Prokaryotes
no nucleus; bacteria, cyanobacteria, and rickettsiae; one chromosome; no histones; no organelles; smaller ribosomes
Eukaryotes
has nucleus; contains organelles; has histones; larger ribosomes
8 cellular functions
1. respiration
2. metabolic absorption
3. excretion
4. reproduction
5. communication
6. secretion
7. movement
8. conductivity
plasma membrane
encloses the cell
cytoplasm
within the plasma membrane; cytoplasmic matrix, excludes nucleus
cytosol
semifluid protion of cytoplasm, contains thousands of enzymes
nuclear envelope
composed of two phospholipid layers
nucleolus
site of synthesis and processing of rRNA; assembly of ribosomal subunits
histones
DNA binding proteins
ribosomes
molecular machine where protein synthesis takes place
rough endoplasmic reticulum
ribosomes direct of synthesis of proteins into the lumen of the rough ER
smooth endoplasmic reticulum
lipid synthesis, detoxification
golgi complex
receives vesicles with proteins modified in the rough ER; further modifies proteins; proteins are released in secretory vesicles
mitochondria
synthesizes ATP
lysosomes
originate from the golgi; contains enzymes that digest proteins, lipids, nucleic acids, and carbs
peroxisomes
contains oxidative enzymes that detoxify wastes
vaults
cytoplasmic ribonucleic proteins; may shuttle molecules from nucleus to other locations
cytoskeleton
maintains the cell's shape and internal organizations; contains microtubules, microfilaments, and intermediate filaments
caveolae
cave-like indents that are the storage site for membrane receptors
phospholipids
main component of plasma membrane; one part is hydrophillic, one part is hydrophobic (amphipathic)
integral membrane proteins
embedded in the bilayer; also amphipathic; float within the plasma membrane
peripheral membrane proteins
on the inner surface of the membrane
6 functions of membrane proteins
1. transport
2. enzymatic activity (catalyze reactions)
3. signal transduction using surface receptors: binding of a ligand causes rxns inside a cell
4. cell surface markers: glycoproteins; cell to cell rocognition
5. cell adhesion molecules
6. attachment
fluid mosaic model
cellular membranes are dynamic; membrane is flexible; can contain receptor proteins
ligands
smaller molecules with specific binding site; can include hormones, neurotransmitters, antigens, complement proteins, lipoproteins, infectious agents, drugs, and metabolites
receptors for drugs
found in plasma membrane, cytoplasm and nucleus; membrane receptors
receptors for infectious microorganisms
antigen receptors on white blood cells; activate immune response
cell to cell adhesion
turn soft cells into firm tissue
3 mechanisms for cell to cell adhesion
1. cell adhesion molecules in plasma membrane
2. extra cellular matrix
3. specialized cell junctions
extracellular matrix
meshwork of fibrous proteins embedded in a watery, gel-like substance composed of complex carbs.; allows transport of nutrients, waste, etc. between blood and tissue cells
3 groups of macromolecules found in ECM
1. fibrous structural proteins
2. adhesive glycoproteins
3. proteoglycans and hyaluronic acid
fibrous structural proteins
1. collagen: forms fibers or sheets
2. elastin: a rubberlike fiber
fibronectin
an adhesive glycoprotein that is used for cell anchorage
2 components of ECM
1. interstitial matrix
2. basement membrane
fibroblasts
cells scattered around the in the matrix
functions of cell junctions
1. holds cell together
2. allows small molecules to pass from cell to cell
desmosomes
hold cell together by forming continuous bands or button-like junctions
tight junctions
barriers to diffusion, blocks transport by transport proteins, prevents leakage of small molecules
gap junctions
allot small molecules to pass from cell to cell via "communicating tunnels
connexons
the joining proteins
3 ways cell communicate
1. membrane receptors detect signals from other cells
2. receptors found within the cell
3. gap junctions between cells
6 modes of intracellular signaling
1. contact-dependent: cells must have membrane-membrane contact
2. paracrine: local chemical mediators
3. autocrine: signaling molecules that affect the producing cell itself
4. hormonal: invovles endocrine cells that secrete hormones
5. neurohormonal: ho
classes of plasma membrane receptors
1. ion channel coupled: found in electrically excitable cells; open in response to neurotransmitters
2. enzyme coupled: act as an enzyme after binding the ligand
3. G-protein coupled: GTP-binding regulatory protein is involved
cellular metabolism
the chemical reactions necessary to maintain cellular function
anabolism
energy using functions (building of molecules)
catabolism
energy releasing functions (breaking down energy rich molecules)
metabolic pathway
a series of chemical reactions that builds a complex molecule or breaks down a complex molecule
ATP
adenosine triphosphate; energy for the cell
