Chapter 1: The Human Body: An Orientation
An Overview of Anatomy and Physiology
The Language of Anatomy
I. Anatomy – study of body organization and
I. Directional Terms
structure, and their relationships; Structure
 Superior (cranial) – toward the head
determines the function
 Inferior (caudal) – towards the tail
 Developmental Anatomy – conception to
 Anterior (ventral) – towards the belly
adulthood
 Posterior (dorsal) – towards the back
 Embryology – first 8 weeks of
 Proximal – near the origin, trunk, or point of
development
attachment
 Structures studied with a microscope
 Distal – farther the origin, trunk, or point of
 Cytology –cell
attachment/ towards the end
 Histology – tissues
 Medial – along the coronal towards the
 Ways to study anatomy
sagittal
 Gross Anatomy – systemic or
 Lateral – along the coronal away from sagittal
regional perspective
 Superficial – near the surface
 Surface Anatomy – using
 Deep – far from the surface
anatomical landmarks to locate
internal features
II. Body Planes
 Anatomical Imaging – non-invasive
 Transverse Plane – parallel to the ground
way of viewing internal body
 Coronal Plane – division from front and
structures
back
II. Physiology – the study of the structure’s function
 Sagittal Plane – division from left and right
 Exercise physiology – study changes in the
III. Body Cavities
body after exercise
 Dorsal – protected by the bone
III. Pathology – study of all disorders
 Cranial – contains the brain
 Spinal – contains the spinal cord
Levels of Structural Organizations
 Ventral – less protected
 Thoracic – extends superiorly to
the diaphragm; where the heart and
lungs are protected by the ribcage
 Abdominopelvic – extends
inferiorly from the diaphragm;
contains digestive, urinary, and
reproductive organs. The abdomen
is only protected by the trunk
muscles while the pelvic is
somewhat protected by the pelvic
bones.
 Smaller body cavities (Oral, Nasal Orbital,
Middle Ear)
Maintaining Life
Necessary Life Functions: (1) Maintain
Boundaries, (2) Movement, (3) Responsiveness, (4)
Digestion, (5) Metabolism, (6) Excretion, (7)
Reproduction, (8) Growth
IV. Regional Terms
Homeostasis
I. Homeostasis – Ability to regulate internal balances
with response to external changes. Disruption can lead
to disorder in the body

3 components of homeostatic reflux – (1)
receptors sense stimuli > (2) control centers
assess and integrate appropriate response to the
stimuli > (3) effectors that execute the response
(output)
II. Negative feedback mechanism – reduce or stop
initial stimuli
III. Positive feedback mechanism – increase initial
stimuli
Chapter 2: The Chemical Basis of Life
Basic Chemistry
III. Chemical Bonding
I. Matter, Mass, Weight



Matter – is anything that occupies space
and has mass. Exists in three forms (solid,
liquid, and gas)
Mass – amount of matter in a substance or
object
Weight – exerted force of gravity on matter

II. Atoms - Atoms are the basic unit of elements





Atoms contain 3 subatomic particles
 Proton – positive charge (inside the
nucleus)
 Neutron – no charge (inside the
nucleus)
 Electron – negative charge (outside
the nucleus)
Important values
 Atomic number - the number of
proton/s in an atom. In a neutral
atom, the number of electrons is
the same as the number of protons
 Atomic mass unit (amu)/Dalton –
the total mass of an atom = number
of protons + number of neutrons
Isotopes
 Elements with the same number of
protons but different number of
neutrons resulting in different
atomic mass
Electronegativity – degree to which an
atom attracts electrons in a chemical bond

Ionic bond – characterized as the
electrostatic attraction between a positively
and negatively charged ion. Between
metals and nonmetals (not all)
 Cation gives up electrons (+) and
Anion gains electrons (-)
ex. NaCl (Sodium chloride) ED = 2.1
note: metals tend to be cations and nonmetals anion
Covalent bond – characterized as the
sharing of electrons between non-metals in
a chemical bond
 Polar covalent bond – when atoms
don’t have enough electronegativity
difference for ionization, the one
with higher electronegativity will
hog all the electrons (partially
negative) from the other (partially
positive)
ex. HCl (Hydrochloric Acid) ED = 0.9
Valence electrons – the electrons in the
outer shell of an atom that will participate
in chemical bonding.
 Octet rule - atoms tend to prefer
having 8 electrons in their valence
shell. (2-8-8).
 Non-polar covalent bond – the
electrons are shared evenly
(typically occurs between atoms of
the same element)

