unit 3 MACROMOLECULES

isotopes

atoms of an element with the same atomic number but a different mass number (different neutrons)

what can isotopes be used for in the body?

can be used as tracers to find different diseases in the body.

• ex: iodine 131 can be used to figure out what the problem is concerning the hormones and metabolism through the thyroid glands

how much water is in the human body

• human body is 65% water

• brain is 70%

• lungs is 90%

• and bone tissue is 22%

why is water the universal solvant?

because it is a very polar molecule - allowing it to form chemical bonds with other molecules and ions, including other water molecules

bonded by hydrogen bonds which are extremely strong bonds (electropositive H and electronegative O, N, or F)

7 strong acids

• H₂SO₄

• HI

• HBr

• HNO₃

• HCl

• HClO_{3 /} HClO₄

what does hemoglobin do in the body

since molecules like oxygen and carbon dioxide cannot form hydrogen bonds with water, and thus, are only soluble

therefore a soluble protein carrier (HEMOGLOBIN) is needed to transport them within the blood

what is a buffer

a buffer’s job is to resist changes in pH levels

• When a biological reaction releases excess H+ ions, buffers combine with H+ ions so they are no longer free in solution.

• Conversely, if the H+ ions in solution decrease, buffers can release H+ ions into the solution

what is a hydrocarbon

molecules of carbon and hydrogen

they are nonpolar B/C of their electronegativity, but become polar when mixed with oxygen

what is a macromolecule

A large molecule composed of a great number of repeating subunits

Four major classes of macromolecules

• carbohydrates

• lipids

• protein

• nucleic acid

what does a condensation reaction (dehydration synthesis) do? what type of reaction is this called and why?

creates a covalent bond between interacting subunits, linking to each other. involves the production of water in order to link the subunits

called anabolic reactions because they ABSORB energy

what does a catabolic reaction do? what type of reaction is this called and why?

breaks macromolecules down to their subunits. the water molecule is needed to break the bonds holding the subunit together

called a hydrolysis reaction because they RELEASE energy

what do both condensation and hydrolysis reactions require?

enzymes (which are biological catalysts), they speed up the reaction without being consumed in the reaction

3 groups of carbohydrates

• monosaccharide (single sugar)

• disaccharides (2 sugar)

• polysaccharides (many sugars)

what are the 2 possible arrangements when glucose forms a ring?

glucose α or glucose ß

• two different arrangements of the -OH group which is bound to the carbon at position 1
  

what are disaccharides?

sugars containing two simple sugars bonded by a glycosidic linkage (condensation reaction with sugars)

what are polysaccharides?

complex carbs that contain hundreds to thousands of monosaccharides held together

• they provide energy, storage, and structural support in living cells

what is polymerization

the process in which identical or variable subunits, called monomers, link together to form a large molecule

what is cellulose

• are straight chain molecules that when intertwined form tough, insoluble fibres

• made with polymer of B glucose

• humans do not have the enzymes to break down cellulose

  • the linkage between the beta glucose cannot be broken down by amylase. it needs to be broken down by glucase

what are lipids

hydrophobic molecules composed of C,H, and O

• are used for storing energy, building membranes and other cell parts, and as chemical signaling molecules

what are the 4 groups of lipids

• fats

• phospholipids

• steroids

• waxes

what is a calorie

• a gram of far stores about 38kJ of chemical energy per grams

• 1 calorie is equivalent to 4.18kJ

  • animals convert excess carbs into far and store the fat as droplets of cells of adipose tissue

what are fatty acids

a long hydrocarbon chain containing a single carboxyl group at one end (usually 16-18 carbons long)

what are saturated fats

fats that only have single bonds between carbon atoms

• solid at room temperature

what are unsaturated fatty acids

fats that have one or more carbon-carbon double bonds

• they are not saturated with hydrogens

• Liquid at room temp 

  • Why? B/C there are kinks and spaces in between bonds and therefore can separate easier

what is hydrogenation

hydrogenation adds hydrogen atoms to the double bonds in unsaturated triglycerides of liquid fats to make them semi-solid so they can be used at room temperature