cellular energy from food: 3 phases
1. digestion: large molecules are broken down
2. glycolysis (and oxidation)
3. citric acid cycle (Kreb's cycle) and oxidative phosphorylation
glycolysis
takes place in cytoplasm; an anaerobic process; produced 2 ATP and 2 pyruvate
passive transport
does not require ATP or transport proteins; membrane is semipermeable; driven by the laws of physics (diffusion, osmosis, hydrostatic pressure)
active transport
requires ATP; requires receptors; transports larger and charger particles
membrane assisted transport
requires ATP; endocytosis (taking in particles) and exocytosis (expelling particles)
diffusion
the movement of solute from a greater concentration to a lesser concentration down the concentration gradient
filtration
the movement of water and solutes through a membrane because of a force on one side of the membrane
hydrostatic pressure
mechanical force of water against a cell membrane
osmosis
diffusion of water through a semipermeable membrane
osmolarity
measure of concentration of molecules/L (volume)
osmolality
measure of concentrtion of molecules/kg (weight)
body fluids
osmolality is greater than osmolarity; normal osmolality is 280-295 mOsm/kg
osmotic pressure
the amount of hydrostatic pressure required to oppose the osmotic movement of water
oncotic pressure
plasma proteins effect osmolality; proteins have a negative charge and attract positive charged ions; the compartment containing the protein tends to maintain an electrical equilibrium which leads to higher osmolality
tonicity
the effective osmolality of a solution; relative to the ICF or ECF
isotonic solution
same concentration of particles
hypotonic
has lower osmolality; more dilute than bodily fluids; water will enter the cell
hypertonic
has higher osmolality; more concentrated than bodily fluids; water will exit the cell
mediated transport
involves transport proteins that are specific for the substance being transported
competitive inhibitor
binds to the same site as the transported molecules
noncompetitive inhibitor
binds to a different site, but alters the structure of the molecule
passive mediated transport
facilitated diffusion; molecules move down the concentration gradient
active mediated transport
molecules move against the concentration gradient; needs ATP
active transport of Na and K
1 ATP moves 3 Na out of the cell and 2 K in the cell; leads to electical potential
two types of endocytosis
1. pinocytosis: cell drinking
2. phagocytosis: cell eating
2 main functions of exocytosis
1. release of molecules into ECM
2. replacement of plasma membrane removed by endocytosis
receptor-mediated endocytosis
ligand binding to certain plasma receptors causes the receptors to cluster which enables the cell to ingest large amounts of specific ligands
resting membrane potential
difference in electrical charge between inside and outside; is -70 to -85 millivolts; results from NaK pump
action potential
a rapid change in the resting membrane potential; after stimulation cell becomes more permeable to Na and Na moves into the cell becoming less negative towards 0; if membrane potential reaches 0 and then becomes positive it results in an action potential
threshold potential
amount resting potential must be reduced by to produce an action potential
repolarization
the negative membrane potential is reestablish; K ions leave cell
the cell cycle
series of events during which the parent cell divides to form two identical daughter cells
interphase
prepares cell for division
1. Gap 1: growth period
2. S: DNA replicated (synthesized)
3. Gap 2: growth, RNA and protein synthesis
M phase
1. mitosis: nuclear division
2. cytokinesis: division of cytoplasm
stages of mitosis
1. prophase: chomatids attached to a spindle at the centromere; spindle fibers radiate from two centrioles
2. metaphase: chromosomes lined up in center of the cell, attached to spindle fibers
3. anaphase: centromeres split; sister chromatids pulled to opp
growth factor
peptides that transmit signals within and between cells and regulate growth and development
retinoblastoma protein
a protein that inhibits cell proliferation
G0 state
arrested state of cell; happens when it is not going through cell division
pattern formation
the process by which differentiated cell create tissues and organs
epithelial tissues
can be squamous, columnar, or cubodial AND simple or stratified
neural tissue
receive and transmit electrical impulses rapidly across synapses
connective tissue
1. loose (aerolar): holds organs in place
2. dense irregular: dermis of skin, protective
3. dense regular: tendons, ligaments
4. elastic: trachea
5. adipose: fat
6. cartilage: firm bone matrix, no blood supply
7. bone
8. plasma-matrix for blood cells
muscle tissues
1. skeletal: striated voluntary (long cylindrical)
2. cardiac: striated involuntary (branching)
3. smooth: no striations, involuntary
Which are principal parts of a eukaryotic cell?
