A&P Chapter 3: Cells Living Unit

voltage-sensitive proteins

Because some plasma membrane proteins are involved in electrical signaling (by responding to changes in the membrane potential), these channels will oprn or close depending on changes in the voltage and polarity of the membrane. (Usually found in neural and muscle tissues!!!)

They are all different sizes!

Briefly describe cell diversity:

phagocytosis

"big eater"; the cell engulfs a large particle by forming projecting pseudopods around it and enclosing it within a membrane sac called a phagosome.

pinocytosis

"small eater"; the cell "gulps" drops of extracellular fluid containing solutes into tiny vesciles; a small portion of the plasma membrane surrounds a small volume of interstitial fluid and fuses with an endosome

2 ; in

How many K+ slots are in the carrier for the Na+/K+ pump? Do they go in or out?

3 ; out

How many Na+ slots are in the carrier for the Na+/K+ pump? Do they do in or out?

50-100 trillion

How many cells are in the human body (approx.)?

No pump, no transport

In active transport, if there is no pump, what happens?

isotonic

When cells retain their normal size and shape in isotonic solutions (concentration on the outside of the cell is the same as the inside of the cell)

What is the concentration?

When looking for tonicity, what are we really looking for? What are we asking?

vesicular trafficking

When vesicles pinch off of organelles and travel to other organelles to unload their contents

Because it helps make the bilayer more fluid, mobile, and flexible.

Why is these cholesterol in the lipid bilayer?

glycocalyx

a collection of glycoproteins and glycolipids that form a thick "sugary" coat to the extracellular surface of the cell; helps cells identify other cells (ex: sperm to egg!)

gap junctions

a nexus bond that allows cells to communicate with one another, making a channel that is selective to the molecule it will allow to pass between cells

centrosome

a region near the nucleus that attaches to microtubules

desmosomes

anchoring junctions that form a plaque with linker proteins that connect two cells, distributing tension to continuous internal support structures

facilitated diffusion

assisted diffusion of glucose, amino acids, or ions through membrane channels or carriers

centrioles

barrel-shaped organelles within the centrosome that are ivnolved in organizing the mitotic spindle during cell division and are the bases of cilia and flagella; in 90 degree angles of one another

endocytosis

bringing molecules into the cell

exocytosis

bringing molecules out of the cell

hypertonic

cells lose water by osmosis and shrink (water goes OUT of the cell to balance the concentrations out, which then DEHYDRATES the cell and it shrink)

hypotonic

cells take on water by osmosis until they become bloated and burst (lyse) in a hypotonic solution (which contains a lower concentration of solutes than are present inside cells)

carriers

facilitated diffusion through a trans-membrane integral protein that is specific for that substance (amino acids or glucose)

channels

facilitated diffusion through a transmembrane integral protein that is specific for that substance (ions or small molecules)

tight junctions

integral proteins that fuse together between adjoining cells, forming an impermeable junction that prevents molecules from entering the extracellular space between cells

second messengers

intracellular messengers that typically activate protein kinase enzymes (that then activate a series of enzymes)

flagella

long but small in number, these propel the cell itself forward or backward

ribosomes

made of proteins and RNA, they float in cytoplasm and bind to ER, and also produce proteins

peroxisomes

membranous sacs that contain oxidases and catalases; can neutralize free radicals like alcohol and formaldehyde

microvilli

minute, finger-like projections of the plasma membrane that increase the cell surface area for better absorption

membranous organelles

organelles which have membrane which include mitochondria, peroxisomes, lysosomes, ER, and golgi apparatus

non-membranous organelles

organelles which lack membranes and include cytoskeleton, centrioles, and ribosomes

glycoproteins

proteins that abut the extracelluar fluid that have sugar groups attached

osmosis

simple diffusion of a solvent (water) through the cell membrane

microfilaments

strandes made of spherical protein and subunits called actin; involved in cell motility and changes in shape

rough ER

studded with ribosomes, this produces proteins secreted from the cell

lysosomes

suicide sacs, which contain digestive enzymes that assist with the digestion of bacteria and cellular debris; also can degrade the cell itself

contact signaling

the actual coming together and touching of cells to allow cells to recognize one another; the contact between cells tell other cells they're not needed anymore

chemical signaling

the binding of plasma membrane receptors to ligans, which activate some downstream effect

cytoplasm

the cellular material between the plasma membrane and the nucleus

inclusions

the chemical substances that are present in specific cell types; not a true organelle, but located in the cell

For movement, shape of the cell, and to know where the organelles will be.

What are the three types of rods used for?

NO, cAMP, and CA++

What are the three types of second messengers?

active and vesicular

What are the two main modes of transport for active processes?

diffusion and filtration

What are the two main modes of transport for passive processes?

primary active transport' secondary active transport

What are the two main types of transports?

The movements of ions across the membrane; K+ channels let K+ leak from inside to the outside of the cell

What creates the electrical charge of the plasma membrane potential?

It opens the pump to either the Na or K sides of the pump

What does the phosphate do for the Na/K pump?

The Na/K pump

What helps maintain both the membrane potential and the osmotic balance?

The exchange ot the ions going back and forth through the NaK pump

What helps maintain the plasma membrane potential?

electrochemical gradient

What ions diffuse according to:

bacteria/amoeba

What is an example of a one-celled organism?

plants/animals

What is an example of multicellular organisms?

It is selectively permeable.

What is it about the plasma membrane which only allows certain things in and certain things out?

A cell is the basic structural and functional unit of living organisms.

What is the cell theory?

Made out of phospholiids, cholesterol, and glycolipids. Proteins are also found in and around the lipid bilayer.

