Early scientists who observed cells made detailed sketches of what they saw. Early scientists who observed cells made detailed sketches of what they saw. CORK
Early scientists who observed cells made detailed sketches of what they saw. CORK These early sketches revealed an important relationship between art and biology, the most visual of the sciences
Microscopes provide windows to the world of the cell The light microscope (LM) enables us to see the overall shape and structure of a cell Eyepiece Ocular lens Objective lens Specimen Condenser lens Light source Light microscopes Magnify cells, living and preserved, up to 1,000 times
Light microscopes Magnify cells, living and preserved, up to 1,000 times The electron microscope Allows greater magnification and reveals cellular details
Different types of light microscopes Use different techniques to enhance contrast and selectively highlight cellular components Different types of light microscopes Use different techniques to enhance contrast and selectively highlight cellular components Figure 4.1E Figure 4.1F 220! 1,000!
Most cells are microscopic and vary in size and shape 10 m 1 m 100 mm (10 cm) 10 mm (1 cm) 1 mm Human height Length of some nerve and muscle cells Chicken egg Frog egg Unaided eye 100 µm 10 µm 1 µm Most plant and animal cells Nucleus Most bacteria Mitochondrion Light microscope 100 nm 10 nm 1 nm Mycoplasmas (smallest bacteria) Viruses Ribosome Proteins Lipids Small molecules Electron microscope 0.1 nm Atoms A small cell has a greater ratio of surface area to volume than a large cell of the same shape. 30 µm 10 µm 30 µm 10 µm Surface area of one large cube = 5,400 µm 2 Total surface area of 27 small cubes = 16,200 µm 2
There are two kinds of cells Prokaryotic and Eukaryotic. Prokaryotic cells Are small relatively simple cells
Prokaryotic cells Are small relatively simple cells Do not have membrane bound organelles Prokaryotic cells Are small relatively simple cells Do not have membrane bound organelles Two main classes: Gram-positive and Gram-negative
Prokaryotic cells Are small relatively simple cells Do not have membrane bound organelles Two main classes: Gram-positive and Gram-negative May have a capsule Prokaryotic cells Are small relatively simple cells Do not have membrane bound organelles Two main classes: Gram-positive and Gram-negative May have a capsule May have a rigid cell wall
Prokaryotic cells Are small relatively simple cells Do not have membrane bound organelles Two main classes: Gram-positive and Gram-negative May have a capsule May have a rigid cell wall May have and outer membrane (Gram-negative) Prokaryotic cells Are small relatively simple cells Do not have membrane bound organelles Two main classes: Gram-positive and Gram-negative May have a capsule May have a rigid cell wall May have an outer membrane (Gram-negative) May have a periplasmic space (Gram-negative)
Prokaryotic cells Are small relatively simple cells Do not have membrane bound organelles Two main classes: Gram-positive and Gram-negative May have a capsule May have a rigid cell wall May have an outer membrane (Gram-negative) May have a periplasmic space (Gram-negative) May have a flagellum (motility) Prokaryotic cells Are small relatively simple cells Do not have membrane bound organelles Two main classes: Gram-positive and Gram-negative May have a capsule May have a rigid cell wall May have an outer membrane (Gram-negative) May have a periplasmic space (Gram-negative) May have a flagellum (motility) Have pili or fimbrae (adhesins)
