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Scientific Method • Steps •Observation •Hypothesis •Experiment •Analysis and Conclusion If wrong form new hypothesis Scientific Method Controlled experiment •Tests effect of a single variable while keeping all other variables the same •Any observed differences should be caused only by the single changed variable Scientific Method • Observations (qualitative and quantitative) •Quantitative– involve numbers, counting, measuring objects. •Qualitative– involve characteristics that cannot be easily measured or counted such as color or texture Scientific Method Hypothesis– a possible explanation, a preliminary conclusion, or even an “educated” guess about some event in nature Theory– As evidence builds up, a particular hypothesis may become so well supported that scientists consider it a theory. Atomic theory Chemistry Organic Compounds •Carbohydrate- main source of energy for animals •Monomer = monosaccharide (single suger) •Polymer = Starch, Cellulose •Protein- functional or structural •Monomer = Amino Acid •Polymer = Protein •Nucleic Acid-controls inheritance •Monomer = Nucleotide •Polymer = DNA, RNA Chemistry Enzymes •Biological Catalyst •Speeds up chemical reactions •Lowers Activation energy (energy needed to get reaction started •Not used up during reaction •A specialized protein •functional protein Chemistry pH •Measured on a scale of 1-14 •Below 7 acid •Above 7 base •pH of 7 = neutral •Speeds up chemical reactions •Lowers Activation energy (energy needed to get reaction started Chemistry Reactants and Products Reactants H2O water Products + H Hydrogen ion + + - OH Hydroxide ion Chemistry Solutions •Solute- “stuff” that is dissolved •Solvent –the liquid that does the dissolvin Chemistry Chemical bonds– links that hold atoms together. Two main types Covalent bonds– formed by sharing electrons between two atoms •Bond found in organic compounds Chemistry Ionic bonds- formed by transfer of 1 more electrons from 1 atom to another •Ion– (+) or (-) charged atom that results from gaining or losing electron Cells • Organelles Nucleus- control center of cell. Contains DNA (genetic material). Found in eukaryotic cells. Ribosome- organelle where proteins are made. Free-floating and some on Endoplasmic reticulum Golgi apparatus- Cells “post office”. Packages proteins Endoplasmic reticulum- Cells transport system. Help make proteins (rough E.R.) Lysosome- “clean-up” crew of cell. Contains enzymes to break down old cell parts, digest food, etc. Cell membrane- flexible, and semipermeable membrane surrounding cell. Cells • Cell membrane- composed of lipid bilayer (2 layers of lipids) Lipid layer also called phospholipids Cells • Semi-permeable- allows some things to pass through but not others Diffusion- movement from areas of high concentration to areas of low concentrations Osmosis- diffusion of water Cells • Active transport- takes energy • (endocytosis and exocytosis) Passive transport- no energy required (diffusion and osmosis) Cells Prokaryotes and Eukaryotes- Scientists divide cells Into two groups depending on whether they have a nucleus or not. 1. Prokaryotes-no nucleus • Smaller and simpler than cells of eukaryotes • Do have cytoplasm and cell membrane • Example: Bacteria Cells Eukaryotes- do contain nucleus and membrane bound organelles (includes plants, animals, fungi) •Contain cytoplasm and cell membrane •Contains organelles Cells Homeostasis- maintain constant internal conditions (example: blood sugar levels, blood pressure, shivering/sweating) Photosynthesis • Equation 6CO2 + 6H2O light C6H12O6 + 6O2 • Energy from sunlight converts carbon dioxide and water into high energy sugar (glucose) • Takes place in chloroplast (organelle) • Affected by: 1. Light intensity 2. Amount of water 3. Temperature • Autotroph- Can make their own food (plants) Cellular Respiration • Heterotroph- can not make their own food. Need to eat something else to obtain energy (fungi, animals, most bacteria • Equation 6O2 + C6H12O6 6CO2 + 6H2O + Energy • Fermentation- still make energy when no oxygen present. Two types: alcoholic and lactic acid fermentation • Mitochondria- where respiration takes place Cellular Respiration Series of events: Glycolysis → krebs cycle → electron transport ENERGY Cellular Respiration Compared to Photosynthesis Cell Division Cell cycle- series of event cell goes through as it grows and eventually divides. Interphase- When cell grows and develops, getting ready to divide again Mitosis- Division of cell nucleus (forms diploid (2N) cells) PMAT Cytokinesis- cell splits in two Cell Division Meiosis- cell division forming sex cells (gametes) •Results in 4 genetically different cells •Gametes are N (haploidhalf the number of chromosomes) Cell Division Cell growth (cell gets bigger, volume increases faster than surface area) so has to divide DNA, RNA, and Protein Synthesis • Replication- DNA making DNA • Transcription- DNA making RNA • Translation- RNA making Proteins DNA, RNA, and Protein Synthesis DNA RNA Sugar- deoxyribose Two stranded ATCG Sugar-ribose Single strand AUCG DNAdouble helix 3 kinds of RNA DNA, RNA, and Protein Synthesis Complementary bases • DNA: C-G A-T • RNA: C-G A-U DNA, RNA, and Protein Synthesis Codon- three letter “word” on mRNA specifying a particular amino acid anticodon codon Genetics homozygous same letters (TT or tt) heterozygous different letters (Tt) Genotype- the alleles (letters) i.e. Tt, TT, tt Phenotype- physical characteristics (Tall, short) Genetics • Gamete- sex cell (N) haploid. • Zygote- fertilized egg • Fertilization- process when sperm and egg join Genetics Dominant / Recessive cross- one allele is dominant over another. I.e. T-tall (dominant) over t-short (recessive) TT X tt gametes T T All tall offspring t Tt Tt t Tt Tt Genetics Incomplete dominance- one allele is not completely dominant over another (RR-red crossed with WW-white yields all RW-pink flowers) RR X WW R R W RW RW W RW RW Genetics Co-dominance- both alleles are dominant. RR-red hair, WW-white hair, RW-roan RR X WW R R W RW RW W RW RW Genetics Dihybrid cross- Mendel’s two-factor experimental results were very close to 9:3:3:1 ratio predicted by punnett square. Proved that genes that segregate independently do not influence each other’s inheritance. Principle of Independent Assortment 9:3:3:1 Genetics Multiple Alleles- ABO blood type is an example. A and B or co-dominant. Genetics Crossing over- when “legs” of chromosomes cross over each other during meiosis and exchange parts of themselves. Genetics Non-disjunction- when chromosomes fail to separate during meiosis. Resulting in missing or extra chromosomes in gametes Genetics “Code of Life”- Reading codons and the amino acids they code for Example: CGA UGC AAU Arg – Cys - Asn Genetics Cloning- a member of a population of genetically identical cells produced from a single cell Genetics Human Chromosomes- body cells contain 46 chromosomes (23 from sperm, 23 from egg. Join in diploid zygote) •Karyotype- picture of chromosomes cut out from photographs and grouped together in pairs •Sex chromosomes- two of 46- these determine sex of individual XX=female and XY=male •autosomes- remaining 44 chromosomes Genetics Egg cells contain a single X chromosome. Sperm cells contain either one X chromosome or one Y chromosome. Approximately half of the zygotes are XX (female) and half XY (male)