Structure & Function Of The Body Chapter 2

Front 1

Nucleus

Back 1

Central core of atom

Front 2

Proton

Back 2

Positively charged particle in nucleus

Front 3

Neutron

Back 3

non-charged particle in nucleus

Front 4

Atomic number

Back 4

number of protons and neutrons combined

Front 5

Energy levels

Back 5

regions surrounding atomic nucleus that contain electrons

Front 6

electron

Back 6

-negatively charged particle

-may contain up to eight electrons in each level

-energy increases with distance from nucleus

Front 7

Element

Back 7

pure substance; made up of only one kind of atom

Front 8

Molecule

Back 8

group of atoms bound together in a group

Front 9

Compound

Back 9

substances whose molecules have more than one kind of atom

Front 10

Chemical bonds form to make atoms more stable

Back 10

-Outermost energy level of each atom is full

-Atoms may share electrons or donate or borrow them to become stable

Front 11

Ionic bonds

Back 11

form when an atom gains or loses electrons in its outer energy level to become stable

Front 12

Positive ion

Back 12

has lost electrons; indicated by superscript positive sign(s), as in Na+ or Ca++

Front 13

Negative ion

Back 13

has gained electrons; indicated by superscript negative sign(s), as in Cl-

Front 14

Ionic bonds form when

Back 14

positive and negative ions attract each other because of electrical attraction

Front 15

Electrolyte

Back 15

molecule that dissociates (breaks apart) in water to form individual ions; an ionic compound

Front 16

Covalent bonds

Back 16

-form when atoms share their outer energy to fill up and thus become stable.

-Do not ordinarily easily dissociate in water.

- = sharing of electrons between atoms

Front 17

Organic Molecules

Back 17

contain carbon-carbon covalent bonds or carbon-hydrogen covalent bonds

Front 18

Inorganic Molecules

Back 18

Do not contain carbon-carbon covalent bonds or carbon-hydrogen covalent bonds

Front 19

examples of inorganic molecules:

Back 19

water and some acids, bases, and salts

Front 20

Water is

Back 20

-solvent (liquid into which solutes are dissolved)

-involved in some chemical reactions

Front 21

Dehydration synthesis

Back 21

chemical reaction in which water is removed from small molecules so they can be strung together to form a larger molecule

Front 22

Hydrolysis

Back 22

chemical reaction in which water is added to the subunits of a large molecule to break it apart into smaller molecules

Front 23

Chemical reactions

Back 23

always involve energy transfers, as when energy is used to build ATP molecules

Front 24

Chemical equations

Back 24

show how reactants interact to form products; arrows separate the reactants from the products

Front 25

Water molecules

Back 25

dissociate (separate) to form equal amounts of H+ (hydrogen ion) and OH- (hydroxide ion)

Front 26

Acid

Back 26

substance that shifts the H+/OH- (hydrogen/hydroxide) balance in favor of H+; opposite of base

Front 27

Base

Back 27

substance that shifts the H+/OH- (hydrogen/hydroxide) balance against H+; also known as alkaline; opposite of acid

Front 28

pH

Back 28

mathematical expression of relative H+ (hydrogen) concentration in an aqueous solution

Front 29

pH 7

Back 29

neutral (neither acid nor base)

Front 30

pH values above 7

Back 30

base (alkaline)

Front 31

pH values below 7

Back 31

acidic

Front 32

(pH) Neutralization occurs

Back 32

when acids and bases mix and form salts

Front 33

Buffers

Back 33

chemical systems that absorb excess acids or bases and thus maintain a relatively stable pH

Front 34

Carbohydrates

Back 34

sugars and complex carbohydrates

Front 35

Carbohydrates

Back 35

-contain carbon (C), hydrogen (H), oxygen (O)

-Made up of SIX-CARBON SUBUNITS called MONOSACCHARIDES or single sugars (e.g., glucose)

Front 36

Disaccharide

Back 36

DOUBLE sugar made up of TWO monosaccaride units (e.g., sucrose, lactose)

Front 37

Polysaccharide

Back 37

complex carbohydrate made up of MANY MONOSACCHARIDE UNITS (e.g., glycogen made up of many glucose units)

Front 38

Function of carbohydrates

Back 38

to STORE ENERGY FOR LATER USE

Front 39

Triglycerides

Back 39

-made up of one glycerol unit and THREE FATTY ACIDS

-store energy for later use

Front 40

Phospholipids

Back 40

-TWO FATTY ACIDS and with a phosphorus-containing group attached to glycerol

-head attracts water and the double tail does not, thus forming stable double layers (bilayers) in water

-FORM MEMBRANES OF CELLS

Front 41

Cholesterol

Back 41

-Molecules have a STERIOD STUCTURE made up of multiple rings

-Cholesterol stabilizes the phospholipid tails in cellular membranes and is also converted into steroid hormones by the body

Front 42

Proteins

Back 42

very LARGE MOLECULES made up of AMINO ACIDS held together in long, folded chains by peptide bonds

Front 43

Structural proteins

Back 43

-form structures of the body

-Collagen is a fibrous protein that holds many tissues together

-Keratin forms tough, waterproof fibers in the outer layer of the skin

Front 44

Functional proteins

Back 44

-participate in CHEMICAL PROCESSES

-examples: hormones, cell membrane channels and receptors, enzymes

Front 45

Enzymes

-Catalysts

Back 45

(increases reactions) help chemical reactions occurs

Front 46

Enzymes

-Lock & Key model

Back 46

each enzyme fits a particular molecule that it acts on as a key fits into a lock

Front 47

Proteins can

Back 47

combine with other organic molecules to form glycoproteins or lipoproteins

Front 48

Nucleic acids

Back 48

-made up of nucleotide units

-sugar (ribose or deoxyribose)

Front 49

Phosphate

Back 49

Nitrogen base (adenine, thymine or uracil, guanine, cytosine)

Front 50

DNA

Back 50

-Used as the cell's "master code" for assembling proteins

-uses deoxyribose as the sugar and A (adenine), T (thymine) (NOT U), C (cystosine), and G (guanine) as bases

-forms a double helix shape

Front 51

RNA

Back 51

-used as a temporary "working copy" of a gene (portion of the DNA code)

-Uses ribose as the sugar and A (adenine), U (uracil) (NOT THYMINE), C (cystosine), AND G (guanine) as bases

-

Front 52

By directing the formation of structural and functional proteins

Back 52

nucleic acids ultimately direct overall body structure and function