Moles – standard quantity to represent the
6.02x1023(Avogadro’s number) of small
substances (atoms, ions, molecules)
IV. Atoms, Molecules, Elements and Compounds
ex. salt and sugar dissolved in water
VII. Chemical structures
Diatomic gases include – Br I N Cl H O F
V. Intermolecular Forces – force that mediates
interaction between molecules

Hydrogen bonding – weak attraction
between a positively charged hydrogen and
negatively charged oxygen or other polar
molecules.
ex. (1) water and (2) ethanol


Carbons live in ends and bends
 suffix -ane means single bond
 suffix -ene means double bond
Hydrogen loves carbons
ex. caffeine (C8H10N4O2)
 Fluorine, Oxygen, and Nitrogen can
also participate in hydrogen bonding
aside from hydrogen
Chemical Reactions and Energy
VI. Solubility and Dissociation
 Solubility is a substance’s ability to
dissolve in another substance
 Electrolytes – ionic compounds that
dissociate in water and conduct electrical
charge
 Non-electrolytes – molecules that do not
dissociate in water and do not create
electrical charge
I. Synthesis Reaction – A+B=AB (cross multiply
the electrical charge then balance)
II. Decomposition Reactions
III. Single Replacement
VII. Energy – ability to do work
 Potential energy – stored energy that could
do work
 Kinetic Energy – energy doing the work
IV. Double Replacement - Metal x Nonmetal

V. Reduction-Oxidation Reactions (Redox
Reactions) always occur together
VI. Reversible Reactions
 characterized when formed products revert
back to their old reactants
ex. Ammonium chloride (NH4Cl) reverts back to
ammonium (NH3) and Hydrogen chloride (HCl)
when heated (thermal decomposition) and both
these reactants react to form NH4Cl crystals.
 Forward – there are more NH4Cl
and less NH3; HCl, thus forward is
faster
 Backward – after a while, there will
be more NH3; HCl thus, backward
rate will be faster
 Equilibrium – the speed rates of
both forward and backward are the
same (does not mean one is more)
Chemical energy – potential energy stored
in the chemical bonds of a substance
 lesser pt of reactant, energy is
required for chemical reaction and
the prodcut will have greater pt
 greater pt of reactant, energy is
released for chemical reaction to
occur and the product will have
greater pt
VIII. Speed of Chemical Reactions
 Activation energy – minimum amount of
required energy for chemical reaction to
occur
 Catalyst – substance that speeds up the rate
of chemical reaction without it being
changed
 Enzymes – protein catalyst that
lowers the activation energy, thus,
increasing the speed and rate of
chemical reaction
note: temperature and concentration can affect the rate of
chemical reaction
Inorganic Chemistry
I. Inorganic Chemistry – are substances that lack
carbon or carbon-hydrogen bonds.
II. Water – polar molecule that forms hydrogen
bonds together or with other polar molecules
 Polarity/Solvent properties
 all chemical reactions in the body
are dependent on water’s solvent
properties
 acts as a transport and exchange
medium as it easily dissolves
nutrients, waste products,
respiratory gases.
 Hydrophilic – substances that
interact with water (polar
molecules and ionic compounds)
 Hydrophobic – substances that
repel water (nonpolar molecules)
 Cohesion – water molecule – water
molecule interaction
 Adhesion – water molecule – another
polar/ionic object



Regulates body temp with its high heat
capacity. Sweating results from evaporation
of water from the body releasing heat
Protects body by acting as a lubricant or
cushion to avoid friction damage or
physical trauma (at joints or body cavities)
Acts as a reactant by adding water
molecules to chemical bonds to break them
down (hydrolysis; water-splitting)
III. Electrolytes – produces + charged and –
charged ions when dissolved in water (has the
ability to conduct electricity in solution)

