Honors Biology Unit 1: The Life of the Cell A: Characteristics of Life Core Concept #1: All forms of life share common features

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CP Biology Unit 1: The nature of Life

Honors BiologyUnit 1: The Life of the Cell

A: Characteristics of Life

Core Concept #1: All forms of life share common featuresStructural and functional unit of lifeTwo kinds of cells: 1) prokaryotic no nucleus- small, simple- quick, easy reproduction- fast exchange with environment

1. Made of one or more cells

Eukaryotic CellsLarger, complex, have nucleusMany organelles, compartmentalizedParts for specific cell functionsCells can specialize form tissues

Can form multicellular organisms

Two Kinds of CellsAll cells share some featuresEnclosed by selective membrane Contain cytoplasm, DNA, complex moleculesMake any needed substances from raw materials from environment2. Common genetic codeDNA - Deoxyribonucleic AcidInstructions for all life functionsGene one section on a DNA strand - codes for one traitCells copy DNA and pass it to offspringUniversal code same for all organisms - Shows unity of life A C T G

Shared genetic code makes gene engineering possibleExamples: Human insulinDrought-resistanceGM foods

Genetically Modified Corn

Bacteria toxin kills wormGene for toxin put into corn Worm eats corn gene makes toxin toxin kills worm Why not hurt humans? Concentration too small

DNA is unique to an individual

DNA fingerprint - a pattern of stripes/bands - different for everyone - depends on order of ACTG3. Obtain and Use Energya. Food for energy and raw materialsAutotrophs - Producers Make their own foodMost use sunlight - photosyntheticCombine water and CO2 to make basic carbsSome use chemical energy - chemosynthetic Base of all food chainsHeterotrophs - Consumers a. find food in environment

Interdependence in NatureCore concept #2: All forms of life depend on each other and on physical parts of environment

Biotic and abioticTake in light, food, water, air - For energy, material for growth and repairSend out wastes, die Decomposers (saprobes/saprophytes) - break down waste, recycle chemicals

Web of Life

Chemicals CYCLEEnvironment autotrophs heterotrophs saprobes back to environment

Light energy chemical energy in food energy used for life functions some lost as heat

Energy does NOT cycle

4. Grow and DevelopGrow increase in size (add more cells)Develop change while maturingMulticelled begin as a single cellCells copy and specialize (differentiate)Form many different kinds of cellsOrganisms change as they grow older

Bones grow longer with maturity

Stem Cells

Can become specific kinds of cellsSome genes are turned on, some offDepends on chemical signals from their environment

With many complex chemicalsHave recognizable size and shapeCells and organisms different parts perform different functions


Core Concept #3: Life proceeds from simple to more complexa. Cells differentiate specialized cellsDifferent kinds of cells form tissuesc. Different kinds of tissues form organsOrgans work together to form organ systemsBody systems work together to keep an organism alive.

Multicellular - Levels of OrganizationSkin TissueMany kinds of cells work together

Coating/lining cells

Skin cells

Muscle cells

Fat cells

Blood/nerve cells

Gland cells

Cells tissues organs organ systems organismEnvironment Levels of OrganizationOrganism individual living thingPopulation members of one species living in same areaCommunity all living things living in the same areaEcosystem biotic and abiotic in one areaBiosphere layer on earth that supports life6. ReproduceNew cells form by cell divisionMake new cells or a new organismAsexual one parent - identical offspringSexual two parents - offspring gets genes from both parents - must be same species

Is mule a species?Parents horse and donkey Hybrid - offspring from two closely-related species - cannot reproduce NOT a species (species - fertile young)

7. Respond to environmenta. Stimulus - causes a reactionb. Response - reaction to a stimulusc. Internal or external stimulid. Must keep homeostasis (constant internal conditions)

8. Evolve Biologys Central Unifying ThemeSpecies can slowly change over time to better fit an environmentTraits fit environment survive and reproduce pass on traitsIndividual organisms DO NOT evolveEarliest life 3.5 billion years ago

Darwins Theory of Evolution

Nature selects those best suited to survive- reproduce and pass on helpful traits - species slowly change over timeCore Concept #4: Evolution explains Unity and DiversityLife is unified shared ancestryall living things have same life traitsdo same life functionssame chemical make-up and processes

