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Spring Interim Review. Biology. Scientific Methods Steps used to solve a problem Observation Questioning and stating problems Hypothesizing Experimenting – including a control and experimental group IV – independent variable DV – dependent variable
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Biology Scientific Methods • Steps used to solve a problem • Observation • Questioning and stating problems • Hypothesizing • Experimenting – including a control and experimental group • IV – independent variable DV – dependent variable • Tables and Graphs • IV on x-axis and DV on y-axis of a graph Enzymes • Catalysts in living things • Decreases activation energy • Specific to a particular substrate • Reusable • Affected by temperature and pH
Ecology • Ecology – is the study of interactions between organisms and the environment • We study an organism’s habitat, niche, and trophic level • Populations – are members of the same species living in the same place at the same time with the potential to interbreed Population growth – exponential (J-shape) and logistic (S-Shape) * Limited by factors like disease and competition that are density-dependent or by density-independent factors like natural disaster. * Carrying capacity is seen in logistic growth – the maximum number the environment can support
Carrying Capacity • Maximum number of individuals that an ecosystem can support • Limiting factors: • Food availability • Competition • Disease • Predation • Natural Disasters
Population GROWTH EXPONENTIAL GROWTH Logistic growth S-curve Occurs because resources are limited Carrying capacity reached • J-curve • Occurs when unlimited resources are available
Ecosystems • Collection of abiotic (nonliving) and biotic (living) factors in an area • Together they influence growth, survival, and productivity of an organism
Symbiotic Relationships • Relationship between two organisms in which one benefits • Types: • Mutualism (+,+) • Parasitism (+,-) • Commensalism (+, o)
Predation • Predator eats prey • Evolve in response to one another
Carbon CYCLE • Cycling of carbon and oxygen • Three main processes • Photosynthesis – plants use carbon dioxide; produce oxygen • Respiration – uses oxygen, produces carbon dioxide (both plants and animals) • Combustion – burning – releases more carbon dioxide • Greenhouse Effect • Carbon dioxide traps heat in the atmosphere, making life possible • Increased carbon dioxide can make temperatures rise more • Human activities can lead to GLOBAL WARMING
Trophic Levels • Steps in a food chain/web • Energy passes from one organism to another • About 10% of the energy at one level passes to the next
Food CHAINS Original source of energy for most chains is the sun 1st trophic level is producer 2nd trophic level is primary consumer 2rd trophic level is secondary consumer Decomposer not shown on chain, but they recycle nutrients Energy is “lost” as you mover “up” the food chain
Human Impacts Positive Negative Acid Rain Deforestation Habitat Destruction Invasive Species Ozone depletion from the release of CFCs • Reforestation • Cover Cropping • Recycling • Sustainable practice
HUMAN POPULATION GROWTH • Overpopulation of humans leads to • Destruction of habitats (pollution and/or destroying) • Less biodiversity (types of life, organisms, THINK OF WHAT HAPPENS IN A FOOD WEB IF ONE IS LOST!!!) • Introduced species • Outcompete nativespecies
Obtain energy from the environment Photosynthesis or chemosynthesis “Producers” Plants Obtain energy from other living things Animals, Fungi “Consumers” Autotroph vs. HeterotrophProducer vs. Consumer
Cell theory - 3 parts 1) cells are basic unit of life 2) cells come from existing cells 3) all organisms are composed of cells Cells identified by Robert Hooke thanks to the invention of the Microscope. Organelles – compartments for carrying out specific jobs / chemical reactions 1) chloroplast – photosynthesis 2) mitochondria – cellular respiration 3) ribosomes – protein synthesis 4) vacuoles – storage 5) nucleus – contains DNA and controls cell actions 6) nucleolus – site of ribosome formation Plant versus Animal A) has cell wall A) no cell wall B) has chloroplasts/plastids B) has no plastids/chloroplasts C) has large vacuole C) has small vacuoles Cells
Prokaryotes Simple, no membrane bound organelles NO NUCLEUS Bacteria only One circular chromosome Includes: chromosome, ribosomes, and plasma membrane Eukaryotes Membrane bound organelles Plants and Animals Has nucleus containing chromosomes Cells
Nucleus • “Control Center” • Contains chromosomes, DNA, nucleolus • Makes ribosomes
“Powerhouse” of the cell Produces energy in the form of ATP Site of Aerobic respiration Site of cellular respiration MitochondriaSingular: Mitochondrion
Site of photosynthesis Plant cells ONLY Contains the pigment chlorophyll stacked in thylakoids Chloroplast
Vacuole • Storage of excess materials • Plant cells usually contain one large vacuole
Ribosomes • Proteins are synthesized • Found in both prokaryotes and eukaryotes
Surrounds the cell Regulates what enters/leaves the cell Helps maintain homeostasis Made of phospholipids (lipid bilayer) with embedded proteins Plasma Membraneaka: Cell Membrane
Cell Wall • Plant cells ONLY • Surrounds cell and provides support and protection. • Made of cellulose
Golgi Apparatus (or Golgi Body) • Like the post office • Prepares, sorts, packages (encases), distributes (sends to where it needs to go.) • Makes lysosomes (Remember Lysol cleans = lysosome cleans
Cellular Transport • Plasma membrane controls homeostasis (balance) • Structure – composed of a phospholipid bilayer with embedded proteins “gates” • Function – acts as a selectively permeable boundary around the cell • Types of Passive Transport – no energy required 1) Diffusion – moves substances from high to low concentrations down their concentration gradient 2) Osmosis – the diffusion of water from high to lower water concentrations down its concentration gradient Ex) cell in salt water – shrivels Ex) cell in fresh water swells 3) Facilitated diffusion – movement of a substance down its concentration through a transport protein channel • Active Transport– requires energy – moves substances against the concentration gradient from low to high concentrations
