Scientific Method Steps Observation Hypothesis Experiment Analysis and

Scientific Method • Steps • Observation • Hypothesis • Experiment • Analysis and Conclusion üIf 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 p. H • Measured on a scale of 1 -14 • Below 7 acid • Above 7 base • p. H of 7 = neutral • Speeds up chemical reactions • Lowers Activation energy (energy needed to get reaction started

Chemistry Reactants and Products Reactants Products

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 6 CO 2 + 6 H 2 O light C 6 H 12 O 6 + 6 O 2 • 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 6 O 2 + C 6 H 12 O 6 6 CO 2 + 6 H 2 O + 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 (2 N) 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 DNA-double 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 m. RNA specifying a particular amino acid anticodon

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 t Tt Tt All tall offspring

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

Genetics Co-dominance- both alleles are dominant. RR-red hair, WW-white hair, RW-roan RR X WW R R 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)