SBI4U - Unit 1: Biochemistry

Isotopes — how are they different from a normal atom? Uses? (2)

• Atoms = neutral; ions = charged

• Isotopes = same element, different neutrons.

  • Radioisotopes used in medicine

Intramolecular bonds: Ionic bonds

what is it? how do they form? solubility? (3)

• metal + nonmetal

• transfer electrons

• soluble in water.

Intramolecular bonds: covalent bonds

what is it? how do they form?

• nonmetals

• share electrons

• Can be polar (unequal sharing, dipoles) or nonpolar (equal sharing).

intermolecular forces:

LDF

• temporary & changing attraction b/w p⁺ & e^- due to movement of electrons

• found in all molecules

• the bigger the molecule/more electrons, the stronger the LDFs

intermolecular forces:

dipole-dipole

• permanent attraction forces between POLAR molecules

• partial + portion of 1 molecule is attracted to the partially - portion of another molecule

intermolecular forces:

H-bonds

• the strongest IMF

• between H and N, O, or F

how to determine if a covalent bond is non polar, polar or ionic-like covalent

• determined by electronegativity difference

• non polar covalent bond: 0.4 or lower

• polar covalent bond: 0.4 < x < 1.7

• ionic-like covalent bond: > 1.7

how to identify if a molecule is polar or nonpolar

1. polar bonds (electronegativity difference)

   • at least polar bond!!!

2. shape/symmetry

   • asymmetrical = polar

   • symmetrical = non polar bc dipoles cancel e/o

functional groups: hydroxyl (3)

what is the molecular formula? properties? (2) found in? (4)

• molecular formula: (-OH)

• properties: polar & electronegative

• found in: Carbohydrates, proteins, nucleic acids, lipids

functional groups: carbonyl (3)

what is the molecular formula? properties? (1) found in? (3) types? (2)

• molecular formula: (-CO)

• properties: polar

• found in: Carbohydrates, nucleic acids, lipids

• 2 types: aldehyde & ketone (refer to chemistry notes)

  • aldehyde: CO at one of the terminal carbon-end

  • ketone: CO at one of the internal carbons (O is double bonded to C, between 2 C)

functional groups: carboxyl (3)

what is the molecular formula? properties? (3) found in? (2)

• molecular formula: (-COOH)

• properties: charged, ionizes to release H⁺, considered acidic bc release H⁺ into solution

• found in: proteins, lipids

functional groups: amino

what is the molecular formula? properties? (3) found in? (2)

• molecular formula: (-NH₃)

• properties: charged, accepts H⁺, considered basic bc can remove H⁺ from solution

• found in: proteins, lipids

functional groups: phosphate

what is the molecular formula? properties? (2) found in? (1)

• molecular formula: (-OPO_3^2- or OPO₃H₂)

• properties: polar, considered acidic

• found in: nucleic acids

functional groups: sulfhydryl

what is the molecular formula? properties? (3) found in? (1)

• molecular formula: (-SH)

• properties: polar, reducing agent, contribute to 3D structure of proteins

• found in: proteins

what are condensation reactions? be able to draw them.

• = the removal of a hydrogen atom from the functional group of one subunit and an OH group from the other subunit’s functional group

• creates a covalent bond b/w 2 subunits, linking them tgt

• the OH and H come tgt to form a H₂O molecule

• results in formation of large molecules from smaller subunits

• reverse of hydrolysis

• = anabolic

what are hydrolysis reactions? be able to draw them.

• = the adding of an H atom to one subunit and an OH group to the other which were provided by a H₂O molecule

• H₂O molecule is used to break a covalent bond holding subunits tgt

• results in deformation of large molecules into smaller subunits

• reverse of condensation reactions

• = catabolic

carbohydrates —

monosaccharides (1) composed of? vs

disaccharides (2) composed of? solubility? vs

polysaccharides (2) composed of? solubility?

1. monosaccharides

• single sugar molecule composed of C₆, H₁₂, O₆

2. disaccharides

• composed of 2 monosaccharides joined tgt in a condensation reaction

• hydrophilic and easily dissolve in water

3. polysaccharides

• a chain of monosaccharides

• very polar → very hydrophilic, but bc very big → attract water & cannot dissolve

lipids —

saturated (3) what bonds & state at room temp? structure? 2 examples? vs

unsaturated (3) what bonds & state at room temp? structure? 2 examples?

monounsaturated vs polyunsaturated

1. saturated

• single bonds

• hydrocarbon chains are long & straight & packed closely tgt to form solid at room temp

• e.g. butter, animals

2. unsaturated

• presence of double bonds creates a kink in molecule → causes bending

• fluid & liquid at room temp bc not that closely packed tgt

• e.g. olive oil/plants

1. monounsaturated = fatty acid w/ one double bond

2. polyunsaturated = fatty acid w/ 2 or more double bonds

lipids —

triglyceride (3) composed of, what linkage, used for? vs

phospholipids (3) composed of? solubility? forms what when added to water?

triglyceride

• composed of 3 fatty acids & glycerol

• linkage bond is called ester linkage

• used for long-term sugar storage or for insulation of a multicellular organism

phospholipids

• glycerol attached to one phosphate group & 1 unsat. chain and 1 sat. chain

• hydrophobic

• form a sphere when added to water

lipids — steroids (3) lack of? composed of? examples? (3) vs waxes (3) composed of? 3 properties? used for? (2)

steroids

• NO fatty acids

• made of 4 hydrocarbon rings w/ several diff functionals groups

• e.g. cholesterol (found in plasma cell membrane in animal cells) & phytosterols (found in plant cells’ membranes) & makes hormones (i.e. estrogen, testosterone, progesterone)

waxes

• composed of long fatty acid chains linked to OH or carbon rings

• hydrophobic, non polar, soft solids

• used as a barrier to infections & diseases, helps plants conserve water

what is an isomer regarding to carbohydrates?

