Chapter 3: Cellular Form and Function Flashcards
scientific study of cells
Cytology
All cell is the simplest structural and functional unit of life
All organisms composed of cells and cell products
Cell division makes new cells
Modern cell theory
Bacteria: No internal membrane
Prokaryotes
Humans: membrane bound organelles
Eukaryotes
Cell membrane, DNA, Ribosomes -build proteins
Both Prokaryotes and Eukaryotes
cell that is thin and flat with nucleus creating bulge
squamous
cell that is irregularly angular shapes with four or more sides
Polygonal
cell that is starlike shape
Stellate
cell that is squarish and about as tall as is wide
Cuboidal
cell that is taller than wide
Columnar
cell that is round to oval
Spheroid to ovoid
cell that is disc-shape
Discoid
cell that is thick in middle, tapered toward the ends (football)
Fusiform
10-15 micrometers in diameter
- egg cells
- nerve cells
Human cell size
Barely visible to the naked eye (very long 100 micrometer diameter)
Egg cells
Longest human cell (1 meter long)
too slender to be seen with naked eye
Nerve cell
Cell growth increases volume more than surface area
Limitations on cell size
_ of a cell is proportional to square of its diameter
Surface area
_ of a cell is proportional to the cube of its diameter
Volume
If cell becomes too large, may rupture like overfilled
Water Balloon
Light microscope reveals plasma membrane nucleus \, and cytoplasm
Basic components of a cell
fluid between the nucleus and surface membrane; space everything except nucleus
Cytoplasm
(ability to reveal detail) of electron microscopes reveals ultrastructure
Resolution
consist of Organelles, cytoskeleton, and cytosol (ICF)
Cytoplasm
cell part that grows slow
surface area
cell part that grows fast
Volume
The bigger the cell gets the move divide in between
Surface area & Volume
why can’t cells get bigger
b/c of surface are to volume ratio
Surrounds cell, defines boundaries, made of proteins and lipids, composition and function can vary from one region of cell to another
Plasma (cell) membrane
Intracellular fluid (liquid0
ICF ; Cytosol
Fluid outside of the cell
Extracellular fluid (ECF)
forms the border of the cell and many of its organelles
Unit (structure) membrane
Unit membrane at cell surface (coats all of cells), defines cell boundaries, governs interactions w/ other cells, controls passage of materials in and out of cells, Intracellular face, Extracellular face
Plasma Membrane
side that faces cytoplasm
Intracellular Face
side that faces outward
Extracellular face
oily film of lipids w/ diverse proteins embedded
Plasma membrane
_ %of molecules in plasma membrane are lipids
98%
75% of membrane lipids are _
Amphiphilic, Hydrophilic, Hydrophobic, Drift laterally from place to place , Movement keeps membrane fluid
Phospholipids
molecule arranged in bilayer
Amphiphilic
phosphate heads face water on each side of membrane
Hydrophobic
directed toward the center avoiding water
Hydrophobic tails
moves around in crowds, its what keeps it flexible
Phospholipids
20% of the membrane lipids, holds phospholipids still and can stiffen membrane, anchors phospholipids & give strength to cell membrane
Cholesterol
5% of the membrane lipids, Phospholipids w/ short carbohydrate chains on extracellular face, Contributes to give glycocalyx
Glycolipids
carbohydrate coating on the cell surface
Glycocalyx
sugar
Glycogen
2% of molecules in plasma membrane
50% of its weight
membrane proteins
Pass through membrane, have hydrophobic regions in contact w/ cytoplasm and extracellular fluid, have hydrophobic regions that pass back and forth through the lipid of the membrane
Transmembrane proteins
most are glycoproteins- carbohydrate chains, can drift about freely in phospholipid film, some anchored to cytoskeleton
Membrane Proteins
Adhere to one face of the membrane, usually tethered to the cytoskeleton
Peripheral proteins
Receptors, second-messenger systems, enzymes, ion channels, carriers, cell- identity makers cell- adhesion molecules
Functions of membrane proteins
Cell communication
Surface proteins on plasma membrane of target cell
Bind hormones and neurotransmitters and is normally specific for one substrate
Receptors
A channel protein that is constantly opens and allows ions to pass into and out of the cell
Gates +or - charge (sodium, calcium, mg)
Ion channel
A gated channel that opens and closes to allow ions through only at certain times
Gates ion channel
A Glycoprotein acting as a thus distinguishing the body’s own cells from foreign cells
Name tag
Cell-identify marker
(CAM) the molecule that binds one cell to another
Stick to each other
Cell-adhesion
Triggers changes within the cell that produce a second messenger in the cytoplasm
Involves transmembrane proteins and peripheral proteins :g protein
Lots of problems happen in 2 messenger system CAMP
Binds to surface of cell and sends messages
Second- Messenger Systems
Help produce second messengers (cAMP)
Break down chemical messengers and hormones whose job is done
If on surface can be channel proteins
