proteoglycans - has rER, Golgi and secretory granules
describe macrophages (3)
- “large-eater” (large nucleus and cytoplasm)
- cytoplasm has inclusions that are phagocytosed particles
- functions in defence
the process of particle internalization, through extended pseudopods from the cell membrane to then form a ____ with the cell which then fuses with enzyme-loaded, low-pH ____ for degradation to form a ____. this process is called ____
phagosome; lysosomes; phagolysosome; phagocytosis
what are phagolysosomes that cannot complete degradation called? what is an example?
residual bodies; tattoo ink
what are histiocytes and how do they compare to macrophages? (2)
- less migratory and local macrophages
- active in phagocytosis
what do macrophages secrete?
- immune, anaphylaxis and inflammation substances
- chemokines
what are foreign body giant cells?
fused macrophages that surround very large particles that have entered the connective tissue
describe mast cells (3)
- cell of lymphatic system
- secrete heparin and histamine (glycosaminoglycans), slow-reacting substances of anaphylaxis, eosinophil chemotactic factor of anaphylaxis
- secretion by simultaneous fusion of membranes in all granules allows entire cell to degranulate for massive simultaneous release
T/F: mast cells are specialized in synthesis of proteins as antibodies (immunoglobulins)
TRUE
describe multiocular adipocytes (4)
- liberated as heat (hibernating gland)
- form brown fat (color due to blood supply/mitochondria)
- smaller
- larger number of small individual lipid droplets
describe the extracellular matrix and its functions
- secretion product of the connective tissue cells
functions:
1. signals
2. communication
3. protection
4. compartment
5. transport
6. controls diffusion
what three component fibres are recognized in the elastic network (what are they)?
- oxytalan fibres (bundles of microfibrils)
- elaunin fibres (microfibrils embedded in amorphous elastin)
- elastic fibres (contains amorphous elastin surrounded by microfibrils)
T/F: elastic components can only exist as fibres
FALSE: fibres OR LAMINAE
what are the 4 types of collagen fibres?
type 1. ordinary connective tissue and bone
type 2. cartilage
type 3. reticular
type 4. basal lamina
describe type 1 collagen fibres (3)
- macromolecule
- 3 helically wounded molecules called alpha chains
- collagen secreted from the Golgi apparatus
describe the reticular fibers (2)
- small
- located beneath basal laminae of epithelia and smooth muscle fibres
how can adipocytes be found (2)?
- dispersed in connective tissue
- connective tissue space as adipose tissue
describe mature adipocytes
- large central lipid droplet
- thin rim of cytoplasm
- associated organelles relegated to perimeter of cell
explain the link between lipids, fatty acids, VLDL
- lipids stored as triglycerides (esters of fatty acids and glycerol)
- fatty acids come from diet and brought to adipocytes by CHYLOMICRON TRIGLYCERIDES in the form of very low density lipoproteins
chylomicra and VLDLs are hydrolyzed at the ____ of blood capillaries by ____
luminal surface; lipoprotein lipase
in the adipocyte, the resultant fatty acids combine with ___ to form ____ which deposits in the ____
glycerol phosphate; triglycerides; triglyceride lipid droplet
what does insulin do in adipocytes?
accelerates fatty acid synthesis
Describe Alzheimer’s disease (3)
- Neurodegeneration in regions including the hippocampus
- Neuropathology includes beta-amyloid plaques (molecular marker)
- ApoE4 allele is a risk factor
what are the beta-amyloid plaques made of? how do they arise?
- Plaques made of a degradation product of the amyloid precursor protein
- Mutations in the APP or enzymes that degrade it (PS1/PS2) –> early-onset AD
T/F: a healthy brain has no beta amyloid in it
FALSE: Healthy person has some beta amyloid but it’s everywhere in AD brain
what is dilantin? how does it work?
- used for epilepsy
- suppresses seizures without sedation by blocking vgated Na+ channels
describe inherited erythromyelalgia
- rare/monogenic inherited disorder
- episodes of redness/pain in feet/hands
- caused by mutations in the Nav1.7 Na+ channel (makes channels more likely to open)
describe the outcome of a mutation in Nav1.7 that causes NON-FUNCTIONAL changes
congenital insensitivity to pain
how do we understand complex disorders?
by studying rare disorders that are rue to a single gene mutation
what did we learn from studying IE?
neuropathic pain involves abnormal function of Nav1.7
T/F: sporadic diseases are due to mutations of multiple genes
TRUE
what two ways have looked at restoring function in patients with spinal cord damage?
- use brain activity recorded from motor cortex to guide a robotic limb
- transmit activity recorded in motor cortex to neurone in the spinal cord
