Chapter 2: Chemical Composition of the Body Flashcards Preview

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Flashcards in Chapter 2: Chemical Composition of the Body Deck (89):
1

Matter

- Anything that takes up space and has mass (solid, liquid, gas)
- composed of elements

2

Element

- substance that can't be chemically broken down into any simpler substance (i.e. oxygen, carbon, gold, helium)
- elements are composed of atoms

3

Subatomic particles

- protons: positive charge and in atoms nucleus
- neutrons: electrically neutral/no charge and in nucleus
- electrons: negative charge and orbit around nucleus

4

Atomic symbol

- letters of the atom

5

Atomic Number

- # of protons (bottom number in symbol)

6

Atomic Mass

- equals # of protons and neutrons
- top number in symbol

7

Isotopes

- different forms of an atom with same number protons, but different number neutrons (i.e. carbon-12, carbon-13, carbon-14)

8

Major elements of body

- 99.3%
- hydrogen 63%
- oxygen 26%
- carbon 9%
- nitrogen 1%

9

Remaining 0.7% of total atoms

- calcium
- phosphorus
- potassium
- sulfur
- sodium
- chlorine
- magnesium

10

Trace Elements

- less than 0.01% total atoms in body
- iron
- iodine
- copper
- zinc
- maganese
- cobalt
- chromium
- selenium
- molybdenum
- flourine
- tin
- silicon
- vanadium

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Molecule

group of 2 or more atoms held together by energy

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Compound

- molecule composed of 2+ elements (i.e. O2 or H2O)
- electrons contain energy and atoms always seek out their lowest energy state meaning a full outer shell of electrons

13

Energy shell levels

- 1st energy level = max 2 electrons
- 2nd energy level = max 8 electrons
- 3rd level = max 8 electrons

14

Lowest energy state

- outermost level needs to be completely filled in order to be a stable atom
- unstable elements seek out other unstable elements

15

Chemical Bond

- force holding 2 atoms together

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Covalent Bonds

form when 2 atoms share a pair of electrons

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Double Covalent Bond

form when 2 atoms share 2 pairs of electrons

18

Polar v Nonpolar

- atoms have different degrees of electronegativity (the power to attract electrons)

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Polar covalent molecule

- unequal sharing of the electron pair between atoms
- unequal charge distribution of the molecule

20

Nonpolar covalent molecules

- equal sharing of electron pair
- equal charge distribution across the molecule

21

Ionic Bonds

- occurs as result of an electrical attraction between 2 ions

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Ion

- a charged atom
- an atom in which the number or protons does not equal the number of electrons

23

Cations

positively charged ions

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anions

negatively charged ions

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electrolytes

the ionic forms of mineral elements because give electrical charge to solution

26

Hydrogen Bond

- form between polar molecules as a result of an electrical attraction between the positive end of one molecule and the negative end of another (i.e. H2O)

27

Strength of Chemical bonds (highest to lowest)

- covalent (share e-)
- ionic (opposite charge attraction)
- hydrogen (attraction of H to O or N)
- hydrophobic interactions/VanDerWaals ( attraction between nonpolar molecules when close together - NOT AN ACTUAL BOND)

28

Molecular shape

- contributes to ability of different molecules to form chemical bonds
- rotations of bonds can rearrange molecules 3-D shape and therefore its molecular function

29

free radicals

atom containing an unpaired (single) electron in its outermost orbital
- highly reactive
- oxidize other atoms

30

Formation of free radcal

- produced in certain cell types ~ used by certain leukocytes to destroy pathogens
- produced as a consequence of exposure to radiation or toxins
--> cause DNA damage and are harmful to cells ~ associated with age-related disorders including cardiovascular, neural and eye diseases
--> antioxidants are protective (i.e. vitamins C and E)

31

Aqueous solution

- chemical reactions in cells occur within an aqueous environment
- aqueous solution = water is solvent

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Important Properties of water

- excellent solvent
- water has great capacity to absorb, store, and release heat
- water is adhesive and cohesive
- water molecules take part in many chemical reactions in the body

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Excellent Solvent Property of Water

- dissolves more compounds in greater amounts than any other liquid

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Solution

homogeneous mixture of 2+ kinds of molecules, atoms, or ions

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Solute

dissolved substance

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solvent

substance in which the solute dissolves

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solute concentration

amount of the solute present in a unit volume of solution (g/L), (moles/L) --> 1M of solute per solution

38

like dissolves likes

- nonpolar solutes will be soluble in nonpolar solvents
- polar solutes will be solutes in polar solutes

39

hydrophilic substances

- dissolve in and interact with water (ions, and polar covalent molecules)

40

hydrophobic substances

- do not interact with water
- are poorly soluble or completely insoluble in water (nonpolar covalent molecules)

41

Water has a great capactiy to absorb, sore and release heat property

- high heat capacity and high heat of vaporization
- high specific heat (amount of energy required to raise the temperature of a substance by 1 degrees celcius
- water serves as a heat "buffer" = keeps internal temperature relatively stable

42

Water is adhesive and cohesive

- cohesion: water molecules cling together
- adhesion: water molecules adhere to surfaces
- facilitate flow of blood to blood vessels

43

Water molecules take part in many chemical reactions in the body property

- hydrolysis reaction
- dehydration reaction
- reactions are good for creating or breaking large organic molecules

