Presentation is loading. Please wait.

Presentation is loading. Please wait.

Microscopy and the Cell

Published byΆκανθα Παπακωνσταντίνου Modified over 6 years ago

Similar presentations

Presentation on theme: "Microscopy and the Cell"— Presentation transcript:

1 Microscopy and the Cell

2 Cell Biology tools: Microscopy & Fractionation
The quality of an image depends on Magnification, the ratio of an object’s image size to its real size Resolution, the measure of the clarity of the image, or the minimum distance of two distinguishable points Contrast, visible differences in parts of the sample

3 Scale of Resolution Naked Eye Light Microscope Electron Microscope
Human height 1 m Length of some nerve and muscle cells 0.1 m Unaided eye Chicken egg 1 cm Frog egg 1 mm 100 µm Most plant and animal cells Light microscope 10 µm Nucleus Most bacteria 1 µm Mitochondrion Figure 6.2 The size range of cells Smallest bacteria Electron microscope 100 nm Viruses Ribosomes 10 nm Proteins Lipids 1 nm Small molecules 0.1 nm Atoms

4 Light Microscopy In a light microscope (LM), visible light passes through a specimen and then through glass lenses, which magnify the image Various techniques enhance contrast and enable cell components to be stained or labeled Most subcellular structures, including organelles (membrane-enclosed compartments), are too small to be resolved by a light microscope

5 Imaging & density Imaging & optics
Viewing Techniques for: Naked Eye Light Microscope Electron Microscope TECHNIQUE RESULTS (a) Brightfield (unstained specimen) Imaging 50 µm (b) Brightfield (stained specimen) Imaging w/ stain (contrast) (c) Phase-contrast Imaging & density (d) Differential-interference- contrast (Nomarski) Imaging & optics (e) Fluorescence Imaging with labeling Figure 6.3a-d Light microscopy 50 µm (f) Confocal Imaging and focal planes 50 µm

6 Video Links Using a light bright-field compound microscope: Human sperm under a light compound microscope:

7 Electron microscopy Two basic types of electron microscopes (EMs) are used to study subcellular structures Scanning electron microscopes (SEMs) focus a beam of electrons onto the surface of a specimen, providing images that look 3-D Transmission electron microscopes (TEMs) focus a beam of electrons through a specimen, used mainly to study the internal structure of cells

8 (b) Transmission electron
TECHNIQUE RESULTS Cilia 1 µm (a) Scanning electron microscopy (SEM) SURFACE Longitudinal section of cilium Cross section of cilium 1 µm Figure 6.4 Electron microscopy (b) Transmission electron microscopy (TEM) SECTION OR SLICE

9 Cell Fractionation Cell fractionation is a process where cells are taken apart, separating the major organelles from one another (fractionation) High speed centrifuges fractionate cells into their component parts Cell fractionation enables scientists to determine the functions of organelles Biochemistry and genetic techniques help correlate cell structure with function

10 Successive steps of centrifugation under different speeds (g forces)
TECHNIQUE Homogenization Tissue cells Homogenate 1,000 g (1,000 times the force of gravity) 10 min Differential centrifugation Supernatant poured into next tube 20,000 g 20 min Successive steps of centrifugation under different speeds (g forces) yield a sedimentaion of different cellular components that can be isolated to relative homogeneity & characterized by biochemical and genetic means. 80,000 g 60 min Pellet rich in nuclei and cellular debris Figure 6.5 Cell fractionation 150,000 g 3 hr Pellet rich in mitochondria (and chloro- plasts if cells are from a plant) Pellet rich in “microsomes” (pieces of plasma membranes and cells’ internal membranes) Pellet rich in ribosomes

11 Molecular Cell Biology
The basic structural and functional unit of every organism is one of two types of cells: either prokaryotic or eukaryotic Only organisms of the domains Bacteria and Archaea consist of prokaryotic cells Protists, Fungi, Animals, and Plants all consist of eukaryotic cells

12 the common ground… All cells have these basic features:
Plasma membrane Chromosomes (carry genes) Ribosomes (make proteins) A semifluid substance called the cytosol

13 Plasma Membrane (a selective phospholipid bilayer) (a) TEM of a plasma
Outside of cell Plasma Membrane (a selective phospholipid bilayer) Inside of cell 0.1 µm Carbohydrate side chain on outer side of protein Hydrophilic region Figure 6.7 The plasma membrane Hydrophobic region Hydrophilic region Phospholipid Proteins (b) Structure of the plasma membrane

14 A Panoramic View of the Prokaryotic Cell
Prokaryotic cells are characterized by having No membrane-bound organelles! No nucleus DNA in an unbound region called the nucleoid A cytoplasm bound by the plasma membrane

