Bio Final Sem 1

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Cell theory

Cell theory

1. All organisms are composed of one or more cells

2. The cell is the most basic unit of life

3. All cells come from other pre-existing cells

*We don’t know what LUCA (last universal common ancestor) is or when it was

Prokaryote

• Bacteria and archaea

• Lack of a nucleus and membrane-bound organelles

Eucaryote

• All forms of life besides bacteria and archaea

• Contain a nucleus and membrane-bound organelles

Endosymbiotic theory

• Mitochondria and chloroplasts have DNA, so it is thought that they used to be prokaryotes

• Chloroplasts did photosynthesis, mitochondria performed cellular respiration

• Mitochondria and chloroplasts may have combined with larger prokaryotes and worked together, creating ancestral eucaryotes

Cell differentiation

The acquisition of a cell’s specific structural and functional features. (Every cell in the body has the same DNA, but there are specific genes that are turned on and off for different cell types)

Phospholipid bilayer

• Composed of phospholipid heads and tails

• Hydrophilic heads face extracellular fluid and the cytoplasm

• Hydrophobic tails line the inside of the bilayer

Fluid mosaic model

• Mosaic of proteins and carbohydrates in fluid consisting of the lipid bilayer

• Integral proteins embedded to lipid bilayer, peripheral proteins attached to surface

Plasma membrane functions

Transport, enzymatic activity, signal transduction, intercellular joining, cell-cell recognition, attachment to the cytoskeleton and extracellular matrix

Hypertonic

Concentration of solute is greater outside of the cell than inside

Plasmolysis

Cells can shrink from the exit of water (like a wilting leaf)

Isotonic

Concentration of solute is equal outside of the cell and inside (dynamic equilibrium)

Hypotonic

Concentration of solute is less outside of the cell than inside

Cytolysis

Cells can expand to the point of bursting from influx of water

Simple diffusion

• Through the phospholipid bilayer

• Small, non-polar molecules and small, uncharged polar molecules

Osmosis

• The phospholipid bilayer

• H2O

Facilitated diffusion

• Integrated protein channels

• Large, uncharged polar molecules and ions

Active transport

• Located in carrier proteins in the phospholipid bilayer

• Ions and molecules move from low to high concentration using energy (ATP)

Endocytosis

• Cell takes in macromolecules by forming vesicles from the plasma membrane

• Ex: phagocytosis (cellular eating), pinocytosis (cellular drinking), receptor mediated endocytosis

Exocytosis

Cell secretes macromolecules when vesicles fuse within the plasma membrane

Concentration gradient

• Difference in concentration from inside and outside of a cell

• Substances move the concentration gradient from high to low

Turgor pressure

Force directed against the cell wall in a plant cell from influx of water in hypotonic extracellular fluid

Cell size issues

• If too large, cannot move nutrients in and waste out efficiently

• When cell grows larger so does the demand placed on DNA

• 37 trillion cells in average adult human

Universal organelles (plants and animals)

Nucleus, ribosomes, endoplasmic reticulum, golgi apparatus, mitochondria, peroxisomes, microfilaments, and microtubules

Animal-only organelles

Centrioles (for mitosis), locomotion organelles (flagellum like on sperm and cilia like little hairs)

Plant-only organelles

Plastids/chloroplasts, cell wall, central vacuole, plasmodesmata

Matter

Anything that has mass and takes up space

element

pure substance that cannot be broken down

Compound

2 or more different elements

molecule

two or more atoms

isotope

forms of element with idfferent number of neutrons

ion

atom with gained/lost electrons

cation

positive ion, lost electrons

anion

negative ion, gained electrons

ionic bonds

gain/loss of electrons, imbalance in electron charge

polar covalent

unequal sharing of electrons (all water based)

non-polar covalent

equal sharing of electrons (all fats/oils except for fatty acids)

polarity

unique properties of water derive from molecular structure - oxygen shares electrons unevenly

surfactants

substances that break surface tension

adhesion

water molecules stick to other charged particles

universal solvent

water dissolves more substances than any other liquid - cannot dissolve fats/oils

hydrophobic

water fearing

hydrophilic

water loving

capillary action

water adheres to the sides of tubes and other charged surfaces, rising against the force of gravity

cohesion

water molecules stick to themselves

high heat of vaporization

more energy required to break water molecules apart because of cohesion

specific heat capacity

amount off heat absorbed/lost for 1g of water to change temperature

high surface tension

water interfaces with air at surface, water coheres, less penetrable surface

surfactants

substances that break surface tension

pH scale

"power of hydrogen", amount of Hydronium (H3O+) or Hydrogen (H+) relative to amount of Hydroxide (OH-)