Salts (Na+Cl-) – ionic compound that
dissociates in water

PH, Acids and Bases
 Acids – substance that release
hydrogen ions (H+) or proton (H+)
donor
o strong acids – completely
ionize and liberate all their
protons (ex. HCl  H+ +
Cl-)
o weak acids – ionize
incompletely (ex.
)
 Bases – grabs protons or donates
OH- when they dissociate (ex.
NaOH Na+ + OH-) or
(OH- + H+  H2O)
 pH – express acidity or alkalinity
of solution (enzymes only work at
certain pH and a change can result
in denaturing)
a change in pH by 1 in solution represents a 10-fold
change of H+ concentration. The lower the value
means H+ is more concentrated, thus, acidic.
 Buffers – molecule that maintains
pH at a constant rate
note: Normal blood pH ranges from 7.35 to 7.45.
Slight deviations outside this range can be fatal
Organic Chemistry
I. Organic Chemistry – Carbon containing
compounds that comprise living matter. Many of
these compounds are polymers (carbohydrate and
protein)
 Polymers - chainlike structures that is
formed by a single unit called monomers
that are joined together by dehydration
synthesis
 Dehydration synthesis – one hydrogen (H)
atom is removed from one monomer and a
hydroxyl group (OH) is removed from the
other monomer (releasing H2O)
 Hydrolysis – adding H2O between bonds to
release the monomers
II. Carbohydrate – it contains carbon-hydrogenoxygen in a 1:2:1 ratio
 acts as a short term (converted to ATP) and
long term (glycogen for animals, starch and
cellulose for plants) energy storage
 suffix -ose is used for describing and
naming carbohydrates
 Monosaccharide – one sugar; the building
block of carbohydrate (fruits, veggies,
honey)
 Glucose – blood sugar; universal
cellular fuel
 Fructose and Galactose – converted
to glucose for cell function
 Deoxyribose and Ribose – part of
nucleic acid structure


Polysaccharides – chains of simple sugars
 Starch – grains or root vegetables
 Glycogen – long term energy
storage molecule in muscles/liver
 Cellulose – can’t be used as
energy but many nutritional
benefits (dietary fibers; leafy
greens)
III. Lipids – energy rich non-polar (hydrophobic)
compounds containing carbon-hydrogen-oxygen in
a 1:2: little oxygen ratio (C57H110O6)
 Triglycerides – one glycerol backbone
with three fatty acids linked to it by
dehydration synthesis
 Saturated fats – single C-C bonds
pack closely at room temperature
 Unsaturated fats – double or triple
bonds between C-C causing it to
curve, thus, not solidify at room
temperature
 Omega-3 and Omega-6
polyunsaturated - heart healthy the first double bond is found at
the 3rd and 6th carbon
Disaccharide – two monosaccharides joined by
dehydration synthesis and is broken down by
hydrolysis for digestion
Sucrose: Table sugar
Lactose: Milk
Maltose: Malt sugar
(beer)
 Trans Fats - chemically altered
unsaturated fat by hydrogenation
(unsuccessful) (rare in nature,
thus, no enzyme to break it down)
 The structure and function of
protein is dictated by the type and
order of amino acids

Phospholipids – same to triglycerides
except that one of the fatty acids is
replaced by a phosphate containing region.
the polar side is the one containing the
phosphate and the nonpolar side which
contains the fatty acids


Steroids – do not contain fatty acids,
instead, have interlocking four carbon ring
structure.
 Cholesterol – found in cell
membranes and synthesize other
steroids
 Bile salts – increase fat absorption
 Reproductive hormones –
testosterone and estrogen for
secondary sex characteristics
Peptide – 2 amino acids bonded by
dehydration or protein synthesis
Dipeptide
2 amino acids joined together
Tripeptide
3 amino acids joined together
Tetrapeptide 4 amino acids joined together
Oligopeptide 2-20 amino acids
Polypeptide 21-49 amino acids
Protein
More than 50 amino acids
 Four Levels of Protein Structure
 Primary – sequence of amino acids
in the polypeptide chain
determined by DNA
IV. Proteins
 Amino Acids – monomers of proteins
 Secondary - hydrogen bonding
(dotted red lines). The hydrogen
bonds cause the amino acid chain
to form pleated (folded) sheets or
helices (coils).
 Tertiary – interaction of side
chains (denaturing occurs when
these interactions break down)
 Quaternary – formed between the
interaction of 2 or more
polypeptide units and can be
globular or fibrous
V. Nucleic Acids – organic living substance found
in cells that can either be a DNA or RNA polymer
made up of nucleotides as monomers (basic unit)
 • Nucleotides – has 3 basic parts
 Pentose sugar – deoxyribose (no O
on carbon 2) for DNA and ribose
(OH in carbon 2) for RNA
 Nitrogenous bases
> Purine (2 rings) – sugar ring will
attach to nitrogenous base at 9th
position
> Pyrimidine (1 ring) - sugar ring
will attach to nitrogenous base at
1st position

