Chapter 2 The Chemistry and Energy of Life Flashcards
Element
A pure substance that contains only one kind of atom
Mass Number
The total number of protons and neutrons in its nucleus
Electron Shells
Electron orbits
Octet Rule
states an atom will lose, gain, or share electrons in order to achieve a stable configuration of 8 outermost shell
Valence Shell
Outermost shell
Chemical Bond
An attractive force that links 2 atoms together in a molecule
Covalent Bond
Form when 2 atoms attain stable electron numbers in their outermost shells by sharing one or more pairs of electrons
Electronegativity
A measure of the tendency of an atom to attract a bonding pair of electrons
Polar Covalent Bond
When 2 atoms of unequal electronegativity bond with each other and are formed
Hydrogen Bond
Is the electromagnetic attraction between polar molecules in which hydrogen is bound to a larger atom (oxygen or nitrogen)
Solvent
A liquid in which other molecules dissolve
Heat Capacity
Multiple hydrogen bonds that shields living things from fluctuating temperature from the environment
Cohesion
The capacity of water molecules to resist coming apart under tension
Adhesion
Refers to substances sticking onto other substances
Hydrophilic
(“Water-loving”) in aqueous solutions, polar molecules become separated from one another and are surrounded by water molecules
Hydrophobic
(“Water-fearing”) for nonpolar molecules, they stick together in water
Ion
Is an electrically charged particles that form when an atom gain or lose more electrons in order to form more stable electron configuration
Cation
Positively charged ions
Anion
Negatively charged ions
Ionic Attractions
They form when ions with the opposite charges attract
Functional Groups
Are covalently bonded groups of atoms that confer specific properties to biological molecules
Macromolecules
Large molecules formed by the covalent linkage between smaller molecules (monomers). Also, polymers are formed and broken apart in reactions involving water
Carbohydrates
A large group of molecules that all have similar atomic compositions but differ greatly in size, chemical properties, and biological functions
Monosaccharides
Simple sugars
Oligosaccharides
Contain several monosaccharides and are polysaccharides and are bound together by glycosidic linkages
Polysaccharides
Large and long polymers of monosaccharides that store energy and provide structural materials
Amylose
linear chain of repeated alpha-glucose monomer
Amylopectin
Branched chain of repeated alpha-glucose monomer
Cellulose
Another polymer of glucose
Lipid
(Fats and oils) fat and fat-like hydrophobic molecules such as waxes, sterols, and fats. They are insoluble in water because of many nonpolar covalent bonds and are held by weak Van de Waal bonds
Triglycerides
Most common units of lipids and also known as simple lipids
Saturated Fatty Acids
all bonds between carbon atoms are sing and are saturated with hydrogens. They form rigid and straight molecules packed tightly together
Unsaturated Fatty Acids
Hydrocarbon chains contain one or more double-deck bonds. They cause kinks (which determines fluidity and melting point of lipid) in the chain and prevent molecules from packing together tightly
Phospholipids
Are made up of 2 fatty acids (long chains of hydrogen and carbon molecules which are attached to glycerol head)
Condensation
Removal of water links monomers together (also called a dehydration reaction)
Hydrolysis
Addition of water breaks a polymer into monomers
What are the components of an atom?
Protons, Neutrons, and electrons
What part of an atom overall has a negative charge?
Electrons
What part of an atom have a positive charge?
Protons
What part of an atom have no charge?
Neutrons
What 6 elements are in the 98% of the mass of every living organism?
- Carbon
- Nitrogen
- Phosphorus
- Oxygen
- Hydrogen
- Sulfur
Valence Shells
The electrons that occupy the outermost shell of an atom
How many electrons can fit in the 1st shell?
2
How many electrons can fit in the 2nd shell?
8
How many electrons can fit in the 3rd shell?
18
How many electrons can fit in the 4th and susequential shells?
up to 32
Van de Waal bond
Interactions of electrons of nonpolar substances
Ionic Bond
Attraction of opposite charges
Hydrophobic Bond
Interaction of nonpolar substances in the presence of polar substances (especially in water)
Why is carbon so special?
Carbons have the unique capability of forming large networks of covalently bonded atoms
What are the 4 kinds of macromolecules are characteristic of living things?
- Proteins
- Carbohydrates
- nucleic acids
- lipids
What are proteins formed from?
They are formed from different combinations of 20 amino acids that all chemical similarities
What are carbohydrates formed from?
They are giant molecules formed by linking similar chemical sugar monomers
What are nucleic acids formed from?
They are formed from 4 kinds of nucleotide monomers linked together in long chains
What are lipids formed from?
they are formed from a limited set of smaller molecules (non-covalent forces maintain the interaction between lipid monomers)
What are the 4 major biochemical roles of carbohydrate?
- They are a source of energy that can be released in a form that organisms can use
- They are used to transport stored energy within a complex organism
- They function as structural molecules that give many organisms their shapes
- They serve as recognition//signaling molecules that can trigger specific biological responses
What is starch?
Primary storage units of carbohydrates in plants and is made from linear and branched chains of glucose
Glycosidic Linkages
Monosaccharides are covalently bonded by condensation reactions
What is glycogen?
A form of glucose storage in animals and is in a more highly branched form
What is cellulose?
Another polymer of glucose that can’t be eaten due to glycosidic linkage arranged in a stable way, making it harder to breakdown
What are triglycerides made of?
3 fatty acid molecules and 1 glycerole molecule
Amphipathic
They have a hydrophilic end and a hydrophobic tail. They are commonly seen in fatty acids
What do fatty acids consist of?
A long nonpolar hydrocarbon chain attached to the polar carboxyl (-COOH) group
What do phospholipids form?
They form a bilayer which is a sheet of 2 molecules thick with water excluded from the core
What is different about Archaea’s membrane?
The phospholipids are based on isoprene, rather than fatty acids
