This document provides an overview of cellular structures, functions, and processes. It describes the key components of eukaryotic cells including the nucleus, cytoplasm, organelles, plasma membrane, and cytoskeleton. It explains cellular functions such as metabolism, communication, transport, and aging. It also discusses cellular building blocks like DNA, RNA, and chromosomes as well as the formation of different tissue types. The document serves as a high-level introduction to cellular biology.

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Cellular Structures, Genes,
Immunity, and Diseases
Week One Lecture

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Cellular Functions
 Movement
 Conductivity
 Metabolic absorption
 Secretion
 Excretion
 Respiration
 Reproduction
 Communication

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Eukaryotic Cell
 Nucleus
 Nuclear envelope
 Nucleolus
 DNA
• DNA replication, repair, and transcription
 Histone proteins
 Cell division
 Genetic information

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Eukaryotic Cell (cont’d)
 Nucleus (cont’d)

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Eukaryotic Cell (cont’d)
 Nucleus (cont’d)

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Eukaryotic Cell (cont’d)
 Cytoplasm
 Cytoplasmic matrix
 Cytosol
 Function
 Cytoplasmic organelles

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Eukaryotic Cell (cont’d)
 Cytoplasm (cont’d)

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Eukaryotic Organelles
 Ribosomes
 RNA protein
 Free ribosomes
 Attached ribosomes
 Endoplasmic reticulum
 Site of protein synthesis
 Smooth vs. rough endoplasmic reticulum

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Eukaryotic Organelles (cont’d)
 Golgi complex
 Flattened, smooth membranes
 Secretory vesicles
 Proteins from the endoplasmic reticulum are
packaged in the Golgi complex
 Cisternae

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Eukaryotic Organelles (cont’d)
 Lysosomes
 Originate from the Golgi
 Catalyze proteins, lipids, nucleic acids, and
carbohydrates
 Role in autodigestion

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Eukaryotic Organelles (cont’d)
 Peroxisomes
 Contain oxidative enzymes
 Break substances down into harmless
products

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Eukaryotic Organelles (cont’d)
 Mitochondria
 Surrounded by a double lipid–bilayer
membrane
 Participates in oxidative phosphorylation
 Increased inner membrane surface area
provided by cristae

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Eukaryotic Organelles (cont’d)
 Cytoskeleton
 “Bones and muscles” of cell
 Maintains the cell’s shape and internal
organization
 Permits movement of substances within the
cell and movement of external projections
 Microtubules
• Centrioles
 Macrofilaments

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Plasma Membrane
 Controls the composition of a space or
compartment they enclose
 Structure
 Caveolae
 Lipids
• Amphipathic lipids
 Hydrophilic and hydrophobic
• Phospholipids, glycolipids, and cholesterol
 Carbohydrates
• Glycoproteins

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Plasma Membrane (cont’d)
 Proteins
 Integral, peripheral, transmembrane
 Functions
• Receptors
• Transport
• Enzymes
• Surface markers
• Cell adhesion molecules (CAMs)
• Catalysts
 Fluid mosaic model

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Plasma Membrane (cont’d)
 Fluid mosaic model
 Flexibility
 Self-regulating
 Impermeability to some substances
 Fluidity impacted by temperature, amount of
cholesterol

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Membrane Fluidity

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Plasma Membrane
 Plasma membrane protein functions

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Cellular Communication
 Plasma membrane bound receptors
 Intracellular receptors
 Gap junctions (contact signaling)
 Chemical signaling
 Paracrine
 Autocrine
 Hormonal
 Neurohormonal
 Neurotransmitters

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Cellular Communication
(cont’d)

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Cellular Communication
(cont’d)

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Cellular Metabolism
 Metabolism
 Chemical tasks of maintaining essential cellular
functions
 Anabolism
• Energy using
 Catabolism
• Energy releasing

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Adenosine Triphosphate
 Created from the chemical energy
contained within organic molecules
 Used in synthesis of organic molecules,
muscle contraction, and active transport
 Stores and transfers energy

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Cellular Energy
 Digestion
 Extracellular breakdown of proteins, fats,
polysaccarides to subunits
 Glycolysis
 Intracellular breakdown of subunits to pyruvate,
then to acetyl CoA
 Anaerobic
 Limited ATP produced

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Cellular Energy (cont’d)
 Citric acid cycle
 Also called Krebs cycle or the tricarboxylic acid
cycle (TCA)
 Much ATP produced via oxidative
phosphorylation if oxygen present
 Waste products excreted

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Cellular Energy (cont’d)
 Oxidative phosphorylation
 Occurs in the mitochondria
 Mechanism producing energy from fats, CHO,
proteins
 Involves the removal of electrons from various
intermediates via a co-enzyme such as
nicotinamide adenine dinucleotide (NAD) to
transfer electrons