15 Bacterial Cell (Prokaryote)
Fimbriae Nucleoid (region) Ribosomes Plasma membrane Bacterial chromosome Cell wall Capsule 0.5 µm Figure 6.6 A prokaryotic cell Flagella (a) A typical rod-shaped bacterium (b) A thin section through the bacterium Bacillus coagulans (TEM)

16 A Panoramic View of the Eukaryotic Cell
Eukaryotic cells are characterized by having Membrane-bound organelles (internal membranes that compartmentalize their functions) DNA in a nucleus that is bounded by a membranous nuclear envelope (nucleus is a membrane bound organelle) Cytoplasm in the region between the plasma membrane and organelles Eukaryotic cells are generally much larger than prokaryotic cells Plant and animal cells have most of the same organelles (some important exceptions)

17 BioFlix: Tour Of An Animal Cell
Animal Cell (Eukaryote) Nuclear envelope ENDOPLASMIC RETICULUM (ER) Nucleolus NUCLEUS Rough ER Smooth ER Flagellum Chromatin Centrosome Plasma membrane CYTOSKELETON: Microfilaments Intermediate filaments Microtubules Ribosomes Figure 6.9 Animal and plant cells—animal cell Microvilli Golgi apparatus Peroxisome Mitochondrion Lysosome BioFlix: Tour Of An Animal Cell

18 BioFlix: Tour Of A Plant Cell
Nuclear envelope Rough endoplasmic reticulum Plant Cell (Eukaryote) NUCLEUS Nucleolus Chromatin Smooth endoplasmic reticulum Ribosomes Central vacuole Golgi apparatus Microfilaments Intermediate filaments CYTO- SKELETON Microtubules Figure 6.9 Animal and plant cells—plant cell Mitochondrion Peroxisome Chloroplast Plasma membrane Cell wall Plasmodesmata Wall of adjacent cell BioFlix: Tour Of A Plant Cell

19 The Endomembrane System is composed of different membrane enclosed systems that divide the cell into functional and structural compartments.

20 Surface of nuclear envelope (SEM)
Nucleus 1 µm Nucleolus Chromatin Nuclear envelope: Inner membrane Outer membrane Nuclear pore Pore complex Rough ER Surface of nuclear envelope (SEM) Ribosome 1 µm Figure 6.10 The nucleus and its envelope 0.25 µm Close-up of a nuclear envelope Pore complexes (TEM) Nuclear lamina (TEM) (internal support)

21 Chromosomes (composed of chromatin – 20% DNA + 80% protein)
Note: The chromosomes are becoming more dense in order to segregate from each other during the process of cell division

22 Cell Division Karyotype Assay Video: Cell Division 10 µm Nucleus
Chromatin condensing 10 µm Nucleolus Chromosomes Cell plate 1 Prophase 2 Prometaphase 3 Metaphase 4 Anaphase 5 Telophase Karyotype Assay Video: Cell Division

23 replicated chromosomes
from dad Karyotype Analysis from mom 5 µm Pair of homologous replicated chromosomes Tetraploid (4n) Centromere Sister Chromatids (from dad) Sister Chromatids (from mom) 23

24 Ribosomes (free v. bound)
Cytosol Endoplasmic reticulum (ER) Free ribosomes (in cytosol; produce cellular proteins) Bound ribosomes (trans- membranous in ER; produce secretory proteins) Large subunit Figure 6.11 Ribosomes (TEM) Small subunit 0.5 µm Diagram of a ribosome

25 Endoplasmic Reticulum (rough v. smooth) Smooth ER Nuclear envelope
Rough ER ER lumen (inside ER cisternae) Cisternae (folds of ER membranes) Transitional ER Ribosomes Transport vesicle Smooth ER Lumen Rough ER Lumen Figure 6.12 Endoplasmic reticulum (ER) (TEM) 200 nm

26 Golgi Apparatus cis face trans face cis side trans side
(“receiving” side of Golgi apparatus) 0.1 µm Cisternae cis side Figure 6.13 The Golgi apparatus trans side trans face (“shipping” side of Golgi apparatus) Golgi apparatus (TEM)

27 Lysozome Nucleus 1 µm Vesicle containing two damaged organelles 1 µm
Mitochondrion fragment Peroxisome fragment Lysosome Digestive enzymes Lysosome Lysosome Figure 6.14a Lysosomes Plasma membrane Peroxisome Digestive Vacuole Food vacuole Digestive Vacuole Mitochondrion Vesicle (a) Phagocytosis (b) Autophagy

28 Plant cell Central vacuole
Central vacuole HUGE SIZE! Cytosol Plant cell Central vacuole Nucleus Figure 6.15 The plant cell vacuole Cell wall Chloroplast 5 µm

29 In Summary: The Endomembrane System
Nucleus Rough ER Smooth ER cis Golgi Plasma membrane trans Golgi

30 Mitochondria and Chloroplasts convert energy from one form to another.
For the Cell Biology Video ER and Mitochondria in Leaf Cells, go to Animation and Video Files. For the Cell Biology Video Mitochondria in 3D, go to Animation and Video Files. For the Cell Biology Video Chloroplast Movement, go to Animation and Video Files.

