BIO 101 - Week 1 Lecture Slides.pdf

An Introduction to the Science of Botany & the Chemical Composition of Cells BIO 101 – General Botany What is Botany? 2 Learning Objectives Demonstrate basic knowledge on the ecological and economic importance of plants Describe and explain the struct...

An Introduction to the Science of Botany & the Chemical Composition of Cells BIO 101 – General Botany What is Botany? 2 Learning Objectives Demonstrate basic knowledge on the ecological and economic importance of plants Describe and explain the structures, functions and processes from cell, tissue, organ and whole plant system and relate its functions to growth, development and reproduction 3 What is Botany? Also known as plant biology Origin, diversity, structure, and internal processes of plants as well as their relationships with other organisms and with the nonliving physical environment Food demand solutions, treatment for AIDS, reducing pollution, etc. 4 Botany Comprises Many Disciplines 5 Characteristics of Plants - Highly Organized 6 Characteristics of Plants – Take In and Use Energy Photosynthesis – Essential for almost all life Convert light energy into chemical energy Stored in molecules such as sugar glucose Provides ready supply of energy that can be used as needed Produces oxygen Can be transferred: Plants → Animals → Humans Cellular Respiration Converts chemical energy into mechanical energy Glucose broken down; in the presence of oxygen All organisms do it 7 Characteristics of Plants – Respond to Stimuli Stimuli – changes in the plant’s environment Ex. Change in direction, environment due to light, gravity, or chemical composition Roots, Venus Flytrap 8 Characteristics of Plants – Grow and Develop Growth – increase in size and mass of organism Results from increase in number of cells and size of cells Most plants continue to grow larger throughout their life Development Includes all changes in a plant or other organism The start of its life through its immature stage, through its mature stage, to its death 9 video Characteristics of Plants – Plants Reproduce Reproduction – formation of a new individual by sexual or asexual means 10 Characteristics of Plants – DNA Transmits information to the next generation Characteristics of an organism are encoded in its genes Units of hereditary information – provides all information Height, color, flower type, tolerate sun vs shade, seed production, etc. Composed of deoxyribonucleic acid (DNA) Stores and carries important genetic information in cells 11 Evolution – Genetic Changes Over Time Adaptations Characteristic that enable an organism to better survive in a certain environment Cactus Stem in the desert Typically requires long periods of time and occur over generations Natural Selection Charles Darwin and Alfred Wallace On the Origin of Species by Means of Natural Selection, 1859 It is the unifying theory of biology 12  Biological Diversity 3 domains: Bacteria, Archaea, Eukarya 6 Kingdoms: Bacteria, Archaea, Protista, Plantae, Animalia, Fungi Kingdom Plantae Possess Cuticle: waxy covering over outer parts Stomata: tiny openings for gas exchange Multicellular gametangia: reproductive organs that protect gametes Vascular : have tissues that conduct food and water Nonvascular: Lack those tissues Do not have nervous system 13 Biological Diversity - Classification 14 Questions Which of the following are features of plants and other organisms that a) Natural Selection distinguish them from b) Photosynthesis nonliving things: c) Cellular Respiration d) Asexual Reproduction e) Contains DNA 15 Questions What are the distinguishing features of the kingdom Plantae? a) Extracranial venous system b) Lack a nucleus c) Have Plasma membrane d) Contain stomata 16 Learning Objectives Demonstrate basic knowledge on the ecological and economic importance of plants Describe and explain the structures, functions and processes from cell, tissue, organ and whole plant system and relate its functions to growth, development and reproduction 17 Plant Cells 18 Plant Cells 19 Methods to Study Cells First microscope invented in late 1500s In 1600s Anton van Leeuwenhoek improved the lenses Robert Hooke identified and named cells Improvements in 19th century Observe organelle; Robert Brown identified first nucleus Cell Theory: cells are the structural units of life All cells come from preexisting cells All cells trace their origin to ancient cells 20 Microscopes Light microscope Uses light on a transparent sample to observe Transmission electron microscope (TEM) Much greater resolving power than a light microscope Uses beam of electrons to pass through sample Scanning electron microscope Sample is coated with thin film of gold or metal Struck by electron beam, secondary electron emissions are recorded 21 Eukaryotic and Prokaryotic Cells 22 Structure of Plant Cells 23 Structure of Plant Cells – Plasma Membrane Outer boundary of the cell Has outer cell wall beyond it Function Keeps contents together Regulates flow of materials Selective process that maintains chemical composition inside cell 24 Structure of Plant Cells – Nucleus Cell control center Function Stores DNA 25 Structure of Plant Cells – Chloroplasts Type of plastid – membrane-bounded organelles in photosynthetic eukaryotic cells Most common Perform photosynthesis Contain chlorophyll (Critical in light absorption) 26 Structure of Plant Cells – Other Plastids Leucoplasts Colorless & store starch, oil, or proteins When exposed to light, they behave like chloroplasts Ex. Potato Chromoplast Contain pigments that make yellow, orange, and red Often form from chloroplasts when chlorophyll breaks down Ex. Ripening fruit 27 Structure of Plant Cells – Mitochondria Converts chemical energy in food molecules to ATP Site of cellular respiration 28 Structure of Plant Cells – Ribosomes Site of protein