• isomers have the same molecular formula but different arrangement of atoms

• thus affecting biological functions

carbohydrates — function (3)

• primary source of energy (immediate & long-term)

• provide structural support

• cell to cell communication

lipids — function (3)

• energy storage

• building membranes & other cell parts

• insulation

proteins — function (7)

• alter rates of metabolic reactions

• transport materials in cells or body

• structural

• blood clotting

• part skin, tendons, ligaments

• assist in metabolism

• assist with immunity

protein structure

primary vs secondary vs tertiary vs quaternary.

why/how does this happen?

1. primary: sequence of amino acids in a linear sequence

2. secondary: alpha-helix (helical shape) or beta-pleated sheet (folded shape)

3. tertiary: additional folding & refining of chain as different “R” groups interact w/ e/o

4. quaternary: 2 or more diff polypeptide chains combine to form a functional protein

why/how: specific sequence of amino acids strongly influences the protein’s biological function

protein denaturing

what is it? why does it matter? (2)

• protein denaturing = process where a protein unfolds & loses its specific structure

• importance: it loses its biological function due to loss of specific 3D shape.

fluid model of the cell membrane — structure

• a mosaic of phospholipids, proteins, and carbohydrates

• asymmetrical — half of the lipid bilayer differ from other half (diff functions)

fluid model of the cell membrane — fluidity

• fluidity is influenced by sterols (lipids)

• e.g. cholesterol acts as membrane stabilizer — can decrease or increase fluidity by loosening or tightening space between phospholipids.

fluid mosaic model of cell membrane & carbohydrates (2)

__ and _ faces the exterior of the cell? functions? (2)

• glycolipids & glycoproteins face the exterior of the cell

• function: identify “self” from “non-self” cells (crucial for immune system) & act as receptors for signalling hormones & neurotransmitters, relaying messages into the cell

fluid mosaic model of cell membrane & lipids (2)

what lipid forms a ?

• phospholipid form a bilayer - hydrophilic heads face outside & inside of the cell

• hydrophobic fatty tails gather tgt inside

fluid mosaic model of cell membrane & proteins:

integral proteins (2) what proteins are exposed to ? environment? made of ? regions to allow ?

& peripheral membrane proteins (3) where are they found?

1. integral proteins

   • transmembrane proteins w/ regions exposed to the aqueous environment on both sides of the membrane

   • made of polar and non polar regions to allow their integration

2. peripheral membrane proteins

   • on surface & DNI w/ hydrophobic core

   • mostly on cytosol (inside) side of the membrane & part of the cytoskeletal

   • structural

passive transport (3) vs active transport (3)

passive

• no energy required

• movement from high conc. area to low conc. area

• spreads out randomly

active

• requires energy (ATP)

• molecules move against the concentration gradient

• carrier proteins are used to transport substances (e.g. ions)

  • (requires energy as it changes shape)

passive transport — diffusion

what type of molecules can pass through?

__ conc to _ conc

examples?

• free flowing

• small non polar particles through concentration gradient

• high conc. to low conc.

• e.g. O2, CO2, (& H2O)

passive transport — osmosis

movement of what?

from __ to _ solute conc?

moves from area of ? or ?? to an area w/ ?

• movement of WATER

• from low to high solute concentration

• moves from area of PURE or more conc. SOLUTE (salts) to an area w/ more SOLVENTS (water)

passive transport — osmosis

ISOTONIC VS HYPOTONIC VS HYPERTONIC

1. isotonic = conc of both the solute & solvent is equal

2. hypotonic = lower conc of solute & more solution

3. hypertonic = higher conc & lower solution

passive transport — facilitated diffusion

uses what to move through conc. gradient?

examples?

• use of integral channel carrier proteins to move through concentration gradient

• e.g. glucose, amino acids, sodium, H2O

• water moves faster through aquaporin protein channels (Is this even on test)

active transport — endocytosis

for bringing INTO or OUT of the cell?

what happens?

can be used for ? or for the cell to ?

• bulk transport of large external or many small molecules INTO the cell

• cell membrane engulfs particles w/ membrane and wraps them to form a vesicle

  • e.g. nutrients & signalling molecules

• could be for cell use or for the cell to destroy

  • e.g. microphage

active transport — exocytosis

what is it? uses? (2)

• fusing vehicles with the cell membrane to release contents OUT of the cell

• used for:

  • removing toxins or waste products from the cell’s interior

  • to move substances made in the cell to outside the cell to be used by the body