cells and tissues
Download
Skip this Video
Download Presentation
Cells and Tissues

Loading in 2 Seconds...

play fullscreen
1 / 49

Cells and Tissues - PowerPoint PPT Presentation


  • 74 Views
  • Uploaded on

Cells and Tissues. Cell Physiology: Membrane Transport. Membrane transport—movement of substances into and out of the cell Two basic methods of transport Passive transport No energy is required Active transport Cell must provide metabolic energy (ATP). Solutions and Transport.

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 ' Cells and Tissues' - laurence-lemaitre


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
cell physiology membrane transport
Cell Physiology: Membrane Transport
  • Membrane transport—movement of substances into and out of the cell
  • Two basic methods of transport
    • Passive transport
      • No energy is required
    • Active transport
      • Cell must provide metabolic energy (ATP)
solutions and transport
Solutions and Transport
  • Solution—homogeneous mixture of two or more components
    • Solvent—dissolving medium; typically water in the body
    • Solutes—components in smaller quantities within a solution
  • Intracellular fluid—nucleoplasm and cytosol
  • Interstitial fluid—fluid on the exterior of the cell
selective permeability
Selective Permeability
  • The plasma membrane allows some materials to pass while excluding others
  • This permeability influences movement both into and out of the cell
passive transport processes
Passive Transport Processes
  • Diffusion
    • Particles tend to distribute themselves evenly within a solution
    • Movement is from high concentration to low concentration, or down a concentration gradient

Figure 3.9

passive transport processes1
Passive Transport Processes
  • Types of diffusion
    • Simple diffusion
      • An unassisted process
      • Solutes are lipid-soluble materials or small enough to pass through membrane pores
passive transport processes3
Passive Transport Processes
  • Types of diffusion (continued)
    • Osmosis—simple diffusion of water
      • Highly polar water molecules easily cross the plasma membrane through aquaporins
passive transport processes5
Passive Transport Processes
  • Facilitated diffusion
      • Substances require a protein carrier for passive transport
      • Transports lipid-insoluble and large substances
passive transport processes7
Passive Transport Processes
  • Filtration
    • Water and solutes are forced through a membrane by fluid, or hydrostatic pressure
    • A pressure gradient must exist
      • Solute-containing fluid is pushed from a high-pressure area to a lower pressure area
active transport processes
Active Transport Processes
  • Substances are transported that are unable to pass by diffusion
    • Substances may be too large
    • Substances may not be able to dissolve in the fat core of the membrane
    • Substances may have to move against a concentration gradient
  • ATP is used for transport
active transport processes1
Active Transport Processes
  • Two common forms of active transport
    • Active transport (solute pumping)
    • Vesicular transport
      • Exocytosis
      • Endocytosis
        • Phagocytosis
        • Pinocytosis
active transport processes2
Active Transport Processes
  • Active transport (solute pumping)
    • Amino acids, some sugars, and ions are transported by protein carriers called solute pumps
    • ATP energizes protein carriers
    • In most cases, substances are moved against concentration gradients
slide16

Extracellular fluid

Na+

K+

Na+

P

Na+

P

Na+

Na+

K+

K+

Na+

P

K+

ATP

ADP

Loss of phosphate restoresthe original conformation ofthe pump protein. K+ isreleased to the cytoplasm andNa+ sites are ready to bind Na+again; the cycle repeats.

Binding of cytoplasmic Na+to the pump proteinstimulates phosphorylationby ATP, which causes thepump protein to change itsshape.

The shape change expelsNa+ to the outside.Extracellular K+ binds,causing release of thephosphate group.

Cytoplasm

Figure 3.11

slide17

Extracellular fluid

Na+

Na+

Na+

P

ATP

ADP

Binding of cytoplasmic Na+to the pump proteinstimulates phosphorylationby ATP, which causes thepump protein to change itsshape.

Cytoplasm

Figure 3.11, step 1

slide18

Extracellular fluid

Na+

K+

Na+

P

Na+

P

Na+

Na+

K+

Na+

P

ATP

ADP

Binding of cytoplasmic Na+to the pump proteinstimulates phosphorylationby ATP, which causes thepump protein to change itsshape.

The shape change expelsNa+ to the outside.Extracellular K+ binds,causing release of thephosphate group.

