Larry M. Frolich, Ph.D. Cells—the fundamental unit of life What is life?What is life? Molecules of lifeMolecules of life Cell as fundamental unitCell as fundamental unit Cell membranes and organellesCell membranes and organelles Cell metabolismCell metabolism Cells organized into tissuesCells organized into tissues Types of tissuesTypes of tissues

Larry M. Frolich, Ph.D. What is Life? Life needs energy Life reproduces Life grows and develops Life maintains a stable condition— homeostasis Life responds to stimulus Life is organized because it has evolved

Larry M. Frolich, Ph.D. Cells are the basic and fundamental unit of life The first life was cellular life The Molecules of Life are what cells and all their internal parts are made up of Cells are fundamental unit of life

Larry M. Frolich, Ph.D. Cells—the fundamental unit of life What is life?What is life? Molecules of lifeMolecules of life Cell as fundamental unitCell as fundamental unit Cell membranes and organellesCell membranes and organelles Cell metabolismCell metabolism Cells organized into tissuesCells organized into tissues Types of tissuesTypes of tissues

Larry M. Frolich, Ph.D. The Carbon-chain Molecules of Life MOLECULEMADE OFFUNCTION CarbohydratesSimple SugarsEnergy ProteinsAmino AcidsCatalyze reactions FatsFatty AcidsCell membranes DNA/RNANucleotides (bases) Information

Larry M. Frolich, Ph.D. Carbohydrates Components are simple sugars Used for energy storage in complex form Broken down to simple sugars to fuel cellular metabolism in mitochondria So, why are simple sugars bad for us? And why do we love them so much? (p. 29 in text)

Larry M. Frolich, Ph.D. Proteins Components are amino acids Very complicated Amino acid chain folds up to give complex form Complex form allows for catalyzing very specific chemical reactino GenBlue

Larry M. Frolich, Ph.D. Fats/Lipids Fundamental to life and origins—separate cell interior from environment as cell membrane Mammals and other vertebrates—long-term energy storage Role in diet=big controversy!

Larry M. Frolich, Ph.D. DNA/RNA (Nucleic Acids) DNA and RNA store and use information Components are nucleotides or “bases” (A,C,T/U,G) One DNA molecule can be very long and complex—millions of bases long DNA duplicates to pass on information Transcription to mRNA to be translated into protein’s amino acid chain What do proteins do?

Larry M. Frolich, Ph.D. Cells—the fundamental unit of life What is life?What is life? Molecules of lifeMolecules of life Cell as fundamental unitCell as fundamental unit Cell membranes and organellesCell membranes and organelles Cell metabolismCell metabolism Cells organized into tissuesCells organized into tissues Types of tissuesTypes of tissues

Larry M. Frolich, Ph.D. Cells are the basic and fundamental unit of life The first life was cellular life The Molecules of Life are what cells and all their internal parts are made up of Cells are fundamental unit of life

Larry M. Frolich, Ph.D. Two types of cells Prokaryotic cells –Relatively Simple –Relatively Small –No organelles with Molecules of Life distributed throughout cytoplasm –Bacteria are all prokaryotic cells Eukaryotic cells –More complex –Much bigger (100 x size of prokaryotic cells) –Internally organized with membrane-bound organelles –Multi-cellular organisms, like plants and animals, are all made up of eukaryotic cells

Larry M. Frolich, Ph.D. Eukaryotic cell

Larry M. Frolich, Ph.D. Endosymbiotic origin of mitochondria and chloroplasts Eukaryotic cells evolved from fusion or integration of prokaryotic cells Best evidence is in bacterial or prokaryotic appearance of mitochondria and chloroplasts These organelles are like little bacterial cells within our cells, now fully functionally integrated They perform fundamental cell functions. Mitochondria process sugars to produce energy; chloroplasts make sugars by photosynthesis But they maintain their own DNA and genetic control

Larry M. Frolich, Ph.D. Prokaryotic cells have: Cell membrane DNA molecule loose in cytoplasm Small Ribosomes where proteins are assembled from DNA information Microtubule structures like flagella and cilia Mitochondria and chloroplasts share most of these features, including their own independent DNA

Larry M. Frolich, Ph.D. WHAT EUKARYOTIC CELLS HAVE: Cell membrane Nucleus Mitochondria (and sometimes chloroplasts for photosynthesis) Larger ribosomes for protein assembly from DNA information Internal membranes that organize cellular spaces and distribution of Molecules of Life within cell (“cytoskeleton”) Eukaryotic cells (like our human cells) have:

