p. 66 © 2015 pearson education, inc.. figure 3-2 the plasma membrane. extracellular fluid cytoplasm...
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p. 66
© 2015 Pearson Education, Inc.
Figure 3-2 The Plasma Membrane.
EXTRACELLULAR FLUID
CYTOPLASM
Glycolipidsof glycocalyx
Phospholipidbilayer
Integral proteinwith channel
Hydrophobictails
Integralglycoproteins
Plasmamembrane
Gatedchannel
CholesterolPeripheralproteins
Hydrophilicheads
Cytoskeleton(Microfilaments)= 2 nm
p. 68© 2015 Pearson Education, Inc.
p. 72
© 2015 Pearson Education, Inc.
Figure 03-04a
p. 74
© 2015 Pearson Education, Inc.
Figure 03-04b
p. 74
© 2015 Pearson Education, Inc.
Figure 3-5a The Endoplasmic Reticulum.
Ribosomes
Cisternae
Nucleus
The three-dimensional relationships between the rough and smooth endoplasmic reticula are shown here.
a
p. 75
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LE 3-6
Secretoryvesicles
Transportvesicles
Secretoryproduct
p. 76
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LE 3-7a
Endoplasmicreticulum
Lysosomes
Golgi apparatusMaturingface
CYTOSOL
Formingface
Plasmamembrane
Secretoryvesicles
EXTRACELLULAR FLUID
Vesicleincorporation in plasma membrane
Transportvesicle
Membrane renewalvesicles
© 2015 Pearson Education, Inc.
Figure 3-7 Protein Synthesis, Processing, and Packaging (Part 1 of 11).
p. 78
© 2015 Pearson Education, Inc.
Figure 3-7 Protein Synthesis, Processing, and Packaging (Part 2 of 11).
p. 79
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LE 3-8-1
Golgiapparatus
Autolysisliberatesdigestiveenzymes Primary lysosome
3
2
1
Reabsorption
Secondarylysosome
Endocytosis
Secondarylysosome
Reabsorption
Damaged organelle
Extracellularsolid or
fluid
Exocytosisejects residue
Exocytosisejects residue
p. 80
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LE 3-9
Organic moleculesand O2
CO2
ATP
Outermembrane
CristaeMatrix
Inner membrane
Glycolysis
Enzymes
Enzymesand
coenzymesof cristae
Cytoplasmof cell Cristae Matrix
CO2
O2
ATPPyruvic acid
GlucoseCYTOPLASM
ADP +phosphateTCA
Cycle
MATRIX
MITOCHONDRION
H p. 81
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Figure 3-10 The Nucleus
Nucleoplasm
Chromatin
Nucleolus
Nuclear envelope
Nuclear pore
Important nuclear structuresare shown here.
Nuclear pores
Nuclear pore
Perinuclear space
Nuclear envelope
A nuclear pore is a largeprotein complex that spansthe nuclear envelope.
Nucleus
Inner membrane ofnuclear envelope
Broken edge ofouter membrane
Outer membrane ofnuclear envelope
Nucleus
TEM 4800
Freeze fracture SEM 9240
This cell was frozen and then broken apart to make itsinternal structures visible. The technique, called freezefracture or freeze-etching, provides a unique perspectiveon the internal organization of cells. The nuclear envelopeand nuclear pores are visible. The fracturing process brokeaway part of the outer membrane of the nuclear envelope,and the cut edge of the nucleus can be seen.
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p.82
LE 3-11Nucleus
Cell preparedfor division
Telomeres of sister chromatids
Visiblechromosome
KinetochoreCentromere
Supercoiledregion
Nondividingcell
Chromatin innucleus
DNAdouble
helixNucleosome
Histones
p. 83
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LE 3-12-1DNA
Gene
Templatestrand
Promoter
Triplet 1
Triplet 2
Triplet 3
Triplet 4
1
2
3
4
4
3
1
2
Co
mp
lem
en
tary
trip
lets
Codingstrand
RNApolymerase
KEYUracil (RNA)Adenine
Guanine Thymine (DNA)
Cytosine
p. 85
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LE 3-12-2
Codon1
RNAnucleotide
KEYUracil (RNA)Adenine
Guanine Thymine (DNA)
Cytosine
p. 85
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LE 3-12-3
Codon1
Codon2
Codon 4(stop codon)
Codon3
mRNAstrand
KEYUracil (RNA)Adenine
Guanine Thymine (DNA)
Cytosine
p. 85
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Figure 03-13-0
pp. 88 & 89
© 2015 Pearson Education, Inc.
Figure 3-13 The Process of Translation (Part 1 of 5).
