scientific method steps observation hypothesis experiment analysis and conclusion if wrong form new...
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Scientific Method• Steps
•Observation•Hypothesis•Experiment•Analysis and Conclusion
If wrong form new hypothesis
Scientific MethodControlled 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 MethodHypothesis– 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
ChemistryOrganic 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
ChemistryEnzymes
•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
ChemistrypH
•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
ChemistryChemical bonds– links that hold atoms together. Two main types
Covalent bonds– formed by sharing electrons between two atoms
•Bond found in organic compounds
ChemistryIonic 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• Cell membrane- composed of lipid bi-
layer (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)
CellsProkaryotes 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
CellsEukaryotes- do contain nucleus and membrane bound organelles (includes plants, animals, fungi)
•Contain cytoplasm and cell membrane
•Contains organelles
CellsHomeostasis- maintain constant internal conditions (example: blood sugar levels, blood pressure, shivering/sweating)
Photosynthesis• Equation
• Energy from sunlight converts carbon dioxide and water into high energy sugar (glucose)
• Takes place in chloroplast (organelle)• Affected by:
1. Light intensity2. Amount of water3. Temperature
• Autotroph- Can make their own food (plants)
6CO2 + 6H2O C6H12O6 + 6O2
light
Cellular Respiration• Heterotroph- can not make their own food.
Need to eat something else to obtain energy (fungi, animals, most bacteria
• Equation
• Fermentation- still make energy when no oxygen present. Two types: alcoholic and lactic acid fermentation
• Mitochondria- where respiration takes place
6O2 + C6H12O6 6CO2 + 6H2O + Energy
Cell DivisionCell 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)
Cytokinesis- cell splits in twoPMAT
Cell DivisionMeiosis- cell division forming sex cells (gametes)
•Results in 4 genetically different cells•Gametes are N (haploid-half the number of chromosomes)
Cell DivisionCell 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 RNASugar- deoxyribose Sugar-ribose
Two stranded Single strand
ATCG AUCG
3 kinds of RNA
DNA-double helix
DNA, RNA, and Protein Synthesis
Codon- three letter “word” on mRNA specifying a particular amino acid
codon
anticodon
Geneticshomozygous 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
GeneticsDominant / Recessive cross- one allele is
dominant over another. I.e. T-tall (dominant) over t-short (recessive)
Tt Tt
Tt Tt
T T
t
t
TT X tt
gametesAll tall offspring
GeneticsIncomplete dominance- one allele is not
completely dominant over another (RR-red crossed with WW-white yields all RW-pink flowers)
RW RW
RW RW
R R
W
W
RR X WW
GeneticsCo-dominance- both alleles are dominant.
RR-red hair, WW-white hair, RW-roan
RW RW
RW RW
R R
W
W
RR X WW
GeneticsDihybrid 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.
9:3:3:1
Principle of Independent Assortment
GeneticsCrossing over- when “legs”
of chromosomes cross over each other during meiosis and exchange parts of themselves.
GeneticsNon-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
CloningCloning- a member of a population of genetically identical cells produced from a single cell
Human ChromosomesHuman Chromosomes- body cells contain 46 chromosomes (23 from sperm, 23 from egg. Join in diploid zygote)
Genetics
•KaryotypeKaryotype- picture of chromosomes cut out from photographs and grouped together in pairs•Sex chromosomesSex chromosomes- two of 46- these determine sex of individual XX=female and XY=male
•autosomesautosomes- remaining 44 chromosomes