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BSCI 124 extra-credit project: 1) Please pick up your plant kit bag 2) Fill out Entry Ballot (yellow paper) to enter textbook raffle… Fold and place ballot in the box. ENTRY BALLOT BSCI 124 Name: ______________ Major: ______________ Reason for taking this class:
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BSCI 124 extra-credit project:1) Please pick up your plant kit bag2) Fill out Entry Ballot (yellow paper) to enter textbook raffle… Fold andplace ballot in the box. ENTRY BALLOT BSCI 124 Name: ______________ Major: ______________ Reason for taking this class: What do you want to getout of this class? Do you have any special Interst in plant biology?
BSCI 124: LECTURE 2 THE AMAZING PLANT CELL Prof. Edgar Moctezuma, Ph.D.
TODAY… • Pick up: Your free Plant Project Kit & fill ballot • Life’s molecules: • Carbohydrates • Lipids • Proteins • Nucleic acids Raffle: borrow a Textbook for free! • What is a cell? • The Cell Theory • Cell components: cell wall, organelles • Endosymbiont Theory
Cell Macromolecules:The Molecules of Life The cell is made of the following four biologically important molecules: • Carbohydrates (sugars, starches, cellulose) • Lipids (fats, oils, waxes, phospholipids, steroids) • Proteins (composed of amino acids) • Nucleic Acids (DNA, RNA)
Life’s molecules • All life’s molecules share the following four characteristics: • Carbon-based • Formed from a few elements: C, H, O, N, P • Modular construction (like bricks, cheap and easy to build small building blocks) • Their function depends on structure(or, structure/shape determines function)
Why should we learn about life’s molecules? • Because we eat them everyday! • We are composed of these bio-molecules
1. Carbohydrates • Organic molecules composed of C, H, O (1:2:1 ratio) • Most abundant of life’s molecules
Carbohydrates There are three types of carbohydrates: Mono- saccharides (one) Di- saccharides (two) Poly- saccharides (many) • Monosaccharides (simple sugars of 3 to 6 carbons) • Glucose C6H12O6 (‘blood sugar’) • Fructose C6H12O6 (fruit) • Ribose C5H10O5 (nucleic acids)
Carbohydrates • Disaccharides • Composed of twomonosaccharides. • Sucrose (table sugar)C12H22O11 Glucose + Fructose = Sucrose + water
Carbohydrates • Polysaccharides (many) – long chains of monosacch. • Starch – energy storage • Cellulose – plant cell walls(wood, paper, cloth)
Function of Carbohydrates • Energy storage (in the C-H bonds) • For structure in plants (cellulose for cell wall) • Carbon sources to make other molecules (nucleic acids, amino acids)
2. Lipids • Composed of C, O, H atoms • Fats and oils are made from two building blocks: • Glycerol molecule (hydrophilic; ‘water loving’) • Fatty Acids (hydrophobic; ‘water hating’)
Lipids • Fats are solid lipids at room temperature (usually animal-derived: lard, butter) • Oils are liquid lipids (usually plant-derived: corn oil, peanut oil, olive oil)
Lipids • Lipids DO NOT dissolve in water • Phosholipids contain phosphorus • The membranes of cells is a lipid bilayer
Function of Lipids • As a high-energy food • As part of cell membrane • As waxes, hormones, vitamins, pigments • Energy storage of lipids • Monoglycerides (glycerol + 1 fatty acid chain) • Diglycerides (monoglyceride + 2nd fatty acid chain) • Triglycerides (diglyceride + 3rd fatty acid chain) • Triglycerides = highest energy!
3. Proteins • Large complex molecules • Composed of C, H, O, S and N • Building blocks are amino acids (20) protein Ribosome
Function of Proteins • Building blocks of cells • Transport: they help control what passes through Plasma Membrane • Animal structure (hair, nails, tendons, muscles) • Enzymes – to speed up chemical reactions
4. Nucleic Acids • Nucleic acids are large organic molecules • Composed of C, H, O, P, N • Basic unit is the Nucleotide: 1) a sugar, 2) a phosphate, and 3) a nitrogenous base
Nucleic Acids • Nucleic acids are long chains of nucleotides Examples • DNA : Deoxyribonucleic acid, carries information about the entire cell • RNA: ribonucleic acid, • a copy of DNA
Nucleic Acids: ATP • Another nucleotide compound is ATP, which has a role of energy transfer/exchange (e.g. like an energy currency) Function of Nucleotides: • Information storage (like a blueprint for the cell; DNA, RNA) • Energy carrier (ATP)
Life’s molecules • All life’s molecules share the following four characteristics: • Carbon-based • Formed from a few elements: C, H, O, N, P • Modular construction – made from simple building blocks • Carbohydrates – monosaccharides (sugars) • Lipids – fatty acids • Proteins – amino acids • Nucleic acids – nucleotides • Their shape and structure determines their function!
