BIO 101 unit 1

Definition of Biology

the study of all life and their interactions

5 properties of all life

1) organization

2) energy processing

3) internal constancy

4) reproduction, growth, development

5) evolution

Hierarchy of organization

atom → molecule → organelle → cell → tissue → organ → organ system → organism → population → community → ecosystem → biosphere

Emergent properties

arise when different levels of organization combine, leading to complex characteristics not present in simpler entities (ex. interaction of brain cells leads to ability to hold memories but single brain cell cannot)

3 diff types of energy processing

primary producers, consumers, decomposers; heat is lost everytime energy is transferred or transformed.

primary producers

these organisms gain energy by converting inorganic compounds into organic matter (photosynthesis: sunlight into sugar and then proceeds to cellular respiration)

consumers

these organisms gain energy by eating other organisms - cellular respiration converts sugar into ATP

decomposers

gain energy from breaking down organic waste and dead organisms (mushrooms, maggots)

internal constancy

homeostasis; ability of organism to maintain stable internal conditions despite external changes (body temp like thermostat, internal chemistry like drinking water / eating)

reproduction, growth and development

organism must grow in size, mature through lifespan (ex. cell specialization) and be able to have offspring

Asexual reproduction

only one parent involved; offspring are genetically identical (ex. sometimes strawberries) - works well in unchanging environments

Sexual reproduction

two parents involved; offspring are genetically different - useful in changing environments for adaptation

evolution

genetic change over time in a population through mutations and adaptations (natural selection)

prokaryotic cells

domains: bacteria + archaea, kingdoms: eubacteria + achaebacteria

unicellular, no nucleus, no membrane bound organelles

eukaryotic cells

domain: eukarya, kingdom: anamalia, plantae, fungi, protista (algae/ameoba)

multicellular, contain nucleus, organelles

steps of the scientific method

1) observations

2) hypothesis

3) experiments

4) analysis/conclusion

5) peer review

observations

using senses and existing knowledge to find connections btwn unrelated observations

hypothesis

testable idea of how to answer a question

experiment variables

independent variable: what is manipulated

dependent variable: what is measured

standard variable: constants

experiment groups

control group: baseline used for comparison

experimental group: treated group that may or may not show differences

scientific theory

broad explanation for natural phenomenon based on years of collected data through 1000s of experiments

define matter

1 or more elements organized into atoms/ molecules

atoms vs elements

atom: smallest piece of elements

element: substance that cannot be broken down chemically

subatomic particles

protons: +

neutrons: =

electrons: -

atomic number of an element

determined by number of protons - doesn’t change

mass number of a specific element

weight total of protons + neutrons

Isotope

same # of protons but elements can have varying number of neutrons

atomic weight of an element

average mass of elements as they exist in nature

electron shells

1st shell: 2e-, 2nd shell and so on: 8e-

valence electrons

number of electrons on outer valence shell determine how many bonds an atom can make

electronegativity

atoms ability to attract e- (ex. in H20, O pulls more which causes molecule to be slightly charged) (in periodic table electronegativity increases as you move up and towards the right)

nonpolar covalent bonds

atoms share electrons equally as they have similar electronegatives and molecules have no slight charges

polar covalent bonds

atoms are slightly charged due to different electronegativity (ex. H2O - O is more electronegative and pulls more causing slight negative charge and Hs hv slight positive charge)

hydrogen bond

because of slight charges on H2O, these bonds occur btwn two H2O molecules (slightly positive H is attracted to slightly negative O)

Ionic bonds

high electronegativity difference; one atoms pulls e- away from other (Na+Cl-) (Ca, F)

cation

positively charged atoms

anion

negatively charged ion

properties of water due to hydrogen bonding

• cohesion/adhesion

• universal solvent

• regulates temperature

• expands when frozen

• pH of 7

cohesion

tendency of water to stick to molecules of each other; leads to high surface tension

Adhesion

tendency of water to stick to other molecules as it forms hydrogen bond with other molecules as well

universal solvent

water dissolves all hydrophillic substances but not hydrophobic ones

how does water regulate its temperature

hydrogen bones make water more resistant to changes in temperature

why is ice less dense than water

when water is frozen, the orientation of hydrogen bonds causes molecules ot push away from one another so ice expands

pH scale

• acids: pH 1 to <7 or 10^0 to 10^< -7

• water = pH 7

• bases: pH >7 to 14 or 10^> -7 to 10^-14

buffer system

help maintain a constant pH by absorbing or releasing H+ into a solution

what are organic molecules

contain C, H (hydrocarbons); carbs, proteins and fats are common in diet

dehydration synthesis

chemical rxn that turns monomers into polymers; byproduct is H2O

• H-mol1-OH + H-mol2-OH → H-mol1-mol2-OH + H2O

hydrolysis

chemical rxn that breaks down polymer into monomer; uses H2O

• H-mol1-mol2-OH + H2O → H-mol1-OH + H-mol2-OH

structural isomer

compound with the same # and type of elements but connected differently

functional groups of molecules

• hydroxyl: -OH

• amino -NH2

• carboxyl: -COOH

• phosphate: -PO4^-2

Carbohydrates

• monomer: monosaccharides (ribose, glucose, fructose)

