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what is biology?
scientific study of life
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What are the themese of biology?
- 1. All forms of licfe share common properties
- 2. Evolution
- 3. Correlation between structure and function
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What are the properties of life?
- Order: the arrangement of organism
- Reproduction: babies birth
- Growth and Devlopment: DNA, inherited info
- Energy Processing: Eating things for energy
- Response to enviornment: shiver when cold
- Regulation: Body temp, homeostasis
- Evolutionary Adaptation: Adaptating to enviornment
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Life's Hierarchy of Organization
- Biosphere: All enivornments on Earth
- Ecosystem: Physical components of area and organism
- Community: entire array of organisms in ecosystem
- Population: all individuals of a certain species
- Organism: animal; individual living thing
- Organ system: nervous system
- Organ: brain
- Tissue: nerve tissue
- Cell: nerve cell
- Organelles: nucleus
- DNA:
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Emergent Properties
"whole is greater than the sum of its parts"
The new properties that comes up in each step of the hierarchy
- System Biology
- Construct models of while systems and study its parts
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What are cells
basic structural and functional units that exhibit properties of life
All organisms have it
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Types of Cells
Both have DNA and plasma membrane
- Systems
- Properties of cells life come from the ordered from the ordered arrangement and interactions of structures of a cell
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What is Eukaryotic cells
- Cells that have DNA in the nucleus
- Plant and animal cells
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What are Prokaryotic cells
No nucleus; simple bacteria cells
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Consumers and Decomposers
- Oragnisms- interact with environment
- plants- produce food
- consumers-eat plants/animals
- take in O2 from air, release CO2 =release energy in food
- Decomposers- recyclers, change comples matter to simple nurtrients
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Flow of Energy
Plants->photosynthesis->chemical energy->consumers->decomposers
energy converted to heat when lost from system
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Molecular Basis of Inheritance
- DNA- making proteins
- common genetic code
- chemical substance of genes
- Double Helix- called 2 nucleotides; names info in genes
- Genes- units of inheritance that transmits info from parents to offspring
- two long chains coiled together
- control activities of cells
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Unity and Diversity of Life
- Unity of life based on DNA
- Diversity of all DNA but different coding
- hallmark of life
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Evolution the core theme of Biology
- accounts for life's dual nature of kinship and diversity
- i.e -natural selection
- kinship- suggest animals are related
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Diversity of Life
- Hallmark of life
- Taxonomy- names species, clasify them into a system of broader groups
- Genuns->family->order->class->Phylom->Kingdom
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What are the Kingdoms
- Kingdom Plantae-plants
- Kingdom Fungi-mushrooms, decomposers
- Kingdom Animals- animals
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What are the 3 domains
- Bacteria-prokaryotes
- Archaea- prokaryotes
- Eukarya- salty lakes, eukaryotes-nucles organelles
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Process of Science
- Scientific Inquiry- used to ask and answer questions
- recording data, making observations, measurements
- Inductive Reasoning-used ot draw gerneral conclusions from many observations
- all organisms are composed of cells
- derives generalizations
- Ddeuctive Reasoning- test hypothesis
- i.e organisms->cells , humans->organisms, humans have cells
- used to come up with ways to hypothesis
- explanation for observations
- Theory vs. Hypothesis
- Scientific Theory- broader than hypothesis, can test multiple hypothesis,
- lots of data
- supported by a lot of evidence
- general
- Forming and Testing a Hypothesis-Hypothesis must be able to be false
- falsiable and testable
- either its true of not
- when false propose another one
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Controlled Experiment
Comparing controlled group to experimental group
- controlled-group that does't change
- used to measure against
- Experimental-group that has changes
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Evolutionary Theory
Teaches environemnt is powerful selective force for traits best adapt to environment
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What is Matter?
- Anything that occupies space and has mass
- chemical elements
- solid, liquid, gas
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What is an element
Substance that cannot be broken down
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What are compounds
- 2 or more elements
- fixed proportion
- 96% O C H V
- in human body
- is in proteins
- important for bone formation
- i.e NaCl and H2O
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What are trace elements?