Adenine
KEY
Guanine
Cytosine
Uracil
mRNA
DNA
NUCLEUS
First amino acid(methionine)
Transfer RNA(tRNA)
Small ribosomalsubunit
tRNA bindingsites
Anticodon
Binding of Small RibosomalSubunit
Start codon mRNA strand
1
Translation begins when the mRNAstrand binds to a small ribosomalsubunit near its P site, one of threeadjacent tRNA binding sites. A tRNAthen binds to the P site and to thestart codon on the mRNA strand.Binding occurs between threenucleotides of the start codon and thethree complementary nucleotides in asegment of the tRNA strand known asthe anticodon.
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Figure 3-13 The Process of Translation (Part 2 of 5).
Largeribosomal
subunit
Formation of Functional Ribosome2
The small and large ribosomal subunits theninterlock around the mRNA strand, forming afunctional ribosome. The initiation complexis now complete and protein synthesis can proceed. The tRNA in the P site holds whatwill become the first amino acid of a peptidechain. The adjacent A site is where anadditional tRNA can bind to the mRNAstrand. More than 20 kinds of transfer RNAexist, each with a different nucleotideSequence in the anticodon. Each tRNAcarries an amino acid, and there is at leastone tRNA anticodon that corresponds toeach of the amino acids used in proteinsynthesis.
p. 88
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Figure 3-13 The Process of Translation (Part 3 of 5).
Peptidebond
Formation of PeptideBond
3
When a complementary tRNA bindsto the A site, ribosomal enzymesremove the amino acid from thetRNA at the P site and attach it tothe amino acid delivered to the Asite by forming a peptide bond.
p. 89
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Figure 3-13 The Process of Translation (Part 4 of 5).
Extension of Polypeptide4
The ribosome then moves onecodon farther along the mRNAstrand. The tRNA that was in the Psite (anticodon UAC) now enters theE site, from where it is released intothe cytoplasm. The released tRNAcan now bind another amino acid ofthe same type and repeat the cycle. p. 89
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Figure 3-13 The Process of Translation (Part 5 of 5).
Largeribosomal
subunit
Completion ofPolypeptide
5
Termination occurs as a proteinreleasing factor, not a tRNAmolecule, recognizes the stopcodon. A ribosomal enzyme thenbreaks the bond between thepolypeptide and the tRNA in the Psite, releasing the polypeptide. Otherribosomal enzymes separatethe ribosomal subunits and freethe intact strand of mRNA.
Small ribosomalsubunit
Completedpolypeptide
Stopcodon
mRNA strand
p. 89
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Figure 3-15 Diffusion across the Plasma Membrane.
Channelprotein
Plasma membrane
EXTRACELLULAR FLUIDLipid-soluble moleculesdiffuse through theplasma membrane
Large molecules that cannotdiffuse through lipids cannotcross the plasma membraneunless they are transportedby a carrier mechanism
Small water-solublemolecules and ionsdiffuse throughmembrane channels
CYTOPLASM
p. 91© 2015 Pearson Education, Inc.
http://www.youtube.com/watch?v=VVORi8Bqlss&feature=related
Images from: http://www.phschool.com/science/biology_place/biocoach/biomembrane1/solutions.html
Figure 3-17 Osmotic Flow across a Plasma Membrane
Solutemolecules
Watermolecules
In an isotonic saline solution, noosmotic flow occurs, and thesered blood cells appear normal.
SEM of normal RBCin an isotonic solution
SEM of RBC in ahypotonic solution
Immersion in a hypotonic salinesolution results in the osmoticflow of water into the cells. Theswelling may continue until theplasma membrane ruptures, orlyses.
SEM of crenated RBCsin a hypertonic solution
Exposure to a hypertonic solutionresults in the movement of waterout of the cell. The red blood cellsshrivel and become crenated.
© 2015 Pearson Education, Inc. p. 94
EXTRACELLULAR FLUIDGlucose moleculeattaches toreceptorsite
Receptorsite Carrier
protein
Change inshape of
carrier protein
Glucose released intocytoplasmCYTOPLASM
p. 95
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Figure 3-18 Facilitated Diffusion.
EXTRACELLULAR FLUID
Sodium–potassiumexchange
pump
CYTOPLASM
3 Na+
ADPATP2 K+
p. 96
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Figure 3-19 The Sodium–Potassium Exchange Pump.
EXTRACELLULAR FLUID
Glucose
CYTOPLASM 3 Na+
ADP ATP
2 K+
Na+
Na+–K+
pump
p. 97
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Figure 3-20 Secondary Active Transport.
EXTRACELLULAR FLUIDLigands binding to receptors
CYTOPLASM
Ligandreceptors
Exocytosis
7
2
3
Coatedvesicle
Endocytosis
1
Ligands
4
Ligandsremoved
Primarylysosome
Secondarylysosome
6
5
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Figure 3-21 Receptor-Mediated Endocytosis.