Prokaryotic cells Are small relatively simple cells Do not have membrane bound organelles Two main classes: Gram-positive and Gram-negative May have a capsule May have a rigid cell wall May have an outer membrane (Gram-negative) May have a periplasmic space (Gram-negative) May have a flagellum (motility) Have pili or fimbrae (adhesins) May have a circular plasmid Prokaryotic cells Are small relatively simple cells Do not have membrane bound organelles Two main classes: Gram-positive and Gram-negative May have a capsule May have a rigid cell wall May have an outer membrane (Gram-negative) May have a periplasmic space (Gram-negative) May have a flagellum (motility) Have pili or fimbrae (adhesins) May have a circular plasmid Are haploid with no nuclear membrane
Prokaryotic cells Are small relatively simple cells Do not have membrane bound organelles Two main classes: Gram-positive and Gram-negative May have a capsule May have a rigid cell wall May have an outer membrane (Gram-negative) May have a periplasmic space (Gram-negative) May have a flagellum (motility) Have pili or fimbrae (adhesins) May have a circular plasmid Are haploid with no nuclear membrane Have inclusion bodies Prokaryotic cells Are small relatively simple cells Do not have membrane bound organelles Two main classes: Gram-positive and Gram-negative May have a capsule May have a rigid cell wall May have an outer membrane (Gram-negative) May have a periplasmic space (Gram-negative) May have a flagellum (motility) Have pili or fimbrae (adhesins) May have a circular plasmid Are haploid with no nuclear membrane Have inclusion bodies Have different ribosomes
Eukaryotic cells are partitioned into functional compartments. Membranes form the boundaries of many eukaryotic cells. membranes
These membranes form compartments in the interior of the cell and enable a variety of metabolic activities membranes One such compartment is the nucleus. A true nucleus distinguishes a Eukaryotic cell from a Prokaryotic cell. Nucleus
A typical animal cell contains a variety of membranous organelles. Smooth endoplasmic Rough reticulum endoplasmic reticulum Nucleus Not in most plant cells Cytoskeleton Flagellum Lysosome Centriole Peroxisome Microtubule Intermediate filament Ribosomes Golgi apparatus Mitochondrion Plasma membrane Microfilament A typical plant cell has some structures that an animal cell lacks such as: chloroplasts a rigid cell wall Not in animal cells Nucleus Golgi apparatus Central vacuole Chloroplast Cell wall Rough endoplasmic reticulum Ribosomes Smooth endoplasmic reticulum Microtubule Intermediate filament Microfilament Cytoskeleton Mitochondrion Peroxisome Plasma membrane
The nucleus The nucleus is the cell s genetic control center Nucleus The nucleus The nucleus is the cell s genetic control center It is separated from the cytoplasm by the nuclear membrane Nucleus Two membranes of nuclear envelope
The nucleus The nucleus is the cell s genetic control center It is separated from the cytoplasm by the nuclear membrane It contains the cell s DNA and ultimately directs the activities of the cell. Nucleus Two membranes of nuclear envelope Many cell organelles are connected through the endomembrane system that manufactures and distributes cell products Smooth endoplasmic Rough reticulum endoplasmic reticulum Nucleus Ribosomes Golgi apparatus
Smooth endoplasmic reticulum has a variety of functions: Synthesizes lipids Processes toxins and drugs in liver cells Stores and releases calcium ions in muscle cells Smooth ER Rough ER Nuclear envelope Smooth ER Ribosomes Rough ER TEM 45,000! Rough endoplasmic reticulum: Manufactures membranes Makes proteins Smooth ER Rough ER Nuclear envelope Smooth ER Ribosomes Rough ER TEM 45,000!
Rough endoplasmic reticulum: Ribosomes on the surface of the rough ER produce proteins that are secreted, inserted into membranes, or transported to other organelles Transport vesicle buds off 4 Ribosome 1 3 Secretory (glyco-) protein inside transport vesicle Sugar chain Polypeptide 2 Glycoprotein Rough ER The Golgi apparatus: finishes, sorts, and ships cell products Receiving side of Golgi apparatus Golgi apparatus Golgi apparatus Transport vesicle from ER New vesicle forming Shipping side of Golgi apparatus Transport vesicle from the Golgi TEM 130,000!