44

hydrolysis reaction

covalent bond is broken when water is added to system

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dehydration reaction

covalent bond is formed when water is removed between molecules

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Acid

- molecule that dissociates in an aqueous solution releasing hydrogen ions (i.e. HCL --> H+ and Cl-)
- increase in H+ in solution = more acidic

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Strong Acid

Completely Ionize in solution

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Weak Acid

Incompletely ionize in solution

49

Base

a molecule that takes up hydrogen ions, or releases hydroxide ions (OH-) in an aqueous solution
- basic solution = alkaline solution

50

pH sclae

- based on -log[H+] of solution
- lower ph = more acidic, higher ph = more basic
- neutral solution = pH 7.0
- acidic solution = pH 7.0
- up to 14

51

pH importance

- cells function in a limited pH range (7.25-7.45) is normal range in human blood
- enzyme activity is affected by pH
- pH changes can cause protein and enzyme denaturation
- buffering systems in body function to keep pH in normal limits

52

Buffer

- chemical that takes up excess H+ or OH- from solution (or donates H+ to solution) to minimize changes in pH

53

Organic Molecules

- life is carbon-based
- organic molecules contain carbon and hydrogen
- each carbon atom can covalently bond to 4 other atoms
- hydrocarbons contain only carbon and hydrogen

54

Macromolecules

-polymers
- structure depends on monomer structure, number, 3-D organization or subunits

55

Polymers

- composed of smaller subunits called monomers
- synthesized by dehydration reactions, broken down by hydrolysis reactions

56

Function Group

- group of atoms attached to an organic molecule that gives it unique chemical properties
- specific combinations of atoms, always reacts the same way chemically
- often provide an electrical charge or polarity to the molecule, make a molecule hydrophobic or hydrophilic

57

4 classes of organic molecules in organisms

- carbohydrates
- lipids
- proteins
- nucleic acids

58

Carbohydrates

- simple and complex sugars; important to energy production and storage

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Simple Sugars

- monosaccharides (monomer) --> most are pentoses or hexoses (i.e. glucose, fructose)
- disaccharides: 2 bonded monosaccharides --> i.e. lactose, maltose, sugar

60

Complex Sugars

- polysaccharides: many joined monosaccharides
- starch & glycogen: store energy. composed of thousands of glucose molecules linked together and differ in degree of branching
- cellulose & chitin: structural components

61

Lipids

- composed mostly of hydrogen and carbon atoms
- nonpolar and hydrophobic
- subclasses: triglycerides (fats&oils), phospholipids, steroids

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Fats

- long-term energy storage and insulation in animals

63

Oils

- long-term energy storage in plants and their seeds

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Phospholipids

- component of plasma membrane

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Steroids

- component of plasma membrane (cholesterol) and sex hormones

66

Triglycerides and fats

- composed of 3 fatty acid molecules and 1 glycerol molecule
- 1 fat molecule = triglyceride

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Saturated Fatty Acid

- all carbons are linked by single covalent bonds

68

Unsaturated fatty acid

- contain 1+ double bonds between carbon atoms

69

Monounsaturated

one double bond

70

polyunsaturated

more than one double bond

71

Cis fatty acid

both hydrogens are on the same side of the double-bonded carbons (most naturally occurring)

72

Trans fatty acid

hydrogens are opposite sides of the double bonded carbons

73

Eicosanoids

altered fatty acids derived from arachidonic acid that regulate certain cell functions

74

phospholipids

glycerol
2 fatty acids
phosphate group
nitrogen containing group

75

Amphipathic

important for phospholipid membrane

76

Steroids

- structure includes 4 interconnected rings of carbon atoms
- i.e. cholesterol, cortisol, testosterone, estrogen

77

Polypeptide

- polymers formed from amino acids joined by peptide bonds
- carbon, hydrogen, oxygen, nitrogen
- peptide has 50 amino acids

78

Amino Acids

- all have an amino group, a carboxyl group, and a varying side chain (R)
- 20 different naturally occurring amino acids
- proteins creating by dehydration reaction of amino acids

79

glycoproteins

one or more monosaccharides covalently attached to the side chains of specific amino acids

80

levels of protein structure

- primary, secondary, tertiary, quaternary

81

Primary structure

- amino acid sequence
- determines 2nd and 3rd structures

82

Secondary structure

- alpha helix
- beta pleated sheet

83

Tertiary structure

- conformation= 3D shape of molecule
- how folds in space
- critical to protein function!

84

Quaternary structure

only in proteins with one or more polypeptide subunits

85

Nucleic Acids

composed of chains of nucleotides

86

DNA

- deoxyribonucleic acid
- contains the sugar deoxyribose
- double-stranded (double-helix)
- genetic material
- nucleotides covalently bind to make DNA
- sugars&phosphates are the backbone
- adenine&thymine = 2H bonds
- cytosine&guanine = 3H bonds

87

RNA

- ribonucleic acid
- ribose
- single-stranded
- involved in converting the info in DNA to proteins

88

ATP

- adenosine triphosphate = energy currency of the cell
- receives energy from breakdown of carbs, proteins, and fats
- releases energy upon hydrolysis
- energy transfer
**energy currency of cell**

89

Cells use ATP for:

- production and force movement
- active transport
- synthesis of organic molecules