Chapter 1
This presentation is the property of its rightful owner.
Sponsored Links
1 / 37

Chapter 1 PowerPoint PPT Presentation


  • 92 Views
  • Uploaded on
  • Presentation posted in: General

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

Download Presentation

Chapter 1

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 membrane1

Plasma Membrane

  • Asymmetrical

  • Fluid structures

  • Distinct from other membranes:

    • Greater CHO content

    • Greater cholesterol content

2009 Cengage-Wadsworth


Plasma membrane2

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 matrix1

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


Mitochondrion1

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


Nucleus1

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


Nucleus2

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


Nucleus3

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


Nucleus4

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 apparatus1

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 peroxisomes1

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 signaling1

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 enzymes1

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 enzymes2

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 enzymes3

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 enzymes1

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 energy1

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 energy2

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 energy3

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 energy4

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


  • Login