 Nucleoside (sugar and base only)
 Phosphate group (PO-34)
• DNA (deoxyribonucleic acid)
- determines the structure and
sequence of amino acids
- store genetic information
 Functional unit is nucleotide
[phosphate group bonds (covalent)
to deoxyribose at carbon 5,
deoxyribose is also bonded to 1
nitrogenous base]
 P-group of another nucleotide
connects to carbon 3, making the
sugar-phosphate backbone of DNA
and sequence of the bases which
are now codes [P-group is now
bonded to two sugars (3’5’
phosphodiester bonds)]
 Complementary base pairs are
present on the other strand which
creates a hydrogen bond between
the bases (2 bonds between AT and
3 bonds between GC)
 The complementary strands are
antiparallel in that the 5' > 3'
direction of one strand runs
counter to the 5' > 3' direction of
the other strand.
 The nucleotide strands coil to form
a double-stranded helix
note: some DNA are non-coding, some makes genes that aren’t
activated, and some makes genes that code for active protein


• RNA (ribonucleic acid) single stranded

 functional unit is nucleotide (Pgroup attached to carbon 5 of
ribose, that is also attached to a
nitrogenous base) and also forms
3’5’ phosphodiester bonds
 nitrogenous base – AU and GC
 3 types – messenger RNA,
ribosomal RNA, and transfer RNA
• Protein Synthesis (1st level of protein structure)
 Transcription – RNA polymerase
binds complementary RNA bases
to DNA template strand in nucleus
to create mRNA based on DNA
sequence  mRNA goes out of
nucleus and attach to ribosome;
rRNA is a component of ribosome
 Translation – tRNA brings amino
acids based on the anticodon tRNA
has and finds the complementary
bases on mRNA by reading it by 3
(codon)  tRNA leaves the
ribosome and leave the amino acid
behind which bond with other
amino acids.
Naming nucleosides/tides
 AMP
(adenine+ribose+monophosphate)
 ADP
(adenine+ribose+diphosphate)
 ATP
(adenine+ribose+triphosphate)
- close proximity of 3 (-) charged
P-groups are unstable, thus, stores
high amount of PE
- when phosphate is released
(hydrolysis) small amount of
energy is released, ATP > ADP
- chemical reactions like
catabolism of glucose or other
nutrient release energy to
synthesize ADP > ATP
- when ATP is produced, it is used
for functions that require energy
like anabolism or propel cell
function (muscle contraction);
ATP > ADP
Chapter 3: Cell Biology
Introduction to Cells
I. Cell Theory
1. All living organisms are made up of cells
2. Cell is the basic structural and functional unit of life
3. All cells arise from pre-existing cells
Important Cell Milestones
II. Parts and Functions of the Cell
Note: Cell size and shape vary depending on their functions