Acid

H3O+ or H+ increase, H3O+ or H+ greater than OH- concentration PH<7

Properties: Pungent odor (vinegar), sour taste, corrosive to biological tissue

acid

Strength = % dissociation of H3O+ or H+

acid

Bases

Increase in OH-, H3O+ or H+ less than OH- concentration PH>7

Properties: Slippery texture, bitter taste, pungent odor (bleach), corrosive with biological tissue

base

Strength = % disassociate of OH-

neutralization

effect of strong acid/base alleviated with addition of base/acid with equal strength (creates saltwater)

Buffers

substances that minimize change in concentration of H3O+ and OH- in blood stream

Organic

compounds contain hydrogen/carbon

inorganic

compounds not containing carbon/hydrogen

C, H, N, O, P , S

Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfur; main elements of biomolecules

tetravalence

tendency to form 4 covalent bonds with other atoms

isomers

same formula, different structure/properties

functional groups

components of chemical reactions - most often in a metabolic reaction

polymerization

formation of molecules with 3 or more identical parts (monomers)

dimer

formation of molecules with 2 monomers

dehydration synthesis

hydrogen/hydroxyl removed from different monomers - join to form water, remaining are covalent and link to form a dimer

hydrolysis

"to split water", converse of dehydration synthesis, water molecules splits

anabolism

metabolic reaction - builds dimers/polymers with purpose of storing energy in bonds

catabolism

metabolic reaction - breaks dimer/polymers with the purpose of releasing energy in broken bonds

Carbohydrates

includes sugars/polumers, composed of C, H, O. H & O always in a 2:1 ratio. Serves as fuel for physiological process, carbon source for growth/development

Monosaccharides

simplest carbohydrate: single sugar (forms ring structure) - glucose, fructose, galactose

Hexose sugars

C6H12O6

glucose

not sweet - vital for life/cellular respiration, insulin stimulates body cells - absorbs glucose

fructose

not sweet - fruit/honey

galactose

sweet - monomer of lactose (milk sugar)

Homeostasis

blood glucose levels maintained near 90-100ml in blood with hormones

insulin

lowers glucose concentration - promotion of glucose uptake

glucagon

raises blood glucose levels

Disaccharide

"double sugar" formed: dehydration synthesis of 2 monomers (sucrose, lactose, maltose)

sucrose

table sugar - sweet: glucose/fructose monomer

lactose

milk sugar - not sweet: glucose/galactose monomer

maltose

malt - sweet: 2 glucose monomers

Polysaccharides

formed by dehydration synthesis/glycosidic linkage formed by 100s of 100s of carb monomers (starch, glycogen, cellulose)

starch

storage of glucose in plants

glycogen

storage in glucose in animals

cellulose

storage in glucose in plants

lipis

fats, phospholipids, and steroids. elements: C, H, O. H/O greater than 2:1 ratio. Serve as long term energy, storage, insulation, cell membrane competition, hormone

bonding in fats

(triacylglycerol) - fatty acid loses OH- group. Glycerol loses 3 hydrogen atoms

Water molecules condensed, fatty acid/glycerol combine as an ESTER LINKAGE

saturated fats

all carbon atoms in the fatty acid chain form 4 single bonds with hydrogen and other carbon atoms. Solid and dense (animals)

unsaturated fats

2 or more carbon atoms form a double bond, liquid at room temp (fish/plants)

trans fat

unsaturated fats synthetically converted to saturated fats by adding hydrogen

phospholipids

composition: 1 glycerol linked to 2 fatty acids and a phosphate group (hydrophilic head & hydrophobic tails)

steroids

cholesterol - component of animal cell membrane and precursor to hormones such as testosterone and estrogen

HDL

high-density lipoprotein: stops accumulation of cholesterol in arteries.

LDL

low-density lipoprotein: leaves arteries clogged with cholesterol

Dipeptides/polysaccharides

20 essential amino acids essential for life. Linkage between 2 amino acis = peptide, 3 or more = polypeptide.

Levels of Protein structure

primary, secondary, tertiary, quaternary

Building blocks of biological macro molecules

Carbohydrates: monomers - monosaccharides

Fats

monomers - 3 fatty acids/glycerol