Biochemistry flashcards - Grade 12 Biology

intramolecular bonds

1. covalent bonds - 2 non metals sharing e- equally
2. ionic bonds - 1 atom loses e- and the other gains the e-
3. polar covalent bonds - sharing of e- less equally

type of intramolecular bond is distinguished by difference in electronegativity (∆EN):

covalent = ∆EN < 0.4 → share equally

ionic = ∆EN > 1.7 → atom w greater EN takes e- from atom w lesser EN, both become charged

polar covalent = ∆EN = 0.5-1.7

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polar covalent bonds

* one atom has a stronger hold on shared e-
* one end of molecule gets slightly + charged, one end gets slightly - charged

δ- = stronger EN end gets - charge

δ+ = weaker EN end gets + charge

influences attraction & biological interaction

water is polar, has polar covalent bonds

e- spend more time near the O than the H, difference in charge btwn poles of the molecules

δ- = O

δ+ = H

due to its polarity, it forms H bonds w itself → a lot of H bonds = a lot of strength

water forms bonds through

* H bonding w itself
* cohesion: water molecules are attracted to other water molecules
* adhesion: water is a polar molecule and thus attracts other polar molecules

intermolecular forces

1. London dispersion forces: v weak attraction btwn all molecules, even non polar ones. increase w molecule size
2. dipole dipole attraction: attractive force btwn 2 polar molecules
3. H bonding: special kind of dipole dipole attraction btwn 2 polar molecules w H bonded to N, O, F

carbon, the backbone of nearly every bio molecule except for water

* organic compound = compound containing C-H bonds and maybe other elements too such as N, O, etc.
* often found in organisms
* C-H is non polar bond → hydrocarbons are non polar but polarity can be achieved by adding other atoms called functional groups

functional groups (FG)

molecules interact w eo at specific regions of their molecules and classifies molecule types

after a rxn btwn 2 molecules’ functional groups, a linkage will be formed

alcohols

* FG: -OH \~ hydroxyl
* simplest = CH3OH

aldehydes

* end group of fg -CO \~ carbonyl
* simplest = HCOH

ketones

* middle fg -CO ; middle carbon
* simplest = CH3COCH3

organic acids

* fg: -COOH \~ carboxyl; end group
* simplest = HCOOH

amine

* fg: -NH2 \~ amino
* simplest = CH3NH2

phosphate group

* fg: -PO4 \~ phosphate ; no official classification

hydrolysis rxns

rupture, use of water to rupture/break down, catabolic, splits a larger molecule apart \~ water required and used up

dehydration synthesis rxns

condenses smaller particles into larger ones. anabolic and builds up molecules \~ water is released as a product

ether linkages

* glycosidic link btw sugars when it occurs btwn sugar molecules
* btwn 2 hydroxyl groups
* used in carbohydrates
* pattern COC

ester linkages

* btw hydroxyl and carboxyl
* used in triglycerides
* pattern OCO

phosphate ester linkages

* btwn hydroxyl (1st) and phosphate (2nd)
* used in phospholipids and nucleic acid - instructs DNA and RNA
* pattern OPO

peptide linkages

* btwn carboxyl (1st) and amino (2nd)
* links amino acids together
* pattern OCNH

carbohydrates

* made of C, H, O - ratio 1:2:1
* formula - (CH2O)n where n is # of carbons
* short term energy source, building blocks, cell surface markers
* 3 kinds - monosaccharides, disaccharides, polysaccharides

monosaccharides

* chain of carbons w hydroxyl groups attached
* contain carbonyl groups
* have diff #s of carbons - commonly 3, 5, 6 carbon sugars
* isomers = compounds with same empirical formula but diff configurations
* glucose, galactose, fructose are isomers - C6H12O6

glucose

galactose

fructose

disaccharides

* 2 simple sugars attached by ether/glycosidic linkage, dehydration synthesis rxn - 2 OH linked together

maltose

glucose + glucose → maltose + water

* linkage btw c1 on glucose 1 and c4 on glucose 2
* a 1-4 glycosidic linkage

lactose

b galactose + glucose → lactose + water

* glucose can be a or b
* linkage btw c1 on galactose 1 and c4 on glucose 2
* b 1-4 glycosidic linkage

sucrose

glucose + fructose → sucrose + water

* flip fructose so hydroxyl on the side for bonding
* linkage btw c1 on glucose 1 and c2 on fructose 2
* 1-2 glycosidic linkage (either a or b depending on the glucose)

polysaccharides

* large molecules - same linkage used to make a strand, several hundred-thousand monosaccharides bonded w glycosidic linkages
* straight chain = a 1-4 glycosidic linkages or brained chains = a 1-6 glycosidic linkages
* energy storage and structural support
* all a or all b linkages

starch

* plant energy storage
* straight chains - amylose
* branched chains - amylopectin
* stored in leaves and roots

glycogen

* animal energy storage
* many side branches
* made in liver, muscle, fat cells

cellulose

* plant structural support
* in cell walls
* H bonds btw chains from fibres, strong
* straight chain of b glucose units - b 1-4 linkages

chitin

* animal structural support and fungi as well
* polymer of straight chain b-N-acetylglucosamine
* 2nd most abundant organic material
* no branches

lipids

* mostly C and H, with few O
* hydrophobic - repel water
* few polar O-H bonds & more non polar C-H bonds
* long term nrg storage, membranes, dissolving fat soluble vitamins ADEK
* fats, phospholipids, sterols, waxes

nucleic acid

* molecules that are polymers made of nucleotides
* 3 components - pentose sugar, phosphate group, nitrogenous base

proteins

* structural support, storage, transport, signalling, cell response, movement, defence, catalysis of rxns
* amino acids make these up
* side chains determine function
* 4 levels of folding:
* 1º - N → C terminus
* order determines folding
* 2º - coils and folds ; stabilized by H bonds btw amino and carboxyl groups
* a helixes and b pleated sheets
* 3º - super coiling involving side groups
* 4º - many polypeptide chains come together

enzymes

* bio catalysts - assist in chemical rxns
* distort substrate chemical bonds
* sometimes need cofactors

cell membrane and transport

* fluid mosaic model
* phospholipids = main molecule
* membrane fluidity
* proteins - integral and peripheral