Lysosomes are digestive compartments within a cell Rough ER Plasma membrane Transport vesicle (containing inactive hydrolytic enzymes) Golgi apparatus Food Engulfment of particle Lysosomes Lysosome engulfing damaged organelle Food vacuole Digestion Lysosomes are digestive compartments within a cell destroy bacteria that have been ingested Rough ER Plasma membrane Transport vesicle (containing inactive hydrolytic enzymes) Golgi apparatus Food Engulfment of particle Lysosomes Lysosome engulfing damaged organelle Food vacuole Digestion
Lysosomes are digestive compartments within a cell destroy bacteria that have been ingested Recycle damaged organelles Rough ER Plasma membrane Transport vesicle (containing inactive hydrolytic enzymes) Golgi apparatus Food Engulfment of particle Lysosomes Lysosome engulfing damaged organelle Food vacuole Digestion Lysosomes are digestive compartments within a cell destroy bacteria that have been ingested Recycle damaged organelles Abnormal lysozymes cause fatal diseases Rough ER Plasma membrane Transport vesicle (containing inactive hydrolytic enzymes) Golgi apparatus Cystinosis Food Engulfment of particle Lysosome engulfing damaged organelle Lysosomes Food vacuole Digestion
Vacuoles function in the general maintenance of the cell: Plant cells contain a large central vacuole with lysosomal and storage functions Protists have contractile vacuoles that pump out excess water Nucleus Contractile vacuoles LM 650! A review of the endomembrane system Rough ER Transport vesicle from ER to Golgi Transport vesicle from Golgi to plasma membrane Plasma membrane Nucleus Vacuole Lysosome Smooth ER Nuclear envelope Golgi apparatus
Chloroplasts: convert solar energy to chemical energy found in plants and some protists Convert solar energy to chemical energy in sugars Chloroplast Stroma Inner and outer membranes Granum TEM 9,750! Intermembrane space Mitochondria: harvest chemical energy from food: carry out cellular respiration uses the chemical energy in food to make ATP for cellular work Mitochondrial disease Mitochondrion Intermembrane space Outer membrane Inner membrane Cristae Matrix TEM 44,880!
The cytoskeleton: helps organize its structure and activities A network of protein fibers Make up the cytoskeleton. Microfilaments of actin (Enable cells to change shape and move) Actin subunit Microfilament 7 nm Fibrous subunits 10 nm Intermediate filament Tubulin subunit Microtubule 25 nm The cytoskeleton: helps organize its structure and activities A network of protein fibers Make up the cytoskeleton. Microfilaments of actin (Enable cells to change shape and move) Intermediate filaments (Reinforce the cell and anchor certain organelles) Actin subunit Microfilament 7 nm Fibrous subunits 10 nm Intermediate filament Tubulin subunit Microtubule 25 nm
The cytoskeleton: helps organize its structure and activities A network of protein fibers Make up the cytoskeleton. Microfilaments of actin (Enable cells to change shape and move) Intermediate filaments (Reinforce the cell and anchor certain organelles) Microtubules give the cell rigidity, provide anchors for organelles, act as tracks for organelle movement, divide the chromosomes, and power cilia and flagella Actin subunit Microfilament 7 nm Fibrous subunits 10 nm Intermediate filament Tubulin subunit Microtubule 25 nm The cytoskeleton: helps organize its structure and activities A network of protein fibers Make up the cytoskeleton. Microfilaments of actin (Enable cells to change shape and move) Intermediate filaments (Reinforce the cell and anchor certain organelles) Microtubules give the cell rigidity, provide anchors for organelles, act as tracks for organelle movement, divide the chromosomes, and power cilia and flagella Figure 4.17A Figure 4.17B Colorized SEM 4,100! LM 600!
