Biology Introduction and Classification PDF

Chapter 1 Introduction to Biology, Anatomy, and Physiology  1.2 Organization of Living Things All organisms can be categorized based on certain characteristics into one of three domains, then six kingdoms There is some debate about this among scientists, so you may find different answers, e....

Chapter 1 Introduction to Biology, Anatomy, and Physiology  1.2 Organization of Living Things All organisms can be categorized based on certain characteristics into one of three domains, then six kingdoms There is some debate about this among scientists, so you may find different answers, e.g. some include a seventh kingdom. 2  1.2 Organization of Living Things The kingdoms are arranged based on organisms' characteristics: single-celled or multicellular prokaryotic (no nucleus) or eukaryotic (with nucleus) environment they live in movement how energy is acquired 3 1.2 Organization of Living Things Kingdoms Domain Archaea Domain Eukarya Domain Bacteria 4 Copyright © 2020 Nelson Education Ltd.  1.2 Prokaryotes and Eukaryotes Prokaryotic organisms (pro:before) Kingdoms: Archaea and Eubacteria All unicellular (one cell per organism). no membrane-bound organelles. DNA is located in the cytoplasm. This Photo by Unknown Author is licensed under CC BY-SA Sometimes called “primitive” Eukaryotic organisms (eu: good or well) Kingdoms: Protists, Fungi, Plants and Animals. Membrane-bound organelles, DNA in nucleus, more complex, also contain ribosomes. SOME are unicellular. This Photo by Unknown Author is licensed under CC BY-SA- NC 5  Archaea 1.2 Organization of Living Things Archaebacteria Single-celled Prokaryotic Primitive Live in extreme environments → very high temperatures → very low temperatures → highly saline environments → highly acidic environments Look at definition of thermophiles, halophiles, methanogens 6 Copyright © 2020 Nelson Education Ltd.  Bacteria 1.2 Organization of Living Things Eubacteria Generally single-celled (some may be multicellular) Prokaryotic Found almost everywhere on Earth Most are harmless or helpful Some can cause human diseases. Examples: tetanus, syphilis, pneumonia, tuberculosis In the Human Gastro-Intestinal Tract: ~500 species and trillions of bacterial cells Copyright © 2020 Nelson Education Ltd. 7  Archaebacteria vs. Eubacteria The difference between Archaebacteria and Eubacteria lies mainly in their ancestral cell lineage. (i.e. they have an independent evolutionary history) Other key differences include: the types of environments that they live in biochemical variations in cell components 8  Eukarya 1.2 Organization of Living Things Protists Single-celled Eukaryotic Various species have characteristics similar to: → Fungi (spores) → Plants (chloroplastsphotosynthetic) → Animals (locomotion) May be photosynthetic May have structures such as flagella or cilia. Protists associated with human disease: Plasmodium causes malaria; Giardia causes severe diarrhea (beaver fever) 9 Copyright © 2020 Nelson Education Ltd.  Eukarya 1.2 Organization of Living Things Fungi Multicellular (except for yeast) Eukaryotic Non-photosynthetic Some are beneficial and some are poisonous to humans. Examples include mushrooms, mold, and mildew. 10 Copyright © 2020 Nelson Education Ltd.  Eukarya 1.2 Organization of Living Things Plants Multicellular Eukaryotic Photosynthetic May live on land or in water 11 Copyright © 2020 Nelson Education Ltd.  Eukarya 1.2 Organization of Living Things Animals Multicellular Eukaryotic Non-photosynthetic Can live on land or in water Have locomotion 12 KAHOOT!  Review: Review the divisions of different organisms into the 3 Domains and 6 Kingdoms. What characteristics would you expect each of the following to have? → Plants Eukaryotic, multicellular, photosynthetic Eukaryotic, multicellular (except → Fungi yeast), non-photosynthetic → Archaea Prokaryotic, single-celled, harsh environments → Animals Eukaryotic, locomotion multicellular, non-photosynthetic, → Protists Eukaryotic, single-celled, maybe photosynthetic → Eubacteria Prokaryotic, single-celled, some are photosynthetic 14  1.6 Properties of Living Things: Macromolecules All living things include the elements: carbon, oxygen, hydrogen, and nitrogen (C O H N). These elements form molecules such as sugars, amino acids, fatty acids, and nucleotides. Small molecules combine into various macromolecules: polysaccharides (complex carbohydrates), proteins, fats, and nucleic acids. Note: there are many other elements that go into making different components of macromolecules. 