31 in the mitochondrial matrix
(generate metabolic energy through cellular respiration) Intermembrane space Outer membrane Free ribosomes in the mitochondrial matrix Inner membrane Figure 6.17 The mitochondrion, site of cellular respiration Cristae Matrix 0.1 µm

32 Chloroplasts Thylakoids membranous sacs, stacked to form a granum
(generate chemical energy from light) Ribosomes Stroma Inner and outer membranes Granum 1 µm Thylakoid Thylakoids membranous sacs, stacked to form a granum Stroma (the internal fluid), which containins chloroplast DNA, ribosomes and enzymes

33 The cytoskeleton organizes cell structure and activity, employing three types of molecular fiber.
For the Cell Biology Video The Cytoskeleton in a Neuron Growth Cone, go to Animation and Video Files For the Cell Biology Video Cytoskeletal Protein Dynamics, go to Animation and Video Files.

34 Components of the Cytoskeleton
For the Cell Biology Video Actin Network in Crawling Cells, go to Animation and Video Files. For the Cell Biology Video Actin Visualization in Dendrites, go to Animation and Video Files. Column of tubulin dimers Keratin proteins Actin subunit Fibrous subunit (keratins coiled together) 25 nm 7 nm 8–12 nm Tubulin dimer

35 Microtubule (Vesicle Transport) Vesicle Receptor for motor protein
ATP Receptor for motor protein Motor protein (ATP powered) Microtubule of cytoskeleton (a) Microtubule Vesicles 0.25 µm Figure 6.21 Motor proteins and the cytoskeleton (b)

36 Microfilament (Cell Motility)
9 Outer microtubule doublets Plasma membrane 0.1 µm Dynein proteins 1 Central microtubule doublet Radial spoke Protein cross-linking outer doublets Microtubules Cross section of cilium Plasma membrane Basal body (anchor) 0.5 µm 0.1 µm Longitudinal section of cilium Figure 6.24 Ultrastructure of a eukaryotic flagellum or motile cilium Triplet Cross section of basal body

37 Intermediate Filament
(Cell Structure) Microvillus Plasma membrane Microfilaments (actin filaments) Figure 6.26 A structural role of microfilaments Intermediate filaments 0.25 µm

38 Extracellular components and connections between cells help coordinate cellular activities.
For the Cell Biology Video Ciliary Motion, go to Animation and Video Files.

39 (different functional layers)
Plant Cell Wall (different functional layers) Secondary cell wall (bark) Primary cell wall (leaves) Middle lamella (between cells) 1 µm Central vacuole Cytosol Plasma membrane Figure 6.28 Plant cell walls Plant cell walls Plasmodesmata (channels for ‘crosstalk’)

40 Plant Cell Plasmodesmata
Cell walls Interior of cell Interior of cell Figure 6.31 Plasmodesmata between plant cells 0.5 µm Plasmodesmata Plasma membranes

41 EXTRACELLULAR FLUID (extracellular matrix) Integral Membrane Proteins
ECM proteins (bind integrins) Collagen Proteoglycan complex Polysaccharide molecule EXTRACELLULAR FLUID (extracellular matrix) Carbo- hydrates Core protein Integrins Integral Membrane Proteins Proteoglycan molecule Figure 6.30 Extracellular matrix (ECM) of an animal cell, part 1 Proteoglycan complex Fibronectin Micro- filaments CYTOPLASM

42 Animal Cell Intercellular Junctions (cell-to-cell communication)
Tight junction Tight junctions prevent fluid from moving across a layer of cells 0.5 µm Tight junction Intermediate filaments Desmosome Desmosome Gap junctions 1 µm Figure 6.32 Intercellular junctions in animal tissues Extracellular matrix Space between cells Gap junction Plasma membranes of adjacent cells 0.1 µm

Download ppt "Microscopy and the Cell"

Similar presentations

Announcements ● Tutoring Center SCI I, 407 M 12-3, 5:30-6:30; W 8-9, 5:30-6:30, Th 8-12, 6-7; F 8-9 ● MasteringBiology Assignment due Tuesday 4/19 ● Exam.

