Lecture exam 2 anatomy

Cell theory

•All organisms composed of cells and cell products
• Cell is the simplest structural and functional unit of life
• An organism’s structure and functions are due to activities
of cells
• Cells come only from preexisting cells
• Cells of all species exhibit biochemical similarities

Squamous

thin, flat, scaly, often a bulge where the nucleus is

Cuboidal

squarish-looking with the width and height being the same

Columnar

looks like column, taller than wide

Polygonal

irregularly angular shapes, 4+ sides, looks like a hexagon

Stellate

star like

Spheroid to ovoid

round to oval shaped

Discoidal

disc shaped

Fusiform

thick in the middle and tapper towards the ends

Fibrous

thread-like shape

Plasma membrane

surrounds cell, defines boundaries

made of proteins and lipids

Cytosol

Intracellular fluid

anything inside the cell

Extracellular fluid

anything outside the cell

Plasma Membrane functions

defines cell boundaries

governs interactions with other cells

controls passage of materials in and out of cell

Phospholipids

make of 75% of the membrane

are amphipathic with a hydrophobic tail and hydrophilic head

are arranged in a bilayer to make up the plasma membrane, the use of the phospholipids is to keep the membranes fluid

Cholesterol

make up 20% of the plasma membrane

attaches to phospholipids and hold them still which stiffens the membrane

Glycolipids

phospholipids with short carbohydrate chains attached on the extracellular face

contributes to glycocalyx carbohydrate coating on the cell surface

Integral proteins

proteins with penetrate the membrane

Transmembrane protein

passed completely through the plasmas membrane, as some hydrophilic parts and the end of the protein with the hydrophobic part of the protein in the middle of the protein

some drift through the membrane were other are anchored to the cytoskeleton

Peripheral protein

Adhere to one face of the membrane and are usually tethered to the cytoskeleton

Receptors

bind to chemical messenger such as horomones or other materials sent by other cells

Enzymes

catalyze reactions including digestion of molecules and production of the second messenger

breaks down chemical messenger so that the signal does not get repeated on a loop

Channel proteins

allows hydrophilic solutes and water to pass through the membrane

Ligand-gated channel

respond to chemical messengers

Voltage gated channel

responds to changes in charge

Mechanically gated channels

reposed to physical stress or pressure in the cell

Carriers

bind solutes and transfer them across the plasma membrane

Cell identity markers

glycoprotein acting as identification tags

Cell-adhesion molecules

binds cell to another

Second Messengers

chemical first messenger binds to a surface receptor

the receptor activates G protein

G protein relays signal to adenylate cyclase which converts ATP to cAMP

cAMP actives cytoplasmic kinases

Kinases add phosphate groups to other enzymes turning some on and other off

Second Messenger steps

a messenger such as epinephrine binds to a receptor in the plasma membrane

The receptor releases a G protein which then travels freely in the cytoplasm

The G protein binds to an enzyme adenylate cyclase in the plasma membrane. Adenylate cyclase converts ATP to cAMP, the second messenger

cAMP activates a cytoplasmic enzyme called kinase

Kinases add phosphate groups to other cytoplasmic enzymes This activates some enzymes and deactives others, leading to a varied metabolic effects in the cell

Glycocalyx functions

protection

cell adhesion

immunity to infections

fertilization

defense against cancer

embryonic development

transplant compatibility

Microvilli

is an extension of the membrane and is developed in cell specialized in absorption, it is used to increase the surface area

Cilia

single nonmotile primary cilium found on every cell

antenna for monitoring near condition

found in light detection in the retina and the sensory cells of the nose

Ciliopathies

defeats in structure and function of cilia

Motile cilia

beats in waves sweeping material across a surface in one direction used to clear out and move materials in the body

Motile cilia location

respiratory tract, uterine tubes, ventricles of brian, ducts of testes

Axoneme

core of the motile cilia

is made up of two central microtubules surround by a nine pair which anchor the cilia to the cell

