Bio Course Notes

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LIVING THINGS
* All living things come from other living things.
* Ex: One single celled organism to another
* DNA is copied & passed to offspring
* The signature molecule of life
* Ex: embryo- cells continually divide & develop
EVOLUTION
* Why do some organisms seem suited for their environment * Ex: Hummingbird- long beak for nectar in certain flowers * Ex: Cheetahs- take down faster prey

* Adaptation- inherited characteristic that enables an organism to successfully survive & reproduce * Individuals with the best adaptations to current environment * Evolution- change in the genetic makeup of a population over time * Population= group of individuals of the same species

Natural selection is one mechanism of evolution
1.
2. Organized in a specific way
3. Need & Acquire energy
4. Maintain internal constancy- homeostasis
5. Reproduce, grow, & develop
6. Evolve

DESIGN A CONTROLLED EXPERIMENT
* Sample size
* Variables
* Independent (manipulated) variable
* Dependent (response) variable
* Standardize variable
* Control- group
SCIENTIFIC METHOD
* Observation
* Frame question that relates
* Prediction
* Design & conduct experiment
* Collect data
* Draw conclusion
* Submit for publication

DIFFERENCE BETWEEN HYPOTHESIS AND THEORY

Hypothesis
* Preliminary question
* If-then statement
* Can incorporate laws
* Tentative, often narrow explanation regarding the natural world * Must be testable & falsifiable

Theory
* Unifying explanation
* Diverse lines of evidence
* A well substantiated explanation of some aspect of the natural world * Unifying explanation
* Broad, ties together existing observations
* Ideas about which we are most certain ex: orange falls to ground

CHEMISTRY OF LIFE

Elements- Pure substances that can’t be broken down by chemical means ex: Ca, O, Ba Atom- Smallest component of an element; protons, neutrons, & electrons

Chemical Bonds- link atoms
* Atoms bond through chemical bonds: forces of attraction that hold atoms together * Molecule= 2 or more chemically bonded atoms ex: H2O
* Electrons- move around nucleus in energy shells
* Octet rule: atoms/ions are most stable when they have 8e- in outer (valence) shell

BASIS OF ALL CHEMICAL RECTIONS
* If octet rule is not satisfied, atoms will lose, gain, or share to fill valence * If stable then it will not react
* Electro negativity= Ability to attract electrons
* Covalent bond= Sharing bong
* Non-polar covalent bond= share electrons equally
* Polar covalent bond= non-equal sharing
* Ionic bond=Stealing bond
* If electro negativity is great enough, one will take an e- from another * Results from electrical attraction between 2 oppositely charged ions * Hydrogen Bonds= bonds of attraction

* Weak force of attraction

WATER

Hydrogen bonds result in a property of water called cohesion: water molecules stick together * Results in high surface tension
* Constantly forming and breaking
PROPERTIES OF WATER
* Polar substances dissolve in water
* ex: NaCl in water ->> Molecules of water surround each ion, and separate them from one another * Substances that dissolve in water are hydrophilic
* Substances that do not dissolve in water are hydrophobic * Ice floats
* When the temperature drops, water molecules slow down and keep their H bonds longer * Locks into a crystalline lattice with its neighbors
* Less molecules in a given space; the density is now lower ORGANIC MOLECULES

Organic Molecules are compounds containing both carbon and hydrogen * Carbon has four vacancies
* Many are macromolecules
* polymers: chains created by linking subunits called monomers

FOUR MAIN TYPES
*...
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