Announcements ● Tutoring Center SCI I, 407 M 12-3, 5:30-6:30; W 8-9, 5:30-6:30, Th 8-12, 6-7; F 8-9 ● MasteringBiology Assignment due Tuesday 4/19 ● Exam.
Microscopy In a light microscope (LM), visible light passes through a specimen and then through glass lenses, which magnify the image The quality of an.

Microscopy In a light microscope (LM), visible light passes through a specimen and then through glass lenses, which magnify the image The quality of an.
Tour of the Cell. Robert Hooke (1635-1703) Robert Hooke -- 1665: examined thinly sliced cork and coined term “cell”

Tour of the Cell. Robert Hooke ( ) Robert Hooke : examined thinly sliced cork and coined term “cell”
10 m 1 m 0.1 m 1 cm 1 mm 100 µm 10 µm 1 µm 100 nm 10 nm 1 nm 0.1 nm

10 m 1 m 0.1 m 1 cm 1 mm 100 µm 10 µm 1 µm 100 nm 10 nm 1 nm 0.1 nm
Lecture 2 Outline (Ch. 6) I. Cell Background II. Organelles

Lecture 2 Outline (Ch. 6) I. Cell Background II. Organelles
A tour of the cell.

A tour of the cell.
4 A Tour of the Cell.

4 A Tour of the Cell.
Fig. 6-7 TEM of a plasma membrane (a) (b) Structure of the plasma membrane Outside of cell Inside of cell 0.1 µm Hydrophilic region Hydrophobic region.

Fig. 6-7 TEM of a plasma membrane (a) (b) Structure of the plasma membrane Outside of cell Inside of cell 0.1 µm Hydrophilic region Hydrophobic region.
LE 7-2 Hydrophilic head Hydrophobic tail WATER. LE 7-3 Hydrophilic region of protein Hydrophobic region of protein Phospholipid bilayer.

LE 7-2 Hydrophilic head Hydrophobic tail WATER. LE 7-3 Hydrophilic region of protein Hydrophobic region of protein Phospholipid bilayer.
Cell Structure and Function

Cell Structure and Function
10 m 1 m 0.1 m 1 cm 1 mm 100 µm 10 µm 1 µm 100 nm 10 nm 1 nm 0.1 nm

10 m 1 m 0.1 m 1 cm 1 mm 100 µm 10 µm 1 µm 100 nm 10 nm 1 nm 0.1 nm
Ch. 7 Diagrams Cell Structure. Figure 6.2 10 m 1 m 0.1 m 1 cm 1 mm 100  m 10  m 1  m 100 nm 10 nm 1 nm 0.1 nm Atoms Small molecules Lipids Proteins.

Ch. 7 Diagrams Cell Structure. Figure m 1 m 0.1 m 1 cm 1 mm 100  m 10  m 1  m 100 nm 10 nm 1 nm 0.1 nm Atoms Small molecules Lipids Proteins.
Fig. 6-2 10 m 1 m 0.1 m 1 cm 1 mm 100 µm 10 µm 1 µm 100 nm 10 nm 1 nm 0.1 nm Atoms Small molecules Lipids Proteins Ribosomes Viruses Smallest bacteria.

Fig m 1 m 0.1 m 1 cm 1 mm 100 µm 10 µm 1 µm 100 nm 10 nm 1 nm 0.1 nm Atoms Small molecules Lipids Proteins Ribosomes Viruses Smallest bacteria.
Cells.

Cells.
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings PowerPoint ® Lecture Presentations for Biology Eighth Edition Neil Campbell.

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings PowerPoint ® Lecture Presentations for Biology Eighth Edition Neil Campbell.
Lecture for Chapter 4 DNA organization Endomembrane System.

Lecture for Chapter 4 DNA organization Endomembrane System.
Organization of the Cell

Organization of the Cell
Chapter 6: Types of Cells and Cell Structures

Chapter 6: Types of Cells and Cell Structures
Basic Unit of Life Cell Song. Principles of Cell Theory 1. Cells are basic units of life 2. Biogenesis - All Cells arise from other cells 3. Energy flow.

Basic Unit of Life Cell Song. Principles of Cell Theory 1. Cells are basic units of life 2. Biogenesis - All Cells arise from other cells 3. Energy flow.
10 m 1 m 0.1 m 1 cm 1 mm 100 µm 10 µm 1 µm 100 nm 10 nm 1 nm 0.1 nm Atoms Small molecules Lipids Proteins Ribosomes Viruses Smallest bacteria Mitochondrion.

10 m 1 m 0.1 m 1 cm 1 mm 100 µm 10 µm 1 µm 100 nm 10 nm 1 nm 0.1 nm Atoms Small molecules Lipids Proteins Ribosomes Viruses Smallest bacteria Mitochondrion.

Similar presentations

Ads by Google