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Cellular Energy (cont’d)
 Oxidative phosphorylation (cont’d)
 Anaerobic glycolysis: if oxygen not available,
CHO is converted to pyruvic acid (pyruvate) in
cytoplasm with production of two ATP
molecules which is insufficient for energy
needs; pyruvate then converted to lactic acid
 Process reverses when oxygen becomes
available and lactic acid is converted back to
either pyruvic acid or glucose, which moves
into the mitochondria and enters the citric acid
cycle

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CellularCellular Energy (cont’d)

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Cellular Energy (cont’d)

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Membrane Transport
 Cellular intake and output
 Cells continually take in nutrients, fluids, and
chemical messengers from the extracellular
environment and expel metabolites, or the
products of metabolism, and end products of
lysosomal digestion

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Body Fluids
 Electrolytes, which are electrically
charged, make up 95% of solutes
 Cations are positively charged and migrate
toward the negative pole (e.g., Na+)
 Anions are negatively charged and migrate
toward the positive pole (e.g., Cl-)

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Movement of Body Fluids and
Electrolytes
 Water and electrolytes move across cell
membranes via multiple passive (no
energy required) and active (energy
required) mechanisms

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Membrane Transport
 Passive transport (small uncharged
solutes)
 No energy expended
 Diffusion of solutes
• Concentrated gradient
 Filtration
• Hydrostatic pressure (BP)
 Osmosis of water
• Osmolarity vs. osmolality
 Tonicity
• Isotonic, hypertonic, and hypotonic
 Passive mediated transport
• Integral or transmembrane proteins
• Channel protein (ion channels) (gating)

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Membrane Transport (cont’d)

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Membrane Transport (cont’d)

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Membrane Transport (cont’d)
 Active mediated transport (active
transport)
 Energy expended
 Protein transport pumps
• Na/K ATPase pump
 Transport by vesicle formation
• Endocytosis
 Pinocytosis
 Phagocytosis
 Receptor mediated
 Caveolae
• Exocytosis

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Active Transport

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Membrane Transport

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Electrical Impulses
 Resting membrane potential
 Action potential
 Depolarization
 Threshold potential
• Hyperpolarized vs. hypopolarized
 Repolarization
 Refractory period
• Absolute and relative

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Propagation of an Action Potential

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Theory of AgingTheory of Aging
 Accumulation of injurious eventsAccumulation of injurious events
 Genetically controlled programGenetically controlled program
 Theories:Theories:
 Genetic and environmental lifestyle factorsGenetic and environmental lifestyle factors
 Alterations of cellular control mechanismsAlterations of cellular control mechanisms
 Degenerative extracellular and vascularDegenerative extracellular and vascular
changeschanges

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AgingAging
 Cellular agingCellular aging
 Atrophy, decreased function, and loss of cellsAtrophy, decreased function, and loss of cells
 Tissue and systemic agingTissue and systemic aging
 Progressive stiffness and rigidityProgressive stiffness and rigidity
 SarcopeniaSarcopenia
 FrailtyFrailty
 Mobility, balance, muscle strength, motorMobility, balance, muscle strength, motor
activity, cognition, nutrition, endurance, falls,activity, cognition, nutrition, endurance, falls,
fractures, and bone densityfractures, and bone density

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Tissue Formation
 Extracellular matrix
 Pattern formation

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Types of Tissue
 Epithelial tissue
 Simple vs. stratified squamous
 Transitional
 Cuboidal
 Simple vs. stratified columnar
 Pseudostratified ciliated

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Types of Tissue (cont’d)
 Connective tissue
 Dense regular or irregular
 Fibers
 Loose and dense connective tissue
 Elastic and reticular connective
 Cartilage, bone, vascular, and adipose

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Types of Tissue (cont’d)
 Muscle tissue
 Smooth
 Striated (skeletal)
 Cardiac

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DNADNA
 Pentose sugar (deoxyribose)Pentose sugar (deoxyribose)
 Phosphate moleculePhosphate molecule
 Four nitrogenous bases:Four nitrogenous bases:
 Pyrimidines: cytosine and thyminePyrimidines: cytosine and thymine
 Purines: adenine and guaninePurines: adenine and guanine
 Double helix modelDouble helix model
 NucleotideNucleotide

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RNARNA
 RNA is synthesized from the DNARNA is synthesized from the DNA
templatetemplate
 RNA polymerase binds to promoter siteRNA polymerase binds to promoter site
 Results in the formation of messengerResults in the formation of messenger
RNA (mRNA)RNA (mRNA)
 RNA polymerase detachesRNA polymerase detaches
 mRNA moves out of the nucleus and intomRNA moves out of the nucleus and into
the cytoplasmthe cytoplasm
 Transcription continues until terminationTranscription continues until termination
sequence is reachedsequence is reached

