Bio Exam Notes PDF

Unit 1: Diversity of Life Types of Biodiversity: Species Diversity: The variety and abundance of species in a given area Genetic Diversity: The variety of heritable characteristics of interbreeding individuals Ecosystem Diversity: The variety of Ecosystems in the biosphere Genetic diversity:...

Unit 1: Diversity of Life Types of Biodiversity: Species Diversity: The variety and abundance of species in a given area Genetic Diversity: The variety of heritable characteristics of interbreeding individuals Ecosystem Diversity: The variety of Ecosystems in the biosphere Genetic diversity: -​ Genes are the genetic materials that control the expression and inheritance of traits -​ The reason we are all different is because of the differences in our genetic makeup -​ Genetic diversity in a population is known as the gene pool -​ The gene pool is the sum of all the versions of all the genes in a population How does Genetic diversity provide resistance to disease? -​ If none of the individuals in a population have the ability to survive a disease, the entire population could be eliminated -​ Genetic diversity allows populations to survive changing environmental conditions (Ex: Change in prey/predator population, climate change, etc.) How does Genetic diversity support conservation biology? -​ Scientists can use their knowledge about the importance of genetic diversity to help struggling populations Ecosystem Diversity: -​ Biotic (living) and Abiotic (non-living) factors contribute to ecosystem diversity -​ Through the relationship between these factors, the Earth’s surface is highly varied physically and chemically, which is what makes ecosystem diversity very rich What are Ecosystem services? -​ Ecosystem services are benefits experienced by organisms (including humans) that are provided by sustainable ecosystems -​ Without ecosystem diversity, Earth would lose most of the services ecosystems provide Services Examples: -​ Wilderness → Habitat for wildlife -​ Recreation → Ecotourism -​ Ecological control → Pest population regulation Comparing Bacteria and Archaea What are some characteristics of Prokaryotic cells? -​ Single celled organisms -​ Organelles not surrounded by a membrane -​ Small (less than 2 micrometers) -​ Hard to tell them apart Structure of Prokaryotic cells: -​ Have a cell wall for structural support and protection -​ DNA doesn’t form a strand but instead forms a ring - called plasmid -​ DNA contains 1/1000th the DNA found in a eukaryotic cell -​ Some bacteria have flagella (whip-like tail) Important Structures: Capsule: -​ Allows prokaryotes to adhere to surfaces -​ Protects it from being eaten by white blood cells -​ Has water to prevent dehydration Cell wall: -​ Made of peptidoglycan and outer membrane -​ Provides rigidity, support, and protection Cell membrane: -​ Controls movement of substances in and out Nucleoid region: -​ Contains DNA, several regions, and RNA Pili: -​ Hair-like structure on bacteria surfaces -​ Different pili have different functions (exchange of genetic info, movement, attachment) Differences between Archaea and Bacteria Cell Wall + Membrane  -​ Bacterial cell membranes include a bilipid layer of phospholipids, and the cell’s walls contain a layer of peptidoglycan -​ Archaea genetically resembles eukaryotes more than bacteria Unique characteristics of Archaea: -​ Can live in extreme environments -​ Include methanogens which help produce energy in oxygen-free environments -​ Mutualistic (Work together so both organisms can benefit) -​ Can decompose organisms -​ Can help with digestion Unique characteristics of Bacteria: Bacterial characteristics differ based on their: -​ Cell wall -​ Movement -​ Metabolism -​ Respiration Cell wall: Gram stain -​ Bacteria are classified by their reaction to a dye made of crystal violet and iodine (Gram stain) -​ Bacteria that have membranes that absorb the stain are gram-positive -​ Bacteria that don't stain our gram negative -​ Bacteria are usually the most pathogenic and cause serious diseases like typhoid, meningitis, and pneumonia Movement: -​ Flagellum: Tail-like structure that whips around to propel the bacteria -​ Cilia: Small hair-like projections surrounding the cell that help it to “swim” -​ Non-motile: Sticky