Download presentation
Presentation is loading. Please wait.
1
How do your brain cells help you learn about biology?
Figure 4.1 Figure 4.1 How do your brain cells help you learn about biology? How do your brain cells help you learn about biology? 1
2
What do you remember about the cell?
1. 2. 3. 4. 5. 6.
3
The Cell and More
4
Introduction to the Cell: Videos
The Cell – Eukaryotic Cell
5
The Fundamental Units of Life
All organisms are made of cells All cells are related by their descent from earlier cells Cells can differ from one another, but they share common features © 2014 Pearson Education, Inc. 5
6
Microscopy Scientists use microscopes to visualize cells
Light microscope (LM), visible light is passed through a specimen and then through glass lenses © 2014 Pearson Education, Inc. 6
7
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 © 2014 Pearson Education, Inc. 7
8
TEM is used mainly to study the internal structure of cells
Transmission electron microscopes (TEMs) focus a beam of electrons through a specimen TEM is used mainly to study the internal structure of cells © 2014 Pearson Education, Inc. 8
9
Super- resolution microscopy
Figure 4.2b 100 m Most plant and animal cells 10 m Nucleus Most bacteria Mitochondrion LM 1 m EM Smallest bacteria Super- resolution microscopy 100 nm Viruses Ribosomes 10 nm Figure 4.2b The size range of cells and how we view them (part 2: EM to LM) Proteins Lipids 1 nm Small molecules Atoms 0.1 nm 9
10
Light Microscopy (LM) 50 m Brightfield (unstained specimen)
Figure 4.3a Light Microscopy (LM) 50 m Brightfield (unstained specimen) Brightfield (stained specimen) Figure 4.3a Exploring microscopy (part 1: light microscopy) Phase-contrast Differential-interference contrast (Nomarski) 10
11
Electron Microscopy (EM)
Figure 4.3c Electron Microscopy (EM) Longitudinal section of cilium Cross section of cilium Cilia Figure 4.3c Exploring microscopy (part 3: electron microscopy) Transmission electron microscopy (TEM) 2 m Scanning electron microscopy (SEM) 11
12
Eukaryotic and Prokaryotic Cells
The basic unit of every organism is one of two types of cells: prokaryotic or eukaryotic Organisms of the domains Bacteria and Archaea consist of prokaryotic cells Protists, fungi, animals, and plants all consist of eukaryotic cells © 2014 Pearson Education, Inc. 12
13
Comparing Prokaryotic and Eukaryotic Cells
Basic features of all cells Plasma membrane Semifluid substance called cytosol Chromosomes (Chromatin) – Genetic Info Ribosomes ( protein assembly) © 2014 Pearson Education, Inc. 13
14
Prokaryotic cells are characterized by having
No nucleus DNA in an unbound region called the nucleoid No membrane-bound organelles Ribosomes Cytoplasm bound by the plasma membrane © 2014 Pearson Education, Inc. 14
15
(a) A typical rod-shaped bacterium (b) A thin section through
Figure 4.4 Fimbriae Nucleoid Ribosomes Plasma membrane Bacterial chromosome Cell wall Capsule 0.5 m Flagella (a) A typical rod-shaped bacterium (b) A thin section through the bacterium Bacillus coagulans (TEM) Figure 4.4 A prokaryotic cell 15
16
Eukaryotic cells are characterized by having
DNA in a nucleus that is bounded by a membranous nuclear envelope Membrane-bound organelles Cytoplasm in the region between the plasma membrane and nucleus © 2014 Pearson Education, Inc. 16
17
Plasma Membrane The plasma membrane is a selective barrier that allows passage of oxygen, nutrients, and waste to service the volume of every cell The general structure of a biological membrane is a double layer of phospholipids Polar molecule and Ions cannot pass through the cell membrane without the aid of transport proteins © 2014 Pearson Education, Inc. 17
18
Carbohydrate side chains
Figure 4.5 (a) TEM of a plasma membrane Outside of cell Inside of cell 0.1 m Carbohydrate side chains Hydrophilic region Figure 4.5 The plasma membrane Hydrophobic region Hydrophilic region Phospholipid Proteins (b) Structure of the plasma membrane 18
19
Why Are Cells so Small Small Small Small……
Metabolic requirements set upper limits on the size of cells The ratio of surface area to volume of a cell is critical As the surface area increases by a factor of n2, the volume increases by a factor of n3 ****Small cells have a greater surface area relative to volume © 2014 Pearson Education, Inc. 19
20
5 1 1 6 150 750 Figure 4.6 Geometric relationships between surface area and volume 1 125 125 6 1.2 6 20