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ChromosomesChromosomes
 Somatic cells:Somatic cells:
 Contain 46 chromosomes (23 pairs)Contain 46 chromosomes (23 pairs)
 Diploid cellsDiploid cells
 Gametes:Gametes:
 Contain 23 chromosomesContain 23 chromosomes
 Haploid cellsHaploid cells
• One member of each chromosome pairOne member of each chromosome pair

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ChromosomesChromosomes
 MeiosisMeiosis
 Formation of haploid cells from diploid cellsFormation of haploid cells from diploid cells
 MitosisMitosis
 Formation of somatic cellsFormation of somatic cells

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Autosomal AneuploidyAutosomal Aneuploidy
 Partial trisomyPartial trisomy
 Only an extra portion of a chromosome isOnly an extra portion of a chromosome is
present in each cellpresent in each cell
 Chromosomal mosaicsChromosomal mosaics
 Trisomies occurring only in some cells of theTrisomies occurring only in some cells of the
bodybody

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Down SyndromeDown Syndrome

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Single-Gene DisordersSingle-Gene Disorders
 EpigeneticsEpigenetics
 Same DNA sequence can produce differentSame DNA sequence can produce different
phenotypes due to chemical modification thatphenotypes due to chemical modification that
alters expression of genesalters expression of genes
 Genomic imprintingGenomic imprinting
 One parent imprints (inactivates) the geneOne parent imprints (inactivates) the gene
during transmission to offspringduring transmission to offspring

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Single-Gene Disorders (cont’d)Single-Gene Disorders (cont’d)
 Autosomal recessive disorderAutosomal recessive disorder
 Abnormal allele is recessive and a person mustAbnormal allele is recessive and a person must
be homozygous for the abnormal trait tobe homozygous for the abnormal trait to
express the diseaseexpress the disease
 The trait usually appears in the children, notThe trait usually appears in the children, not
the parents, and it affects the genders equallythe parents, and it affects the genders equally
because it is present on a pair of autosomesbecause it is present on a pair of autosomes
 Cystic fibrosis gene encodes a chloride ionCystic fibrosis gene encodes a chloride ion
channel in some epithelial cells that alterschannel in some epithelial cells that alters
sodium balancesodium balance

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Sex-Linked DisordersSex-Linked Disorders
 Sex-linked (X-linked) disorders are usuallySex-linked (X-linked) disorders are usually
expressed by males because femalesexpressed by males because females
have another X chromosome to mask thehave another X chromosome to mask the
abnormal geneabnormal gene
 Can you name a disorder that is a sex-Can you name a disorder that is a sex-
linked disorder?linked disorder?

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ImmunityImmunity
 First line of defenseFirst line of defense
 Innate (natural) (native) immunityInnate (natural) (native) immunity
 Second line of defenseSecond line of defense
 InflammationInflammation
 Third line of defenseThird line of defense
 Adaptive (acquired) immunityAdaptive (acquired) immunity

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First Line of DefenseFirst Line of Defense
Physical barriers:Physical barriers:
 SkinSkin
 Linings of the gastrointestinal,Linings of the gastrointestinal,
genitourinary, and respiratory tractsgenitourinary, and respiratory tracts
• Sloughing off of cellsSloughing off of cells
• Coughing and sneezingCoughing and sneezing
• FlushingFlushing
• VomitingVomiting
• Mucus and ciliaMucus and cilia

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PhagocytesPhagocytes
 NeutrophilsNeutrophils
 Also referred to as polymorphonuclearAlso referred to as polymorphonuclear
neutrophils (PMNs)neutrophils (PMNs)
 Predominate in early inflammatory responsesPredominate in early inflammatory responses
 Ingest bacteria, dead cells, and cellular debrisIngest bacteria, dead cells, and cellular debris
 Cells are short lived and become a componentCells are short lived and become a component
of the purulent exudateof the purulent exudate

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Phagocytes (cont’d)Phagocytes (cont’d)
 Monocytes and macrophagesMonocytes and macrophages
 Monocytes are produced in the bone marrow,Monocytes are produced in the bone marrow,
enter the circulation, and migrate to theenter the circulation, and migrate to the
inflammatory site, where they develop intoinflammatory site, where they develop into
macrophagesmacrophages
 Macrophages typically arrive at theMacrophages typically arrive at the
inflammatory site 24 hours or later afterinflammatory site 24 hours or later after
neutrophilsneutrophils

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Phagocytosis (cont’d)Phagocytosis (cont’d)
 Steps:Steps:
 AdherenceAdherence
 EngulfmentEngulfment
 Phagosome formationPhagosome formation
 Fusion with lysosomal granulesFusion with lysosomal granules
 Destruction of the targetDestruction of the target