- Added to food to prevent disease
- i.e- Iron- is in cereal and pasta
- need for oxygen
- Iodine-salt
- Production of thyroid hormones
- Fluorine- water
- reduce tooth decay
- Help Preserve food
- makes it look better
- more nutrients
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What are atoms
Smallest unit of matter retains properties of an element
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What is the structure of an atom
- Protons- pos. charge demtermine the element
- Neutrons-no charge determine if its an isotope
- Electrons- neg. charge
- determine chemical behavior
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What is the atomic number
- number of protons
- All atoms of same element have same atomic number
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What is the atomic mass or mass numbr
- Equal to mass number
- sum of number of protons and neutrons in nucleus
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What are isotopes
- Same number of protons
- different number of neutron
- behave identically in chemical reactions
- Cells cant distinguish between istopes of same element
- i.e C-12 and C-13
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What are radioactive Isotopes
- nucleues decays spontaneiously
- give off particles and energy
- cause abnormal bonds
- used for treatments
- Iodine- kills cancer cells
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What are radioactive trcers
used in medical diagnosis
- follow molecules as they undergo chemical changes
- imaging instruments used to detect them
- PET scans-detect location of injected radioactive material
- diagnosing heart disorders, cancer
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What are Chemical bonds?
electrons involved in chemical activity- farther electrons from nucleus the more energy it has
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What are the chemical properties of atoms?
- Electrons occur in energy levels
- It has different orbitals which holds a max of 2 electrons
- called electron shells
- the 1st shell holds 2
- 2nd holds 8
- number of electrons on outermost shell determines the chemical properties of atom
- Valence shell
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What is the octet rule?
- Atoms with incomplete outermost shell tend to react so both have completed outermost shell
- share, donate, recieve elecrons called Chemimcal bonding
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What are covalent bonds?
- Strongest
- 2 atoms share electrons
- 2 or more atoms held together by covalent bonding
- called a molecule
- O2- double covalent bond
electronegativity- attraction for shared electrons
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Type of covalent bonds
- Nonpolar covalent- equal force between atoms
- i.e methane , O2, H2
- Polar Covalent- unequal force
- more negative atom has stronger force
- i.e- H2O
- O sronger force
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What is an ionic bond
- Ion- an atom/ molecule with charge
- loss or gain of electron
- if loss then postive
- if gain then negative
- attraction hold ions together
- called ionic bond
- i.e NaCl
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What are hydrogen bond
- Weakest bond
- consists of H atom
- polar covaent bonds
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Chemical Reactions
Structure of atoms and molecules detmerminbes the way they behave
- break and make chemical bonds
- doesnt create of destroy matter
- i.e photsynthesis- carbon dioxide, air and water
starting material are the reactants and the final material are the products
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How does hydrogen bonds give water its properties
- it makes water cohesive
- tendency for molecules of the same kind to stkck together-cohesion
- stongest for water
- Adhesion- clinging of substances to another
- Gives water high surface tension
- how difficult to stretch or break the surface of a liquid
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Water properties
- Temp-moderation: of humand body temp
- polarity and hydrogen bonds between molecules determines structure and interactions
- intensity of heat
- H bonds resist to temp changes
- heat energy- associated with movemnt of atoms and moleulces in body of water
- Absorbed to break H bonds
- released when H bonds form
- Evaportaiting cooling- molevules of greatest energy to leave
- Ice vs. liquid
- ice floats on water
- ice less dense
- H bonds makes ice more spacious
- Solute and solvent =solution
- Solute- substance dissolved
- solvent- dissolving agent
- solution- liquid consisting of uniform mixture of 2 or more substnaces
- aquesous solution- water is the solvent
- disolves ionic compounds
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Acids and Bases
- Acids- release H atoms
- HCl: more H ions than OH ions
- donates H atoms
- Bases- accepts H atoms
- reduce H atom concentration
- pH scale- 10 fold change
- water-pH of 7
- blood plasma- 7.4
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What are organic compounds?
- Carbon based molecules
- i.e methane
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What are the properties of carbon?
- Methane: simplest organic compounds
- 4 covalent bonds CH4
- Hydrocarbons: molecules of Hydrogens and carbons
- vary in length
- difference in branching
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How do carbon skeletons differ?
- Chains pf carbon atoms in organic molecules
- vary in
- 1.Length i.e Ethane and Propane
- 2. Location of double bonds
- 3. Branching
- 4.Rings
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What are isomers?
Compounds with same formula differeing in structural arrangement
- Structural isomers- straight or branched
- Geometric Isomers-
- Enantoisomers- mirror image of each other
different shapes of isomers result in unique properties and add greatly to diversity of organic molecules
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