Raffle! • Borrow one Textbook • Also ordered a few textbooks on reserve at the Mckeldin Library
What is a cell? • Basic building blocks of living organisms • Form tissues and organs • Each cell is functionally independent – it can live on its own under the right conditions • Uses sugars to get energy and stay alive • Contains all necessary info to replicate produce a multicellular organism • Can make a whole plant from a single cell!
The Cell All plants are composed of cells. • First discovered by Robert Hooke in 1665 • Cell Theory: 1) Cell is the basic unit of life 2) Organisms are composed of cells 3) Cells arise from other cells
Two types of cells: Simple cells, lack organelles Bacteria are prokaryotic 10 to 100 times smaller than animal or plant cells • PROKARYOTIC • EUKARYOTIC They have organelles: nuclei, mitoch., etc. Many multicellular organisms are eukaryotic: Cells of plants, animals, fungi, are eukaryotic Some unicellular organisms are eukaryotic: algae, amoeba, etc.
ProkaryotesEukaryotes Older organisms (3.5 byo) More recent (1.5 byo) Smaller 10 – 100 times bigger No organelles Have organelles
THE PLANT CELL: Eukaryotic or prokaryotic? EUKARYOTIC: HAS ORGANELLES!
Plant vs. animal cells • Plant cells have 3 things animal cells don’t: 1) Cell walls 2) Vacuoles 3) Chloroplasts
Plant Cells • Structural building blocks to form tissues and organs • Plant cells: potentially can function independently. Can even create a whole plant from a single cell (plant cloning)
THE PLANT CELL: outside Outside: Cell wall Plasma membrane
Cell wall • Cell wall protects and supports cell • Is made of CELLULOSE • Allows water and other molecules to pass through (like a cardboard box)
Primary vs. Secondary cell wall • Primary wall is formed early, located on the outermost layer. • Secondary wall is deposited on the inside, between Primary cell wall and Plasma membrane. • Middle lamella: what ‘glues’ adjacent cells together.
Cell membrane (or plasma membrane) • Is a lipid bi-layer: hydrophilic “heads” (outer), hydrophobic “tails” (inside) • Differentially permeable: Lets water pass through, but not other molecules
Cell membrane (plasma membrane) • Fluid Mosaic Model: A double layer of phospholipids with scattered proteins… (looks like “protein icebergs in a sea of lipids”)
Inside the Plant Cell: • Cytosol: a matrix of water (90%), proteins, organic molecules, ions • Cytoplasm: cytosol and organelles only • Protoplast: all of the plant cell enclosed by the cell wall (plasma membrane, cytosol, organelles)
Cytoskeleton • Microtubules & microfilaments: Make up the Cytoskeleton, a network of protein ‘cables’ that provide structure to the cell – they help in cell division & elongation. • Important for mitosis
Plant Cell Organelles • Organelles are membrane-bound sub-compartments within the cell. • Each has its own function. • Nucleus • Mitochondria • Chloroplast • Vacuole • Ribosomes • Endoplasmic reticulum • Golgi apparatus
Nucleus Nucleus: contains all genetic information (DNA) in chromosomes.
Plant nucleus • Chromosomes: DNA & proteins • Nucleolus Bodies where ribosomes are made
Mitochondria Mitochondria: Provides energy to cell by converting sugars into chemical energy (respiration) • “The powerhouse of the cell”
Chloroplasts • Chloroplasts: Site for photosynthesis. • Produce sugars from carbon dioxide, water and sunlight.
Chloroplasts • Contain chlorophyll (makes the plant green)
Vacuole • Vacuole: Stores a watery solution of sugars, salts, acids, proteins.
Vacuole • Makes up to 90% of plant cell volume • Makes cells turgid • Has its own membrane, called tonoplast vacuole
Vacuole contents • Often acidic content (sap), it’s what makes lemons and limes taste tart!
Ribosomes • Ribosomes: are the site for protein synthesis • Use information contained in DNA to produce proteins. • Not membrane bound.
Endoplasmic Reticulum (ER) • Endoplasmic Reticulum (ER): a network of folded membranes throughout the cytoplasm