15 15 1.6 Properties of Living Things: Cellular Structure All living things are composed of one or more cells. All cells have a membrane that separates the inside of the cell from the outside of the cell. Some organisms are single celled, such as bacteria, yeast, or some algae. Some organisms are multicellular, such as zebra muscles, trees, and cobra chickens (Canada geese). 16  Examples of cell types / cell structure Airways in lung made up of epithelial Mucous-producing goblet cells in cells (with bacteria in airways) gastro-intestinal tract. This Photo by Unknown Author This Photo by Unknown Author is licensed under CC BY-SA is licensed under CC BY Striated muscle cells Red blood cells are one of the 17 simplest cell types  1.6 Properties of Living Things: Growth and Metabolism All living things use energy for metabolism, growth, movement, etc. Most energy on our planet comes from the sun. The sun’s energy is captured by photosynthetic organisms, that are consumed by other organisms (herbivores, omnivores). Carnivores eat other animals for energy. Metabolism is the transfer of energy from one form to another: for example, our muscles converting glucose into ATP for movement, growth, etc. 18  1.6 Properties of Living Things: Reproduction All organisms reproduce. Reproduction can be just cellular, e.g. body cells reproducing. Some organisms reproduce every 20 minutes (bacteria), some reproduce every 6 weeks (mice), and some reproduce only a few times in their lifetimes (humans). Different ways to reproduce: binary fission (copies of DNA) and sexual reproduction (intermixing of DNA). more details in Chapter 5 later. 19  1.6 Properties of Living Things: Heredity Material All living organisms have genetic material: DNA (some viruses, e.g. SARS COV-2, use RNA, but they’re not considered “living”) The DNA in all organisms must divide before the organism itself can divide. (Chapter 8, next semester) DNA contains genes that partially determine an organism’s characteristics. But the environment can also affect characteristics. 20 1.6 Properties of Living Things: Evolution All populations of organisms continuously change genetically from one generation to the next. This depends on occasional mutations. Humans have 46 chromosomes, but the versions of genes on those chromosomes vary, such as the genes that encode for skin pigmentation or body height. This Photo by Unknown Author is licensed under CC BY-SA 21  1.6 Properties of Living Things: Homeostasis Every organism must maintain a stable internal environment. e.g. humans must maintain consistent blood pH, blood sugar levels, and body temperature, regardless of the food we eat or the weather. To maintain homeostasis, organisms use positive and negative feedback mechanisms. 22  1.6 Homeostasis: Receptors Homeostasis depends on receptors to detect changes in the internal environment: Chemoreceptors detect chemical concentrations, such as of neurotransmitters, drugs, or hormones. Osmoreceptors detect changes in osmolarity; i.e. water and ion concentrations. Tactile receptors detect touch, pressure, and vibration. Baroreceptors detect blood pressure. 23  1.6 Homeostasis: Receptors Photoreceptors detect light (the retina in humans). Mechanoreceptors detect stretching (e.g., spindle fibres in muscles). Proprioceptors detect body position. Nociceptors detect pain. Thermoreceptors detect temperature. 24  1.6 Properties of Living Things: Homeostasis (Feedback Mechanisms) Response Causes less stimulus (negative feedback) OR  or  increased stimulus (positive Start here: feedback) This is the change in a Stimulus variable that moves away from equilibrium. This is the cell type, Effector(s) tissue, or organ, that is able to produce a These sense the change. response to the stimulus. See list and role of Receptors different receptor types on preceding slides. Integrating This is the region that Centre interprets the stimulus and initiates a command to the effector. 25  1.6 Homeostasis: Negative Feedback Most systems in our body work this way. It helps to restore things back to the “set point” The response tends to diminish the stimulus, so eventually the loop will stop itself. e.g. sweating cools your blood, so the thermoreceptors in your hypothalamus (part of brain) are less stimulated. Copyright © 2020 Nelson Education Ltd. 26  1.6 Homeostasis: Positive Feedback Sometimes called a “feed-forward” system. These usually only function short-term because they are unsustainable: the response feeds the stimulus again, which creates more of a response e.g) In the initial stages of inflammation, cells produce proteins that bind receptors to trigger more inflammatory protein production. Copyright © 2020 Nelson Education Ltd. 27  Chapter 2: Water, Macromolecules and Protein 28  2.1 Water Often called “the universal solvent” because so many molecules dissolve into it. More substances dissolve into water than any other solvent. The substance something dissolves into is the solvent. The substance which dissolves into the solvent is the solute. 