Cell surfaces: protect, support, and join cells interact via their surfaces Plasma membrane Plant cells Are supported by rigid cell walls made largely of cellulose Connect by plasmodesmata, which are connecting channels Vacuole Walls of two adjacent plant cells Plasmodesmata Layers of one plant cell wall Cytoplasm Plasma membrane
Animal cells are embedded in an extracellular matrix Which binds cells together in tissues Tight junctions can bind cells together into leak-proof sheets Anchoring junctions link animal cells into strong tissues Gap junctions allow substances to flow from cell to cell Tight junctions Anchoring junction Gap junctions Plasma membranes of adjacent cells Extracellular matrix Space between cells A typical animal cell contains a variety of membranous organelles. Smooth endoplasmic Rough reticulum endoplasmic reticulum Nucleus Not in most plant cells Cytoskeleton Flagellum Lysosome Centriole Peroxisome Microtubule Intermediate filament Ribosomes Golgi apparatus Mitochondrion Plasma membrane Microfilament
A typical plant cell has some structures that an animal cell lacks such as: chloroplasts a rigid cell wall Nucleus Rough endoplasmic reticulum Ribosomes Smooth endoplasmic reticulum Golgi apparatus Microtubule Not in animal cells Central vacuole Chloroplast Cell wall Intermediate filament Microfilament Cytoskeleton Mitochondrion Peroxisome Plasma membrane Review Eukaryotic organelles comprise four functional categories Manufacturing Breakdown Energy processing Support, movement, and communication between cells
Review Eukaryotic organelles comprise four functional categories Manufacturing Nucleus» DNA and RNA synthesis, assembly of ribosomes Ribosomes» Protein synthesis Rough ER» Synthesis of membrane proteins, secretory proteins, hydrolytic enzymes, formation of transport vesicles Smooth ER» Lipid synthesis, carbohydrate metabolism, detoxification, and calcium ion storage Golgi» Macromolecule modification, temporary storage, transport, and lysosome formation Breakdown Energy processing Support, movement, and communication between cells Eukaryotic organelles comprise four functional categories Manufacturing Breakdown Lysosomes» Digestion / recycling Vacuoles Review» Digestion / recycling, storage of chemicals, and water balance Energy processing Support, movement, and communication between cells
Eukaryotic organelles comprise four functional categories Manufacturing Breakdown Energy processing Chloroplasts Review» Conversion of light energy to chemical energy (sugars) Mitochondria» Conversion of chemical energy of sugars, fats, proteins to the universal energy source, ATP Support, movement, and communication between cells Review Eukaryotic organelles comprise four functional categories Manufacturing Breakdown Energy processing Support, movement, and communication between cells Plasma membrane and associated proteins» Cell barrier, communication, transport Cell wall» Cell shape, protection, connection to other cells Cytoskeleton» Cell shape, anchorage and movement of organelles, cell movement, signaling, transport of molecules Extracellular matrix» Connection of cells, regulation of cell function Cell junctions» Communication, connection of cells
Review Eukaryotic organelles comprise four functional categories Manufacturing Breakdown Energy processing Support, movement, and communication between cells Review Eukaryotic organelles comprise four functional categories Manufacturing Nucleus» DNA and RNA synthesis, assembly of ribosomes Ribosomes» Protein synthesis Rough ER» Synthesis of membrane proteins, secretory proteins, hydrolytic enzymes, formation of transport vesicles Smooth ER» Lipid synthesis, carbohydrate metabolism, detoxification, and calcium ion storage Golgi» Macromolecule modification, temporary storage, transport, and lysosome formation Breakdown Energy processing Support, movement, and communication between cells
Eukaryotic organelles comprise four functional categories Manufacturing Breakdown Lysosomes» Digestion / recycling Review Vacuoles» Digestion / recycling, storage of chemicals, and water balance Energy processing Support, movement, and communication between cells Eukaryotic organelles comprise four functional categories Manufacturing Breakdown Energy processing Chloroplasts Review» Conversion of light energy to chemical energy (sugars) Mitochondria» Conversion of chemical energy of sugars, fats, proteins to the universal energy source, ATP Support, movement, and communication between cells
Review Eukaryotic organelles comprise four functional categories Manufacturing Breakdown Energy processing Support, movement, and communication between cells Plasma membrane and associated proteins» Cell barrier, communication, transport Cell wall» Cell shape, protection, connection to other cells Cytoskeleton» Cell shape, anchorage and movement of organelles, cell movement, signaling, transport of molecules Extracellular matrix» Connection of cells, regulation of cell function Cell junctions» Communication, connection of cells