Chapter 1: Cellular Biology (In Class Notes)
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Eukaryotic: larger, much more extensive anatomy
o Organelles
o Nucleus
o Chromosome
o Histone that bind DNA and involved in supercoiling of DNA
Prokaryotic: much more simple than eukaryotic
o No organelles
o Single chromosome
o Lack of distinct nucleus
o Lack nuclear membrane
8 chief functions of cells:
Movement: contraction of smooth muscle in the intestine (peristalsis)
Conductivity: electrical potential of cells; nerve cells
Metabolic absorption: our kidney absorb fluids/proteins
Secretion: synthesize new substances and can secrete new ones; testes and ovaries
Excretion: can remove waste from metabolic breakdown of cells; lysosomes
Respiration: absorb oxygen which transforms nutrients into energy into ATP; in
mitochondria occurs
Reproduction: new cell production; even without growth cellular turnover is required
because of cell death) it will continue to happen regardless); not a function of all cells
Communication: cells need to talk to each other to signal things such as signal death or so
that cells in the pancreas can signal to release more insulin
Nucleus: primary function is cell division and control of genetic information
o Tertiary functions: replication/ repair/ transcription of DNA
o It is surrounded by cytoplasm and nucleoplasm
o Has a double membrane/ nuclear envelope
o Nucleolus: consists of RNA/DNA
 Histone: allow DNA to coil – it is important bc it takes genetic code and
makes it into more portable vesicles
o Cytoplasm: made of cytosol (aqueous solution)
 Surrounds the cells
 Separates nuclear envelope and plasma membrane
CYTOPLASMIC ORGANELLES:
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Endoplasmic reticulum: synthesizes and transport protein/lipid components
o SMOOTH ER:
o RUGH ER:
Ribosomes: cellular protein synthesis (RNA protein complex)
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Golgi apparatus: processes/packages proteins
Lysosomes: sac like structure coming from golgi complex
o Contain digestive enzymes that break down bons (proteins, lipids, nucleic acids,
and carbs)
Peroxisomes: similar to lysosome but larger
o Contain oxidative enzymes (catalase and urate oxidase)
o Use oxygen to create hydrogen peroxide
o Role with free radicals
o Synthesize phospholipids for nerve cell myelination
o Break down fatty acids
Mitochondria: metabolic machinery for cellular metabolism/ respiration
o Oxidative phosphorylation
o Have an outer/inner membrane (electron transport chain)
o Produce energy (ADP to ATP)
o Citric acid cycle, Krebs cycle – “be familiar with them but don’t have to recite
them”
Vaults: octagonal shape; unsure of what their function nis
o They surround proteins
o Right now we think that they transport messenger RNA from nucleus to
cytoplasmic ribosome
Cytoskeleton: produces cell structure; think of “bones”
o Maintains cell shape & internal organization
o Allows for movement of substance within the cell and movement of external
projections
o Microtubules: add strength and aid in cell division
o Actin microfilaments: link through the cell junction
Plasma membrane: maintains cell shape
o Defines boundaries of cells
o Includes/excludes molecules; determines what’s coming in and out
o Functions: structure, protection, cell activation (hormone regulation), transport
(endocytosis – things brought into cell, exocytosis – exit out of cell), and cell-cell
interaction
 See pg 12 in textbook (table)
o Caveolae: dimpled areas of the plasma membrane – increases cell surface area
(dimpling on anything)
 Help facilitate transport into and out of cell
 Participate in calcium signaling
Lipids: major component of cell (form phospholipid bilayer)
o Maintain structure
o Key to membrane repairs; phospholipids will spontaneously rearrange to avoid
tears
o Impermeable to water soluble molecules – amphipathic water loving (hydrophilic)
head, but water hater (hydrophobic) tail
o ****understand amphipathic structureof plasma membrane
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Proteins: amphipathic
o Made of ribosomes – consist of chains of amino acids
 20 diff types of amino acids
o Job is determine by sequencing of amino acids
o Facilitate transport by serving as receptors, enzymes, and transporters
o Transport ions like K+ and Na+
o Involved in recognition and receptors
 Attached to the membrane (integral)
 Adhere temporarily to the membrane (peripheral)
Carbs (CHO)
o Oligosaccharides
 bound to proteins (glycoproteins)
 bound to lipids (glycolipids)
o function in tissue formation and intracellular recognition
cell-cell adhesions
o cells are squishy, not hard. Plasma membrane keeps them together
o held together by extracellular matrix – pathway for the diffusion of cellular waste
 regulates cell growth
 provides movement and cell differentiations
 collagen: provide strength
 elastin: stretch and recoil
 fibronectin: holds cells together
 combines with cells to form connective tissue
Cell adhesion molecules (CAMs)
o Cell surface proteins that bind cell to adjacent cell
o 4 types:
1. Integrins:
2. Cadherins
3. Selectins
4. Immunoglobulin superfamily
Cell junctions: holds cells together and allow small molecules to pass
o Gating system: what’s allow through there? They determine that