© 2015 Pearson Education, Inc.
Figure 3-22 Overview of Membrane Transport (Part 7 of 8).
Example:Cholesteroland iron ionsare transportedthis way.
Endocytosis Endocytosis is the packaging of extracellular materials into a vesicle for transport into the cell.
Extracellular fluid Target molecules
Receptorproteins Vesicle
containingtarget molecules
Cytoplasm
Pinosome
Pinocytic vesicleforming
Pseudopodiumextends to
surround object
Phagosome
Example:Once thevesicle is insidethe cytoplasm,water and smallmolecules enterthe cell acrossthe vesiclemembrane.
Example:Large particlesare broughtinto the cell bycytoplasmicextensions(calledpseudopodia)that engulf theparticle andpull it into thecell.
Cell
Cell
Receptor-MediatedEndocytosis
Pinocytosis Phagocytosis
In receptor-mediatedendocytosis, targetmolecules bind to receptor proteins onthe membrane surface, triggering vesicleformation.
Substances Involved: Targetmolecules called ligands
Factors Affecting Rate: Number ofreceptors on the plasma membrane andthe concentration of target molecules
Substances Involved: Extracellular fluid, with dissolvedmolecules such as nutrients
Substances Involved: Bacteria,viruses, cellular debris, and otherforeign material
Factors Affecting Rate: Stimulusand mechanism not understood
Factors Affecting Rate: Presenceof pathogens and cellular debris
In pinocytosis, vesicles form atthe plasma membrane and bringfluids and small molecules into thecell. This process is often called“cell drinking.”
In phagocytosis, vesicles form atthe plasma membrane to bring solidparticles into the cell. This process isoften called “cell eating.”
LE 3-22b
Secondarylysosome
Phagosomefuses witha lysosome
Lysosome
Phagosome
PhagocytosisBacterium
Pseudopodium
Golgiapparatus
Exocytosis
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© 2015 Pearson Education, Inc.
Figure 3-22 Overview of Membrane Transport (Part 8 of 8).
Example:Cellular wastes invesicles areejected from thecell.
ExocytosisMaterialejected
from cell
Cell
In exocytosis, intracellular vesiclesfuse with the plasmamembrane to releasefluids and/or solids fromthe cells.
Substances Involved: Fluid andcellular wastes; secretory productsfrom some cells
Factors Affecting Rate: Stimulusand mechanism incompletelyunderstood
Segment 2DNA nucleotide
Segment 1
DNA polymerase
DNA polymeraseAdenine
Guanine
Cytosine
Thymine
KEY
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Figure 3-23 DNA Replication.
Centrioles(two pairs)
Astral rays andspindle fibers
Chromosomewith two sister
chromatids
Chromosomalmicrotubules
Metaphaseplate
Daughterchromosomes
Cleavagefurrow
Daughtercells
Anaphase Telophase Cytokinesis
Anaphase (AN-a-f z; ana-, apart) begins when the centromere of each chromatidpair splits and thechromatids separate. The two daughterchromosomes are now pulled toward opposite ends of the cell along thechromosomalmicrotubules.
During telophase(T¯L- -f z; telo-,end), each new cellprepares to return to the interphase state. The nuclearmembranes re-form, the nuclei enlarge, and thechromosomesgradually uncoil.This stage marks the end of mitosis.
Cytokinesis is thedivision of thecytoplasm into twodaughter cells.Cytokinesis usually begins with the formation of a cleavage furrow andcontinuesthroughouttelophase. Thecompletion ofcytokinesis marksthe end of celldivision.
E aa o
MetaphaseLate prophaseEarly prophase
Prophase (PR¯ -f z;pro, before) beginswhen thechromosomes coil so tightly they become visible as single structures under a light microscope. Anarray of microtubules called spindle fibersextends between the centriole pairs.Smaller microtubules called astral rays radiate into the cytoplasm.
Metaphase(MET-a-f z; meta,after) begins as the chromatids move to a narrow central zone called themetaphase plate.Metaphase endswhen all thechromatids arealigned in the plane of the metaphase plate.
O a
o
oE
a
e
As a result of DNAreplication during the Sphase, two copies of each chromosome now exist. Each copy, called a chromatid (KRO-ma-tid), is connected to itsduplicate copy at a single point, the centomere (SEN-tr -m r).Kinetochores(ki-N¯-t -korz) are theprotein-bound area of the centromere; theyattach to spindle fibers forming chromosomalmicrotubules.
¯
© 2015 Pearson Education, Inc.pp. 104-105