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N106 > Chapter 2- Chemical Level Of Organization > Flashcards

Chapter 2- Chemical Level Of Organization Flashcards

1
Q

The chemical level of organization

A
  • body’s most basic level of organization
  • consists of atoms and molecules
  • affects characteristics and functioning of the entire organism
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2
Q

What is chemistry?

A

Science that investigates matter and it’s interactions

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3
Q

What is matter?

A
  • anything that takes up space and has mass
  • mass is amount of matter an object contains
  • matter is composed of substances called elements
  • elements cannot be changed or broken down into simpler substances

Eg: oxygen and carbon

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4
Q

What is atomic structure?

A
  • smallest stable unit of matter is an atom

- atoms contain three major subatomic particles that include: protons, neutrons, and electrons

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5
Q

Protons

A

-have a positive electrical charge

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6
Q

Neutrons

A

Are neutral (uncharged)

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7
Q

Electrons

A

Have a negative electrical charge

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8
Q

What is a subatomic particles?

A
  • protons and neutrons
  • similar in size and mass
  • both found in the nucleus
  • electrons
  • much lighter than protons (1/1836 as massive)
  • orbit space around the nucleus at high speed
  • form electron cloud represented as electron shell
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9
Q

What is an atomic number?

A

-the number of protons in an atom is the atomic number
-all atoms of an element contain same number of protons
Eg: all helium atom contain 2 protons

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10
Q

What is an isotope?

A
  • atoms of an element with different numbers of neutrons in the nucleus are called isotopes
  • neutron number generally has no effect on chemical properties
  • distinguished by their mass number
  • total of protons and neutrons in the nucleus
  • unstable isotopes are radioactive
  • spontaneously emit subatomic particles
  • weak radioisotopes can be used in diagnostic procedures
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11
Q

What is atomic weight?

A

-the average mass of an element’s atoms is the atomic weight
Eg: Hydrogen
Mass # = 1
Atomic weight = 1.0079

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12
Q

What are electron shells?

A
  • atoms are electrically neutral
  • each positive proton balanced by a negative electron
  • electrons orbit nucleus in shells
  • only electrons in outer shell can interact with other atoms
  • chemical properties of an element determined by number of electrons in the outer electron shell
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13
Q

How the electron shells interact?

A
  • filling of electron shells
  • first shell(closest to nucleus) holds only 2 electrons
  • second shell holds up to 8 electrons
  • reactivity
  • atom with unfilled outer shell reacts with other atoms
  • usually in ways to give them a full outer shell
  • atom with filled outer shell is very stable or inert
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14
Q

What are chemical bonds?

A
  • Atoms interact with each other to form larger structures
  • Can share, gain, or lose electrons through chemical reactions
  • Form chemical bonds that hold atoms together after reaction has ended
  • Process forms molecules and compounds
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15
Q

Molecules and compounds

A

Molecules

  • Contain more than one atom bonded together by shared electrons
  • Compounds
  • Made up of atoms of two or more different elements in a fixed proportion
  • New chemical substance
  • Properties may be different from component elements
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16
Q

Types of ions

A
  • Ions
  • Atoms or molecules that have an electric charge
  • Electrical charge comes from unequal numbers of protons and electrons
  • Cations
  • Ions with a positive (+) charge
  • Formed when atom loses electrons
  • Anions
  • Ions with a negative (–) charge
  • Join to form ionic compound sodium chloride
  • Formed when atom gains electrons
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17
Q

What are ionic bonds?

A
  • Chemical bonds created by the electrical attraction between anions and cations
  • Formed in a process called ionic bonding
  • Example
  • Sodium atom donates an electron to a chlorine atom
  • Resulting sodium ion (+1) and chloride ion (–1)
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18
Q

Covalent bonds

A
  • Formed by sharing of electrons between atoms
  • Resulting bond is very strong
  • Single covalent bond
  • Sharing of one pair of electrons
  • Double covalent bond
  • Sharing of two pairs of electrons
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19
Q

