Anatomy and Physiology Chapter 2

atom

the smallest stable unit of matter

molecule

a chemical component that consists of two or more atoms that are joined together by covalent bonds

cell

the smallest unit of life

tissue

a group of similar cells that work together to perform a particular function

4 major types of tissue

epithelial tissue

connective tissue

muscle tissue

nervous tissue

organ

a component of the body that consists of two or more different types of tissues that have a specific function and typically have a characteristic shape

organ system

a group of organs that perform a common function

organism

the living individual formed by the interaction of all the organ systems of the body

element

matter that consists of only one type of atom

compound

matter that is formed from the chemical combination of two or more atoms of different elements

protons

have a positive charge

located in the nucleus of the atom

neutrons

neutral

located in the nucleus of the atom

electrons

have a negative charge

located outside the nucleus in electron shells or in an electron cloud

dalton

atomic mass unit (amu)

atomic number

refers to the amount of protons in an atom

mass number

the sum of the number of protons and neutrons in an atom

isotopes

atoms of an element that have different numbers of neutrons and therefore different mass

the electrical neutrality of atoms

the number of electrons in an atom of an element always equals the number of protons

ion

an atom that gives up an electron or gains an electron. becomes a charged particle called an ion

ionization

the process of giving up or gaining electrons

cations

an ion with a positive charge

when an atom gives up one or more electrons to another atom

anions

an atom with a negative charge

forms when an atom gains one or more electrons from another atom

chemical bonds

the forces that hold together the atoms of a molecule or compound

valence shell

the number of electrons in its outermost shell

ionic bonds

chemical bonds that form between ions with opposite charges due to the transfer between atoms

covalent bonds

chemical bonds that involve the sharing of electrons between atoms

single covalent bonds

when two atoms share one electron pair

double covalent bond

when two atoms share two pairs of electrons

triple covalent bond

when two atoms charge three pairs of electrons

nonpolar covalent bonds

two atoms share electrons equally

polar covalent bonds

the sharing of electrons between two atoms is unequal.

the nucleus of one atom attracts the shared electrons more strongly than the nucleus of the other atom

electronegativity

the power to attract electrons to itself

hydrogen bonds

chemical bonds that form between a hydrogen atom with a partial positive charge and a neighboring electronegative charge

free radical

an atom or molecule with an unpaired electron in the outermost shell

chemical reaction

occurs when new bonds form or old bonds break between atoms

reactants

the starting substances

products

the ending substances

reversible reaction

the products can revert to the original reactants

chemical equilibrium

the rate of the forward reaction is equal to the rate of the reverse reaction

hydrophilic

dissolves easily in water

polar

water-soluble

hydrophobic

nonpolar

lipid-soluble

acid

a substance that dissociates into one or more hydrogen ions and one or more anions

also referred to as a proton donor

base

removes positive hydrogen ions from a solution and is therefore a proton acceptor

ph scale

extends from 0 to 14

7 being the midpoint and therefore neutral

acidic solution

has more H+ than OH-

ph of less than 7

basic (alkaline) solution

more OH- than H+

ph above 7

macromolecules

large molecules that have important biological roles, including energy storage, structural support, storing and retrieving genetic information and catalysis.

4 major macromolecules

carbohydrates

lipids

proteins

nucleic acids

organic compound

consists primarily of carbon atoms

inorganic compounds

very few, if any carbon atoms

carbon skeleton

the chain of carbon atoms in a macromolecule, usually held together by covalent bonds

polymer

a large molecule that consists of 3 or more monomers linked together by covalent bonds

dehydration synthesis

aka condensation

the process where two monomers are covalently linked to each other through the loss of a molecule of water

dimer

formed if only two monomers come together via dehydration synthesis

hydrolysis

means water-splitting

the process by which a monomer is released from a polymer via the addition(splitting) of a water molecule

carbohydrates

organic compounds that consist of carbon, hydrogen, and oxygen in a ratio of 1:2:1

3 major types of carbohydrates

monosaccharides

disaccharides

polysaccharides

monosaccharides

single sugar molecules that serve as monomers for larger carbohydrates

glucose, fructose, and galactose are nutrients for the cells of the body

DNA and RNA are structural components of nucleic acids

disaccharides

carbohydrates formed from the combination of two monosaccharides by dehydration synthesis

sucrose, lactose, maltose

polysaccharides

carbohydrates formed from the union of 3 or more monosaccharides by dehydration synthesis

glycogen, starch

lipids

organic compounds that contain carbon, hydrogen, and oxygen but the ratio of oxygen to the other atoms is lower than in carbohydrates

