chapter 1 l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Chapter 1 PowerPoint Presentation
Download Presentation
Chapter 1

Loading in 2 Seconds...

play fullscreen
1 / 37

Chapter 1 - PowerPoint PPT Presentation


  • 275 Views
  • Uploaded on

Chapter 1. The Cell: A Microcosm of Life. Cells--the essence of life. Basic units of the body Eukaryotic cells Have a defined nucleus Evolved from prokaryotic cells (which don’t) Specialization. Components of Typical Cells. Plasma membrane Cytoplasmic matrix Mitochondrion Nucleus

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Chapter 1' - xanthe


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
chapter 1

Chapter 1

The Cell: A Microcosm of Life

2009 Cengage-Wadsworth

cells the essence of life
Cells--the essence of life
  • Basic units of the body
  • Eukaryotic cells
    • Have a defined nucleus
    • Evolved from prokaryotic cells (which don’t)
  • Specialization

2009 Cengage-Wadsworth

components of typical cells
Components of Typical Cells
  • Plasma membrane
  • Cytoplasmic matrix
  • Mitochondrion
  • Nucleus
  • Endoplasmic reticulum
  • Golgi apparatus
  • Lysosomes
  • Peroxisomes

2009 Cengage-Wadsworth

plasma membrane
Plasma Membrane
  • Sheetlike structures made of phospholipids & proteins
  • Have hydrophobic & hydrophylic moiety
  • Phospholipids = phosphoglycerides & phosphingolipids
  • Proteins give them their functions

2009 Cengage-Wadsworth

plasma membrane5
Plasma Membrane
  • Asymmetrical
  • Fluid structures
  • Distinct from other membranes:
    • Greater CHO content
    • Greater cholesterol content

2009 Cengage-Wadsworth

plasma membrane6
Plasma Membrane
  • Lipid bilayer concept
  • Glycocalyx
  • Glycoproteins
  • Membrane proteins
    • Integral
    • Peripheral

2009 Cengage-Wadsworth

cytoplasmic matrix
Cytoplasmic Matrix
  • Microtrabecular lattice or cytoskeleton
    • Microtubules
    • Microfilaments
  • Fluid

2009 Cengage-Wadsworth

cytoplasmic matrix8
Cytoplasmic Matrix
  • Structural arrangement influences metabolic pathways:
    • Glycolysis
    • Hexose monophosphate shunt
    • Glycogenesis & glycogenolysis
    • Fatty acid synthesis
  • Communication

2009 Cengage-Wadsworth

mitochondrion
Mitochondrion
  • Energy production & oxygen use site
  • Matrix surrounded by double membrane
  • Mitochondrial membrane
    • Outer membrane - porous
    • Inner membrane - selectively permeable; site of electron transport chain

2009 Cengage-Wadsworth

mitochondrion10
Mitochondrion
  • Mitochondrial matrix
    • Site of TCA cycle & fatty acid oxidation
    • Contains DNA so organelle can divide
  • In all cells except erythrocytes

2009 Cengage-Wadsworth

nucleus
Nucleus
  • Contains DNA (genome)
  • Surrounded by nuclear envelope
  • Nucleoli - condensed chromatin
  • DNA replication
  • Protein synthesis = transcription, translation & elongation

2009 Cengage-Wadsworth

nucleus12
Nucleus
  • Nucleic acids
    • DNA & RNA
    • Consist of nucleotides or bases
      • Adenine, guanine, cytosine in both
      • Uracil in RNA only
      • Thymine in DNA only
    • Complementary base pairing

2009 Cengage-Wadsworth

nucleus13
Nucleus
  • Cell replication
    • DNA unravels and nucleotides are added to each strand to make 2 sets
  • Cell transcription
    • mRNA created from sequence of 1 DNA strand (sense strand)
    • Genes
    • Introns - intervening sequences
    • Exons - no posttranslational processing

2009 Cengage-Wadsworth

nucleus14
Nucleus
  • Translation
    • mRNA codes for amino acid sequence to form protein
    • mRNA is synthesized in nucleus, then moves to RER in cytoplasmic matrix
    • Codons - 3-base sequences that code for amino acids
    • tRNA bring AAs to mRNA on ribosomes

2009 Cengage-Wadsworth

nucleus15
Nucleus
  • After AAs are positioned, peptide bonds form between them = elongation
  • “Nonsense” codon signals end of protein

2009 Cengage-Wadsworth

endoplasmic reticulum golgi apparatus
Endoplasmic Reticulum & Golgi Apparatus
  • ER = network of membranous channels
  • Types:
    • Rough ER (studded with ribosomes) - protein synthesis
    • Smooth ER - lipid synthesis
    • Sarcoplasmic reticulum (SER in muscle) - calcium ion pump

2009 Cengage-Wadsworth

endoplasmic reticulum golgi apparatus17
Endoplasmic Reticulum & Golgi Apparatus
  • Golgi apparatus
    • Protein trafficking & sorting
    • 4-8 cisternae
    • Tubular networks at either end:
      • Cis-Golgi network - entrance
      • Trans-Golgi network - exit
    • Connected to ER by transport vesicles

2009 Cengage-Wadsworth

lysosomes peroxisomes
Lysosomes & Peroxisomes
  • Enzyme-filled organelles
  • Lysosomes - cell’s “digestive system”
  • Peroxisomes - site of oxidative catabolic reactions