• Plasma Membrane/Cell Membrane
 Transparent fluid barrier that separates the cell from its environment
 Semi-permeable/selectively permeable - allows only specific substances or molecules to enter the
cell
 Lipid-soluble/non-polar molecules can easily pass while polar molecules cannot
 ECF (extracellular fluid) - high levels of sodium - low levels of potassium
 ICF (intracellular fluid) - high levels of potassium - low levels of sodium
Fluid-Mosaic Model - represents the biological structure of a plasma membrane along its components that
determine its fluid-like nature
Plasma Membrane/Cell Membrane
> Transparent fluid barrier that separates the cell from its environment
> Semi-permeable/selectively permeable - allows only specific substances or molecules to enter the cell
> Lipid-soluble/non-polar molecules can easily pass while polar molecules cannot
> ECF (extracellular fluid) - high levels of sodium - low level of potassium + calcium a + chloride ions
> ICF (intracellular fluid) - high levels of potassium - low levels of sodium +enzymes +proteins
+glycogen + potassium ions
Fluid-Mosaic Model - represents the biological structure of a plasma membrane along its components that
determine its fluid-like nature
Membrane Lipids
> Polar heads oriented to face the ICF and ECF > Nonpolar
Phospholipid
> Hydrophilic, polar head (phosphate group + R (choline)
> Hydrophobic, non-polar tail composed of two fatty acids (saturated and unsaturated)
Cholesterol
> Maintains fluidity of the phospholipid bilayer:
1) preventing it to solidify in low temperatures by pushing them apart and 2) preventing it to be too
fluid in high temperatures by holding the phospholipids together.
Fluid-mosaic model
> Explains that the plasma membrane is fluid-like (like a dense liquid) and is neither static nor
rigid
> Flexible, thus, can change shape and composition through time
Membrane Proteins and their Functions
> Integral proteins - proteins that are embedded within the phospholipid bilayer
> Peripheral proteins - proteins that attach to either the inner or outer surfaces of the bilayer > Surface
proteins - proteins that lies on inner or outer cell surface
Marker Molecules
Helps the cell recognize other cells (Carbohydrate)
Glycoprotein - carbohydrate attached to protein
Glycolipids - carbohydrates attached to lipid
Ex. 1. sperm cell recognizing oocyte
2. white blood cells recognizing foreign invaders
(distinguishing bacteria from donor cells)
Attachment Proteins
○
Cadherins
> Proteins that attach to the protein of another cell
○
Integrins
> Proteins that attach with other molecules from inside and outside the cell
Transport Proteins
> Integral proteins that extend from each side of the membrane (act as a passageway of
substances)
Three common characteristics: a) Specificity - substances can only enter through a protein
specific to the substance b) Competition - substances with the same shape bind to a common
protein (substances in higher concentration are transported at a faster rate) c Saturation - substances
that get transported are limited by the number of transport proteins.
○
Channel Proteins
> solutes don't bind to channel proteins
■
Leak Ion Channels
A Passive Transport Protein
> always open for transport of specific substances
■
Gated Ion Channels
●
Ligand Gated Ion Channel
> Ligand (chemical signal) binds with the protein receptor to open
●
○
Voltage-Gated Ion Channel
> Gates open in response to change in membrane potential
Carrier Proteins
> Proteins bind to protein receptors which triggers a conformational change
■
Uniport
> Carries one specific substance at a time
■
Symport
Cotransport
> Transports two different substances together in the same direction
■
Antiport
Counter-transport
> transports one substance to a different side, then transport a different substance
back to the first side
○
ATP-Powered Pumps
> Have 2 binding sites
> One for the ion to be transported and one for ATP which will release energy to fuel the
transport
Receptor Proteins
> Proteins with exposed specific receptors wherein chemical signals (or other substances) bind to
initiate a response
> can be membrane proteins or glycoproteins
○
Receptor Linked to Channel Proteins
> channel proteins have an exposed receptor wherein chemical signals bind to change
○
Receptors Linked to G Protein Complexes
> the receptor site of a protein binds with a chemical signal which causes the G protein
complex to bind to the protein.
> the guanosine diphosphate from the a-subunit of the complex will then be replaced
with guanosine triphosphate (activation)
> the g-complex leaves the protein and the a-subunit will then dissociate from the
complex to be used for cell
Enzymes
> are integral proteins that catalyze chemical reactions from the inner or outer surface of the cell
> are either always active or activated by G protein complexes
Movement Through the Plasma Membrane
Passive Membrane Transport