Diffusion • Form of passive transport • (NO ENERGY NEEDED) across a membrane • Solutes move from high concentration to low concentration
Osmosis • Diffusion of water (also passive transport) • No energy
Active Transport • Particles moving against the concentration gradient which REQUIRES NEEDS ENERGY (ATP) • Low concentration to high concentration
Energy storing molecule Can be used for quick energy by the cell Energy is stored in the phosphate bonds ATP
Photosynthesis • The process used by producers to convert sunlight to chemical energy in glucose • Overall equation: 6CO2 + 6H2O C6H12O6 + 6O2 • Occurs in the leaves • Guard Cells open and close the Stomata where gases are exchanged • Large numbers of chloroplasts are found in these mesophyll cells. • Chloroplasts are the cellular site of photosynthesis. The light reaction of photosynthesis occurs on the inner membrane called the thylakoid. • Pigments absorb light energy
Water and Carbon Dioxide used to produce Glucose and Oxygen H2O+CO2C6H12O6+O2 Occurs in the chloroplast Photosynthesis
Cellular Respiration • Cellular respiration is the process by which organisms break down food to release its energy. This energy is then stored in ATP (Adenosine triphosphate) • Overall equation: C6H12O6 + 6O2 6CO2 + 6H2O + 38 ATP • Respiration can be aerobic or anaerobic Aerobic Anaerobic O2 required no O2 required most organisms are aerobes few anaerobes (yeast/bacteria) 38 ATP 2 ATP 3 steps – glycolysis, Krebs cycle, 2 steps – glycolysis and electron transport fermentation (alcoholic and lactic acid) • Glycolysis is the first step of both forms of respiration and occurs in the cytoplasm • If no oxygen is present after glycolysis, then fermentation occurs
Used to release energy (ATP) for cellular use C6H12O6+O2H2O+CO2 Occurs in the mitochondria USES OXYGEN Aerobic Respiration
Anaerobic Respirationaka Fermentation • Does not require Oxygen • Products include CO2 and lactic acid or alcohol • Two Types: Alcoholic Fermentation and Lactic Acid Fermentation
Cell Division • Haploid – having one set of chromosomes (n) – gametes – sperm/egg • Diploid – having two sets of chromosomes (2n) – body cells – one set is maternal and one is paternal • The cell cycle – Interphase – growth - Mitosis – division • Mitosis creates diploid cells and is for the purpose of tissue repair and growth in animals • DNA coils to form chromosomes during cell division • Stages of the cell cycle Interphase, Prophase, Metaphase, Anaphase, Telophase, Cytokinesis IPMATC I Pinch Monkeys And They Cry (Don’t pinch a monkey!!!) • Meiosis – cell division that creates 4 haploid cells called gametes – aka – reduction division • Meiosis involves 2 divisions – Meiosis I and Meiosis II • Meiosis I has some special events: • In Prophase I homologous chromosomes pair up and crossing over occurs. This recombination increases genetic variation for the species • Metaphase I – Pairs line up • Anaphase I – pairs are separated • Meiosis II is similar to mitosis
Cell division Produces two identical diploid daughter cells Occurs in body cells to grow and repair Asexual Reproduction Mitosis
Cell division Produces four different haploid daughter cells (gametes) Occurs in sex cells to form gametes Sexual reproduction GAMETES: Sperm and Eggs Meiosis
Homologous chromosomes exchange parts of their DNA Creates variation in gametes Crossing Over In Prophase 1 of Meiosis 1: Does NOT happen in Mitosis
Cancer • Error in cell growth with causes uncontrolled cell growth • Cells just grow and grow, cell cycle is constant! • Has environment and genetic variables
Evolution • Charles Darwin – proposed that organisms (species or populations) change over time • Occurs by Natural Selection – “survival of the fittest” • Lines of evidence 1) fossils (geologic time) 2) Homologous Structures – same basic structure formed from same embryonic tissue 3) Analogous Structures – same basic functions due to same environmental pressures 4) Vestigial Structures – structures that have lost function ex) appendix 5) Embryology – embryos of various species appear identical 6) Biochemistry – DNA and protein amino acid sequence comparisons • Adaptive radiation – an ancestral species radiates or diverges into many species. Ex) Galapagos Finches • Origin Ideas Urey and Miller simulated Earth’s early environment and created organic compounds like amino acid Endosymbiont theory – eukaryotic cells formed when prokaryotic cells began to live together permanently Homologous Vestigial
Origin of Life • Abiotic earth LACKED Oxygen • Early organisms anaerobic, prokaryotes, autotrophs (producers) Miller and Urey Experiment recreating The abiotic atmosphere: Shows that molecules could have been produced in our early atmosphere.
Abiogenesis Biogenesis Living from Living • Living from non-living or spontaneous generation • Disproved by Redi and Pasteur’s experiments
Natural Selection • Theory of Evolution • Fit organisms survive, reproduce, and pass on traits Requirements: • Variation • Competition • Mutations can be helpful
Adaptations • Trait that increases survival • For Example, • Beaks that make it easier to eat insects • Bright flowers to attract pollinators • Vascular tissue in plants to adapt to life on land
Evidence for Evolution • Fossil Record: Shows change over time (like whales came from ancient wolves [land animal], we can see the change thanks to the fossils and the little bones left behind.) • Biochemical Similarities • Similar embryos (embryology) • Homologous structures
Speciation • Evolution of a new species • must be isolation between populations