Carbohydrates and Lipids (not finished)

what is the monomer of carbohydrates?

monosaccharides

what is the monomer of lipids?

fatty acids, glycerol, phosphate groups

what is the monomer of proteins?

amino acids

what is the monomer of nucleic acids?

nucleotides

how are macromolecules formed?

condensation reactions → molecules combine together forming covalent bonds and resulting in polymers, water removed

how are polysaccharides formed?

when two hydroxyl (OH) groups on different monosaccharides interact to form a (covalent) glycosidic bond

how are polypeptides formed?

by condensation reactions where two amino acid monomers interact to form a strong covalent peptide bond

how are nucleic acids formed?

• separate nucleotides are joined by condensation reactions to form a phosphodiester bond

• occur between the phosphate group of one nucleotide and the pentose sugar of the next

what is the name of the reaction that breaks macromolecules into their monomers?

hydrolysis (breaking with water)

what is the general formula of monosaccharides?

C_nH_2nO_n

what are the properties of monosaccharides?

• colourless crystalline molecules

• soluble in water

what is the formula of glucose?

C₆H₁₂O₆

what is the difference between alpha glucose and beta glucose?

what polysaccharides are formed from alpha glucose?

starch and glycogen

what polysaccharide is formed from beta glucose?

cellulose

what are the properties of glucose?

• stable structure due to strong covalent bonds

• soluble in water as it is polar

• soluble in water (easily transported)

• source of chemical energy when bonds are broken

properties of carbohydrates

• compact → large quantities stored in a small space

• insoluble

• useful structurally as strong and durable, insoluble and slightly elastic, chemically inert → eg cellulose

what is the structure of amylose?

• unbranched helix-shaped chain with 1,4 glycosidic bonds between a glucose molecules

• helix shape = compact = resistant to digestion

what is the structure of amylopectin?

• 1,4 glycosidic bonds between a glucose molecules as well as 1,6 glycosidic bonds = branched

• branches result in many terminal glucose molecules that are easily hydrolysed for use

what is the structure of glycogen?

• a glucose joined by 1,4 and 1,6 glycosidic bonds

• more branched than amylopectin = more free ends where glucose can be hydrolysed

• means glucose can be broken down quickly

what is the structure of cellulose?

• can be straight and unbranched

• polymer of b glucose monomers

• every alternate molecule of b glucose must flip

• alternating pattern allows hydrogen bonding adding strength

what are microfibrils?

linking of several molecules of cellulose through hydrogen bonds

how are glycoproteins formed?

covalent bonds between carbohydrates and polypeptides

what is the function of glycoproteins?

• receptors in cell recognition and identification

• receptors for cell signalling molecules (like hormones and neurotransmitters)

• endocytosis

• cell adhesion and stabilisation

how do glycoproteins link to ABO blood types?

• glycoproteins act as antigens that identify cells as self or non self

• cells recognised as non self trigger immune responses

which glycoprotein antigens correspond to which blood type?

• type A → type A glycoprotein antigens

• type B → type B

• type AB → both types

• type O → neither

what are some examples of lipids in living organisms?

fats, oils, waxes, steroids

what do saturated fatty acids contain?

only single carbon-carbon bonds

what do unsaturated fatty acids contain?

one or more carbon-carbon double bond

how are triglycerides formed?

esterification

• ester bond formed when hydroxyl group of a glycerol molecule bonds with the carboxyl group of a fatty acid

• ester bond is a condensation reaction

how are phospholipids formed?

• glycerol and fatty acids

• unlike triglycerides they only have two fatty acids bonded to a glycerol molecule

• the third has been replaced with a phosphate ion

what are the properties of phospholipids?

• phosphate is polar, soluble in water (hydrophilic)

• fatty acid tails are nonpolar, insoluble in water (hydrophobic)

• amphipathic → hydrophilic and hydrophobic regions

what is released from the hydrolysis of triglycerides?

glycerol and fatty acids

what are lipids (in terms of energy)?

energy dense due to high number of C-H bonds

what is produced when lipids are respired?

• a lot of water compared to carbohydrates → metabolic water and can be used as a dietary water source in the absence of drinking water

• camel’s hump filled with lipids that provide metabolic water

• bird’s egg is filled with lipids to provide energy and metabolic water

where are lipids stored in animals?

adipose tissue

• subcutaneous fats below the skin

• visceral fats around major organs

what are the properties of saturated fatty acids?

• only single carbon-carbon bonds

• ‘saturated’ with hydrogen

• straight molecules so lipids can pack tightly together

  • increases their melting point causes them to be solid at room temp

what are the properties of unsaturated fatty acids?

• not all the carbon-carbon bonds are single bonds

• ‘unsaturated’ with hydrogen

• double bonds cause kinks in the structure so they cannot pack as tightly together

• often liquid at room temp

what is a monounsaturated fatty acid?

a fatty acid with one C=C double bond

what are polyunsaturated fatty acids?

a fatty acid with many C=C double bonds