Enzymes
Transmembrane proteins with pores that allow water & dissolved ions to pass through membranes
Some are constantly open, gated channels that response to stimuli( ligand, voltage, mechanically )
Play an important role in the timing of nerve signals and muscle contractions
Channel proteins
Ligand (chemically) , voltage, mechanically(stretch and pressure) are
Are regulated gates
Family of disease that result from defects in channel proteins
Channels patties
Transmembrane proteins bind to glucose, electrolytes and other membrane
These transform them across membranes
Carriers and pumps
This consumes ATP in the process of transferring
It requires energy
Pumps
Transfers the proteins that bind to soultes using no energy
Carriers
Enables our bodies to identify which cells belong to it and which are foreign invaders
Example : glycoproteins contribute to the glcocoalyx
-carbohydrates surface coating and act like a cells “identification tag”
Cell- identity markers
Adhere cells to each other and to extracellular material
Cells do not grow or survive normally unless they are mechanically linked to the extracellular material except sperm to egg and immune cell to cancer cell that requires this
Cell-Adhesion molecules (CAMs)
Chemical first messenger (epinephrine) binds to a surface receptor which triggers within that produces ___ in the cytoplasm
It receptor activates G proteins
Second messengers
What relays signal to adenylate Cyclades which converts ATP to cAMP (second messenger)
G protein
Unique fuzzy coat external to the plasma membrane
Orientation of carbohydrate chain; Carbohydrate moieties of membrane glycoproteins and glycolipids (unique in everyone but identical twins)
FUNCTIONS :protection, immunity to infection, defense against cancer, transplant compatibility , cell adhesion, fertilization, embryonic development
Glycocoalyx
extension of membrane (1-2 micrometers) serves to increase cells surface area: specialized on absorption rate (15 - 40 times more)
Microvilli
Long extensions of the cell membrane, hairlike processes (7- 10 micrometers); Single, nonmotile primary cilium found on nearly every cell (inner ear, retina, nasal cavity, and kidney)
Cilia
respiratory tract, uterine tubes, ventricles of the brain, efferent ductules of test; beat in waves that move body fluids ( Power strokes followed by recovery strokes)
Motile Cilia
Hereditary disease in which cells make chloride pumps, but fail to install them in the membrane
Cystic fibrosis
Tail of sperm- only functional in flagellum
Whiplike structure w/ axoneme identical to cilium (much longer than cilium); snakelike movements (no power stroke or recovery stroke as in cilia)
Flagella
Plasma membrane, passive transport mechanisms, active transport mechanisms, and carrier- mediated mechanisms are all
membrane transports
A membrane transport that has a barrier and a gateway between the cytoplasm and ECF , Selectively permeable
Plasma membrane
Under the plasma membrane, it allows some things through, and prevents other things from entering and leaving the cells
Selectively permeable
A membrane transport that requires no ATP; random molecular motion of particles provides the necessary energy (filtration, diffusion, osmosis)
EXAMPLE: Popping a balloon
Passive transport mechanisms
A membrane transport that consumes ATP; ___ and vesicular transport
EXAMPLE: Blowing up a balloon
Active transport mechanisms
A membrane transport that uses a membrane protein to transport substances from one side of the membrane to the other (assist)
Carrier- mediated mechanisms
Process in which particles are driven through a selectively permeable membrane by hydrostatic pressure ( force exerted on a membrane by water)
Passive transport, reverse osmosis, filtering out only what we need
Filtration
The net movement of the particles from area of high concentration to area of low concentration; due to their constant spontaneous motion: Also known as movement down the concentration gradient (concentration differs from one point to other)
Simple Diffusion
Factors affecting ___ rate through a membrane: temperature (temp up= motion of particles up), molecular weight(larger are slower), steepness of concentration gradient (different up = rate up) membrane surface area ( area up= rate up) membrane permeability: amount of holes (permeability up= rate up)
Simple diffusion
- can’t get through membrane easy if +
Diffusion through lipid bilayer: nonpolar &small (hydrophobic, lipid- soluble substances
Diffusion through channel proteins: (need to be neutral) water and charged& big, hydrophilic solutes diffuse through channel proteins
Cells control Permeability: by regulating # of channel proteins or by opening and closing gate
Simple diffusion
Flow of water from one side of a selectively permeable to the other (Passive transport); higher -> lower, hydration spheres
Osmosis
Reversible attraction of water to solute particles forms __ (water trapped to solute)
Hydration spheres
Why do the water molecules move to the side with more solute ?