Life is Diverse Living things are diverse - special features for different environments

Diversity of Life

6 Kingdom System of Classification1. Archaebacteria oldest kind of bacteria2. Eubacteria most bacteria3. Protista one-celled eukaryotes4. Fungi mostly decomposers5. Plantae multicelled photosynthetics6. Animalia multicelled heterotrophs6 Kingdoms

3 Domain System

Archaea ArchaebacteriaBacteria EubacteriaEukarya all eukaryotic organismsNewest Tree of Life

Shares genes with EukaryaStructure and FunctionForm follows functionFeatures evolve to perform a function betterDifferent environments need different kinds of adaptations

Are viruses alive?NOT part of living kingdomsLACK MOST traits of life, have only 3:Have DNA and proteinOrganized, recognizable size and shapeCan evolveBETWEEN living and nonliving

Core Concepts in BiologyAll life forms share common features DNA, life traits, cell basic unit of life2. Living things interact with each other and with the environment (food chain, cycling)3. Life proceeds from simple to complex- levels of organization in organism, in environment4. Evolution explains unity and diversity a. Unity - All life forms share common traits - cells, DNA, life functions b. Diversity - Life evolves to suit its environment form and function

Life ProcessesHow do living things stay alive?All life processes work to maintain homeostasis(stable internal conditions)

Metabolism all the chemical processes an organism performs Includes: Anabolic build a molecule Catabolic break a molecule down

1. Cellular RespirationMake energy for all life processesRelease energy in food molecules NOT digestion, NOT breathingAerobic gets max energyAnaerobic

2. NutritionGet or make food; process it for cells to useNutrients for energy, raw materials

Autotrophs (producers) a. Make their own food b. Photosynthesis c. Base for all food chains d. Plants, algae, some bacteria

2. Heterotrophs (consumers) a. Ingest take in food from environment b. Digest break large molecules down c. animals, fungi, many bacteria 3. Saprobes (decomposers) a. Break down wastes, dead organisms b. Recycle nutrient molecules c. Fungi, many bacteria

Digestive SystemBreaks down food into molecules small enough to enter cellsNutrients and water absorbed by cellsLiver, pancreas, and others make enzymes

3. TransportCirculate materials in a cell or organismCross cell membranesSpread throughout cellDeliver needed materials, remove wastesMulticellular need way to transport throughout organism

Animals: circulatory system - heart, blood, vesselsPlants : transport tissue (veins)

4. ExcretionRemove metabolic wastesOut of cell or organism environmentWastes are toxic Animals have excretory systemKidneys, skin, liver, lungsPlants have pores in leaves

Excretory System in Humans

Kidneys filter bloodLiver detoxify wastesLungs exhale CO2Skin - sweat5. SynthesisCells make any needed substanceUse molecules from food or raw materials in environmentUse energy from cellular respiration Example: make muscle tissue from protein

6. ReproductionMake new cells or new organismNew cells for growth, repairNew organism continues the species

7. Grow and Develop Increase in size and matureOne cell multicellularDevelop: cells differentiate Egg embryo young adult

8. RegulationControl rate and kinds of chemical reactionsRespond to stimuliKeep homeostasisUnicellular and Plants chemical messagesAnimals nerves and chemicals

Nervous systemElectric signals along nervesFast but short-lived

Endocrine system

Hormones sent into blood streamCause response only in specific tissueSlower, but last longerExample: adrenaline, growth hormone Plants have hormones, but not nerves

Endocrine SystemHormones made in different endocrine organs control specific life functions.The Process of ScienceEvidence: can be observed or measured1. Discovery science - tries to describe nature2. Experimental science - tries to explain nature - hypothesis possible answer/ solution - can be testedQuestion hypothesis test it confirmation

Independent or Dependent?Variables affect outcomeControlled Experiment change ONE variable Independent variable the one you changeManipulated Dependent variable depends on the independent variableResponding

Eastern coral snake (poisonous)

Scarlet king snake (nonpoisonous)

Artificial snakes: king snake (left); brown snake (right)

Results of mimicry experiment

Percent of total attackson artificial snakes10080604020083%17%16%84%Artificial king snakesArtificial brown snakesCoral snakesabsentCoral snakespresent