What is the lipid bilayer made out of? What is also found either immersed or laying right on the surface of the bilayer?

-50 to -100 mV

What is the resting membrane potential? (the range, so numbers!!!)

ATP

What is the source of energy for primary active transport?

solute pumps

What moves solutes against the concentration gradient?

When a membrane is permeable to solutes

When can both water and solutes diffuse freely? What causes this?

Parts of the cytoskeleton may anchor the proteins, which may help maintain the cell shape and fix the location of certain membrane proteins. Also may help join some cells together.

Describe the attachment to cytoskeleton and extracellular matrix role of membrane proteins.

Some glycoproteins may serve as identification tags that are specifically recognized by other cells.

Describe the cell-cell recognition role of membrane proteins.

The protein may be enzymatic with its active site exposed to the substances in the adjacent solution.

Describe the enzymatic activity role of membrane proteins.

Membrane proteins of adjacent cells may hook together to join cells, and even use these as channels to migrate contents of the two cells from one to the other.

Describe the intercellular joining role of membrane proteins.

May have a binding site at surface of protein to outside to a chemical messenger, which can then change the shape of the protein that may then initiate a chain of chemical reactions in the cell.

Describe the receptors for signaling transduction role of membrane proteins.

They may span entire membrane, providing a channel across the membrane which is selectively permeable. Some may be transports using ATP.

Describe the transport role of membrane proteins.

Nope

Does secondary active transport use ATP?

No, the concentration is higher

Is the concentration of the K+ lower on the inside?

When a membrane is impermeable to solutes. So, since the solutes couldn't move, the water did.

When can only water diffuse freely? What causes this? Why?

microtubules

These are large in diameter, made of tubulin, and determines the shape of the cell and organelle distribution; they are constantly assembling and dissassembling

lipid rafts

These are made of tightly packed saturated phospholipids which act in cellular signaling.

glycolipids

These are phospholipids with attached sugar groups

caveolin-coated vesicles

These capture specific molecules and participate in some forms of transcytosis; involved in cellular signaling and cross-talk.

CAMs

These help hold cells together

integral proteins

These type of membrane proteins are firmly inserted into the lipid bilayer, is transmembranous, with hydrophilic and hydrophobic regions in order to act as carriers or channels for substances to travel into or out of the cell. May even act as a receptor for hormones as second messengers.

peripheral proteins

These type of membrane proteins are not embedded in the lipid bilayer, though can be attached to integral proteins. They usually assist in the support of intracellular filaments, as well as provide an anchor transport of cellular vesicles, cell division, or muscle contraction.

Na+/K+ pump

This maintains a high concentration of K+ inside the cell, while keeping a low concentration of Na+ inside the cell

clathrin

This protein collects within the plasma membrane, deforming the membrane and interacting with interstitial fluid substances.

secondary active transport

This type of transport is driven indirectly by energy stored in ionic gradients; a coupled system, it moves several substances at one time, and helps bring additional substances into the cell

1.) transport 2.) receptors for signaling 3.) attachment to cytoskeleton and extracellular matrix 4.) Enzymatic activity 5.) Intercellular joining 6.) Cell-cell recognition

What are the six roles of membrane proteins? (What do they do?)

1.) cell adhesion molecules (CAMs) 2.) Membrane receptors 3.) Voltage-sensitive channel proteins

What are the three main types of cell-environment interaction

microtubules microfilaments intermediate filaments

What are the three main types of rods in the cytoskeleton?

cytosol sytoplasmic organelles inclusions

What are the three parts of cytoplasm?

Plasma Membrane Cytoplasm and Organelles and Nucleus

What are the three parts of the cell?

cytoplasmic organelles

the metabolic machinery of the cell

mitochondria

the powerplant of the cell, providing ATP, which controls the environment with 2 layers; also has its own DNA and RNA so they can replicate themselves; also makes its own proteins

filtration

the process that forces water and solutes through a membrane or capillary wall by hydrostatic pressure (high pressure to low pressure)

cells

the structural units of all living things

diffusion

the tendency of molecules to scatter evenly throughout the environment, when the molecules moves from a higher concentration to lower concentration until it is all balanced out; ends when we reach equilibrium

vesicular transport

the transport of large particles, macromolecules, and fluids across plasma and intracelluolar membranes; allows for exocytosis, endocytosis, and transcytosis. Requires ATP.GTP energy, since it transfers BIG molecules.

cytosol

the viscous, semitransparent fluid that supports the other cytoplasmic elements; the fluid in the cell, made mostly of water

G protein receptors

these bind cells together, also binding the receptors, and activiates second messengers which then release kinase to enzymes to start different chemical effects and changes within the cell

smooth ER

this communicates with its rough version and synthesizes steroids and lipids; also makes cholesterol

plasma membrane

this is a flexible barrier that separates the intracellular fluid from the extra cellular fluid

golgi apparatus

this is like the post office of the cell, which sorts out all of the materials within the cell and then brings it to the right location; pretty much it packages and transports proteins for export

phosphorylate

this transfers phosphate ATP to the pump

intermediate filaments

tough, insoluble protein fibers constructed like woven ropes

simple diffusion

unassisted diffusion of lipid-soluble or very small particles

active transport

when cells use energy in ATPto move solutes across the membrane; requires carrier proteins that combine specifically and reversibly with the transported substances

receptor-mediated endocytosis

when extracellular substances bind to specific receptor proteins in regions of coated pits, enabling the cell to ingest and concentrate specific substances in protein-coated vesicles. Receptors within are recycled to the plasma membrane in vesicles.