21
A Panoramic View of the Eukaryotic Cell
A eukaryotic cell has internal membranes that divide the cell into compartments—organelles Tour of an Animal Cell Tour of an Plant Cell © 2014 Pearson Education, Inc. 21
22
ENDOPLASMIC RETICULUM (ER) Nuclear envelope Smooth ER NUCLEUS
Figure 4.7a ENDOPLASMIC RETICULUM (ER) Nuclear envelope Smooth ER NUCLEUS Nucleolus Flagellum Rough ER Chromatin Centrosome Plasma membrane CYTOSKELETON: Microfilaments Intermediate filaments Ribosomes Microtubules Figure 4.7a Exploring eukaryotic cells (part 1: animal cell cutaway) Microvilli Golgi apparatus Peroxisome Mitochondrion Lysosome 22
23
Rough endoplasmic Nuclear envelope reticulum Nucleolus
Figure 4.7b Rough endoplasmic reticulum Nuclear envelope Nucleolus Smooth endoplasmic reticulum Chromatin NUCLEUS Ribosomes Central vacuole Golgi apparatus Microfilaments Intermediate filaments CYTO- SKELETON Microtubules Figure 4.7b Exploring eukaryotic cells (part 2: plant cell cutaway) Mitochondrion Peroxisome Plasma membrane Chloroplast Cell wall Plasmodesmata Wall of adjacent cell 23
24
A single yeast cell (colorized TEM)
Figure 4.7e 1 m Cell wall Vacuole Nucleus Figure 4.7e Exploring eukaryotic cells (part 5: fungal cell, TEM) Mitochondrion A single yeast cell (colorized TEM) 24
25
The eukaryotic cell’s genetic instructions are housed in the nucleus
The nucleus contains most of the DNA in a eukaryotic cell Ribosomes use the information from the DNA to make proteins © 2014 Pearson Education, Inc. 25
26
The nuclear envelope encloses the nucleus, separating it from the cytoplasm
The nuclear membrane is a double membrane; each membrane consists of a lipid bilayer © 2014 Pearson Education, Inc. 26
27
Pores regulate the entry and exit of molecules from the nucleus
© 2014 Pearson Education, Inc. 27
28
Close-up of nuclear envelope Chromatin Nucleus Nucleolus Chromatin
Figure 4.8a Nucleus Nucleolus Chromatin Nuclear envelope: Inner membrane Outer membrane Nuclear pore Rough ER Pore complex Figure 4.8a The nucleus and its envelope (part 1: detail of art) Ribosome Close-up of nuclear envelope Chromatin 28
29
Pore complexes (TEM) 0.25 m Figure 4.8c
Figure 4.8c The nucleus and its envelope (part 3: pore complexes, TEM) 29
30
In the nucleus, DNA is organized into discrete units called chromosomes
Each chromosome is one long DNA molecule associated with Histone Proteins also called Chromatin The nucleolus is located within the nucleus and is the site of ribosomal RNA (rRNA) synthesis © 2014 Pearson Education, Inc. 30
31
Ribosomes: Protein Factories
Ribosomes are complexes of ribosomal RNA and protein Ribosomes carry out protein synthesis in two locations In the cytosol (free ribosomes) On the outside of the endoplasmic reticulum © 2014 Pearson Education, Inc. 31
32
Free ribosomes in cytosol
Figure 4.9 0.25 m Ribosomes ER Free ribosomes in cytosol Endoplasmic reticulum (ER) Ribosomes bound to ER Large subunit Small subunit Figure 4.9 Ribosomes TEM showing ER and ribosomes Diagram of a ribosome 32
33
The endomembrane system regulates protein traffic and performs metabolic functions in the cell
Components of the endomembrane system Nuclear envelope Endoplasmic reticulum Golgi apparatus Lysosomes Vacuoles Plasma membrane These components are either continuous or connected through transfer by vesicles © 2014 Pearson Education, Inc. 33
34
The Endoplasmic Reticulum: Biosynthetic Factory
The ER membrane is continuous with the nuclear envelope There are two distinct regions of ER Smooth ER: lacks ribosomes Rough ER: surface is studded with ribosomes © 2014 Pearson Education, Inc. 34
35
0.2 m Smooth ER Rough ER Smooth ER Rough Nuclear ER envelope ER lumen
Figure 4.10 0.2 m Smooth ER Rough ER Smooth ER Rough ER Nuclear envelope Figure 4.10 Endoplasmic reticulum (ER) ER lumen Cisternae Transitional ER Ribosomes Transport vesicle 35
36
The smooth ER Synthesizes lipids Metabolizes carbohydrates
Detoxifies drugs and poisons Stores calcium ions © 2014 Pearson Education, Inc. 36
37
The rough ER Has bound ribosomes, which secrete glycoproteins (proteins covalently bonded to carbohydrates) Distributes transport vesicles, proteins surrounded by membranes Makes proteins to be secreted out of the cell or for extra- cellular matrix proteins © 2014 Pearson Education, Inc. 37
38
The Golgi Apparatus: Shipping and Receiving Center