> does not require energy (substance moves along the concentration gradient which allows
substances to move from high to low concentration)
> collisions from concentrated area creates energy
○
Diffusion
> movement (high-to-low concentration) of lipid-soluble substances directly through the
phospholipid bilayer to the opposite side of the membrane
> small polar molecules can diffuse (ex. water)
> water diffusion is called osmosis
○
Osmosis
> movement of water from high to low concentration (requires aquaporins)
■
Tonicity
> behavior of cells when placed in a solution (shrink or expand and burst)
> 3 types of solutions
●
Hypotonic
> hypo[less]+tonic[solute]
> less solute, thus more water
> cell has more solute and less water
> water moves from solution to cell (expand and burst)
●
Hypertonic
> hyper[high]+tonic[solute]
> more solute, thus, less water
> cell has less solute and more water
> water moves from cell to solution (shrink)
●
○
Isotonic
> concentration of solute and solvent is the same throughout the sides,
thus, no net movement (no gradient)
Facilitated Diffusion
> movement of large lipid-insoluble (hydrophilic, polar) substances across the membrane
through the help of transmembrane proteins
> specificity, competition, and saturation
Active Membrane Transport
> requires energy (ATP) for substances to move against the gradient or from low to high
concentration
○
Active Transport
> transport of inorganic or ionic substances through ATP-powered pumps (require
energy) from high to low concentration or vice versa
> ex.: In the ECF, Na is higher and K is lower which means in ICF, Na is lower and K is
higher. In a sodium-potassium pump, K moves to ICF (low to high) and Na moves to
ECF (low to high)
> from ICF, sodium attaches to ATP pump, when ATP binds to pump and breaks down,
it undergoes a conformational change which pumps sodium to ECF
> K attaches to the pump from ECF, when phosphate is released, it goes back to its
original shape, thus, releasing the K to ICF
note: for every ATP, Na moves to ECF and K moves from ECF back to ICF
○
Secondary Active Transport
> movement of organic or ionic substances (glucose and Na) along and against the
concentration gradient
> ex.: when Na accumulates in the ECF, it moves down to its gradient which creates
energy for Glucose to move inside the cell (against the gradient)
Vesicular Transport
> transport of large substances across the membrane > requires ATP
○
Endocytosis
> moves substances from outside to inside the cell
■
Phagocytosis
> phago (to eat) > cell-eating > ex.: macrophage (a wbc) finds a streptococcus (a
bacterium) > strep attaches to macro receptors > macro extends pseudopods
across the strep to envelope > vesicle is formed then separated from the
membrane (phagosome) > phagosome meets lysosome > lysosome digests phago
with its digestive enzymes > leftovers are expelled
note: phagocyte is an immune cell
■
Pinocytosis
> cell drinking > membrane engulfs random molecules and fluid from ICF and
delivers it deep into the cytosol where it is released
■
Receptor-Mediated Endocytosis
> are special receptors that carry specific into the cell to increase cell uptake on
these specific substances
> ex. LDL (low-density lipoprotein) receptor is found in clathrin-coated pits in
the cell membrane > LDL bind to the receptors > pseudopods form then clathrins
link up around it and gets released back to the membrane when vesicle separates
from the membrane > endosome engulfs the vesicle and separated LDL from the
receptor > 2 vesicles form for LDL and receptor > LDL goes to the lysosome for
digestion > receptor goes back to membrane
> when LDL receptor is low, cholesterol uptake of the cell is low thus, cells
produce more cholesterol inside (hypercholesterolemia) when cholesterol
accumulates it blocks blood vessels (Atherosclerosis) which causes heart attack
or stroke
○
Exocytosis
> ICF substances expelled out of the cell
○
> ex.: Golgi apparatus packs proteins, lipids, and hormones from the endoplasmic
reticulum through a vesicle > vesicle is transported through cytoskeleton to the
membrane > vesicular membrane fuse with cell membrane > vesicular contents rupture to
the ECF
Cell Junctions
> cells need to connect and communicate with each other through different types of junctions
Tight Junctions
> holds cell very tightly where waters and ions can't pass through with the help of proteins
> ex. bladder, intestine, stomach, kidney, etc.
Desmosomes
> connects cell through cadherins (proteins) that extends to the cytoskeleton
> waters and ions can pass through for flexibility and reduced pressure
> skin, heart muscle, and intestine
Gap Junctions
> creates a connection between cells (connexon) for intercellular communication (ions and
molecules pass through or spread action potential)
Plasma Membrane/Cell Membrane
> Transparent fluid barrier that separates the cell from its environment > Semi-permeable/selectively