A. Fat, carbs and proteins
B. Minerals and water
C. Organelles
D. Phospholipids and protein
E. Protoplasm and nucleus
C. Organelles, plasma membrane and nucleus
The cell membrane is described as a fluid mosaic model. Some proteins have a degree of mobility within the lipid bilayer.
A. The first sentence is true.
B. The first sentence is false.
C. The second sentence is true.
D. The second sentence is false.
E. Th
A. The first sentence is true.
C. The second sentence is true.
E. The second sentence is relevant to the first.
Which particle can penetrate cell membranes most easily?
A. lipid soluble, uncharged
B. neutral charge, water soluble
C. smaller, water soluble
D. uncharged, larger
A. lipid soluble, uncharged
For a cell to engage in active transport processes, it requires:
A. mitochondria
B. appropriate fuel
C. ATP
D. enzymes
E. All of the above are correct
E. All of the above are correct
Which is inconsistent with the others?
A. diffusion
B. osmosis
C. filtration
D. phagocytosis
E. facilitated diffusion
D. phagocytosis
Which can transport substances uphill against the concentration gradient?
A. active transport
B. osmosis
C. dialysis
D. facilitated diffusion
E. None of the above are correct
A. active transport
Caveolae:
A. serve as repositories for some receptors
B. provide a route for transport into a cell
C. relay signals into cells
D. All of the above are correct
D. All of the above are correct
Which state is true for cytoplasm?
A. It is located outside the nucleus
B. It provides support for organelles
C. It is mostly water
D. A, B, and C
E. A and B
D. A, B and C are correct
The retinoblastoma (Rb) protein:
A. is a brake on the progress of the cell cycle
B. binds to gene regulatory proteins
C. slows cell proliferation
D. A and C
E. A, B and C
E. A, B, and C
A major function of connective tissue is:
A. to form glands
B. support and binding
C. covering and lining
D. movement
E. to conduct nerve impulses
B support and binding
Which are characteristic of epithelial tissue?
A. elasticity
B. protection
C. fills spaces between organs
D. secretion
B. protection
D. secretion
Signaling molecules cause all of the following except:
A. acceleration/initiative of intracellular protein kinases
B. arrest of cellular growth
C. apoptosis
D. conversion of an intracellular signal into an extracellular response
D. conversion of an intracellular signal into an extracellular response
Ligands that bind with membrane receptors include which of the following?
A. Hormones
B. Antigens
C. Neurotransmitters
D. Drugs.
E. infectious agents
All
The products from the metabolism of glucose include which of the following?
A. kilocalories
B. CO2
C. H2O
D. ATP
All
Identify the correct sequence of events for initiation and conduction of a nerve impulse.
1. Na moves inside
2. K leaves cell
3. Na permeability changes
4. Resting potential is reestablished
5. K permeability changes
3, 1, 5, 2, 4
Increased cytoplasmic calcium:
A. causes one cell to adhere to another
B. increases permeability at the junctional complex
C. decreases permeability at the junctional complex
D. None of the above
C. decreases permeability at the junctional complex
Cell junctions:
A. coordinate activities of cells within tissues
B. are an impermeable part of the plasma membrane
C. hold cells together
D. permits small molecules to pass from cell to cell
E. A C and D
E. A C and D
Anaphase
chromatid migration
Chromatin
within the nucleus, stored RNA
metaphase
chromatid pair alignment
mitochondria
generation plant" for ATP
prophase
centriole migration
ribosome
within the nucleus, stored RNA
Lining of the kidney tubules
simple cuboidal
lining of the upper respiratory tract
simple columnar, ciliated
mediated transport
two molecules move simultaneously in one direction (symport) or in opposite directions (antiport) or a single molecules moves in one direction (uniport)