o Process that control permeability of cells
 Ca+ released from injured cells as sort of waving their flag to demonstrate
they are damaged ******
1. Desmosome: hold cell together
2. Tight junctions: form a barrier, if it’s tight they won’t allow anything through
3. Gap junctions: cluster of communicating tunnels = connexons
a. Small ions/molecules to pass from inside one cell to another
Cellular communication and signal transductions
o Gap junctions
o Direct link up –
o Hormones that initiate a signaling to talk
 Hormone is gonna hit blood stream and go to the target cell
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o Neurohormonal signaling
 Nerve is gonna secrete the chemical modulator and go into the blood and
will go to target cell to cause intended response
 Paracrine: cells secrete local chemical mediators
 Autocrine: cell secretes chemical that targets itself
o Neurotransmitters
 Secretes neurotransmitter which falls on target cell
Signal transduction
o Extracellular chemical messengers communicate with plasma membrane
o First messenger: transfers, amplifies, distributes, and modulates signal
o Second: triggers cascade of events within cell – modulated by cyclic adenosine
monophosphate (cAMP)
o Ca+ -- injured cells will release calcium and calcium is a major signaling ion
**Read book for messenger system**
o Form = function for a protein – if you change the shape, you are changing its
function
Cellular metabolism
o Chemical processes that are essential for a cellular function
o Anabolism: “using up energy”
o Catabolism: “energy breaking down”
o ATP (adenosine triphosphate): the fuel inside of a cell; chemical energy created
for metabolism
 Required for synthesis of organic molecules, muscle contraction, & active
transport
 1 mole of glucose = 686 kcal of energy released
Cellular energy:
o Phase one: digestion
 proteins – amino acids
 Polysaccharides – simple sugars
 Fats – fatty acids
o Phase two: glycolysis
 glycolysis = splitting glucose
 produces two molecules of ATP per glucose molecule
 sugar is broken down in pyruvate which is then turned into acetyl
CoA
o CoA are catalysts to reactions; they will release energy or
start a reaction
 occurs in cytoplasm
 anaerobic v aerobic
 will determine what happens with pyruvate
 if it’s aerobic and has O2 it will be converted to pyruvic acid and
go into the krebs cycle
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if anaerobic it lacks O2 and will create lactic acid; think of
working out after not doing it for a while. Your muscles hurt
because there is a buildup of lactic acid in your muscles
o Phase three: kreb’s cycle
 Citric acid = kreb’s cycle = tricarboxylic acid cycle
 Most amount of energy is created in this phase
 Oxidative phosphorylation: occurs in the mitochondria
 Produces energy from carbs, fats, and proteins and transfers energy
to ATP
o Electric transfer facilitated through coenzymes (reaction
catalysts); “they are friends that help facilitate a reaction”
Membrane transport:
o Passive transport: water and small electrically charge molecules pass through
plasma membrane
 Does NOT require energy
 Diffusion, filtration, osmosis
o Active transport: larger molecules and fluids
 Occurs against a transport gradient and uses transport pumps
 Requires energy
Body fluids:
o Electrolytes: particles in the blood stream that have a plethora of purposes to
maintaining homeostasis in our bodies
 95% of solute molecules
 Monovalent: Na+, K+, Cl Divalent: Ca++, Mg++
 mEq/L: milliequivalents/liter
 mg/dL: milligrams/deciliter
o Non electrolytes:
 Glucose
 Urea – byproduct of our kidney filtration
 Creatinine –kidney function value
o Polarity:
 Cation
 Anion
Lab values: these values differ from lab to lab
***know laboratory values from the book!!!!***
o Sodium
o Potassium
o Chloride
o Blood glucose
o Creatinine
o Blood urea nitrogen (BUN)
Diffusion:
o Movement of solute molecule from HIGH to LOW concentration
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 Concentration gradient: difference in concentration
o Solute: small particle of dissolved substance; ex. Salt water -- the solute is the salt
o Rate of diffusion:
 Depends on the electrical potential, size, and lipid solubility
o Nonpolar = diffuse rapidly
 O2, CO2, H2O, N, urea, and glycerol
o Polar: macromolecules = diffuse slowly
 Charge molecules may also repel; they’re like magnets, you need a + and 
o Water readily diffused
 Small ad uncharged
Filtration:
o Movement of water and solutes through the membrane due to greater pressure on
one side of membrane
o Hydrostatic pressure: force of H2O pushing AGAINST on the cell membrane
 Ex. If you have a cell and you have pressure moving out against the cell
membrane
o Oncotic pressure: pressure moving IN to the cell
o Partially balanced by osmotic pressure
 You lose some of it form the lymphatic system
Osmosis: movement of H2O DOWN a concentration gradient or ACROSS a semi
permeable membrane more permeable to H2O
o Movement of HIGHER H2O to LOWER H2O
o Related to hydrostatic pressure and solute concentration
o Osmolality: # milliosmoles per kg
 Concentration of molecules of H2O per WEIGHT
o Osmolarity: # of milliosmoles per L (volume)
 Concentration of molecules of H2O per VOLUME
Tonicity:
o Effect of osmolality of a solution
o Isotonic (normal) solution: same osmolality of particles (285 mOsm/kg) as ICF or
ECF
 Even exchange in and out of cell; the cell remains a normal size
o Hypotonic (lower) solution: lower concentration of particles; more dilute
 If someone is severely dehydrated
 Causes cells to swell because water is moving into the cell
o Hypertonic (higher) solution: higher concentration of particles
 Causes cells to shrink because water is moving out of cell
Mediated transport (passive and active transport):
o Active transport: moves molecules up or against a concentration gradient
 Small solute and ion transport
 Na+ and K+
 Active transport pumps
 Na+ - K+ pumps – crucial to cardiac conduction
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o 3 sodiums and ATP enter the molecule and cause a reaction
o 2 potassium ions exit, protein changes shape and the
process starts again
o **extremely important to the cardiac component of our
body
 Require energy – ATP
Transport by vesicle formation
o Transport of macromolecules:
o Endocytosis: engulf substance outside the cell; that particle that’s swallowed
becomes an edocytic vesicle (or invagination)
 Pinocytosis: can be used interchangeably with endocytosis
 Phagocytosis: larger particles can be engulfed so they can be destroyed by
lysosomes
o Exocytosis: secretion from intracellular vesicles at cell surface
 Take waste that was digested and secrete it outside of the cell
Electrical impulses: our cells are all polarized; helps maintain homeostasis
o Inside cell: more negative
o Outside cell: more positive charge
 Difference of the charges inside and outside cell is known as resting
membrane potential
o Action potential: nerve or muscle cell receiving a stimulus that exceeds
membrane threshold
 Change in the resting membrane (basal membrane)
o Depolarization: where membrane potential decreases to negative
o threshold potential: where the cell can take no more stimulus; it’s depolarized
without further stimulation
o Repolarization: where it reestablishes the negative polarity
o Absolute refractory period: plasma membrane cannot respond to any stimulus
 Related to changed in permeability in Na+
o Relative refractory period: plasma membrane can respond
 Permeability to K+ increases
 Occurs in latter phase of action potential
 Stronger than normal stimulus can evoke action potential (reset to 0)
Cell reproduction
o Meiosis: reproduction of gametes (sperm and egg cells)
o Mitosis: reproduction of other body or somatic cells
 Where nucleus divides
 Cytokinesis: cytoplasmic division
CELL CYCLE
o Chromatin v chromosome
o Interphase: longest phase; where chromatin starts to organize
 G1 phase:
 S phase:
 G2 phase:
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o Prophase: primitive appearance of a chromosome
 Chromatids start to line up and centromeres (where they join) start to
organize
 Not perfect, bt you can see organization
o Metaphase
o Anaphase: 92 chromosome
 At the end of this cycle there are 46 chromosome
o Telophase: 2 identical diploid cells
Rates of cellular division
o Complete cell cycles take 12-24 hours **know this for test but be aware that
several factors can impact depending on the overall health of the body**
o Mitosis/ cytokinesis: 1 hr
o Continuous dividing cells
 Intestine, lungs, skin – they undergo a lot of trauma
o Non continuous dividing cells – At rest in the G0 phase (they aren’t gonna
differentiate any further and are gonna stay the way they are)
 Adult cells like nerve, lens of eye, muscles
o s/n: cellular division rates are rapid in kids because they are constantly growing
growth factors: cytokines
o peptides that transmit signals—with or between cells
o serve as chemical signals – to signal growth
o platelet derived growth factors (PDGF)
 stimulate growth of connective tissue cells and neuroglia cells
o epidermal growth factors (EGF)
 stimulate proliferation of epidermal cells
o interleukin 2 (IL-2)
 stimulate proliferation of T lymphocytes
tissues:
o comprised of cells that form a structure that has a function
o 4 primary types:
 Epithelial: line our lungs and skin
 Internal and external surfaces
 Simple/ stratified
 Squamous
 Cuboidal
 Columnar
 Pseudostratified
 Structures: cilia and microvilli **know function, where they’re
found, and why they’re important**
 Connective tissue
 Varies in structure and function
 Common framework for epithelial cells to form organs
 Really abundant cellular matrix – connect tissue
o Ground substance
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o Collagenous fibers
o Elastic fibers
o Reticular fibers
Loose/ dense connective tissues **look into text
Classified according to consistency
o Cartilage, adipose, bones, organs
Muscle
 Smooth
 Cardiac
 Skeletal
Neural
 Neurons
 Synapses
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Formed by MITOSIS and migration
 Mitosis: founder cells and basic precursor cells
 Migration
o Chemotaxis: mvmt of chemical gradient
 Chemotactic factor: chemical that is released; like a
pheromone that attracts
o Contact guidance: mvmt along a pathway or a pavement
 Can be like bowling or bumper cars
o Cellular reproduction
o Stem cells: cells with ability to develop into many different
cell types (pluripotent)
o