B/c it starts working on sugar and never makes it back, but water is always moving both ways
In osmosis, its a special protein, channel proteins in plasma membrane specialized for passage of water: increase the rate of osmosis, decrease rate by removing them
Aquaporins
amount of hydrostatic pressure required to stop osmosis
Osmotic Pressure
Pressure applied to one side, overrides pressure, drives against concentration gradient; heart drives water out of capillaries by reverse osmosis - capillary filtration( pressure on water goes into other side solute left over when bottom out)
Reverse osmosis
High -> low
Facilitated diffusion
high <- low
Active transport
Has a lower concentration of nonpermeating solutes than intracellular fluid (ICF);high water concentration, cells absorb water, swell, and may burst (lyse)
Hypotonic solution
Has a higher concentration of nonpermeating solutes; low water concentration, cells lose water, shrivel(crenate)
hypertonic solution
Concentration in cell and ICF are the same, cause no changes in cell volume or cell shape, normal saline
Isotonic solution
Under Carrier- Mediated transport : in the plasma membrane that carry solutes from one side of the membrane to the other
Transport proteins
Under Carrier- Mediated transport: as the solute concentration rises, the rate of transport rises, but only to a point- transport maximum (Tm)
Saturation
Facilitated diffusion and active transport are types of what
Carrier- mediated transport
Carriers only one solute at a time
Uniport
Carriers two or more solutes simultaneously in same direction (cotransport)
Example: Sodium -Glucose transport
Symport
Carrier two or more solutes in opposite directions (countertransport)
Example: Sodium Potassium pump which brings in potassium and removes sodium from the cell
Antiport
Carriers employ two methods of transport
Facilitated diffusion and Active transport
Carrier- mediated transport of solute through a membrane down its concentration gradient
Doesn’t consume ATP
Facilitated Diffusion
Carrier- mediated transport of solute through a membrane up (against) its concentration gradient
ATP energy consumed to change carrier
Active transport
“Fixed anions” attract cations causing osmosis
Cell swelling stimulates the sodium potassium pump to decrease ion concentration , decrease osmolality and cell swelling
Regulation of Cell Volume
Pump keeps inside more negative, outside more positive
Necessary for nerve and muscle function
Maintenance of a membrane potential
Thyroid hormone increase number of Sodium- Potassium pumps
Consume ATP and produce __ as a by- product
Maintain out temperature
Heat Production
3 Things that keep the cell alive
Maintenance of membrane potential, Heat Production, and regulating cell volume
Processes that move large particles , fluid droplets, or numerous molecules at once through the membrane in vesicles ( Endocytosis: Phagocytosis, Pinocytosis, and Receptor-mediated endocytosis; Exocytosis)
Vesicular Transport
Bubblelike enclosures of membrane
vesicles
Vesicular processes that bring material into the cell (phago- and pino-)
Endocytosis
A form of endocytosis: “cell eating” engulfing large particles
Pseudopods, phagosomes, macrophages
Phagocytosis
A form of endocytosis: "cell drinking" raking in droplets of ECF containing molecules useful in the cell Pinocytic vesicle (Adjust volume)
Pinocytosis
A form of endocytosis: particle bind to specific receptors on plasma membrane
Clathrin- coated vesicle
Receptor- mediated endocytosis
discharging material from the cell
Exocytosis
All endocytosis and exocytosis require what
Energy ATP : Active Transports
Organelles, cytoskeleton, and inclusions (other particles)
All embedded in a clear gelatinous cytosol are structures of what
Cytoplasm
collection of filaments and cylinders
Determines shape of cell, lends structural support, organizes its contents, directs movement of substances through the cell, and contributes to the movements of the cell as a whole : Made of Proteins
Composed of: Microfilaments, Intermediate fibers, Microtubules
Cytoskeletons
Microfilaments, Intermediate fibers, Microtubules
Smallest -> biggest Parts of the cytoskeleton
6nm thick, actin, forms terminal web
Microfilaments
8- 10 nm, support, strength, and structure
Intermediate fibers
25nm, tubulin, movement
micotubules