permeable - allows only specific substances or molecules to enter the cell > Lipid-soluble/non-polar
molecules can easily pass while polar molecules cannot > ECF (extracellular fluid) - high levels of
sodium - low level of potassium + calcium a + chloride ions > ICF (intracellular fluid) - high levels of
potassium - low levels of sodium +enzymes +proteins +glycogen + potassium ions Fluid-Mosaic Model represents the biological structure of a plasma membrane along its components that determine its fluidlike nature
Membrane Lipids
> Polar heads oriented to face the ICF and ECF > Nonpolar
Phospholipid
> Hydrophilic, polar head (phosphate group + R (choline) > Hydrophobic, non-polar tail
composed of two fatty acids (saturated and unsaturated)
Cholesterol
> Maintains fluidity of the phospholipid bilayer: 1) preventing it to solidify in low temperatures by
pushing them apart and 2) preventing it to be too fluid in high temperatures by holding the
phospholipids together.
Fluid-mosaic model
> Explains that the plasma membrane is fluid-like (like a dense liquid) and is neither static nor
rigid > Flexible, thus, can change shape and composition through time
Membrane Proteins and their Functions
> Integral proteins - proteins that are embedded within the phospholipid bilayer > Peripheral proteins proteins that attach to either the inner or outer surfaces of the bilayer > Surface proteins - proteins that lies
on inner or outer cell surface
Marker Molecules
Helps the cell recognize other cells (Carbohydrate) Glycoprotein - carbohydrate attached to
protein Glycolipids - carbohydrates attached to lipid Ex. 1. sperm cell recognizing oocyte
2.
white blood cells recognizing foreign invaders (distinguishing bacteria from donor cells)
Attachment Proteins
○
Cadherins
> Proteins that attach to the protein of another cell
○
Integrins
> Proteins that attach with other molecules from inside and outside the cell
Transport Proteins
> Integral proteins that extend from each side of the membrane (act as a passageway of
substances) Three common characteristics: a) Specificity - substances can only enter through a
protein specific to the substance b) Competition - substances with the same shape bind to a
common protein (substances in higher concentration are transported at a faster rate) c) Saturation substances that get transported are limited by the number of transport proteins.
○
○
Channel Proteins
> solutes don't bind to channel proteins
■
Leak Ion Channels
A Passive Transport Protein > always open for transport of specific substances
■
Gated Ion Channels
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Ligand Gated Ion Channel
> Ligand (chemical signal) binds with the protein receptor to open
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Voltage-Gated Ion Channel
> Gates open in response to change in membrane potential
Carrier Proteins
> Proteins bind to protein receptor which triggers conformational change
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Uniport
> Carries one specific substance at a time
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Symport
Cotransport > Transports two different substances together in the same
direction
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Antiport
Counter-transport > transports one substance to a different side, then transport a
different substance back to the first side
ATP-Powered Pumps
> Have 2 binding sites > One for the ion to be transported and one for ATP which will
release energy to fuel the transport
Receptor Proteins
> Proteins with exposed specific receptors wherein chemical signals (or other substances) bind to
initiate a response > can be membrane proteins or glycoproteins
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Receptor Linked to Channel Proteins
> channel proteins have an exposed receptor wherein chemical signals bind to change
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Receptors Linked to G Protein Complexes
> the receptor site of a protein binds with a chemical signal which causes the G protein
complex to bind to the protein. > the guanosine diphosphate from the a subunit of the
complex will then be replaced with guanosine triphosphate (activation) > the g-complex
leaves the protein and the a subunit will then dissociate from the complex to be used for
cell
Enzymes
> are integral proteins that catalyze chemical reactions from the inner or outer surface of the cell >
are either always active or activated by G protein complexes
Movement Through the Plasma Membrane
Passive Membrane Transport
> does not require energy (substance moves along the concentration gradient which allows
substances to move from high to low concentration) > collisions from concentrated area creates
energy
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Diffusion
> movement (high-to-low concentration) of lipid-soluble substances directly through the
phospholipid bilayer to the opposite side of the membrane > small polar molecules can