Polar and non polar covalent bonds

A
  • Nonpolar covalent bonds
  • Formed when electrons are shared equally
  • Polar covalent bonds
  • Formed by unequal sharing between atoms of different elements
  • Form polar molecules
  • One end (pole) has a slightly negative charge
  • Other end (pole) has a slightly positive charge
  • Example: a water molecule
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20
Q

Hydrogen bonds

A
  • Weak attractive force
  • An attraction between:
  • A slight positive charge on the hydrogen atom of one polar covalent bond and
  • A slight negative charge on an oxygen or nitrogen atom of another polar covalent bond
  • Example: bond between adjacent water molecules
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21
Q

Surface tension

A
  • Hydrogen bonds
  • Too weak to create molecules
  • But can alter shapes of molecules or pull molecules closer together
  • Attraction between water molecules forms surface tension
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22
Q

Chemical reaction

A
  • Chemical reaction
  • Existing bonds between atoms are broken or
  • New chemical bonds form between atoms
  • Reacting substances (reactants) rearrange to form products
  • Metabolism
  • Sum of all the chemical reactions in the body
  • Chemical notation used to describe complex events
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23
Q

What is a chemical reaction?

A
  • Chemical reaction
  • Existing bonds between atoms are broken or
  • New chemical bonds form between atoms
  • Reacting substances (reactants) rearrange to form products
  • Metabolism
  • Sum of all the chemical reactions in the body
  • Chemical notation used to describe complex events
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24
Q

Energy concepts

A
  • Energy
  • Capacity to perform work (movement of an object or change in physical structure of matter)
  • Two types
  • Kinetic energy or energy of motion
  • Potential energy or stored energy
  • Cannot be created or destroyed
  • Can be converted from one form to another
  • Some energy released as heat with each conversion
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25
Q

Types of chemical reactions

A

Three types of chemical reactions important to study of physiology are:

  1. Decomposition reactions
  2. Synthesis reactions
  3. Exchange reactions
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26
Q

What is a decomposition reaction?

A
  • Break a molecule into smaller fragments
  • Hydrolysis reactions are decomposition reactions involving water
  • Catabolism
  • Decomposition reactions of complex molecules (such as food molecules) within cells
  • Releases kinetic energy that can perform work
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27
Q

What is a synthesis reaction?

A
  • Assemble larger molecules from smaller parts
  • Dehydration synthesis (condensation reaction)
  • Forms a complex molecule by the removal of waterEq-4
  • Anabolism
  • Synthesis of new compounds in the body
  • Requires energy
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28
Q

What is an exchange reaction?

A
  • Shuffle parts of reacting molecules
  • Reactant molecules break apart (decomposition)
  • Resulting components interact to form new products (synthesis)
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29
Q

What is a reversible reaction?

A
  • Symbolized by two opposite arrows
  • Arrows indicate two reactions occurring at the same time
  • At equilibrium, the rates of the two reactions are balanced
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30
Q

What is the role of an enzyme?

A
  • Activation energy
  • Amount of energy required to start a reaction
  • Can come from changes in temperature or pH
  • Often these required changes would be deadly to cells
  • Cells use enzymes to speed up reactions
  • Enzymes lower activation energy
  • Negates need for extreme temperature or pH changes
  • Categorized as catalysts
  • Accelerate reaction without being permanently changed
31
Q

What are exergonic and endergonic reactions?

A

Exergonic reactions
-Release energy
-Amount released greater than activation energy to start
-Relatively common in the body
-Generate heat to maintain body temperature
Endergonic reactions
-Absorb energy
-More energy needed to begin than is released

32
Q

What are nutrients and Metabolites?

A
  • Nutrients
  • Substances from food necessary for normal physiological functions
  • Include: carbohydrates, proteins, fats, vitamins, minerals, water
  • Metabolites
  • Substances involved in (or by-product of) metabolism
33
Q

What are inorganic and organic compounds?

A

Inorganic compounds

  • Usually without carbon and hydrogen
  • Include small molecules and ionic compounds
  • Important inorganic compounds in the body: water, carbon dioxide, oxygen, acids, bases, salts

Organic compounds

  • Contain carbon covalently bonded with one or more other elements
  • Much larger and more complex molecules
34
Q

What are the properties of water?

