PART 5

a molecule that contains a large number of atoms

Cells that are made of water, small molecules, ions, and specialized structures. 4 small molecules are sugar, fatty acids, amino acids, and nucleotides.

Human body is mostly water 70% by weight. The rest of the body 25% is macromolecules.

Polysaccharides, proteins, and nucleic acids. Every macromolecule is a polymer built by linking together small subunits.. These subunits are called monomers and each of the three type macromolecules is made from a specific class of monomer.

are built from sugar molecules. The bond that holds one sugar to the next is a covalent blond. Forming a covalent bond in a macromolecule requires an energy input that comes from the removal of phosphate from ATP or a similar high energy molecule. This energy drives a water molecule from the two adjacent sugar molecules, enabling the covalent bond to form. Forming a covalent bond by displacing a water molecule is called dehydration reaction or condensation reaction This type of reaction happens in building proteins from amino acids and nucleic acids from nucleotides. .

every function within a cell requires a macromolecule. The covalent bonds that link monomers to form a macromolecule are essential, but not enough to make a functional structure. String of monomers covalently bound together interact with each other to form three dimensional shapes that give each macromolecule its special functional properties.

The two strands of nucleotides that make up a DNA molecule automatically wind around each other, driven by the chemistry of the bases to interact with each other on the inside of the molecule, and by the sugar phosphate backbone to be exposed to the outside where it interacts with water molecules. these type of bonds are not covalent bonds

hydrogen and ionic bonds are examples of non covalent bonds not strong and dont require an input of energy to form individual non covalent bonds are weak enough to form spontaneously but also break easily noncovalent bonds work together to give macromolecules shape, structure, and function

Polysaccharides and sugars are better known as carbohydrates function as a great source of energy and as structural components of organisms

starch is a polysaccharide used as an energy storehouse in plants. the energy storehouse in animals is glycogen and starch and glycogen are polymers made of glucose.

One way that we get the energy we need is to break down stored glycogen into glucose, which is then used by our cells to make ATP. the chemical reaction that converts a polymer of glycogen into monomers of glucose is called a hydrolysis reaction because molecules of water hydrolyse the covalent bonds. Hydrolysis is the opposite of a dehydration reaction.

are two of the most abundant molecules on Earth. Both are polysaccharide that is used to provide a support skeleton to certain animals or plants.

There are many different protein but every protein is built from the same raw materials-20 kinds of amino acids. Amino acids are linked together by a dehydration reaction to form a covalent bond that is called a peptide bond. once all amino acids in a particular protein are linked together, this polypeptide spontaneously folds into a specific three dimensional shape driven by hundreds of non covalent bonds leading to a functional protein or protein submit. it is a subunit because some proteins only become functional when several proteins subunits join together. An example is when hemoglobin is made of four separate polypeptide chains that each fold up spontaneously, and then they interact with each other to form a molecule of hemoglobin.

Proteins are the workhorses of the cell every chemical reaction in a cell and theres a lot of them are carried carried out by an enzyme nearly every enzyme is a protein that catalyzes (speeds up) a chemical reaction by reducing the activation energy. Think of the activation energy as a hill that reactants have to climb before they can slide quickly down the other side to become products.

Proteins can be structural, like collagen found in our tendons and ligaments other proteins can form structures that move, like the proteins in muscle. proteins also serve as transporters, like ions channels moving molecules across cell membranes or like hemoglobin carrying oxygen to cells throughout our body. Proteins serve as antibodies within the body’s immune system.

DNA and ENA are the two types of nucleic acids found in cells

is made of two nucleic acid polymers that wind around each other to form the famous DNA double helix. DNA stores the hereditary information within a cell

Ribonucleic acid is chemically very similar to DNA each monomer of RNA is a type of nucleotide called ribonucleotide ribonucleotide which is made up of a ribose sugar linked on one side to a trio of phosphates and on the other side to a nitrogenous base.

Differs from RNA because the nucleotides that make up DNA called deoxyribonucleotides are slightly different from ribonucleotides. RNA perform a number of critical functions within cells RNA is also essential for converting the information stored in DNA into proteins

Lipids are sometimes grouped among the macromolecules, but lipids are not polymers. They are not polymers because they are not built from monomers joined together via dehydration reactions. Lipids are diverse sets of molecules that are group together because of how they interact with water. Hydrophobic meaning they do not dissolve in water because most lipids is made up mostly of C-C and C-H and these type of bonds do not interact with water.

Lipids known as phospholipid which form the cell membrane that encloses a cell. also function as concentrated energy stores for the body and these triglycerides store 5x as much energy as a comparable amount of carbohydrate. 3rd class of lipids is steroids, which includes chlosterol and the hormones testosterone and estrogens.

Phospholipids and triglycerides are both made from the same components fatty acids and glycerol.

Fatty acids are long hydrocarbon chains with a carboxylic acid on one end.

is a type of sugar