cilia-like structures that keep the bacterium from moving Bacterial Reproduction -​ Binary Fission (asexual reproduction) -​ Conjugation (transfer of genetic info) -​ Endospore Formation (Protection and dispersal of genetic info) Binary Fission: -​ The bacteria copies its genetic info, then splits into 2 identical daughter cells -​ In good conditions, bacteria could reproduce very quickly - every 20 minutes -​ Not a lot of genetic variation - only one source of DNA, but lots of opportunity for mutations to arise Conjugation: -​ Plasmid naturally occur in bacteria -​ Plasmids often provide bacteria with genetic advantages like antibiotic resistance -​ 1 bacterial cell can pass a copy of a plasmid DNA through a hollow pilus, passing on the genes to another bacteria -​ Allows for genetic variation Antibiotic resistance: -​ Antibiotics work by interfering with a bacteria's ability to -​ Form a cell wall -​ Perform cell processes -​ Reproduce Antibiotic resistance occurs when a bacteria mutates, acquiring a trait that renders the antibiotic ineffective against it, and it can spread quickly within a population due to quick binary fission and conjugation. Endospore Formation: -​ Some bacteria can protect themselves from harmful environmental conditions -​ Some bacteria form endospores, a highly resistant structure that forms around the DNA when the cell is under some sort of environmental stress such as: -​ Nutrient Deficiency -​ High temp. -​ UV radiation -​ Disinfectants When conditions improve, endospore germinates into full bacterial cell -​ Endospores of tetanus and anthrax can survive in soil for many years Endosymbiosis: Theory: -​ The organelles mitochondria and chloroplasts found in today’s eukaryotic cells were once prokaryotic microbes, billions of years ago Application: -​ Viruses Definition: -​ Small, infectious non-living, non-cellular particles -​ Contains no cytoplasm -​ Cannot grow or reproduce on their own (need a host cell) -​ Do not produce or use energy -​ Do not create waste -​ Have genetic material that helps create virus copies when it gets passed along Size: -​ Less than 0.1 micrometers in diameter -​ Hundreds of thousands can fit inside a typical human cell Protist Kingdom: Protist: A eukaryotic organism, usually unicellular, that is not a fungus, plant, or animal. Characteristics: -​ Most are unicellular -​ They are grouped in this kingdom because they don't fit anywhere else -​ Some live as parasites within the bodies of animals -​ Most reproduce through binary fission Divided into 3 groups: Animal-like: -​ Consume other organisms for food (heterotrophs) -​ E.g Flagellates Fungus-like: -​ Absorb nutrients from other organisms, living or dead -​ E.g Slime moulds Plant-like:  -​ Make their own food via photosynthesis -​ E.g Euglenoids Fungi Kingdom: Common Characteristics: -​ Multicellular (mostly) -​ Eukaryotic -​ Cells are surrounded by a cell wall made of chitin -​ Reproduction is sexual and asexual -​ Are heterotrophic -​ Most are saprophytes (feed off organic matter and recycled nutrients) -​ Many are stationary and found in soil Fungi structure: Fungal tissues are special for: -​ Absorption of nutrients -​ Reproduction How does absorption of nutrients happen? In multicellular types, absorption of nutrients takes place in mycelia. Where is mycelium found? Mycelium is found underground or attached to what the fungus is feeding on. Each filament, called a hyphae grows in and around a food source -​ It secretes digestive enzymes to the outside and then absorbs the broken down nutrients into hyphae cells -​ Therefore, fungal digestion is considered extracellular Important example of Fungi Bread mould: -​ The mature forms are multicellular -​ *Fungus spores* found everywhere (including air) land on bread or other food and start to grow hyphae (fuzzy extensions) which feed off the bread -​ The speed of growth is dependent on temp., humidity, preservation, and etc. Yeast: What is yeast? -​ Yeast is a single celled microscopic fungi Where is it found? It is found in most soil near plants and decaying matter What can it do? -​ Some cause humans infections or cause fruit to spoil -​ Some carry out anaerobic respiration, known as fermentation -​ It is used in the making of alcohol and bread.