Internal structures , carry out specialized metabolic tasks: membranous organelles, nonmembranous organelles
Organelles
Nucleus, mitochondria, lysosomes, peroxisomes, endoplasmic reticulum, and Golgi complex
Membranous organelles (membrane bound)
Ribosomes, centrosomes, centrioles, basal bodies
Nonmembranous organelles ( nonmembrane bound)
largest organelle (5 micrometers in diameter)
most cells have one __
A few cell are a__ or multi__
Nucleus
two unit membranes surround nucleus
Perforated by nucleus pores formed by rings of proteins
Nucleus envelope
formed by rings of proteins: regulate molecular traffic through envelope, hold two unit membranes together
Nucleus Pores
Plays role in regulation of the cell life cycle : House to protect the DNA (aka the office)
contains nucleoplasm :chromatin and nucleoli
the Nucleus
material in nucleus contains chromatin and nucleoli
Nucleoplasm
(threadlike matter) composed of DNA and protein
Chromatin
one or more dark masses where ribosomes are produces
Nucleoli
composed of parallel, flattened sacs covered with ribosomes: produces the phospholipids and proteins of the plasma membrane
Ribosomes= construction workers
Rough endoplasmic reticulum (rougher)
small granules of protein and RNA: found in nucleoli, in cytosol, and o outer surfaces of rough ER, and nuclear envelope & mitochondria
Find them read blueprint builds proteins out of amino acids
Ribosomes
they “ read” coded genetic messages and assemble amino acids into proteins specified by the code
Function: Fill the Proteins
messenger RNA
A small system of cisternae that synthesize carbohydrates and put the finishing touches on proteins and glycoprotein synthesis ( gathers and packages proteins)
Sorts them, cuts, splices some of them, adds carbohydrate moieties to some, and package the protein into membrane- bound Golgi vesicles
Golgi complex
The carbohydrates the Golgi complex is synthesizing can become lysosomes, migrate to plasma membrane and fuse to it, and become secretory vesicles or later release (storage)
Golgi vesicles : out going supplies
package of enzymes bound by a single unit membrane ; extremely variable in shape
FUNCTIONS: intracellular hydrolytic digestion of proteins, nucleic acids, complex carbohydrates, phospholipids, and other substances (come from cell, cellular structure (come from absorption and leftover cell structure), Autophagy, Autolysis
Lysosomes
digest and dispose of worn out mitochondria and other organelles
Autophagy
“cell suicide” some cells re meant to do a certain job and then destroy themselves
Autolysis
resemble lysosomes but contain different enzymes and are not produced by the Golgi Complex
FUNCTION: use molecular oxygen to oxidize organic molecules ,these reactions produce hydrogen peroxide, Catalase breaks down excess peroxide to h2o and o2, neutralize free radicals, detoxify alcohol, and drugs, and a variety of blood-borne toxins, break down fatty acids into acetyl groups for mitochondrial use in ATP synthesis , abundant liver and kidney( DETOXIFY things in Blood Stream)
Peroxisomes
organelles specialized for synthesizing ATP
“Powerhouse” of the cell ; energy is extracted from organic molecules and transferred to ATP(PRODUCE ATP)
Mitochondria
Mitochondrial ribosomes are more like bacterial ribosomes; Mitochondrial DNA is almost exclusively inherited through the mother ; Ancient Bacteria lots of indications they are more like bacteria then humans
Evolution of Mitochondrion
Nucleus, 46 strands chromsomes, genes, size: Big, CM: Phosolipids, Ribosomes: RNA& Protein
Human
circle DNA , ATP ,small: ribosomes , membrane
Mitochondria and bacteria
a short cylindrical assembly of microtubules arranged in nine groups of three microtubules each,
Centriole
two centrioles lie perpendicular to each other within a small, clear area of cytoplasm : play role in cell division , cellular movement- mitosis
Centrosome
each basal body of a cilium or flagellum is a single centriole oriented perpendicular to plasma membrane, basal bodies originate in centrioles organizing center : Anchors cilia& flagellum
Cilia and flagella formation
Two kinds of__ : Stored cellular products for the body ; Glycogen granules, pigments, and fat droplets, Foreign bodies: Viruses, intracellular bacteria, dust particles, and other debris phagocytized by a cell
NEVER enclosed in a unit membrane
NOT essential for that cells survival
Inclusions