29  2.1 Water All living things contain water. Infants: about 75% water, which decreases with age (mostly in the first 10 years of life but continues into old age) Healthy adult males: about 60% water Healthy adult females: about 55% water (and usually have more body fat than men) Obese people: can have as little as 45% water 30  2.1 Water The water in your body is divided into two compartments: 1. Intracellular: inside your cells. This is where most of your body’s water is found. 2. Extracellular: outside your cells Interstitial fluid: between your cells Blood plasma: non-cellular part, made of proteins, ions and mostly water 31  2.1 Water is Polar Oxygen pulls the hydrogen’s electrons closer, so that end has a slight negative charge. The H ends have a slight positive charge. Polar molecules have a slight charge on opposite ends. e.g.) water, sugars, amnio acids. They are neutral overall. Polar molecules are hydrophilic (water- loving). Non-polar molecules are hydrophobic (water-hating). Copyright © 2020 Nelson Education Ltd. 32  2.1 Water: Hydrogen Bonding Since a single water molecule has both positive and negative ends: Many water molecules together will attract each other’s oppositely- charged ends and form hydrogen bonds. This causes surface tension. Hydrogen bonds are very weak, but biologically very important Copyright © 2020 Nelson Education Ltd. 33  2.1 Water: Dissolving Solutes Non-polar molecules don’t dissolve in water Charged or polar molecules dissolve in water (hydrophobic) e.g.) cholesterol, steroids, fats (hydrophilic). (triglycerides), oils. Ions are molecules with a full positive or negative Some molecules have a polar and a non-polar charge because of an extra or missing electron e.g.) region (amphipathic). These types of molecules are Na+, Cl-, Ca2+, (sulfate) SO42-, (phosphate) PO43- very important for cell membranes (Chapter 3). 34 Copyright © 2020 Nelson Education Ltd.  Three Types of Bonds Ionic Bonds between charged ions (e.g. Na+, Cl–) Hydrogen Bonds – dipole-dipole interactions between –OH, – NH, or –FH bonds and other polar or charged molecules. Often depicted by dotted line. H O H C H Covalent Bonds involve sharing of electrons (e.g. H H H2O, CH3) often depicted by a solid line. H KAHOOT!  2.2 Macromolecules All living things are based on carbon atoms and make organic molecules. The four primary atoms that make up all living things: Carbon, oxygen, hydrogen and nitrogen COHN 37  2.2 Macromolecules The building materials of the body are known as macromolecules because they can be very large. There are four types of macromolecules. 1. Proteins 2. Nucleic acids 3. Carbohydrates (not just sugar!) 4. Lipids/fats You are probably familiar with foods that contain a lot of each of these. 38  2.2 Macromolecules: Polymers Large macromolecules are assembled from many similar small components called monomers (building blocks). Many similar monomers covalently bound together form a polymer. All biological polymers are assembled by dehydration synthesis. 39  2.2 Macromolecules: Dehydration Synthesis A covalent bond is formed by removing a hydroxyl group (OH) from one subunit and a hydrogen (H) from another subunit. This process of linking together two subunits to form a polymer is called dehydration synthesis because this amounts to the removal of a molecule of water (H2O). Dehydration synthesis requires an enzyme to complete the chemical reaction. 40  2.2 Macromolecules: Dehydration Synthesis Note: the new dipeptide has a hydroxyl group at the end. What does this mean for continuing the polymer? Copyright © 2020 Nelson Education Ltd. 41  2.2 Macromolecules: Hydrolysis Breaking polymers into their monomers (disassembling) is the reverse of dehydration synthesis. A molecule of water is added to break the covalent bond between the monomers. This process is known as hydrolysis (water-breaking) and usually requires an enzyme. 42 2.2 Macromolecules: Hydrolysis —OH Copyright © 2020 Nelson Education Ltd. 43  Make a Chart for Studying Polymer Type of Monomer Special Features 44