Larry M. Frolich, Ph.D. WHAT CAN EUKARYOTIC CELLS DO? WHAT STRUCTURES ARE INVOLVED? Separate inside of cell from external environment and control what substances pass across membrane Cell Membrane Produce proteins/enzymes that catalyze chemical reactions or control movement across membrane Nucleus (DNA), Ribosomes on rough endoplasmic reticulum Break down sugars to form energy which is stored in phosphate bonds of ATP Mitochondria Organize distribution of Molecules of Life (macromolecules) and ions throughout cell Internal membrane system and “cytoskeleton” (ER, lysosomes, vessicles, microtubules) MoveFlagella, cilia, pseudopods

Larry M. Frolich, Ph.D. Cells—the fundamental unit of life What is life?What is life? Molecules of lifeMolecules of life Cell as fundamental unitCell as fundamental unit Cell membranes and organellesCell membranes and organelles Cell metabolismCell metabolism Cells organized into tissuesCells organized into tissues Types of tissuesTypes of tissues

Larry M. Frolich, Ph.D. A cell membrane or plasma membrane separates cell from outside world—creates ability to regulate internal environment (homeostasis)

Larry M. Frolich, Ph.D. cell membrane

Larry M. Frolich, Ph.D. What are some characteristics of the plasma membrane? It is a phospholipid bilayer It is embedded with proteins that move in space It contains cholesterol for support It contains carbohydrates on proteins and lipids Selectively permeable cell membrane

Larry M. Frolich, Ph.D. What does selectively permeable mean? The membrane allows some things in while keeping other substances out cell membrane

Larry M. Frolich, Ph.D. How do things move across the plasma membrane? 1. Diffusion 2. Osmosis 3. Facilitated transport 4. Active transport 5. Endocytosis and exocytosis cell membrane

Larry M. Frolich, Ph.D. What are diffusion and osmosis? 1. Diffusion is the random movement of molecules from a higher concentration to a lower concentration 2. Osmosis is the diffusion of water molecules cell membrane

Larry M. Frolich, Ph.D. How does tonicity change a cell? Hypertonic solutions have more solute than the inside of the cell and lead to lysis (bursting) Hypotonic solutions have less solute than the inside of the cell and lead to crenation (shriveling) Isotonic solutions have equal amounts of solute inside and outside the cell and thus does not affect the cell cell membrane

Larry M. Frolich, Ph.D. What are facilitated diffusion and active transport? 3. Facilitated transport is the transport of molecules across the plasma membrane from higher concentration to lower concentration via a protein carrier 4. Active transport is the movement of molecules from a lower to higher concentration using ATP as energy; requires a protein carrier cell membrane

Larry M. Frolich, Ph.D. What are endocytosis and exocytosis? 5. Endocytosis transports molecules or cells into the cell via invagination of the plasma membrane to form a vesicle 6. Exocytosis transports molecules outside the cell via fusion of a vesicle with the plasma membrane cell membrane

Larry M. Frolich, Ph.D. Protein synthesis Remember that proteins control cell metabolism—how and where are they made, or synthesized in the cell?

Larry M. Frolich, Ph.D. What structures are involved in protein synthesis? Nucleus Ribosomes Endomembrane system Protein synthesis

Larry M. Frolich, Ph.D. What is the structure and function of the nucleus? Bound by a porous nuclear envelope Houses DNA and associated proteins called chromatin Contains nucleoplasm Nucleolus region(s) that contain ribosomal RNA (rRNA) Protein synthesis

Larry M. Frolich, Ph.D. What is the structure and function of ribosomes? Organelles made of RNA and protein Found bound to the endoplasmic reticulum and free floating in the cell Site of protein synthesis Protein synthesis

Larry M. Frolich, Ph.D. What is the endomembrane system? A series of membranes in which molecules are transported in the cell It consists of the nuclear envelope, endoplasmic reticulum, Golgi apparatus, lysosomes and vesicles Protein synthesis

Larry M. Frolich, Ph.D. How does the endomembrane system function and appear? Protein synthesis

Larry M. Frolich, Ph.D. Summary of the parts of the endomembrane system? Rough endoplasmic reticulum – studded with ribosomes used to make proteins Smooth endoplasmic reticulum – lacks ribosomes but aids in making carbohydrates and lipids Golgi apparatus – flattened stacks that process, package and deliver proteins and lipids from the ER Lysosomes – membranous vesicles made by the Golgi that contain digestive enzymes Vesicles – small membranous sacs used for transport Protein synthesis

Larry M. Frolich, Ph.D. What are cilia and flagella? Both are made of microtubules Both are used in movement Cilia are about 20x shorter than flagella

Larry M. Frolich, Ph.D. What do mitochondria do and what do they look like? A highly folded organelle in eukaryotic cells Produces energy in the form of ATP They are thought to be derived from an engulfed prokaryotic cell

