HUMAN ANATOMY AND PHYSIOLOGY I

Lecture: M 6-9:30 Randall Visitor Center

Lab: W 6-9:30 Swatek Anatomy Center, Centennial Complex

Required Text: Marieb 9th edition

Dr. Trevor Lohman DPT

(949) 246-5357

tlohman@llu.edu

THE CELL

CH. 3: THE FUNCTIONAL UNIT OF LIFE

THE CELLULAR BASIS OF LIFE The Smallest Living Unit

Cell Theory:

Generalized or Composite Cell

• Plasma Membrane

• Cytoplasm

• Nucleus

Fig 3.2

THE PLASMA MEMBRANE: STRUCTURE

The Fluid Mosaic Model

Membrane Lipids

• Phospholipids

• Glycolipids

• Cholesterol

• Lipid Rafts

• Fig 3.3

PLASMA MEMBRANE: STRUCTURE

Membrane Proteins:

• Integral Proteins

• Peripheral Proteins

• The Glycocalyx

• Fig 3.3-3.4

CELL JUNCTIONS

Tight Junctions:

Desmosomes:

Gap Junctions:

THE PLASMA MEMBRANE: MEMBRANE TRANSPORTPassive Processes

• Osmosis

• Aquaporins• Osmolarity• Hydrostatic vs. osmotic pressure• Tonicity (Iso, Hyper, Hypo)• Fig 3.9

• Diffusion

• Simple diffusion• Facilitated diffusion• Carrier-Mediated facilitated diffusion• Channel-Mediated facilitated diffusion• Fig 3.6, 3.7, 3.8

THE PLASMA MEMBRANE: MEMBRANE TRANSPORT

Active Transport

• Primary Active Transport (3.10)

• Sodium-potassium pump• Secondary Active Transport (3.11)

• Symport system vs. antiport system• Vesicular Transport (3.12- 3.13)

• Endocytosis, Transcytosis, Vesicular Trafficking Fig 3.12• Phagocytosis• Pinocytosis• Receptor Mediated endocytosis• Exocytosis

THE PLASMA MEMBRANE: GENERATION OF A RESTING MEMBRANE POTENTIAL

Membrane Potential and Resting Membrane Potential

Selective Diffusion Establishes Membrane Potential

• Fig 3.15

• Step 1• Step 2• Step 3

Active Transport Maintains Electrochemical Gradients

THE PLASMA MEMBRANE: CELL-ENVIRONMENT INTERACTIONS

Roles of Cell Adhesion Molecules

• Molecular Velcro

• The “arms”

• Send SOS signals

• The Mechanical Sensors

• The Transmitters of intracellular signals

THE PLASMA MEMBRANE: CELL-ENVIRONMENT INTERACTIONS

Roles of Plasma Membrane Receptors

• Contact Signaling

• Chemical Signaling

• Ligands• Catalytic receptor proteins• Chemically gated channel-link

receptors• G-linked receptors

• Second messengers• Cyclic AMP• Ionic calcium• Fig 3.16

THE CYTOPLASM

The Cytosol

Organelles

Inclusions

CYTOPLASMIC ORGANELLES

Mitochondria

Ribosomes

CYTOPLASMIC ORGANELLES

Endoplasmic Reticulum

• Smooth endoplasmic reticulum

• Rough Endoplasmic reticulum

CYTOPLASMIC ORGANELLES

Golgi Apparatus

• Trans face

• Cis face

CYTOPLASMIC ORGANELLES

Peroxisomes

• Neutralize free radicals

Lysosomes

CYTOPLASMIC ORGANELLES

Cytoskeleton

• Microfilaments

• Intermediate filaments

• Microtubules

CYTOPLASMIC ORGANELLES

• Centrosome

• Centrioles

• Fig 3.25

THE NUCLEUSThe Nucleus

• Multinucleate

• Anucleate

3 distinguishable regions

• The Nuclear Envelope

• Nuclear Pores• Nucleoli

• Chromatin

• 30% DNA• 60% globular histone proteins• 10% RNA chains• Nucleosomes• Chromosomes

CELL CYCLE: INTERPHASE/M-PHASEInterphase (Metabolic/Growth Phase)

• Subphases

• G1 (gap 1 subphase)/(G0 phase)

• S Phase• G2 (gap 2 subphase)

• DNA Replication

• Enzymatic Unwinding• Replication bubble

forms

• RNA Primer Formation• DNA Polymerase

CELL DIVISION

Cell Division

• M (mitotic) phase

• Mitosis• Prophase• Metaphase• Anaphase• Telophase

• Cytokinesis

MITOSISProphase

• Early Prophase

• Chromatin condenses, forms chromosomes

• Centrosome separation, Mitotic spindle forms

• Late Prophase

• Nuclear envelope dissolves• Spindle microtubules attach to

kinetochores at each centromere• Polar microtubules slide past

each other forcing the poles apart

Fig 3.33

MITOSIS

Metaphase

• Centromeres are at opposite poles of the cell

• Chromosomes align along the equator of the spindle or metaphase plate

• Enzymatic separation of chromatids begins

ANAPHASE• Shortest Mitotic Phase

• Begins with simultaneous chromatid separation

• Motor proteins within the kinetochores pull chromosomes toward the poles

• Polar microtubules continue to expand, pushing the poles further apart

TELOPHASE• Begins when

chromosomal movement stops

• Resembles prophase in reverse

• Chromosomes unravel and revert to chromatin

• New nuclear envelopes form and nucleoli reform

• Mitotic spindle disappears

• Mitosis ends, and cell is now binucleate

CYTOKINESIS• Actin ring forms and

constricts until cell is pinched in two

• Begins during late Anaphase

• Continues beyond Telophase

PROTEIN SYNTHESIS

Deoxyribose Nucleic Acid

• DNA is the master blueprint

• Composed of 4 nucleotide bases A, T, C, G

• Triplets code for individual amino acids

• Exons and introns

• DNA is useless without RNA

PROTEIN SYNTHESIS

RNA

• Messenger RNA (mRNA)

• The “transcript” from which protein synthesis is performed

• Ribosomal RNA (rRNA)

• Building block of ribosomes

• Transfer RNA (tRNA)

• Transport cytoplasmic amino acids to ribosomes

PROTEIN SYNTHESIS

Transcription

• Initiation

• RNA Polymerase• Promoter• Helix pulled apart

• Elongation

• Helix unwound and rewound and as mRNA formed

• Termination

• Termination signal• mRNA separation

PROTEIN SYNTHESISTranslation

• Nucleic acid language translated to amino acid language

• Codons (64 possible)

Translation Events

• Initiation

• Ribosomal subunit binds to initiating tRNA which scans for start codon

• Elongation

• Codon recognition• Peptide bond formation• Translocation

• Termination

• Stop codon reached• Polypeptide chain released

PROTEIN SYNTHESIS

Fig 3.4

Fig 3.39

CH 3: THE CELL

Study Guide