Cytoplasm

Figure 3.11, step 2

slide19

Extracellular fluid

Na+

K+

Na+

P

Na+

P

Na+

Na+

K+

K+

Na+

P

K+

ATP

ADP

Loss of phosphate restoresthe original conformation ofthe pump protein. K+ isreleased to the cytoplasm andNa+ sites are ready to bind Na+again; the cycle repeats.

Binding of cytoplasmic Na+to the pump proteinstimulates phosphorylationby ATP, which causes thepump protein to change itsshape.

The shape change expelsNa+ to the outside.Extracellular K+ binds,causing release of thephosphate group.

Cytoplasm

Figure 3.11, step 3

active transport processes3
Active Transport Processes
  • Vesicular transport
    • Exocytosis
      • Moves materials out of the cell
      • Material is carried in a membranous vesicle
      • Vesicle migrates to plasma membrane
      • Vesicle combines with plasma membrane
      • Material is emptied to the outside
active transport processes4
Active Transport Processes
  • Vesicular transport (continued)
    • Endocytosis
      • Extracellular substances are engulfed by being enclosed in a membranous vescicle
    • Types of endocytosis
      • Phagocytosis—“cell eating”
      • Pinocytosis—“cell drinking”
active transport processes endocytosis

Extracellularfluid

Extracellularfluid

Cytoplasm

Plasmamembrane

Pit

Recycling of membraneand receptors (if present)to plasma membrane

Transport to plasmamembrane andexocytosis ofvesicle contents

Ingestedsubstance

Vesicle

Lysosome

Detachmentof vesicle

Release ofcontents tocytoplasm

Vesicle containingingested material

Plasmamembrane

Vesicle fusingwith lysosomefor digestion

(a)

Active Transport Processes: Endocytosis

Figure 3.13a

active transport processes endocytosis1

Extracellularfluid

Extracellularfluid

Plasmamembrane

Cytoplasm

Pit

Ingestedsubstance

Plasmamembrane

(a)

Active Transport Processes: Endocytosis

Figure 3.13a, step 1

active transport processes endocytosis2

Extracellularfluid

Extracellularfluid

Plasmamembrane

Cytoplasm

Pit

Ingestedsubstance

Detachmentof vesicle

Vesicle containingingested material

Plasmamembrane

(a)

Active Transport Processes: Endocytosis

Figure 3.13a, step 2

active transport processes endocytosis3

Extracellularfluid

Extracellularfluid

Plasmamembrane

Cytoplasm

Pit

Ingestedsubstance

Vesicle

Lysosome

Detachmentof vesicle

Vesicle containingingested material

Plasmamembrane

Vesicle fusingwith lysosomefor digestion

(a)

Active Transport Processes: Endocytosis

Figure 3.13a, step 3

active transport processes endocytosis4

Extracellularfluid

Extracellularfluid

Plasmamembrane

Cytoplasm

Pit

Ingestedsubstance

Vesicle

Lysosome

Detachmentof vesicle

Release ofcontents tocytoplasm

Vesicle containingingested material

Plasmamembrane

Vesicle fusingwith lysosomefor digestion

(a)

Active Transport Processes: Endocytosis

Figure 3.13a, step 4

active transport processes endocytosis5

Extracellularfluid

Extracellularfluid

Plasmamembrane

Cytoplasm

Pit

Transport to plasmamembrane andexocytosis ofvesicle contents

Ingestedsubstance

Vesicle

Lysosome

Detachmentof vesicle

Release ofcontents tocytoplasm

Vesicle containingingested material

Plasmamembrane

Vesicle fusingwith lysosomefor digestion

(a)

Active Transport Processes: Endocytosis

Figure 3.13a, step 5

active transport processes endocytosis6

Extracellularfluid

Extracellularfluid

Plasmamembrane

Cytoplasm

Pit

Recycling of membraneand receptors (if present)to plasma membrane

Transport to plasmamembrane andexocytosis ofvesicle contents

Ingestedsubstance

Vesicle

Lysosome

Detachmentof vesicle

Release ofcontents tocytoplasm

Vesicle containingingested material

Plasmamembrane

Vesicle fusingwith lysosomefor digestion

(a)