Cystic Fibrosis

hereditary disease in which cells make chloride pumps, but fail to install them in the plasma membrane this creates there to not be enough saline above the cell sot he cilia can not clear the track causes thick mucus to build up which plugs the pancreatic ducts and respiratory tract this leads to inadequate digestion of nutrients and absorption of oxygen

Flagella

tail of the sperm and has the function to propel things along (the cell), it is a whip like structure like cilium but longer and stiffened by coarse fibers movement is snake like

Pseudopods

continually changing extensions of the cell that vary in shape and size can be used for cellular locomotion and capturing foreign particles

Passive Membrane Transport

require no ATP

used when moving down the gradient

random molecular motion of particles provides necessary engery

Types of Passive Transport

Filtration

diffusion

osmosis

Active Membrane Transport

needs to consume ATP for process to work

Filtration

particles are driven through membrane by physical pressure

ex)filtration of water and small solute through gaps in capillary walls

Filtration function

allows deliverity of water and nutrients to tissues

allows removal of waste from capillaries in kidneys

Diffusion

net movement of particles from place of high concentration to a place of lower concentration

moving down the concentration gradient

Due to constant spontaneous molecular motion

molecules collide and bound off each other

Factors affecting diffusion rate through a membrane

if temperature increase then the motion of particles increase so diffusion increases

if molecular weight increase the motion of particles decrease, diffusion deceases

Steepness of concentration gradient increases then the diffusion rate increases

If the membrane area increases then the rate increase since there is more space and opportunties for diffusion

membrane permeability increases then diffusion increases

Osmosis

net flow of water through a selectively permeable membrane

water moves from the side where there is more water than solute to the side that has more solute then water

solute particles that can not pass through the membrane draw water from the other side

Aquaporins

a channel protein in membrane specialized for water passage

Osmotic pressure

hydrostatic pressure required to stop osmosis which increases as the concentration of solute increases in a solution

Reverse osmosis

process of applying mechanical pressure to override osmotic pressure which allows the purification of water

Tonicity

ability of a surrounding solution to affect fluid volume and pressure in a cell which depends on the concentration of nonpermeating solutes

Hypotonic solution

causes cell to absorb water and swell

has lower concentration of solute that fluid

Hypertonic solution

causes cell to lose water and shrivel(crenate) has high concentration of solute than fluid

Isotonic solution

causes no change in cell volume

concentration of solute and fluid are the same

Transport proteins

transport proteins are specific for particular solutes

solute (ligand) bind to receptor site on carrier protein

solute is released unchanged on the other side of the membrane

Saturation

as solute concentration rises, the rate if transport rises but only to a point

Facilitated Diffusion

carrier moves solute down its concentration gradient

this is passive transports

solute attaches to binding site on carrier, carrier changes conformation, then releases solute on the other side of the membrane

Facilitated Diffusion steps

a solute particles enters the channel of a membrane protein (carrier)

the solute binds to a receptor site on the carrier and the carrier changes conformation

the carrier releases the solute on the other side of the membrane

Primary Active Transport

carrier moves solute through a membrane up its concentration gradient

uses ATP

Primary active transport examples

calcium pump uses atp while expelling calcium from the cell to where it is already more concentrated

sodium potassium pump uses atp while expelling sodium and importing potassium into the cell

Sodium-Potassium pump

each pump cycle consumes one ATP and exchanges three Na+ (sodium) for two K+(potassium)

keeps K+ concentration higher and NA concentration lower within the cell

this is necessary because NA+ and K+ constantly leak through the membrane

Sodium-Potassium pump functions

maintains steep NA+ concentration gradient allowing for secondary active transport

regulates solute concentration and thus osmosis and thus cell volume

maintains negatively charged resting membrane potential

produces heat

Secondary active transport

carriers move solute through membrane but only use ATP indirectly

Vesicular Transport

moves large particles, fluid droplets, or numerous molecules at one through the membrane in vesicles which are bubble like enclosures of membrane utilizes motor proteins and energizes by ATP

Endocytosis

vesicular processes that bring material into the cell

Phagocytosis

cell eating engulfing large particles

Pinocytosis

cell drinking taking in droplets of extracellular fluid containing molecules useful in the cell

