Chapter 2: Biological Chemistry Flashcards
Atom is
The basic unit of matter
Proton
Positive charge (+), having mass
Neutron
Neutral (no charge), having mass
Electron
Negative charge (-), essentially no mass
Element
The substance that cannot be chemically broken down into any other substance
1) Ex: hydrogen (H), oxygen (O)
2) Life requires ~ 25 elements
3) Your body is almost entirely composed of 10 elements (Nitrogen-fixing bacteria)
4) 15 are trace elements, those found in very small concentration
Electron Shells (Level max)
1) Max 2 electrons on the inner shell
2) Max 8 electrons in the outermost shell
Octet rule
Atoms will gain or shed electrons to attain a full outermost shell
Atoms that lose or gain electrons become
Ions (charged atoms)
Molecules
Two or more atoms held together
Compound
A molecule containing two or more elements
Covalent bonds
Sharing of electrons
Ionic bonds
Attraction of charges
Hydrogen bonds
1) Weak bonds that form between Hydrogen and other polar molecules
2) Weaker than ionic or covalent bonds
3) Hydrogen bonds cause many unusual properties and characteristics
Water is
an excellent solvent because it is polar
Hydrophilic molecules (water-loving) are
Polar & form hydrogen bonds; they are water-soluble
Hydrophobic molecules (water-hating) are
Non-polar & do not bond with water, and they are not water soluble
Solutions are formed when
Solutes are dissolved in solvents
If the solute increases H+ (hydrogen ion) it is an
Acids
If the solute reduces H+ it is a
Base
Rigid, crystalline structure as
Solid
As a liquid, H-bonds constantly break & form, pulling molecules in
More closely
Liquid water is
More dense than solid water
Ice floats, preventing what?
Bodies of water from freezing solid
The high specific heat energy is required to
Change temperature
Oceans store solar heat without
Large temperature changes
Oceans without temperature changes include:
1) Mild coastal climates
2) Life exists within a small temperature window
Also allows evaporative cooling
Aka sweating
Cohesion
1) “Gripping” of other water molecules via H-bonds
2) Makes it difficult to separate
Adhesion
1) “Gripping” of substances
2) Allows water transport against gravity
Surface tension
1) Difficulting of breaking the surface
2) Animal can walks in water
Macromolecules (Polymer)
Large molecules
Macromolecules (Monomers)
Composed of chains of monomers
Major macromolecule groups:
1) Carbohydrates
2) Proteins
3) Nucleic acids
Lipids aren’t macromolecules or polymers, but are necessary for, what?
For life
Lipids aren’t macromolecules or polymers, but are necessary for, what?
For life
Carbohydrates - Typically consist of C, H, and O
C-H bonds are easily broken to release energy
Carbohydrates function
1) Fuel (energy source) for cellular functions
2) Flexible uses: immediate use, storage
3) Support cell structures (building materials)
Simple (monosaccharides ) or, what else?
Complex (polysaccharides)
Non-food structure roles
1) Chitin (the reason bugs and other invertebrates are crunchy)
2) Cellulose (plant cell walls) aka “fiber”
Indigestible by most animals
Require microbes to chemically break down
Lipids
Not formed from polymers
1) Unlike carbs, no distinct monomers
2) Categorized by behavior: Always hydrophobic (oily or greasy)
Lipids including:
1) Fats
2) Sterols
3) Phospholipids
Structure of Fat
All fats have a head + 2 or 3 tails
Fat head =
glycerol
Fat tails =
fatty acids
2 tails =
diglyceride
3 tails =
Triglyceride
Uses of Fats Energy storage:
A molecule of fat has more than twice the energy of a molecule of carb or protein
Uses of Fats Examples:
1) Blubber
2) Adipose tissue
Uses of Fats because of the energy
Humans crave fats (milk)
Types of Fats
Two different types:
1) Saturated fat
2) Unsaturated fat
Saturated fat
Fatty acids filled with H
Unsaturated fat
Have one or more double bonds that cause kinks
Anything that is partly hydrogenated has
Unsaturated fat with H added to it to improve the texture
AKA trans fat
Increase bad cholesterol production; decrease good cholesterol
Sterols
1) Crucial to growth & development
2) Modification of a basic 4-carbon ring structure
3) Cholesterol at high blood concentrations can attach to vessel walls, thickening or blocking
4) Necessary to form sex hormones
Phospholipids
1) Necessary to form cell membranes
2) Similar in structure to fats, but have an extra phosphorus group on the glycerol head & 2 tails
Proteins
1) 50% of cellular dry weight
2) Uses:
1. Structural support
2. Storage
3. Transport
4. Signaling (hormones)
5. Movement
6. Defense against the foreign substance
7. Enzymes
Protein structure
Made of amino acids (AAs)
1) Organic molecules with a carboxyl and amino group + varying functional group
2) 20 AAs make up all proteins connected by covalent peptide bonds
The Importance of Shape
For proteins to work, need the correct shape
Denaturation
A protein loses its 3D structure
Primary structure
AA sequence (order)
Secondary structure
H-bond patterns
Tertiary structure
Bending/folding
Quaternary structure
Subunits
Proteins structure is determined by
Genes, which are nucleic acids
Store information
Blueprint
Nucleic acids are composed of
Monomers known as nucleotides
Nucleic Acids (two types):
1) Deoxyribonucleic acids (DNA)
2) Ribonucleic acids (RNA)
Nucleic Acid Structure
Composed of sugar-phosphate backbone plus nitrogen-containing bases
Nucleic Acid Structure information is stored by
1) Varying the sequence of bases
2) Bases in DNA:
1. Adenine (A)
2. Thymine (T)
3. Guanine (G)
4. Cytosine (C)
DNA
1) Has a double helix structure (2 strands twisted together)
2) Held together by base-pair bonds (A-T and C-G)
Strands are complementary:
The sequence is predictable between one strand and the other
RNA
Differences between DNA/RNA
Differences between DNA/RNA
1) RNA is a single strand
2) Extra oxygen on backbone
3) Exchanges T with U (Uracil)
Lots of monosaccharides
++ Orange/red
Some of the monosaccharides
+ Yellow/green
No monosaccharides
- Blue
Positive starch
+ Blue/black
Negative starch
- Yellowish
Positive protein (peptide bonds)
+ Violet
Negative protein (peptide bonds)
- Blue
Positive fat
+ Bright/orange
Negative fat
- Dull red
