Tài liệu Basic Cell Biology pptx

© 2002 by Bruce Alberts, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts, and Peter Walter.... © 2002 by Bruce Alberts, Alexander Johnson, Julian Lewis, Martin Raff, Keith Ro

Basic Cell Biology

© 2002 by Bruce Alberts, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts, and Peter Walter.

Asymmetrical arrangement of

phospholipids in plasma membrane

Molecular Cell Biology, Lodish et al., 4 th edition.

Figure 2—1 The ultrastructure and molecular organization (right)

of the cell membrane The dark lines at left represent the two dense layers observed in the electron microscope; these are caused by the deposit of osmium in the hydrophilic portions of the phospholipid molecules.

© 2002 by Bruce Alberts, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts, and Peter Walter.

Figure 11—14 Electron micrograph of a transverse section of a continuous capillary Note the nucleus (N) and the junctions between neighboring cells (arrowheads)

Numerous pinocytotic vesicles are evident (small arrows)

C Ribosomes

„ Structure- 2 subunits, composed of 4 types of RNA and 80 different proteins.

„ Characteristics

hematoxylin , toluidine blue

together by a strand of RNA.

Ribosome

Polyribosomes

Ribosome function

used in the cytoplasm

to synthesize

Three dimensional ribosome structure, L1 is a ribosomal protein

© 2002 by Bruce Alberts, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts, and Peter Walter.

•Ribosome-two thirds RNA, one third protein

•Each ribosome has three binding sites for tRNA, and a binding site for mRNA

© 2002 by Bruce Alberts, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts, and Peter Walter.

Endoplasmic Reticulum

from the cytoplasm

RER structure

„ RER

„ Functions

„ Storage in lysosomes

„ Storage in secretory granules

„ Use as integral proteins

SRP- 6 non-identical

proteins, 7 S RNA

© 2002 by Bruce Alberts, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts, and Peter Walter.

Figure 2—19 The ultrastructure

of a cell that synthesizes (but does not secrete) proteins on free polyribosomes (A); a cell that synthesizes, segregates, and stores proteins in organelles (B);

a cell that synthesizes,

segregates, and directly exports proteins (C); and a cell that

synthesizes, segregates, stores in supranuclear granules, and

exports proteins (D)

… Steroid synthesis (gonad, adrenal)

… Ca2+ reservoir in skeletal muscle

Golgi apparatus

glycosylation, phosphorylation, proteolysis

granules

Basal

„ Membrane bound vesicles that contain

hydrolytic enzymes for digestion

„ Heterophagy

„ Autophagy digestion of intracellular organelles

„ Review Table 2-3 for clinical correlations

nerves

Figure 2—27 Current concepts of the functions of lysosomes

Synthesis occurs in the rough

endoplasmic reticulum (RER), and the enzymes are packaged in the Golgi complex Note the

heterophagosomes, in which

bacteria are being destroyed, and the autophagosomes, with RER and mitochondria in the process of digestion Heterophagosomes and autophagosomes are secondary lysosomes The result of their digestion can be excreted, but sometimes the secondary

lysosome creates a residual body, containing remnants of undigested molecules In some cells, such as osteoclasts, the lysosomal

enzymes are secreted to the

extracellular environment Nu, nucleolus.

granules)

„ Form cilia and flagella

two central microtubules

„ Immotile cilia syndrome of Kartagener

Microfilaments

Intermediate filaments

cells (astrocytes)

10 nm

© 2002 by Bruce Alberts, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts, and Peter Walter.

Nuclear envelope

two sheaths of nuclear envelope

… < 10 nm pass freely through

and cytoplasm

Nuclear

pore

Nuclear envelope

Perinuclear space

Figure 3—5 Illustration to show the structure, the localization, and the

relationship of the nuclear lamina with chromosomes The drawing also shows that the nuclear pore

complex is made of 2

protein rings in an

octagonal organization From the cytoplasmic ring, long filaments penetrate the cytosol, and from the

intranuclear ring arise

filaments that constitute a basketlike structure The presence of the central

cylindrical granule in the nuclear pore is not

universally accepted.

Figure 3—6 Electron

micrographs of nuclei showing their envelopes composed of 2 membranes and the nuclear pores (arrows) The two upper pictures are of transverse sections; the bottom is of a tangential section Chromatin, frequently condensed below the nuclear envelope, is not usually seen in the pore

regions x80,000.

Figure 3—7 Electron micrograph obtained

by cryofracture of a rat intestine cell,

showing the two

components of the nuclear envelope and the nuclear pores (Courtesy of P Pinto

da Silva.)

© 2002 by Bruce Alberts, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts, and Peter Walter.

© 2000 by Geoffrey M CooperPhosphorylation of lamins causes dissolution

basophilic

… Light staining- active

… Dark staining- not active

outside the DNA filament.

Figure 3—10 The orders of

chromatin packing believed to

exist in the metaphase

chromosome Starting at the top, the 2-nm DNA double helix is

shown; next is the association of DNA with histones to form

filaments of nucleosomes of 11 nm and 30 nm Through further

condensation, filaments with

diameters of 300 nm and 700 nm are formed Finally, the bottom drawing shows a metaphase

chromosome, which exhibits the maximum packing of DNA

Cell division (mitosis)

© 2002 by Bruce Alberts, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts, and Peter Walter.

Figure 3—12 Human karyotype preparation made by means of a banding technique Each

chromosome has a particular pattern of banding that facilitates its identification and also the

relationship of the banding pattern to genetic anomalies The chromosomes are grouped in numbered pairs according to their morphologic characteristics.

Figure 3—16

Photomicrograph of cultured cells to show cell division Picrosirius-hematoxylin stain Medium magnification A: Interphase nuclei Note the chromatin and nucleoli inside each nucleus B: Prophase

No distinct nuclear envelope,

no nucleoli Condensed

chromosomes C: Metaphase The chromosomes are located

in a plate at the cell equator D: Late anaphase The

chromosomes are located in both cell poles, to distribute the DNA equally between the daughter cells

Figure 3—18 Electron

micrograph of a section of a rooster spermatocyte in

metaphase The figure

shows the two centrioles in each pole, the mitotic

spindle formed by

microtubules, and the

chromosomes in the

equatorial plane The

arrows show the insertion of microtubules in the

centromeres Reduced from x19,000 (Courtesy of R

McIntosh.)

Figure 3—21 The 4 phases of the cell cycle In G1 the cell either continues the cycle or enters a quiescent phase called G0 From this phase, most cells can return to the cycle, but some stay in G0 for a long time or even for their entire lifetime The checking or

restriction point (R) in G1 stops the cycle under

conditions unfavorable to the cell When the cell passes this restriction point, it continues the cycle through the synthetic phase (S) and the G2 phase, originating 2 daughter cells in mitosis (M) except when

interrupted by another

restriction point (not shown)

in G2

Figure 3—20 Phases of the cell cycle in bone tissue The G1 phase (presynthesis) varies in duration, which depends on many factors, including the rate of cell

division in the tissue In bone tissue, G1 lasts 25 h The S phase (DNA synthesis) lasts about 8 h The G2-plus-mitosis phase lasts 2.5—3 h (The times indicated are courtesy of RW Young.)