Receptor mediated endocytosis

particles bind to specific receptors on plasma membrane

Exocytosis

discharging material from the cell

Phagocytosis steps

a phagocytic cell encounters a particle of foreign material

the cell surrounds the particle with its pseudopod

the particle is phagocytized and contained in a phagosome

the phagosome fuses with a lysosome and become a phagolysosome

enzymes from the lysosome digest the foreign matter

the phagolysosome fuses with the plasma membrane

the indigestible reside is voided by exocytosis

Receptor mediated endocytosis

more selective endocytosis

enables cells to take in specific molecules that bind to extracellular receptors

Receptor mediated endocytosis steps

extracellular molecules bind to receptors on plasma membrane and receptor cluster together

plasmas membrane sink inward form clathrin coated pit

pit separates from plasma membrane forms clathrin coated vesicles containing concentrated molecules from extracellular fluid

Transcytosis

transport of materials across the cell by capturing it on one side and releasing it on the other

receptor mediated endocytosis movies it into the cell and exocytosis moves it out on the other side

Exocytosis

secreting materials

replacement of plasmas membrane removed by endocytosis

Exocytosis steps

a secretory vesicle approaches the plasma membrane and docks on it by means of linking proteins. The plasma membrane caves in at that point to meet the vesicle

the plasma membrane and vesicle unite to form a fusion pore through which the vesicle contents are released

Cytoskeleton

network of protein filaments and cylinders

Cytoskeleton functions

determine cells shape, supports structure, organizes cell contents, directs movement of material within the cell, contributes to movement of the cell as a whole

Cytoskeleton composition

microfilaments, intermediate fibers, and microtubules

Microfilaments

made of actin protein which has contractile properties and forms terminal webs

smallest

Intermediate filaments

within skin cells made of the protein keratin and gives the cell shape and resists stress

middle size

Microtubules

consists of protofilaments made of protein tubulin, radiates from centrosome, and can come and go

maintains cell shape, hold organelles, act as railroad tracks for walking motor proteins, make axonemes of cilia and flagella ,and forms the mitotic spindle

the largest

Organelles

internal structure of a cell carry out specialized metabolic tasks

Nucleus

the largest organelle

most cell have only one some cell have more than one

Nuclear envelope

double membrane around the nucleus

perforated by nuclear pores formed by rings of proteins

regulates molecular traffic through the envelope and hold the two membrane layers together

Nuclear lamina

web of protein filaments

provides point of attachment for chromatin

helps regulate cell life cycle

Nucleoplasm

material in the nucleus

Chromatin

thread like composed of DNA and proteins

Nucleoli

masses where ribosome are produced

Endoplasmic reticulum

system of channels enclosed by membrane

Rough endoplasmic reticulum

parallel flattened sacs covered with ribosome

continuous with out membrane of nuclear envelope, often the largest organelle

produces phospholipids and proteins of nearly all cell membranes

synthesize proteins that are packaged in other organelles or secreted from the cell

Smooth Endoplasmic reticulum

lack ribosomes

cistern more tubular and branching

cisterns through to be continuous with rough ER

synthesizes steroids and other lipids

detoxifies alcohols and other drugs

calcium storage

Ribosomes

small granules of protein and RNA

they read coded genetic messages and assemble amino acids into protein specified by the code

Golgi Complex

a system of cisterns that synthesizes carbohydrates and puts finishing touches on protein synthesis

receives newly synthesized protein from rough ER

sorts protein, splices some, add carbohydrates moieties to some, and packages them into membrane bound Golgi vesicles

some vesicles become lysosomes

some vesicles migrate to plasma membrane and fuse to it

some become secretory vesicles that store protein product for later release

Lysosomes

packages of enzymes bound by a membrane

Lysosome functions

intracellular hydrolytic digestion of proteins, nucleic acids, complex carbohydrates, phospholipids, and other substances

Autophagy

digestion of cells surplus organelles

Autolysis

cell suicide

digestion of a surplus cell itself

Peroxisomes

resemble lysosomes but contain different enzymes and are produced by the endoplasmic reticulum