• polymer: polysaccharides

• two monomers: disaccharides

• cellulose - structure

• starch + gluten - energy

• basic formula: CH2O

Proteins

• monomer: amino acids (20 diff) composed of amino grp, carboxyl grp and R grp

• polymer: polypeptide - folds to form protein shape which determines function

• peptide bond: joins amino acids together

• Function as specialized worker enzymes

protein denaturation

breaking down protein structure (unfolding) resulting in loss of function

4 structures of proteins

1) primary structure: amino acid sequence of a polypeptide

2) secondary structure: coils and sheets stabilized by hydrogen bonds

3) tertiary structure: overall shape of one polypeptide

4) quaternary structure: full protein shape made of multiple polypeptides

nucleic acids

• monomer: nucleotides (phosphate grp, sugar, 1 of 5 nitrogenous base - C/G, A/T in DNA or A/U in RNA)

• polymer: DNA (double helix) + RNA (single strand)

Lipids

• all hydrophobic - fat + oils are energy rich - not made of monomers

• triglycerides: glycerol head (hydrophilic) + 3 fatty acids (hydrophobic)

• Phospholipid: hv only two fatty acid tails

• steroids: regulates fluidity of animal cell membranes + sex hormones (ex. cholesterol)

• waxes: fatty acids + alcohols = form waterproof seals

saturated vs unsaturated fatty acid

• saturated = no double bonds (straight)

• unsaturated = double bonds (bent)

• each give triglycerides different properties

cell theory

• all organisms made out of one or more cells

• cell is the fundamental unit of life

• all cells come from preexisting cells

microscopes

• light; view entire cells

• electron: view parts of cells

parts of a prokaryotic cell

domains: bacteria + eukarya - ribosomes and DNA in form of nucleoid are free in cytoplasm

organelles only found in plant cells

central vacuole, chloroplasts, cell wall, plasmodesmata

central vacuole

provides cellular digestion and regulates size + water balance only in plant cells

chloroplasts

conduct photosynthesis in plants turning sunlight into sugar which is then used in cellular respiration where mitochondria turns sugar into ATP (thylakoid sacs inside stroma liquid)

cell wall

functions of provide strength, regulate volume, prevent bursting and plays a role in cell specialization in plant cells

plasmodesmata

channels that pass through cell wall to sed nutrients and biochemicals btwn plant cells

list all organelles in a eukaryotic animal cell

cell membrane, nucleus, robosomes, ER (smooth/rough), golgi, lysosomes, peroxisomes, mitochondria, centrosomes/centrioles, cilia/flagella

Cell membrane

• forms barrier btwn cell and outside, regulates in/out, maintains homeostasis

• made of phospholipids - selectively permeable phospholipid bilayer

• contains proteins - transport channels, enzymes, receptor/adhesion/recognition proteins

• carbohydrates protrude out for cell-cell communication

• contains steroids to keep membrane at optimal fluidity

fluid mosaic of cell membrane

combination of phospholipids and proteins allow for fluid movement and mobility of cell

genetic control in eukaryotic cell

• nucleus controls protein production via DNA and nucleolus (synthesizes ribosomes)

• RNA transcribed from chromatin in chromosmes inside nucleus

• mRNA travels through pore in nuclear envelope onto ribosome

• free floating or rough ER ribosome synthesizes protein

endomembrane system

• proteins move from ribosomes to ER to be folded into their shape

• proteins exit ER using transport vesicles and fuse w/ golgi

• golgi processes + packs proteins for cell export

• vesicles fuse with cell membrane to expel proteins and lipids that were made by smooth ER

• lysosomes: larger vesicles where cellular digestion of large molecules occur

• peroxisomes: break down toxins + aid in digestion - originate in ER

energy processing in animals

mitochondria converts sugar into ATP (folded cristae membrane inside matrix fluid)

endosymbiosis theory

chloroplasts and mitochondria were once prokaryotes that were absorbed by eukaryotic cells and then passed down.

cytoskeleton

network of protein tracks and tubules in eukaryotes

• microfilaments: actin - cell contraction + shape

• intermediate filaments: protein subunits - strong mechanical strength

• microtubules: tubulin - trackways for transport

centrosomes/ centrioles

made of microtubules: in cell division, pull chromosomes apart and are located net to nucleus

cilia / flagella

made of microtubules

• cilia: protrudes from cells - push dust or clear airways

• flagella: sperm use flagella to swim

cell-cell communication

• gap junctions: proteins form tunnel through two neighboring cell membranes

• tight junctions: proteins sew membrane of two cells together to create leak proof barrier

• Anchoring/adhering junctions: proteins reach insde cells to bind to cytoskeleton for added mechanical strength

light microscope

lowest level of magnicifcation, live samples, true color, lowest resolution

transmission electron microscope

highest level of resolution, used for small sctructures inside cells

scanning electron microscope

coated in metal particles, can only provide surface images

golgi appartaus

modifies and sorts proteins received from ER

smooth ER

synthesizes lipids and detoxifies drugs

parts of allll cells

ribosomes, cell membrane, DNA