PART 5 Flashcards
Macromolecules
a molecule that contains a large number of atoms
What are humans made of ?
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 composition
Human body is mostly water 70% by weight. The rest of the body 25% is macromolecules.
Three classes of 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.
POLYSACCHARIDES
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. .
Functions of Macromolecules
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.
DNA
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
Noncovalent 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
Carbohydrates
Polysaccharides and sugars are better known as carbohydrates
function as a great source of energy and as structural components of organisms
Starch
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.
How do we get energy?
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.
Chitin and Cellulose
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.
Amino Acids
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.
Enzyme
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.
Protein function
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.
Nucleic Acids
DNA and ENA are the two types of nucleic acids found in cells
DNA
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
RNA
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.