The Golgi apparatus consists of flattened membranous sacs called cisternae Two sides: cis and trans Functions of the Golgi apparatus Modifies products of the ER Manufactures certain macromolecules Sorts and packages materials into transport vesicles © 2014 Pearson Education, Inc. 38
39
cis face trans face Golgi apparatus 0.1 m (“receiving” side of
Figure 4.11 Golgi apparatus 0.1 m cis face (“receiving” side of Golgi apparatus) Cisternae Figure 4.11 The Golgi apparatus trans face (“shipping” side of Golgi apparatus) TEM of Golgi apparatus 39
40
Lysosomes: Digestive Compartments
A lysosome is a membranous sac of hydrolytic enzymes that can digest macromolecules Lysosomal enzymes work best in the acidic environment inside the lysosome © 2014 Pearson Education, Inc. 40
41
A lysosome fuses with the food vacuole and digests the molecules
Some types of cell can engulf another cell by phagocytosis; this forms a food vacuole A lysosome fuses with the food vacuole and digests the molecules Lysosomes also use enzymes to recycle the cell’s own organelles and macromolecules, a process called autophagy © 2014 Pearson Education, Inc. 41
42
Lysosomes: Phagocytosis
Figure 4.12a Digestive enzymes Lysosome Plasma membrane Digestion Food vacuole Figure 4.12a Lysosomes: phagocytosis (part 1: detail of art) Lysosomes: Phagocytosis 42
43
Vesicle containing two damaged organelles 1 m
Figure 4.13 Vesicle containing two damaged organelles 1 m Mitochondrion fragment Peroxisome fragment Lysosome Figure 4.13 Lysosomes: autophagy Peroxisome Mitochondrion Digestion Vesicle Lysosomes: Autophagy 43
44
Vacuoles: Maintenance Compartments
Vacuoles are large vesicles derived from the endoplasmic reticulum and Golgi apparatus © 2014 Pearson Education, Inc. 44
45
Food vacuoles are formed by phagocytosis
Contractile vacuoles, found in many freshwater protists, pump excess water out of cells Central vacuoles, found in many mature plant cells, hold organic compounds and water © 2014 Pearson Education, Inc. 45
46
Central vacuole Cytosol Central vacuole Nucleus Cell wall Chloroplast
Figure 4.14 Central vacuole Cytosol Central vacuole Nucleus Figure 4.14 The plant cell vacuole Cell wall Chloroplast Plant cell vacuole 5 m 46
47
The Endomembrane System: A Review
The endomembrane system is a complex and dynamic player in the cell’s compartmental organization © 2014 Pearson Education, Inc. 47
48
Nucleus Rough ER Smooth ER Plasma membrane Figure 4.15-1
Figure Review: relationships among organelles of the endomembrane system (step 1) Plasma membrane 48
49
Nucleus Rough ER Smooth ER cis Golgi Plasma membrane trans Golgi
Figure Nucleus Rough ER Smooth ER cis Golgi Figure Review: relationships among organelles of the endomembrane system (step 2) Plasma membrane trans Golgi 49
50
Nucleus Rough ER Smooth ER cis Golgi Plasma membrane trans Golgi
Figure Nucleus Rough ER Smooth ER cis Golgi Figure Review: relationships among organelles of the endomembrane system (step 3) Plasma membrane trans Golgi 50
51
Mitochondria and chloroplasts change energy from one form to another
Mitochondria are the sites of cellular respiration, a metabolic process that uses oxygen to generate ATP Chloroplasts, found in plants and algae, are the sites of photosynthesis © 2014 Pearson Education, Inc. 51
52
The Evolutionary Origins of Mitochondria and Chloroplasts
Mitochondria and chloroplasts have similarities with bacteria Enveloped by a double membrane Contain free ribosomes and circular DNA molecules Grow and reproduce somewhat independently in cells © 2014 Pearson Education, Inc. 52
53
The endosymbiont theory
An early ancestor of eukaryotic cells engulfed a nonphotosynthetic prokaryotic cell, which formed an endosymbiont relationship with its host The host cell and endosymbiont merged into a single organism, a eukaryotic cell with a mitochondrion At least one of these cells may have taken up a photosynthetic prokaryote, becoming the ancestor of cells that contain chloroplasts © 2014 Pearson Education, Inc. 53
54
The endosymbiont theory
55
using nonphotosynthetic prokaryote, which becomes a mitochondrion
Figure 4.16 Endoplasmic reticulum Nucleus Engulfing of oxygen- using nonphotosynthetic prokaryote, which becomes a mitochondrion Nuclear envelope Ancestor of eukaryotic cells (host cell) Mitochondrion Engulfing of photosynthetic prokaryote At least one cell Figure 4.16 The endosymbiont theory of the origin of mitochondria and chloroplasts in eukaryotic cells Chloroplast Nonphotosynthetic eukaryote Mitochondrion Photosynthetic eukaryote 55