Larry M. Frolich, Ph.D. Cells—the fundamental unit of life What is life?What is life? Molecules of lifeMolecules of life Cell as fundamental unitCell as fundamental unit Cell membranes and organellesCell membranes and organelles Cell metabolismCell metabolism Cells organized into tissuesCells organized into tissues Types of tissuesTypes of tissues

Larry M. Frolich, Ph.D. What is cellular respiration? Occurs in the mitochondria Production of ATP in a cell Usually glucose is main “energy” molecule enters cellular respiration Includes: –Glycolysis –Citric acid cycle –3. Electron transport chain

Larry M. Frolich, Ph.D. What other molecules besides glucose can be used in cellular respiration? Other carbohydrates Proteins Lipids

Larry M. Frolich, Ph.D. How can a cell make ATP without oxygen? Fermentation –Occurs in the cytoplasm –Does not require oxygen –Involves glycolysis –Makes 2 ATP and lactate in human cells –Is important in humans for a burst of energy for a short time

Larry M. Frolich, Ph.D. All of cell metabolism Cell metabolism is much more than simply making ATP, or cellular respiration, which is just how the cell has an energy supply. What does the cell do with that energy? Get ready for what you are about to see… The cell runs all the reactions that make it alive— see the first part of this presentation: grow, reproduce, develop, move, maintain internal homeostasis, respond to stimuli. This involves a LOT of chemical reactions. Here it is: most of the reactions involved in keeping the simplest of cells—an E. coli bacteria— alive!

Larry M. Frolich, Ph.D. Ecocyc—database of complete E. coli metabolism

Larry M. Frolich, Ph.D. What’s it all mean? Every little box represents a stage in a particular chemical reaction. The sum of those reactions is the total cell metabolism—what makes the cell alive! You’ll actually visit the ecocyc database under the web links for this section as the last thing you do Remember three things: 1.every one of these reactions is catalyzed by a protein 2.The amino acid sequence for those proteins are coded for in the DNA 3.The world’s biggest super-computers are trying to figure out how, based on their unique amino acid sequence, all the different cellular proteins take on the particular shape they have, and control the particular reaction they catalyze. (You’ll also visit the Blue Gene IBM super-computer website in the web links for this section.)

Larry M. Frolich, Ph.D. Cells—the fundamental unit of life (review) What is life?What is life? Molecules of lifeMolecules of life Cell as fundamental unitCell as fundamental unit Cell membranes and organellesCell membranes and organelles Cell metabolismCell metabolism Cells organized into tissuesCells organized into tissues Types of tissuesTypes of tissues

Larry M. Frolich, Ph.D. What is Life? Life needs energy Life reproduces Life grows and develops Life maintains a stable condition— homeostasis Life responds to stimulus Life is organized because it has evolved

Larry M. Frolich, Ph.D. The Carbon-chain Molecules of Life MOLECULEMADE OFFUNCTION CarbohydratesSimple SugarsEnergy ProteinsAmino AcidsCatalyze reactions FatsFatty AcidsCell membranes DNA/RNANucleotides (bases) Information

Larry M. Frolich, Ph.D. Cells are the basic and fundamental unit of life The first life was cellular life The Molecules of Life are what cells and all their internal parts are made up of Cells are fundamental unit of life

Larry M. Frolich, Ph.D. WHAT CAN EUKARYOTIC CELLS DO? WHAT STRUCTURES ARE INVOLVED? Separate inside of cell from external environment and control what substances pass across membrane Cell Membrane Produce proteins/enzymes that catalyze chemical reactions or control movement across membrane Nucleus (DNA), Ribosomes on rough endoplasmic reticulum Break down sugars to form energy which is stored in phosphate bonds of ATP Mitochondria Organize distribution of Molecules of Life (macromolecules) and ions throughout cell Internal membrane system and “cytoskeleton” (ER, lysosomes, vessicles, microtubules) MoveFlagella, cilia, pseudopods

Larry M. Frolich, Ph.D. A cell membrane or plasma membrane separates cell from outside world—creates ability to regulate internal environment (homeostasis)

Larry M. Frolich, Ph.D. Protein synthesis Remember that proteins control cell metabolism—how and where are they made, or synthesized in the cell?

Larry M. Frolich, Ph.D. Ecocyc—database of complete E. coli metabolism

Larry M. Frolich, Ph.D. What is a tissue? Multi-cellular organisms are composed of millions and millions of cells whose metabolism is organized to work together. A tissue is a collection of cells of the same type that perform a common function There are 4 major tissue types in the body: 1.Connective 2.Muscular 3.Nervous 4.Epithelial

Larry M. Frolich, Ph.D. This initial review of life and cells is crucial! Please read your book chapters, review the web links and get this part of the course. We’ll come back to cells and how they work again and again. I am aware this is a LOT of information! But master this, and the rest of the course will seem easy.