diffuse (ex. water) > water diffusion is called osmosis
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Osmosis
> movement of water from high to low concentration (requires aquaporins)
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Tonicity
> behavior of cells when placed in a solution (shrink or expand and burst) > 3
types of solutions
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Hypotonic
> hypo[less]+tonic[solute] > less solute, thus more water > cell has more
solute and less water > water moves from solution to cell (expand and
burst)
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Hypertonic
> hyper[high]+tonic[solute] > more solute, thus, less water > cell has
less solute and more water > water moves from cell to solution (shrink)
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Isotonic
> concentration of solute and solvent is the same throughout the sides,
thus, no net movement (no gradient)
Facilitated Diffusion
> movement of large lipid-insoluble (hydrophilic, polar) substances across the membrane
through the help of transmembrane proteins > specificity, competition, and saturation
Active Membrane Transport
> requires energy (ATP) for substances to move against the gradient or from low to high
concentration
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Active Transport
> transport of inorganic or ionic substances through ATP-powered pumps (require
energy) from high to low concentration or vice versa > ex.: In the ECF, Na is higher and
K is lower which means in ICF, Na is lower and K is higher. In a sodium-potassium
pump, K moves to ICF (low to high) and Na moves to ECF (low to high) > from ICF,
sodium attaches to ATP pump, when ATP binds to pump and breaks down, it undergoes
a conformational change which pumps sodium to ECF > K attaches to the pump from
ECF, when phosphate is released, it goes back to its original shape, thus, releasing the K
to ICF note: for every ATP, Na moves to ECF and K moves from ECF back to ICF
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Secondary Active Transport
> movement of organic or ionic substances (glucose and Na) along and against the
concentration gradient > ex.: when Na accumulates in the ECF, it moves down to its
gradient which creates energy for Glucose to move inside the cell (against the gradient)
Vesicular Transport
> transport of large substances across the membrane > requires ATP
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Endocytosis
> moves substances from outside to inside the cell
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Phagocytosis
> phago (to eat) > cell-eating > ex.: macrophage (a wbc) finds a streptococcus (a
bacterium) > strep attaches to macro receptors > macro extends pseudopods
across the strep to envelope > vesicle is formed then separated from the
membrane (phagosome) > phagosome meets lysosome > lysosome digests phago
with its digestive enzymes > leftovers are expelled note: phagocyte is an
immune cell
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Pinocytosis
> cell drinking > membrane engulfs random molecules and fluid from ICF and
delivers it deep into the cytosol where it is released
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Receptor-Mediated Endocytosis
> are special receptors that carry specific into the cell to increse cell uptake on
these specific substances > ex. LDL (low-density lipoprotein) receptor is found in
clathrin-coated pits in the cell membrane > LDL bind to the receptors >
pseudopods form then clathrins link up around it and gets released back to the
membrane when vesicle separates from the membrane > endosome engulfs the
vesicle and separated LDL from the receptor > 2 vesicles form for LDL and
receptor > LDL goes to lysosome for digestion > receptor goes back to
membrane > when LDL receptor is low, cholesterol uptake of cell is low thus,
cells produce more cholesterol inside (hypercholesterolemia) when cholesterol
accumulates it blocks blood vessels (Atherosclerosis) which causes heart attack
or stroke
Exocytosis
> ICF substances expelled out of the cell > ex.: Golgi apparatus packs proteins, lipids,
and hormones from the endoplasmic reticulum through a vesicle > vesicle is transported
through cytoskeleton to the membrane > vesicular membrane fuse with cell membrane >
vesicular contents rupture to the ECF
Cell Junctions
> cells need to connect and communicate with each other through different types of junctions
Tight Junctions
> holds cell very tightly where waters and ions can't pass through with the help of proteins > ex.
bladder, intestine, stomach, kidney, etc.
Desmosomes
> connects cell through cadherins (proteins) that extends to the cytoskeleton > waters and ions can
pass through for flexibility and reduced pressure > skin, heart muscle, and intestine
Gap Junctions
> creates a connection between cells (connexon) for intercellular communication (ions and
molecules pass through or spread action potential)