ch 2: the chemistry of life PT 2

four essential macromolecules

-carbs

-lipids

-proteins

-nucleic acids

monosaccharides

-simple carbohydrate

-three important monomers → glucose, galactose & fructose

disaccharides (carb)

-sugars made of two covalently bonded monosaccharides

-three important disaccharides → sucrose, lactose & maltose

polysaccharides (carb)

long chains of multiple monosaccharides

three important polysaccharides → glycogen, starch & cellulose

HDL (high-density lipoprotein) = “good cholesterol”

• Lower ratio of lipid to protein
• May help to prevent cardiovascular disease

50% protein to 50% fat

LDL (low-density lipoprotein) = “bad cholesterol”

• High ratio of lipid to protein
• Contributes to cardiovascular disease

25% protein to 75% fat

amino acids have a central carbon with three attachments

- Amino group
-Carboxyl group
- R (radical) group️

enzymes (3 characteristics)

-speed up chemical reaction by lowering the activation
energy

-highly specific for substrates

-used again and again in reactions

Nucleotides components

- Nitrogenous base (single or double carbon–nitrogen ring)
-Sugar (monosaccharide)
-One or more phosphate groups

DNA

-contains millions of nucleotides

-constitutes genes, the instructions for synthesizing proteins

*more stable

RNA

-carries out genetic instruction for synthesizing proteins

-assembles amino acids in right order to produce proteins

*more reactive & flexible

primary protein structure

-amino acid sequence joined by peptide bonds

secondary protein structure

-local coils fold

-alpha helix / beta sheet formed by hydrogen bonding

tertiary protein structure

overall 3D shape

-polypeptide chain folded & coiled by interactions in the R groups

quaternary protein structure

-most complex

-multiple chains joining & cluster of several tertiary units

ex→ HEMOGLOBIN