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 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: - PowerPoint PPT PresentationTRANSCRIPT
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 andplace ballot in the box.
ENTRY BALLOTBSCI 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 CELLTHE AMAZING PLANT CELL
Prof. Edgar Moctezuma, Ph.D.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:
1. Carbon-based
2. Formed from a few elements: C, H, O, N, P
3. Modular construction (like bricks, cheap and easy to build small building blocks)
4. 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
CarbohydratesThere 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)
Ribosome
protein
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:
1. Carbon-based2. Formed from a few elements: C, H, O, N, P3. Modular construction – made from simple building
blocks1. Carbohydrates – monosaccharides (sugars)2. Lipids – fatty acids3. Proteins – amino acids4. Nucleic acids – nucleotides
4. Their shape and structure determines their function!
• Borrow one Textbook
• Also ordered a few textbooks on reserve at the Mckeldin Library
Raffle!
The plant cell
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:• PROKARYOTIC
• EUKARYOTIC
Simple cells, lack organellesBacteria are prokaryotic10 to 100 times smaller than animal or plant cells
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.
Prokaryotes EukaryotesOlder 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 wallPlasma 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.1. Nucleus2. Mitochondria3. Chloroplast4. Vacuole5. Ribosomes6. Endoplasmic reticulum7. Golgi apparatus
Nucleus
Nucleus: contains all genetic information (DNA) in chromosomes.
Plant nucleus
• Chromosomes:DNA & proteins
• NucleolusBodies where ribosomes are made
MitochondriaMitochondria: Provides energy to cell by
converting sugars into chemical energy (respiration)
• “The powerhouse of the cell”
Parts of the Mitochondria
Chloroplasts
• Chloroplasts: Site for photosynthesis.
• Produce sugars from carbon dioxide, water and sunlight.
Parts of a chloroplast
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
Endoplasmic Reticulum (ER)
Smooth ER: lacks ribosomes, used for packaging and transport of proteins, also to make lipids
Rough ER : has ribosomes for protein synthesis
Golgi apparatus• Golgi apparatus:
• A stack of flattened, hollow, membranous sacs
• Modifies proteins, lipids from the ER.
• Packages these materials in vessicles to the plasma membrane.
• “UPS of the cell”
Ribosomes, ER & Golgi in action:
The plant cell is like a “Chemical Factory”
Endosymbiont Theory
How did eukaryotic organisms evolve?
How did chloroplasts and mitochondria evolve?
Chloroplasts and mitochondria:
• Same size as bacteria
• Have their own DNA
• Divide similarly
Cyanobacteria Chloroplasts
Endosymbiont Theory (p.26, box 2.2)• Chloroplasts and Mitochondria are descendants
of once free-living prokaryotes that were engulfed by larger cells…
establishing a symbiotic (mutually beneficial) relationship.
THANKS!
Next week: Plant anatomy & physiology…
Have a great weekend!