Chemical Composition of the Body (Pt. 1) Flashcards Preview

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Flashcards in Chemical Composition of the Body (Pt. 1) Deck (47):
1

Atoms

Smallest unit of an element

 

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What is the composition of an atom?

Made up of three basic subatomic particles

  • Protons – positively charged
    • = Atomic Number
  • Neutrons – neutrally charged
  • Electrons – negatively charged particles, circulating around nucleus.

 

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Where can electrons be found in the atom?

They can be found revolving around the nucleus in energy levels called shells.

4

Valence Electrons

These are the electrons found in the outer shell

  • Participate in chemical reactions
  • Atoms most stable when the outermost shell is full

 

5

Chemical Bonds

Interactions of valence electrons that hold atoms together. 

Types:

  • Covalent
  • Ionic
  • Hydrogen (Sort of)

 

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Molecules

Two or more atoms bound together by chemical bonds

 

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Covalent Bonds

Two or more atoms share pairs of valence electrons

Strongest Bond

Types:

  • Nonpolar Covalent Bond
  • Polar Covalent Bond

 

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Nonpolar Covalent Bond

Atoms share electrons equally

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Polar Covalent Bond

  • Unequal sharing of electrons
  • Unequal charge between different regions of the molecule

 

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Ionic Bonds

One atom gives electrons to another so that both have filled valence shells.

Generates ions – atoms or molecules with unequal numbers of protons and electrons.

  • Cations
  • Anions

 

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What attraction is experienced in ionic bonds?

Strong electrostatic attraction between oppositely charged ions

Ex: NaCl

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Hydrogen Bonds

Weak attraction between polar molecules; the (–) end of one polar molecule is attracted to the ( + ) end of another polar molecule.

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13

For what is hydrogen bonding responsible?

  • Water surface tension
  • Water capillary action
  • Shape of proteins
  • DNA structure

 

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What are some of the characteristics of water?

  • Polar molecule
  • Good solvent (ionic and polar substances dissolve in it)
  • Can form hydrogen bonds

 

15

What defines something as hydrophobic versus hydrophilic?

  • Substances that dissolve in water are called hydrophilic.
  • Substances that do not dissolve in water are called hydrophobic.

 

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Acids

These are solutes that release H+ when mixed with water

  • ↑ [H+]
  • Acidic Solution

 

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Bases

These are solutes that bind H+ when mixed with water

  • ↓ [H+]
  • Alkaline

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How do you quantify acidity or alkalinity of a solution?

For this, you would use the pH rating system.

  • pH = log[H+]

Scale on the system goes from 0 - 14, with neutral pH rated as a 7 in the scale.

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Macromolecules

Very large molecules

Four Classifications:

  • Carbohydrates
  • Lipids
  • Proteins
  • Nucleic Acids

Macromolecules come in distinct structures and functions.

 

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Carbohydrates

Sugars & Starches (Plant)

Molecules that contain hydrogen, oxygen, and carbon 1:2:1 ratio

  • General Formula = CnH2nOn (e.g. glucose – C6H12O6)

Function = major source of energy in body

 

 

21

What are the three classifications of carbohydrates?

Monosaccharides

  • Basic Unit
  • One carbon ring

Disaccharides

  • Two monosaccharides joined by a covalent bond

Polysaccharides

  • Polymer of Glucose
  • Glycogen, Starch, Fiber

 

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Starch

Starch is a plant product formed by the bonding together of thousands of glucose subunites into long chains. 

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Glycogen

Glycogen, sometimes called animal starch, is similar to starch, but more highly branched.

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Fibers

Plant material containing substances such as cellulose, lignin, and pectin, which are resistant to the action of digestive enzymes.

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Lipids

Includes: Fats, Oils

Contain compounds that are not soluble in water (hydrophobic compounds)

Major Classes

  • Triglycerides
  • Phospholipids
  • Steroids

 

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Triglycerides

These are the fats and oils in the body

Structure

  • 3 Fatty Acids
  • Glycerol Backbone

Types of Fatty Acids:

  • Saturated
  • Unsaturated

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Saturated Fatty Acids

Fatty acids in which carbon atoms within the hydrocarbon chain are joined by a single covalent bonds so that each carbon atom can also bond with 2 hydrogen atoms.

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Unsaturated Fatty Acids

Fatty Acids that contain a number of double covalent bonds within the hydrocarbon chain so that each carbon atom can bond with only 1 hydrogen atom.

 

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Phospholipids

Contain a phosphate group (PO4) instead of third fatty acid.

Amphipathic = possess both polar and nonpolar ends

  • Lowers surface tension of water
  • Enables hydrophobic substances to be suspended in polar solvents

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Steroid

Basic Backbone of four interlocking carbon rings

Different functional groups attached to basic structure

Ex:

  • Cholesterol
  • Corticosteroids
  • Sex Steroids

 

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Cholesterol

Precursor for other steroid hormoens, regulation of cell membrane fluidity.

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Corticosteroids

Hormone produced by adrenal glands.

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Sex Steroids

Hormones produced by gonads (testosterone, estradiol)

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Prostaglandins

A type of fatty acid

Function as communication molecules between cells

Variety of roles in body

  • Inflammation Regulation
  • Regulate Hormones
  • Control Cell Growth

 

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Proteins

Diverse in structure and function

Amino acids = building blocks

Basic Structure of Amino Acid:

  • Amino Group
  • Carboxyl Group
  • A Functional side-chain
    • "R"
    • Specific for each AA

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Amino Acid Side Chains

Functional group differentiates 20 different AA

Side chains interact with each other

  • Give protein shape

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How are proteins made?

Formed from polypeptides – molecule consisting of many amino acids joined by peptide bonds.

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Primary Structure

Sequence of amino acids in a polypeptides chain

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Secondary Structure

Formation of helix or sheet shape in a protein chain

Due to hydrogen bonds dorming between peptide bond regions

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Tertiary Structure

Twisting and folding of a single polypetide chain

Due to chemical interactions involving the amino acid side-chains

3D Shape

 

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Quaternary Structure

Bonding and interactions of multiple polypeptides.

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How many levels of proteins structures are there?

Four levels of protein structure:

  1. Primary Structure
  2. Secondary Structure
  3. Teritary Structure
  4. Quaternary Structure

 

45

Nucleotides

Building blocks for nucleic acids

Composed of a five-carbon sugar, a phosphate group, and nitrogenous base. 

Sugars are deoxyribose (DNA) or ribose (RNA).

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47

RNA

Similar to DNA (polymer of nucleotides)

Differences:

  • Usually single-stranded
  • Different sugar (ribose)
  • Different Nitrogen Base (uracil instead of thymine)

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51

Conjugated Proteins

Sometimes proteins are combined with other molecules to become functional

  • Glycoprotein = Protein + Carbohydrate
    • Ex: Cell Membranes
  • Lipoprotein = Protein + Lipid
    • Carrier molecules in blood

 

52

Give examples of the function of proteins in the body

Structural: collagen fibers in connective tissues; keratin in skin

Enzymes: assist every chemical process in the body

Antibodies: part of the immune system

Receptors: receive communication from other cells for regulation of cell activity.

Carriers: across cell membranes or in blood.

 

 

54

DNA Structure

Sugar = deoxyribose

Double Helix = two strands linked together by hydrogen bonds between nitrogenous bases

Complementary base pairing between strands:

  • Adenine binds to thymine
  • Guanine binds to cytosine