synthesis Use instructions from DNA to assemble proteins More common in cytoplasm Free-floating or bounded to Endoplasmic Reticulum 29 Structure of Plant Cells – Endoplasmic Reticulum Major manufacturing centers of the cell - has many functions Catalyze chemical reactions that synthesize biologically important reactions Smooth vs. Rough Rough: site of protein synthesis, has ribosomes attached to it Smooth: associated with lipid synthesis, no ribosomes attached 30 Structure of Plant Cells – Golgi Apparatus Site for processing and packaging proteins and polysaccharides Composed of Golgi bodies (dictyosomes) Consists of flattened sacs surrounded by membrane Sacs detach vesicles containing cellular products Transported throughout the cell (exported) 31 Structure of Plant Cells – Vacuoles Large, membrane-bound sacs Inside = water + salts + ions +pigments + waste products Can get to 90% of cell volume Function Makes the cell turgid – maintains shape Turgid=swollen/firm due to water uptake Temporary storage area Stores excess materials (ions, pigments, waste) 32 Structure of Plant Cells – Cytoskeleton Network of fibers that extends throughout the cytoplasm Provides structure to the cell Important for cell movement Microtubules Help with addition of cellulose to cell wall Helps move chromosomes during cell division Cell movement: Flagella & Cilia Microfilaments Responsible for cytoplasmic streaming (cytoplasm movement within cell) Orients for optimal exposure to light 33 Structure of Plant Cells – Cell Wall Only seen in plant cells Algae, fungi, some prokaryotes, other protists Composed of cellulose Long-stranded polysaccharide, strengthens the cell wall Pectin: thickens jellies Function Support & Protection (strength) Provides routes for water/ dissolved materials Communication via plasmodesta 34 Structure of Plant Cells – Cell Wall (cont.) Structure Primary cell wall Thin, stretches and expands as cell increases in size Middle lamella Layer of pectic compounds Cements primary cell walls of adjacent cells together Secondary cell wall Form after cell growth ceases Multiple layers form between the primary cell wall and plasma membrane Usually contain lignin Hard substance where cellulose fibers become embedded 35 Biological Membranes – Fluid Mosaic Model 36 Passage of Materials across Biological Membranes - Diffusion Movement of a substance from a region of higher concentration to a region of lower concentration Move along a concentration gradient From a point of higher concentration to lower concentration 37 Passage of Materials across Biological Membranes - Osmosis Diffusion of water across a selectively permeable membrane Follows a concentration gradient Solution: mixture in which salts, sugars, and other materials are dissolved Solvent: substances that are dissolved Solute: substance that is doing the dissolving (commonly water) 38 Real-life Example: Roots Roots exposed to soil water (aka dilute solution of inorganic mineral salts) Soil water has lower concentration of solutes than cytoplasm of a root cell– hypotonic solution Cell walls can withstand increasing pressure caused by internal pressure of water against the cell wall, the turgor pressure As turgor pressure increases an equilibrium s reached in which the pressure forces water molecules out of the cell in numbers qual to that of molecules coming in by osmosis 39 Real-life Example: Roots 40 Passage of Materials – Facilitated Diffusion & Active Transport Facilitated Diffusion: materials follow a concentration gradient through special passageways in the membrane Active Transport: Assisted movement of a substance that goes against the concentration gradient Requires ATP Uses carrier proteins in the membrane 41 Questions Which of the following plant A) Mitochondria, which generate energy for cell structures is primarily the plant cell through photosynthesis responsible for supporting the B) Chloroplasts, which provide structural plant's ability to maintain its support by producing glucose shape and store nutrients C) The central vacuole, which stores water essential for growth? and maintains turgor pressure, helping the plant cell maintain its shape D) The cell membrane, which controls the movement of nutrients and wastes into and out of the plant cell. 42 Questions A cell is placed in a solution where the concentration of A) Water will move into the cell by osmosis. solute outside the cell is B) Water will move out of the cell by higher than the concentration osmosis. inside the cell. Which of the C) There will be no net movement of following best describes the water. D) Solutes will move into the cell until movement of water across the equilibrium is reached. cell membrane? 43 Introduction to Basic Chemistry 44 Atoms – smallest particles of elements Atoms are “indivisible” Composed of proton(+), neutron, and electron(-) Proton and neutron is the same mass Electron is 1/1800 the size of proton Each atom has atomic number and mass Atomic number: # of protons Atomic mass: # of protons + # of neutrons Isotopes: same proton but different neutrons 45 Chemical Bonds Atoms can unite to form compounds/ molecules Formed by chemical bonds →dependent on number and arrangement of atom’s electrons Ionic bond – atoms gain/ lose electrons Ion: charged atom Covalent bonds – atoms share a pair of electrons Single and double bonds Hydrogen bonds Attraction between positively charged hydrogen atom in one polar molecule and a negatively charged oxygen or nitrogen atom in another polar molecule 46 Inorganic Compounds Inorganic compounds Composed of elements other than carbon Organic compounds Contains carbon and usually hydrogen Water = most essential inorganic compound Almost all chemical reactions occur in aqueous solutions Polarity of water causes unique properties Ex. High boiling temp, cohesion, adhesion, dissolver 47 Acids & Bases 48