2009 Cengage-Wadsworth

lysosomes peroxisomes19
Lysosomes & Peroxisomes
  • Lysosome functions:
    • Phagocytosis
    • Autolysis
    • Bone resorption
    • Hormone secretion & regulation
  • Peroxisome functions:
    • Oxidize fatty acids to acetyl CoA
    • Amino acid catabolism
    • Detoxifying reactions

2009 Cengage-Wadsworth

cellular proteins
Cellular Proteins
  • Types:
    • Receptors - modify cell’s response to environment
    • Transport proteins - regulate flow of materials into & out of cell
    • Enzymes - catalysts

2009 Cengage-Wadsworth

receptors intracellular signaling
Receptors & Intracellular Signaling
  • Ligands - molecular stimuli that attach to receptors
  • Types of receptors:
    • Bind to ligand & convert it to internal signal
    • Serve as ion channels
    • Internalize stimulus intact

2009 Cengage-Wadsworth

receptors intracellular signaling22
Receptors & Intracellular Signaling
  • Internal chemical signal
    • E.g. 3’, 5’-cyclic adenosine monophosphate (cyclic AMP, cAMP)
  • Ion channel
    • E.g. receptor for acetylcholine
  • Internalization stimulus
    • E.g. insulin, triiodothyronine

2009 Cengage-Wadsworth

transport proteins
Transport Proteins
  • May act as pumps
  • May provide pores through which molecules diffuse
  • Most studied = sodium (Na+) pump
    • Na+/K+ -ATPase

2009 Cengage-Wadsworth

catalytic proteins enzymes
Catalytic Proteins (Enzymes)
  • Functionality depends on protein & prosthetic group or coenzyme
  • Specificity
  • Maximum velocity (Vmax) - enzyme velocity at substrate saturation
  • Km (Michaelis constant) - concentration of substrate when reaction is at 1/2 of maximum velocity

2009 Cengage-Wadsworth

catalytic proteins enzymes25
Catalytic Proteins (Enzymes)
  • Reversibility
  • Regulation
    • Covalent modification - usually addition/removal of phosphate groups
    • Allosteric - enzymes with another site besides catalytic site that can bond with modulator
    • Induction - changes in concentrations of inducible enzymes

2009 Cengage-Wadsworth

catalytic proteins enzymes26
Catalytic Proteins (Enzymes)
  • Examples of enzyme types
    • Oxidoreductases - reactions in which 1 compound is oxidized, another reduced
    • Transferases - functional group transferred from 1 substrate to another
    • Hydrolases - hydrolysis of carbon-? bonds

2009 Cengage-Wadsworth

catalytic proteins enzymes27
Catalytic Proteins (Enzymes)
  • Lyases - cleavage of C-C, C-S, & C-N bonds (no hydrolysis/O-R)
  • Isomerases - interconversion of optical or geometric isomers
  • Ligases - catalyze formation of C-? Bonds (O, S, N, others)

2009 Cengage-Wadsworth

practical clinical application of cellular enzymes
Practical Clinical Application of Cellular Enzymes
  • Conditions for diagnostic suitability
    • Enzyme’s degree of organ/tissue specificity
    • Steep concentration gradient of enzyme activity between cell and surroundings
    • Enzyme must function in cytoplasm
    • Enzyme must be stable

2009 Cengage-Wadsworth

practical clinical application of cellular enzymes29
Practical Clinical Application of Cellular Enzymes
  • Increased production factors
    • Malignant disease
      • Results in tumor markers

2009 Cengage-Wadsworth

apoptosis
Apoptosis
  • Programmed cell death
  • Potential mechanisms
    • Intracellular stimuli
      • Create DNA damage
      • Release of cytochrome c
    • Extracellular stimuli
      • Tumor necrosis factor family of hormones or agonists
    • Oncosis

2009 Cengage-Wadsworth

biological energy
Biological Energy
  • ATP - major storage form in cells
  • Energy needed for:
    • Exertion
    • Anabolism
    • Active transport
    • Transfer of genetic information

2009 Cengage-Wadsworth

biological energy32
Biological Energy
  • Energy release and consumption in chemical reactions
    • Energy comes from macronutrients
    • Transferred from one form to another
  • Units of energy
  • Free energy (G) - potential energy in bonds of nutrients that is released

2009 Cengage-Wadsworth

biological energy33
Biological Energy
  • Exothermic and endothermic reactions
  • Activation energy - energy to raise reactants to transition state
  • Cellular energy
  • Reversibility of chemical reactions
  • Standard free energy change
    • 25°C, 1.0 atm, reactants/products at 1.0 mol/L concentrations

2009 Cengage-Wadsworth

biological energy34
Biological Energy
  • Equilibrium constant (Keq) and standard free energy change
  • Standard pH - 7
  • Nonstandard physiological conditions
    • In cells: ~37°C, concentrations often not 1.0 mol/L, etc.

2009 Cengage-Wadsworth

biological energy35
Biological Energy
  • The role of high-energy phosphate in energy storage
  • Coupled reactions in the transfer of energy
    • Phosphorylation - adding phosphate
  • Reduction potentials
    • Standard reduction potential (E0) - tendency of compound to donate & receive electrons

2009 Cengage-Wadsworth

perspective 1

Perspective 1

Nutritional Genomics: The Foundation for Personalized Nutrition

2009 Cengage-Wadsworth

nutritional genomics
Nutritional Genomics
  • What is nutritional genomics?
  • Pharmacogenomics as a model
  • Mechanisms underlying nutritional genomics
  • Nutritional genomics & lipid metabolism
  • Opportunities for nutrition professionals

2009 Cengage-Wadsworth