4 types of lipids

fatty acids

triglycerides

phospholipids

steroids

fatty acids

serve as the monomers for larger lipids

consists of a long hydrocarbon chain and carboxyl group which functions as an acid

triglycerides

consists of three fatty acids and one molecule of glycerol that are covalently joined via dehydration synthesis reactions

can be either solids or liquids at room temperature

solids: fats

liquids:oils

adipocytes

fat storage cells

located in adipose tissues

phospholipids

consists of 2 fatty acids, a glycerol molecule, a phosphate group, and a nitrogen containing group

a major component of the plasma membrane of cells

lipid bilayer

a double layer that is organized such that the non polar tails face each other internally and the polar heads face the water in the ECF and the ICF

steroids

consists of 4 hydrocarbon rings that are fused together

ex: cholesterol, estrogen, testosterone, cortisol

protein

organic compounds that contain carbon, hydrogen, oxygen, and nitrogen

types of proteins

structural proteins

transport proteins

contractile proteins

antibodies
enzymes

hormones

receptors

structural proteins

provide support

ex: collagen, elastin, keratin

transport proteins

involved in the transport of substances across a membrane or through the blood

ex: an ion channel through the plasma membrane

contractile proteins

involved in muscle contraction, resulting in the movement of body parts

ex: actin and myosin

antibodies

proteins that protect the body from disease by destroying microbes

enzymes

proteins that catalyze (accelerate) chemical reactions

ex: sucrase

hormones

regulate the activities of specific cells in the body

receptors

proteins that allow binding of a specific ligand

amino acids

consists of a carbon atom covalently bonded to 4 components

4 main amino acids

amino group

carboxyl group

hydrogen atom

variable group (R group)

dipeptide

formed when two amino acids are joined together by a peptide bond via dehydration synthesis

polypeptide

consists of 3 to 100 amino acids covalently joined by peptide bonds

protein

consists of more than 100 amino acids, often thousands, covalently joined by peptide bonds

primary structure of proteins

refers to a proteins unique sequence of amino acids

secondary structure of proteins

refers to areas within a protein where regions of amino acids twist and fold in regular patterns

2 major types: alpha helix and beta pleated sheet

alpha helix

coiled regions of secondary structure within a protein

beta pleated sheet

zig-zag regions of secondary structure within a protein

tertiary structure of a protein

refers to the overall three-dimensional shape of an individual protein chain

quaternary structure of a protein

refers to the overall arrangement of the subunits of a protein

only used for proteins that have more than one subunit

nucleic acids

organic compounds that consist of carbon, hydrogen, oxygen, nitrogen, and phosphorus

consists of two types:

deoxyribonucleic acid (DNA)

ribonucleic acid (RNA)

three types of RNA

messenger RNA (mRNA)

transfer RNA (tRNA)

ribosomal RNA (rRNA)

nucleotide

the monomers of a nucleic acid

each nucleotide contains the following:

phosphate group

pentose sugar

nitrogenous base

nitrogenous base

2 major types:

pyrimidines

purines

pyrimidines

consist of a single ring of carbon, hydrogen, nitrogen, and oxygen atoms

three types:

cytosine

thymine

uracil

purines

consist of a double ring of carbon, hydrogen, and nitrogen atoms

2 types:

adenine

guanine

components of a body cell

plasma membrane

cytosol

organelles

ribosomes

endoplasmic reticulum

golgi complex

lysosome

mitochondrion

cytoskeleton

plasma membrane

also known as the cell membrane

functions as a barrier that surrounds the cell and also regulates the movement of substances into and out of the cell

cytosol

the fluid interior of the cell

also known as the intracellular fluid (ICF)

consists mainly of H20 and dissolved substances

organelles

tiny structures located in the cytosol of the cell

7 major types types of organelles

nucleus

ribosomes

endoplasmic reticulum

golgi complex

lysosomes

mitochondria

cytoskeleton

nucleus

contains the cells DNA, organized into chromosomes

surrounded by a nuclear envelope, seperates the DNA from the cytosol