56
Mitochondria Mitochondria are in nearly all eukaryotic cells
They have a smooth outer membrane and an inner membrane folded into cristae Some metabolic steps of cellular respiration are catalyzed in the mitochondrial matrix Cristae present a large surface area for enzymes that synthesize ATP © 2014 Pearson Education, Inc. 56
57
Outer membrane Inner membrane
Figure 4.17 Mitochondrion Intermembrane space Outer membrane DNA Inner membrane Free ribosomes in the mitochondrial matrix Figure 4.17 The mitochondrion, site of cellular respiration Cristae Matrix 0.1 m 57
58
Chloroplasts Chloroplasts contain the green pigment chlorophyll, as well as enzymes and other molecules that function in photosynthesis Chloroplasts are found in leaves and other green organs of plants and in algae © 2014 Pearson Education, Inc. 58
59
Chloroplast structure includes
Thylakoids, membranous sacs, stacked to form a granum Stroma, the internal fluid © 2014 Pearson Education, Inc. 59
60
Inner and outer membranes
Figure 4.18a Ribosomes Stroma Inner and outer membranes Granum DNA Figure 4.18a The chloroplast, site of photosynthesis (part 1: detail) Thylakoid Intermembrane space 1 m (a) Diagram and TEM of chloroplast 60
61
Peroxisomes: Oxidation
Peroxisomes are specialized metabolic compartments bounded by a single membrane Peroxisomes produce hydrogen peroxide by removing hydrogen from certain molecules . It also has enzymes to then convert it to water since hydrogen peroxide is toxic. © 2014 Pearson Education, Inc. 61
62
The cytoskeleton is a network of fibers that organizes structures and activities in the cell
The cytoskeleton is a network of fibers extending throughout the cytoplasm It organizes the cell’s structures and activities, anchoring many organelles © 2014 Pearson Education, Inc. 62
63
Figure 4.20 Figure 4.20 The cytoskeleton 10 m 63
64
Roles of the Cytoskeleton: Support and Motility
The cytoskeleton helps to support the cell and maintain its shape It interacts with motor proteins to produce motility Inside the cell, vesicles and other organelles can “walk” along the tracks provided by the cytoskeleton © 2014 Pearson Education, Inc. 64
65
Motor proteins “walk” vesicles along cytoskeletal fibers.
Figure 4.21 Vesicle ATP Receptor for motor protein Motor protein (ATP powered) Microtubule of cytoskeleton Motor proteins “walk” vesicles along cytoskeletal fibers. Microtubule Vesicles 0.25 m Figure 4.21 Motor proteins and the cytoskeleton (b) SEM of a squid giant axon 65
66
Microtubules Microtubules are hollow rods constructed from globular protein called tubulin Functions of microtubules Shape and support the cell Guide movement of organelles Separate chromosomes during cell division © 2014 Pearson Education, Inc. 66
67
Plant cell walls may have multiple layers
Primary cell wall: Middle lamella: Secondary cell wall Plasmodesmata are channels between adjacent plant cells © 2014 Pearson Education, Inc. 67
68
Secondary cell wall Primary cell wall Middle lamella 1 m
Figure 4.25 Secondary cell wall Primary cell wall Middle lamella 1 m Central vacuole Cytosol Figure 4.25 Plant cell walls Plasma membrane Plant cell walls Plasmodesmata 68
69
Plasmodesmata in Plant Cells
Plasmodesmata are channels that perforate plant cell walls Through plasmodesmata, water and small solutes (and sometimes proteins and RNA) can pass from cell to cell © 2014 Pearson Education, Inc. 69
70
Tight Junctions, Desmosomes and Gap Junctions in Animal Cells
Tight Junctions: Prevent leakage of fluid from cells Desmosomes: anchoring cells together ( all cells but especially in muscle cells ) Gap Junctions: are channels made up of protein to allow communication and passage of substance to other cells © 2014 Pearson Education, Inc. 70
71
The Cell: A Living Unit Greater Than the Sum of Its Parts
Cellular functions arise from cellular order For example, a macrophage’s ability to destroy bacteria involves the whole cell, coordinating components such as the cytoskeleton, lysosomes, and plasma membrane © 2014 Pearson Education, Inc. 71
72
Figure 4.UN02 Figure 4.UN02 Summary of key concepts: nucleus and ribosomes 72
73
Figure 4.UN03 Figure 4.UN03 Summary of key concepts: endomembrane system 73
74
Figure 4.UN04 Figure 4.UN04 Summary of key concepts: mitochondria and chloroplasts 74
Similar presentations