A

Water is the most important substance in the body.

Three general properties of importance in the body

  1. Water is an essential reactant in the chemical reactions of living systems
  2. Water has a very high heat capacity
  3. Water is an excellent solvent
35
Q

Water as an essential reactant

A
  • Chemical reactions in our bodies take place in water
  • Water molecules participate in some reactions
  • Dehydration synthesis releases water molecules
  • Hydrolysis uses water molecules to break apart complex molecules
36
Q

Aqueous solutions

A
  • Solutions
  • Consist of a fluid solvent and dissolved solutes
  • If solvent is water, forms aqueous solution
  • Dissociation or ionization
  • Occurs when ionic compounds break apart into their charged ions in water
  • Substances releasing ions when dissolved in water are called electrolytes
  • An organic molecule is soluble when it contains polar covalent bonds
37
Q

Body fluid PH

A
  • Hydrogen atom that loses its electron becomes a hydrogen ion (H+)
  • H+ is very reactive

• Can break chemical bonds, change shapes of molecules, disrupt
cell function

• Concentration of H+ in the body must be precisely regulated

38
Q

The PH scale

A
  • pH represents the concentration of H+ in a solution
  • The higher the concentration of H+, the lower the pH
  • Numbers from 0–14
  • Difference of one pH unit equals a tenfold change in H+ concentration
  • A solution with a pH of 7.0 is neutral
  • A solution with a pH below 7 is acidic
  • A solution with a pH above 7 is basic or alkaline
39
Q

Normal PH

A
  • Normal pH of blood and most body fluids is 7.35–7.45
  • Variations outside that range can damage cells and disrupt cell functions
  • Blood pH below 7.0 can produce coma
  • Blood pH higher than 7.8 causes uncontrollable, sustained muscular contractions
40
Q

Acids

A
  • Any substance that breaks apart in solution to release hydrogen ions is an acid
  • Often referred to as “proton donors”
  • The stronger the acid, the more completely dissociation occurs
  • A strong acid dissociates completely
  • Example: hydrochloric acid
41
Q

Bases

A
  • A substance that removes hydrogen ions from a solution is a base
  • Often releases a hydroxide ion OH– that binds with hydrogen ions to form water
  • The stronger the base, the more completely dissociation occurs
  • A strong base dissociates completely
  • Example: sodium hydroxide
42
Q

Weak acids and bases

A
  • Acids and bases that do not dissociate completely in solution are called weak acids and weak bases
  • Important in maintaining pH balance in the body
  • Example: weak bases counteract lactic acid produced during muscle contraction
43
Q

Salts

A
  • A salt:
  • Is composed of a cation that is not H+ and an anion that is not OH–
  • Is held together by ionic bonds
  • Dissociates in water
  • Example: table salt (NaCl)
  • In solution dissociates into Na+ and Cl– ions
  • Dissociation of some salts may indirectly affect H+ or OH– concentrations
  • Makes solution slightly acidic or slightly basic
44
Q

Electrolytes

A
  • Substances whose ions can conduct an electrical current in solution are called electrolytes
  • Include acids, bases, and salts
  • Examples of ions released: sodium, potassium, calcium, chloride, bicarbonate
  • Body needs to maintain even level of all electrolytes for proper function
45
Q

Buffers

A
  • Buffers
  • Compounds that stabilize pH by:
  • Removing H+ out of solution or
  • Replacing H+ into solution
  • Example: antacids bind to excess hydrogen ions in stomach
  • Buffer systems in the body work to maintain body fluid pH within normal range of 7.35–7.45
46
Q

Carbohydrates

A
  • Organic compounds with carbon, hydrogen, and oxygen in a ratio near 1:2:1
  • Include sugars and starches
  • A good source of energy
  • Three major types
  1. Monosaccharides
  2. Disaccharides
  3. Polysaccharides
47
Q

Monosaccharides

A
  • Simple sugar or monosaccharide
  • Carbohydrate containing from 3 to 7 carbon atoms
  • Building blocks for larger carbohydrates
  • Dissolve readily in water
  • Example: glucose
  • Most important “fuel” in the body
48
Q

