Chapter 2

what are the most abundant type of biomolecule?

- *carbohydrates* - monosaccharides, disaccharides, polysaccharides

secondary structure

- as polypeptide forms it takes on this structure, which is a spatial arrangement or shape. -stablized by hydrogen bonding between different parts of the molecule. The three most common shapes for polypeptide chains are a spiral called the *helix*, B-strand whose bond angles create a zigzag shape rather than a spiral, and *U-shaped* B turns. In a polypeptide, B-strands often assemble into side-by-side pleated sheets.

Primary Roles of Electrons in physiology.

- formation of covalent bonds -fomation of ions -the capture and transfer of energy -formation of destructive free radicals

high energy electrons

- in certain atoms can capture energy from their environment and transfer it to other atoms, so that the energy can be used for synthesis, movement, and other life processes. The released energy may also be emitted as radiation

what do monosaccharides have?

- most common monosaccharides are the building blocks of complex carbohydrates and have either five carbons, like *ribose*, or six carbons, like glucose (also known as dextrose).The major disaccharides are formed when glucose combines with another monosaccharide.You can recognize most mono- and disaccharides by the -ose end- ing on their names.

how are lipids and phospholipids similar?

- most similar in structure - Both groups contain a simple 3-carbon molecule known as *glycerol* plus long molecules known as *fatty acids*. Phospholipids also include a phosphate group+H( 2PO4).

primary structure

- sequence of amino acids in a peptide or protein chain - genetically determined and is essential to proper function. For

polar molecules

- uneven sharing -When the electrons are shared unevenly, the atom with the stronger attraction for electrons develops a slight negative charge (indicated by ,+), and the atom with the weaker attraction for electrons develops a slight positive charge( ,*). Molecules that develop these regions of partial positive and negative charge -*hydrophilic*

Protein Interactions

-*enzymes* -*membrane Transporters* proteins in cell membranes help move substances between intra and extracellular compartments. -*signal molecules* act as hormones and other signal molecules -*receptors* bind signal molecules and initiate cellular responses -*binding proteins* mostly in extracellular fluid bind and transport molecules throughout body -*regulatory proteins* turn cell processes on and off/up and down. Transcription bind to DNA and alter gene expression and protein synthesis -*immunoglobulins* antibodies

What two large groups are proteins assembled into?

-*fibrous proteins*are found as pleated sheets or in long chains of helices -insoluble in water and form important structural components of cells and tissues. Examples include collagen, a fibrous protein found in many types of connective tissue, and keratin, a fibrous protein found in hair and nails.

what are the most structurally diverse biomolecules.

-*lipids* or fats made up of carbon, hydrogen, and oxygen. contain less oxygen than carbs. -not very soluble in water -solid at room temperature.

How are covalent bonds formed?

-Covalent Bonds Are Formed When Adjacent Atoms Share Electrons -strong bonds that result when two atoms share a pair of electrons, one electron from each atom -*double bond* share adjacent atoms rather than just one pair.

Globular Proteins

-amino acid chains that fold back on themselves to create a complex tertiary structure containing pockets, channels, or protruding knobs. The tertiary structure of globular proteins arises partly from the angles of covalent bonds between amino acids, and partly from hydrogen bonds, van der Waals forces, and ionic bonds that stabilize the tertiary structure -amino acid cysteine also plays an important role in globular protein shape.Cysteine contains sulfur as part of a sulfhydryl group. -soluble in water act as carriers for water insoluble lipids in blood -enzymes that increase the rate of chemical reactions

ions

-charged atoms -gains or looses an electron an atom becomes an ion -*Cations* positively charged - loss of electrons -*anions*- negatively charged (-)

shells

-electrons move around the nucleus in a series of energy levels. -lowest energy level is closest to nucleus. -arrangement of electrons in the outer shell of an atom determines its ability to bind with other atoms.

list of essential elements

-oxygen, carbon and hydrogen. -nitrogen, phosphorus, sodium, potassium, calcium, magnesium, sulfur, and chlorine)

quaternary structure

-several protein chains associate with one another to form a functional protein

nonpolar molecule

-shared electrons are distributed so evenly that there are no regions of partial positive or negative charge -*hydrophobic*

atomic mass

-total mass of the protons and neutrons in the atom, expressed in atomic mass units, where 1 amu , 1.6605 - 10+27 kg.