Active Transport Processes: Endocytosis

Figure 3.13a, step 6

cell life cycle
Cell Life Cycle
  • Cells have two major periods
    • Interphase
      • Cell grows
      • Cell carries on metabolic processes
    • Cell division
      • Cell replicates itself
      • Function is to produce more cells for growth and repair processes
dna replication
DNA Replication
  • Genetic material is duplicated and readies a cell for division into two cells
  • Occurs toward the end of interphase
  • DNA uncoils and each side serves as a template
dna replication1
DNA Replication

Figure 3.14

events of cell division
Events of Cell Division
  • Mitosis—division of the nucleus
    • Results in the formation of two daughter nuclei
  • Cytokinesis—division of the cytoplasm
    • Begins when mitosis is near completion
    • Results in the formation of two daughter cells
stages of mitosis
Stages of Mitosis
  • Prophase
    • First part of cell division
    • Centrioles migrate to the poles to direct assembly of mitotic spindle fibers
    • DNA appears as double-stranded chromosomes
    • Nuclear envelope breaks down and disappears
stages of mitosis1
Stages of Mitosis
  • Metaphase
    • Chromosomes are aligned in the center of the cell on the metaphase plate
stages of mitosis2
Stages of Mitosis
  • Anaphase
    • Chromosomes are pulled apart and toward the opposite ends of the cell
    • Cell begins to elongate
stages of mitosis3
Stages of Mitosis
  • Telophase
    • Chromosomes uncoil to become chromatin
    • Nuclear envelope reforms around chromatin
    • Spindles break down and disappear
stages of mitosis4
Stages of Mitosis
  • Cytokinesis
    • Begins during late anaphase and completes during telophase
    • A cleavage furrow forms to pinch the cells into two parts
stages of mitosis5

Centrioles

Spindlemicrotubules

Centrioles

Chromatin

Centromere

Centromere

Formingmitoticspindle

Plasmamembrane

Chromosome,consisting of twosister chromatids

Fragments ofnuclear envelope

Spindlepole

Nuclearenvelope

Nucleolus

Early prophase

Interphase

Late prophase

Nucleolusforming

Metaphaseplate

Spindle

Cleavagefurrow

Nuclearenvelopeforming

Sisterchromatids

Daughterchromosomes

Telophase and cytokinesis

Metaphase

Anaphase

Stages of Mitosis

Figure 3.15

stages of mitosis6

Centrioles

Chromatin

Plasmamembrane

Nuclearenvelope

Nucleolus

Interphase

Stages of Mitosis

Figure 3.15, step 1

stages of mitosis7

Centrioles

Centrioles

Chromatin

Centromere

Formingmitoticspindle

Plasmamembrane

Chromosome,consisting of twosister chromatids

Nuclearenvelope

Nucleolus

Interphase

Early prophase

Stages of Mitosis

Figure 3.15, step 2

stages of mitosis8

Centrioles

Spindlemicrotubules

Centrioles

Chromatin

Centromere

Centromere

Formingmitoticspindle

Plasmamembrane

Chromosome,consisting of twosister chromatids

Fragments ofnuclear envelope

Spindlepole

Nuclearenvelope

Nucleolus

Interphase

Early prophase

Late prophase

Stages of Mitosis

Figure 3.15, step 3

stages of mitosis9

Metaphaseplate

Spindle

Sisterchromatids

Metaphase

Stages of Mitosis

Figure 3.15, step 4

stages of mitosis10

Metaphaseplate

Spindle

Daughterchromosomes

Sisterchromatids

Metaphase

Anaphase

Stages of Mitosis

Figure 3.15, step 5

stages of mitosis11

Nucleolusforming

Metaphaseplate

Spindle

Cleavagefurrow

Nuclearenvelopeforming

Daughterchromosomes

Sisterchromatids

Metaphase

Anaphase

Telophase and cytokinesis

Stages of Mitosis

Figure 3.15, step 6

stages of mitosis12

Centrioles

Spindlemicrotubules

Centrioles

Chromatin

Centromere

Centromere

Formingmitoticspindle

Plasmamembrane

Chromosome,consisting of twosister chromatids

Fragments ofnuclear envelope

Spindlepole

Nuclearenvelope

Nucleolus

Early prophase

Interphase

Late prophase

Nucleolusforming

Metaphaseplate

Spindle

Cleavagefurrow

Nuclearenvelopeforming

Sisterchromatids

Daughterchromosomes

Telophase and cytokinesis

Metaphase

Anaphase

Stages of Mitosis

Figure 3.15, step 7

ad