• becomes semisaturated

what is a triglyceride

most well-known fats

• contains three fatty acid chains linked to a glycerol molecule

• fatty acids are joined to the glycerol through dehydration synthesis

what is a phospholipid

a glycerol molecule with two non-polar fatty acid chains and a highly polar phosphate group

what is an example of phospholipids in action

cell membranes are mostly made up by phospholipids

• polar head is at the top, non-polar items come through

• polar items cannot go through

what are steroids

Compact hydrophobic molecules containing 4 fused HC rings with several different functional groups

what are some examples of steroids

• vitamin D

• bile salts

• testosterone, estrogen, and progesterone

what are waxes

lipids containing long-chain fatty acids linked to alcohols or carbon rings

• they are very hydrophobic

what are proteins

polymers made up of many subunits of amino acids folded into a 3D structure which specifies its function

what is an amino acid

organic molecule possessing a central carbon atom attached to a

• amino group

• carboxyl group

• hydrogen

• r group

amino acids can either be

• nonpolar

• polar

• acidic

• basic

• essential

• nonessential

what is an essential amino acid

amino acids that must be taken by consumption

what is a nonessential amino acid

amino acids that can be produced by the body

what are the 9 essential amino acids

PVT TIM HiLL

• phenylaline

• valine

• threonine

• tryptophan

• isoleucine

• methionine

• histidine

• leucine

• lysine

what are peptide bonds

bonds that hold amino acids together

• formed from the amino group of one to the carboxyl group of the other

  • called an amide bond

what is a polypeptide chain

• chain of amino acids held together by peptide bonds

  • contains an amino acid at one end and a carboxyl group at the other

• go through 4 levels of structures to become a protein

what is the primary structure of a polypeptide chain

• the unique linear sequence of its amino acids in each polypeptide chain

  • amino acids in the polypeptide is called a residue

• as the chain grows in protein synthesis, it folds at various locations along its length

• linking is done by hydrogen bonding

what is the secondary structure of a polypeptide chain

• the coils and folds of the polypeptide chain

• depending on how the H-bonds for, the secondary structure can be either folded into:

  • ß-pleated sheet which forms by a side-by-side alignment of the amino acid chain 

  • α-helix which is a delicate coil held together by hydrogen bonds between every 4th amino acid 

what is the tertiary structure of a polypeptide chain

• the overall 3D shape of the protein due to a range of bonding interactions among the amino acid R groups

• the intermolecular reactions of the R groups determine the shape

what are the 2 types of intermolecular reactions of the R groups

• hydrophobic interactions= nonpolar side groups cluster together

• disulfide bridges= when two cysteine amino acids line up and react

what is denaturing

the unraveling of a protein

what causes denaturing

if a protein’s environment changes

• temperature

• pH

• ionic concentration

what is an enzyme

an enzyme is a catalyst, it allows reactions to speed up without increasing temperature.

it is important that temperature doesn’t change because if the temperature changes, it can cause proteins to denature

what is a substrate

the reactant that an enzyme acts on when it catalyzes a chemical reaction

• the substrate binds to a particular site on the enzyme

what is an active site

the location on the enzyme where the substrate binds to

what is the induced-fit model of an enzyme

when the substrate enters the active site, its functional groups come close to the functional groups of a number of amino acids

this causes the protein to change shape and better accommodate the substrate

• the enzyme converts the substrates into one or more products and remains unchanged after the reaction

what are the 4 conditions that will affect enzyme activity

• concentration of both the enzyme and substrate

  • if there is excess substrate, the rate of the enzyme reactions limits the rate of reaction

• age causes enzymes to break down over time

• the lower the temperature, the lower the enzyme activity

• if the pH changes, the enzyme changes/dies.

what is a coenzyme

an organic element inside an enzyme that causes the enzyme to work. without the coenzyme, enzyme would not work

what is enzyme inhibition

when you don’t want the enzyme to do its job

what are the 3 types of enzyme inhibition

• competitive inhibitors

• noncompetitive inhibitors

• allosteric inhibitors

what are competitive inhibitors

they compete for the active site of the enzyme

• competitive inhibitors are so similar to the enzyme’s substrate that they are able to enter the enzyme’s active site and block the normal substrate from binding

  • substrate cannot be broken down by enzyme

what are noncompetitive inhibitors

they do not compete for the active site, but they attach themselves to the enzyme to either slow the enzyme reaction rate down or change the job of the enzyme

what are allosteric inhibitors

they attach to the enzyme to change the shape of the enzyme so that i doesn’t fit lock and key with the substrate

what is feedback inhibition

its when the products inhibit the reactant

• a method used by cells to control metabolic pathways involving a series of sequential reactions, each catalyzed by a specific enzyme

• basically, the product of the full reaction will inhibit an enzyme at the beginning of the reaction keeping all the products “in check”