Disaccharides

A
  • Disaccharides
  • Two monosaccharides linked by covalent bonds
  • Example: sucrose (table sugar)
  • Very soluble in water
  • Formed by dehydration synthesis
  • Broken down by hydrolysis
  • Must be broken down before providing energy
49
Q

Polysaccharides

A
  • Polysaccharides
  • Multiple monosaccharides and/or disaccharides linked by covalent bonds
  • Examples
  • Starches – manufactured by plants; important energy sources; easily broken down in digestive tract
  • Cellulose – component of plant cell walls; cannot be digested
  • Glycogen – animal starch – composed of interconnected glucose molecules
50
Q

Lipids

A
  • Contain a carbon-to-hydrogen ratio of 1:2
  • Oxygen content much lower than in carbohydrates
  • May contain a variety of other elements
  • Include fats, oils, and waxes
  • Most are insoluble in water
  • Carried in the blood by special transport molecules
  • Form essential parts of cell structure
  • Important as energy reserves
  • Major types: fatty acids, fats, steroids, phospholipids
51
Q

Fatty acids

A
  • Long chains of carbon atoms with
  • attached hydrogen atoms and
  • a carboxyl group (—COOH) at the end
  • Carboxyl end can dissolve in water
  • The carbon chain, or hydrocarbon tail, is fairly insoluble
52
Q

Saturated and unsaturated fatty acids

A
  • Saturated fatty acid
  • Has only single covalent bonds on each carbon atom
  • Unsaturated fatty acid
  • Has one or more double covalent bonds between carbons
  • Monounsaturated has only one double bond
  • Polyunsaturated has multiple double bonds
53
Q

Fats

A
  • Formed by fatty acids attached to glycerol
  • Triglyceride
  • Glycerol attached to three fatty acids
  • Most common fat in the body
  • Serve as energy reserve
  • Also serve as insulation and cushioning
54
Q

Steroids

A
  • Large lipid molecules composed of four connected rings of carbon atoms
  • Cholesterol is most common steroid
  • Component of cell membranes or plasma membranes
  • Precursor of sex hormones (testosterone and estrogen)
  • Obtained from diet
  • Also synthesized by the liver
  • Strong link between high blood cholesterol levels and heart disease
55
Q

Phospholipids

A
  • Components
  • Glycerol and two fatty acids linked to
  • A nonlipid group by a
  • Phosphate group
  • Nonlipid group is soluble in water
  • Fatty acid tails are fairly insoluble
  • Most abundant lipid component in cell membranes
56
Q

Proteins

A
  • Most abundant organic molecules in the human body
  • Account for about 20 percent total body weight
  • Contain carbon, hydrogen, oxygen, and nitrogen
  • Sulfur and phosphorus may also be present
57
Q

Protein functions

A

• Seven major categories of protein function in the body:

  1. Support
  2. Movement
  3. Transport
  4. Buffering
  5. Metabolic regulation
  6. Coordination and control
  7. Defense
58
Q

Proteins: support and movement

A
  1. Support
  • Structural proteins create framework
  • Provide strength and organization
  1. Movement
  • Contractile proteins responsible for muscular contraction
  • Also allow movement of individual cells
59
Q

Proteins: transport and buffering

A
  1. Transport
  • Transport proteins act as carriers in the blood for a variety of substances
  • Others transport materials between parts of a cell
  1. Buffering

• Provide buffering action helping prevent changes in pH in body fluids

60
Q

Proteins: regulations,coordination, defence

A
  1. Metabolic regulation

• Working as enzymes, speed up chemical reactions in living cells

  1. Coordination and control

• Acting as hormones, influence metabolic activities and functions

  1. Defense
  • Antibodies protect from disease
  • Clotting proteins restrict bleeding
61
Q

Protein structure

A
  • Long chains of amino acids
  • 20 different amino acids in the body
  • Each amino acids contains:
  • A central carbon atom bound to a hydrogen atom
  • An amino group (—NH2)
  • A carboxyl group (—COOH)
  • An R group (variable side chain of one or more atoms)
  • Gives each amino acid its own chemical properties
62
Q

