Chapter 3 - CELLS

40 trillion

Somatic and sex cells

A cell membrane
cytoplasm
cytoskeleton
numerous organelles

Ribosomes and Rough ER

cell membrane

50:50

50:1

myelin

A molecule that has both a hydrophilic region and a hydrophobic region.

For stability and flexibility

Integral and peripheral

usually go through the entire cell membrane (transmembrane proteins)

Proteins on either the inside or outside of the cell

receptors
enzymes
transporters
cell identification
cell adhesion
ion channel
gated ion channel

states that a membrane is a fluid structure with a "mosaic" of various proteins embedded in it

Coating of molecules external to the cell wall, made of sugars and/or proteins.
Important in cell-to-cell recognition, communication and adhesion.

fingerlike extensions of the plasma membrane that increase epithilial tissues surface area. (Look like hairs)

1. tight junctions
2. desmosomes
3. gap junctions

Cells that make close contact are held together by a variety of membrane junctions, providing stability and strength.

Transmembrane proteins of adjacent cells fuse together and form an impermeable junction that surrounds the cell.

Adjacent cells are held together by linker protein filaments that inter-digitate in a zipper like fashion.

channel proteins from two neighboring cells align to allow material exchange between the two cells

lining of blood vessels

passive transport and active transport

substances pass across the membrane without direct energy input from the cell. The energy comes from the diffusion concentration gradient.

The cell provides energy (ATP) to drive the movement across the membrane. Movement is usually against the concentration gradient.

simple diffusion, facilitated diffusion, osmosis

movement of a solute from an area of high concentration to an area of low concentration.
Without the need of membrane proteins.

The passive movement of a particle across a cell membrane via a channel protein.
Required membrane proteins.

carrier mediated and channel mediated

the random thermal motion of molecules.

High
low
(down the concentration gradient)

A measure of disorder or randomness.

Nature strives towards maximal entropy, maximal chaos

releases

requires

thermodynamical

temperature
molecular weight of the molecule
concentration gradient
area of diffusion
distance to diffuse
viscosity
electrical field

faster

faster

faster

more and faster

slower

FLUX = A x D x (C2 - C1)
Rate of speed: FLUX
A: sectional area through which diffusion occurs
(C2-C1): concentration gradient across a distance
D: diffusion constant

distance

diffusion of water across a selectively permeable membrane

the number of moles of solute per liter of solution

total solute concentration of a solution

The ability of an extracellular solution to make water move into or out of a cell by osmosis

Having the same solute concentration as another solution.

A solution with a higher salt concentration than in the cells
(cells shrink) LESS WATER THAN IN CELL

A solution with lower salt concentration than in the cells
(cells burst) MORE WATER THAN IN CELL

Sodium

channel proteins
carrier proteins

Water filled tunnels that are very small and very specific as to what small molecules can pass.

Require "binding" and "release" of the transported molecule.

*Occurs for small ions that move through water filled channels created by the membrane protein.
*No direct "binding" between ion and channel protein
*Movement of the ions is from high to low concentration

Leakage channels
gated channels

always open

chemically-gated
voltage-gated
mechanically-gated

any molecule that binds specifically to a receptor site of another molecule

Type of plasma membrane ion channel that opens and closes in response to membrane potential.

Type of plasma membrane ion channel that opens and closes in response to physical deformation of receptors. (touch, hearing, bladder, intestines, muscles)

Refers to the movement of molecules down their concentration gradient into the cell by means of an integral membrane protein or transporter (carrier)
Selective &n highly specific as the molecule has to recognize and bind to the carrier molecule. Protein changes shape in order to execute process.

Moves one substance in one direction

Moves two substances in the same direction at the same time

Two substances are moved but in opposite direction.

a carrier protein that uses ATP to actively transport sodium ions out of a cell and potassium ions into the cell

primary, secondary, vesicular

the process in which energy (ATP) is directly used to move against a concentration gradient.

Coupling an ion's movement WITH its gradient to power another ion's movement AGAINST its gradient. DOES NOT require ATP input directly.

Materials move into or out of the cell in vesicles; two major categories are endocytosis and exocytosis

take in large molecules in the cell

process by which the cell expels materials that are too large to pass through

chromatin, nucleoli, and distinct compartments with specific proteins

DNA, globular proteins and newly forming mRNA

Subunits of ribosome are assembled.

DNA molecules that are tightly coiled around proteins call histones.

a network of membranous tubules within the cytoplasm of a eukaryotic cell, continuous with the nuclear membrane. It usually has ribosomes attached and is involved in protein and lipid synthesis.

no ribosomes, breakdown of glycogen in the liver, detox of drugs
synthesis of steroid-based hormones in testes,
absorption, synthesis and transport of fats in intestinal cells,
storage container for calcium

a complex of vesicles and folded membranes within the cytoplasm of most eukaryotic cells, involved in secretion and intracellular transport.

the digestive center and contain acid hydrolase that breaks down waste inside the cells

Peroxisomes are vesicles that produce and break down hydrogen peroxide which have several different functions in different cell types, including de-toxification and breakdown of fatty acid chains.

group of organelles/membranes that work together to modify, package, and transport proteins and lipids that are entering/exiting a cell

power house of the cell and produces and supplies the cell with energy

a microscopic network of protein filaments and tubules in the cytoplasm of many living cells, giving them shape and coherence.

microfilaments, intermediate filaments, microtubules

threadlike structures made up of a protein called actin

fibers with diameters in a middle range

hollow structures made up of the protein tubulin, they maintain a cells shape

The entire set of genetic material in an organism

The process of making RNA from DNA

the decoding of an mRNA message into a protein

the process where the information within a gene becomes expressed.

The region of mRNA where RNA polymerase binds and starts transcription

a segment of a DNA or RNA molecule containing information coding for a protein or peptide sequence.

a segment of a DNA or RNA molecule that does not code for proteins and interrupts the sequence of genes.

Removing introns from RNA and sealing exons together

proteins that bind to the DNA promoter sequence

•The organisms regulate whether or not an enzyme is produced....
•Turns on or off the process of transcription.....
•Much greater regulation of resources and energy than the other systems....

1. Degradation by proteasomes
-utilizes ubiquitin tags (ubiquitin-protein ligase recognizes them- destroys the protein- no lysosome is necessary here. Works via proteasome)
2. Degradation by lysosomes
3. Calcium-dependent enzymes

The binding of a regulatory molecule to a protein at one site that affects the function of the protein at a different site.

When proteins have different groups covalently attached to them to regulate their activity

Ex. phosphorylation to hydroxyl group of serine, threonine, or tyrosine by kinase or phosphorylase

transfer phosphates from ATP to protein, a process called phosphorylation

remove phosphates