radioisotopes

-unstable and emit energy called radiation. Radioisotopes emit three types of radiation:alpha,beta,,and gamma. -can have medical uses - nuclear medicine

tertiary structure

3D shape of a protein

eicosanoids

20-carbon fatty acid found in animals - thromboxanes, leukotrienes, and prostaglandins

nucleic acids

DNA and RNA nucleotide polymers -store genetic information within the cell and transmit it to future generations of cells

biomelcules

Organic molecules associated with living organisms -Four major groups: Carbohydrates, lipids, proteins, and nucleotides - *polymers* made up of repeating units - several combinations of atams *functional groups*, occur repeatedly in biological molecules.

what are other required elements called but are needed in smaller quantities?

Trace elements or minor essential elements

buffer

any substance that moderates change in pH -many contain anions

glycolyids

carbs and lipids

glycoproteins

carbs and proteins

solution

combo of solvents and solutes

Atoms

composed of protons, neutrons and electrons. - building blocks of all matter, including the human body were once thought to be the smallest particles of matter [atomos, indivisible].

pH

concentration of H+ in body fluids

compounds

contain more than one element

solubility

degree to which a moleculte is able to dissolve

isotopes

different number of neutrons - equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic mass but not in chemical properties

purines

double ring structure -adenine and guanine

Starch

glucose for energy stored in cells for energy in the form of a polysaccharide in plants. - digestable by humans - most abundant organic molecule on earth

Steroids

lipid related molecules -structure: 4 linked carbon rings -Cholesterol source of steroids

solvents

liquids into which solutes dissolve

fatty acids

long chains of carbon atoms bound to hydrogens with a carboxyl group. -*saturated* if there are no double bonds between carbons -*monosaturated* one double bond -*polyunsaturated* two or more double bonds - the more saturated the more likely to be solid at room temp

organic molecules

molecules that contain carbon

Triglycerides

most important form of lipid in the body, more than 90% of our lipids -predictors of artery disease

electrons

negatively charged. -name number as protons -travel around nucleus in orbits

What elements make up more than 90% of the body's mass?

oxygen, carbon and hydrogen.

basic/alkaline

pH greater than 7

Proteins

polymers of smaller building block molecules called *amino acids* -*essential amino acids* 9 that must be obtained from dietary proteins -*peptide bond* two amino acids link together, the amino group of one is joined to the carboxyl group of the other -*oligopeptide*

proton

positively charged -same number as electrons, electrical charge of zero -in nucleus

Conjugated proteins

protein molecules combined with another kind of biomolecule

lipoprotiens

proteins and lipids

ionic bonds

result when an atom has such a strong attraction for electrons that it pulls one or more electrons completely away from another atom.

covalent bonds

shared electrons form strong covalent bond to create molecules

element

simplest type of matter. -listed in periodic table

pyrimidines

single ring -cytosine, thymine and uracil

acid

solutions have a pH less than 7

free radicals

some types of radiation alter the distribution of electrons in atoms, converting the atoms into unstable free radicals. Every free radical has at least one unpaired electron.

glycogen

stored glucose in cells for energy in form of a polysaccharide in animals

solutes

substances that dissolve in liquid

Antioxidants

substances that prevent damage to our cells by giving up electrons without becoming free radicals. Many antioxidants occur naturally in fruits and vegetables. The most common antioxidants promoted in vitamin supplements are vitamins C and E.

atomic number

the number of protons in the nucleus -determines which element the atom is

nucleotides

three-part molecule composed of (1) one or more phosphate groups, (2) a 5-carbon sugar, and (3) a carbon-nitrogen ring structure called a *nitrogenous base* - two possible sugars: ribose or deoxyribose

molecules

two or more atoms link by sharing electrons

neutrons

uncharged -in nucleus

hydrogen bond

weak attractive force between a hydrogen atom and a nearby oxygen, nitrogen, or fluorine atom.

Van der Waals forces

weak, nonspecific attractions between the nucleus of any atom and the electrons of nearby atoms. Two atoms that are weakly attracted to each other by Van der Waals forces move closer together until they are so close that their electrons begin to repel one another. Consequently, van der Waals forces allow atoms to pack closely together and occupy a minimum amount of space.