Peptides

A
  • Typical protein contains 1000 amino acids
  • Peptides
  • Molecules made up of amino acids connected by peptide bonds
  • Two amino acids = dipeptide
  • Three or more amino acids = polypeptide
  • Polypeptide more than 100 amino acids called protein
63
Q

Protein structure

A
  • Protein structure established by sequence of amino acids
  • Protein characteristics determined partly by R group
  • Complex shape of protein determines function
  • Four levels of structure: primary, secondary, tertiary, quaternary
64
Q

Levels of protein structure

A
  1. Primary structure

• Sequence of amino acids linked by peptide bonds

  1. Secondary structure
  • Shape resulting from hydrogen bonding at points along polypeptide chain
  • May create alpha helix or beta sheet
  1. Tertiary structure
  • Complex coiling and folding giving three-dimensional shape
  • Results from interactions between R groups
  1. Quaternary structure

• Shape from interaction between polypeptide subunits forming protein complex

65
Q

Structural classes of proteins

A

• Two classes based on shape and properties

  1. Fibrous proteins
  • Form sheets or strands
  • Tough, durable, usually insoluble in water
  • Important in maintaining structure
  1. Globular proteins
  • Compact, rounded, usually soluble in water
  • Active, functional roles in the body
66
Q

Protein function depends on shape

A
  • Denaturation
  • Change in three-dimensional shape of protein
  • Caused by changes in temperature, pH, or ionic composition of surroundings
  • Results in nonfunctional protein
  • Causes irreparable damage to organs and organ systems with loss of structural proteins and enzymes
67
Q

Enzyme functions

A
  • Enzymes catalyze reactions that sustain life
  • Substrates (reactants) bind to active site on enzyme
  • Active site specific to substrate (like lock and key)
  • Binding temporarily changes shape of enzyme
  • Substrates interact to form a product
  • Product released
  • Enzyme free to catalyze another reaction
68
Q

Nucleus acids

A
  • Large organic molecules
  • Composed of carbon, hydrogen, oxygen, nitrogen, and phosphorus
  • Store and process information inside cells
  • Two classes
  1. DNA—deoxyribonucleic acid
  2. RNA—ribonucleic acid
69
Q

Structure of nucleic acids

A
  • Composed of subunits called nucleotides
  • Nucleotides composed of three parts
  • A sugar
  • Ribose in RNA
  • Deoxyribose in DNA
  • A phosphate group

• A nitrogenous (nitrogen-containing) base

70
Q

Nucleotide bases

A
  • Five nitrogenous bases found in nucleic acids
  • Adenine (A)
  • Guanine (G)
  • Cytosine (C)
  • Thymine (T)
  • Found only in DNA
  • Uracil (U)
  • Found only in RNA
71
Q

DNA and RNA structure

A
  • RNA
  • Single chain of nucleotides
  • DNA
  • Two nucleotide chains twisted together in double helix shape
  • Held together by hydrogen bonds between nitrogenous bases
  • Bases form complementary base pairs
  • Adenine only bonds with thymine

Cytosine only binds with guanine

72
Q

ATP: A High-Energy Compound

A
  • High-energy bond
  • Covalent bond storing unusually large amount of energy
  • When broken, energy released under controlled conditions
  • ATP (adenosine triphosphate)
  • Most important high-energy compound in the body
  • Adenosine monophosphate joined to two phosphate groups by high-energy bonds
73
Q

ATP Energy Storage and Release

A
  • Energy is required to attach phosphates
  • One phosphate added to AMP (adenosine monophosphate) results in ADP (adenosine diphosphate)
  • A second phosphate added results in ATP (adenosine triphosphate)
  • Energy is released as high-energy bonds broken
  • Energy used to power all vital functions
74
Q

Chemicals Form Functional Units

A
  • Biochemical building blocks are components of cells
  • Carbohydrates provide energy and form specialized compounds
  • Lipids form membranes separating cell from environment and creating compartments within cell
  • Proteins form internal support and act as enzymes
  • Nucleic acids direct cellular activity and synthesis of all cellular proteins

N106 (6 decks)

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