Chap. 2: The Chemical Level of Organization Flashcards
Chemistry
is the science of the structure and interactions of matter
Matter
is anything that has mass and takes up space
Mass
is the amount of matter a substance contains,
Weight
is the force of gravity acting on a mass
Chemical elements
both living and nonliving—are made up of a limited number of building blocks
chemical symbol
one or two letters of the element’s name
major elements
oxygen, carbon, hydrogen, and nitrogen
lesser elements
calcium (C) phosphorus (P) potassium (K) sulfur (S) sodium chlorine (Cl) magnesium (Mg) iron (Fe)
trace element
are present in tiny amounts
cation
positively charged ion
anion
negatively charged ion
enzymes
molecules that increase the rate of chemical reactions in organisms
Atoms
the smallest units of matter that retain the properties and characteristics of an element
Atomic number
the number is the number of protons in the nucleus of an atom
Mass number
is the number of protons and neutrons in an atom
subatomic particles
- compose individual atoms
- only 3 types protons, neutrons, and electrons
nucleus
the dense central core of an atom
isotopes
- two or more forms of the same element
- contains an equal number of protons, but a different number of neutrons in the nuclei
Ion
– an atom that has lost or gained an electron
Molecule
– 2 or more atoms sharing electrons
Compound
– a substance that can be broken down into 2 or more different elements
dalton
- standard unit for measuring the mass of atoms and their subatomic particles
- also known as an atomic mass unit (amu).
A free radical
has an unpaired electron in its outermost electron shell.
compound
is a substance that contains atoms of two or more different elements
chemical bonds
forces that hold together the atoms of a molecule or a compound
valence shell
the outermost shell of an atom
ionic bond
The force of attraction that holds together ions with opposite charges
covalent bond
two or more atoms share electrons rather than gaining or losing them
Cohesion
is the tendency of like particles to stay together
Surface tension
is a measure of the difficulty of stretching or breaking the surface of a liquid
chemical reaction
occurs when new bonds form or old bonds break between atoms
Law of conservation of energy
– energy can neither be created nor destroyed but it can be converted from one form to another
potential energy,
energy stored by matter due to its position
kinetic energy,
the energy associated with matter in motion
Chemical energy
is a form of potential energy that is stored in the bonds of compounds and molecules
Exergonic reactions (ex‐ = out)
release more energy than they absorb
endergonic reactions (end‐ = within)
absorb more energy than they release
activation energy
The collision energy needed to break the chemical bonds of the reactants
Catalysts
are chemical compounds that speed up chemical reactions by lowering the activation energy needed for a reaction to occur
Synthesis Reactions - Anabolism
When two or more atoms, ions, or molecules combine to form new and larger molecules
Decomposition Reactions - Catabolism
split up large molecules into smaller atoms, ions, or molecules
exchange reactions
they consist of both synthesis and decomposition reactions
reversible reaction
the products can revert to the original reactants
oxidation-reduction reactions
are essential to life, since they are the reactions that break down food molecules to produce energy.
Oxidation
refers to the loss of electrons; in the process the oxidized substance releases energy
Reduction
refers to the gain of electrons; in the process, the reduced substance gains energy
Inorganic compounds
usually lack carbon and are structurally simple
Organic compounds
always contain carbon, usually contain hydrogen, and always have covalent bonds
solvent
dissolves another substance called the solute
hydrophilic (hydro‐ = water; ‐philic = loving),
which means they dissolve easily in water
hydrophobic (‐phobic = fearing).
They are not very water‐soluble
hydrolysis
(hī‐DROL‐i‐sis; ‐lysis = to loosen or break apart
decomposition reactions break down large nutrient molecules into smaller molecules by the addition of water molecules
Mixture
– a combination of elements or compounds that are physically blended together but not bonded together
Percentage (mass per volume)
Number of grams of a substance per 100 milliliters (mL) of solution
Molarity
‐ moles (mol) per liter A 1 molar (1 M) solution = 1 mole of a solute in 1 liter of solution
Dissociation
is the separation of inorganic acids, bases, and salts into ions in a solution.
buffer systems,
which function to convert strong acids or bases into weak acids or bases.
carbon skeleton
chain of carbon atoms in an organic molecule
hydrocarbon
Many of the carbons are bonded to hydrogen atoms
simple sugars
Monosaccharides and disaccharides.
Monosaccharides
- three to seven carbon atoms, glucose & a hexose
- main energy supplying compound
Disaccharides
- formed from two monosaccharides by dehydration synthesis
- can be split back into simple sugars by hydration
- glucose + sucrose = sucrose
polysaccharide molecule
contains tens or hundreds of monosaccharides joined through dehydration synthesis reactions
glycogen
The main polysaccharide in the human body
Starches
are polysaccharides formed from glucose by plants
Cellulose
is a polysaccharide formed from glucose by plants that cannot be digested by humans but does provide bulk to help eliminate feces.
lipids
lipids contain carbon, hydrogen, and oxygen. Unlike carbohydrates, they do not have a 2:1 ratio of hydrogen to oxygen
hydrophobic
insoluble in polar solvents such as water
lipoproteins.
the smallest lipids (some fatty acids) can dissolve in watery blood plasma. To become more soluble in blood plasma, other lipid molecules join with hydrophilic protein molecules
fatty acids
- the simplest lipids
- used to synthesize triglycerides and phospholipids
- can also be catabolized to generate adenosine triphosphate (ATP 0
- consists of a carboxyl group and a hydrocarbon chain
saturated fatty acid
- contains only single covalent bonds between the carbon atoms of the hydrocarbon chain
- they lack double bonds, each carbon atom of the hydrocarbon chain is saturated with hydrogen atoms
unsaturated fatty acid
- contains one or more double covalent bonds between the carbon atoms of the hydrocarbon chain
- not completely saturated with hydrogen atoms
- has a kink (bend) at the site of the double bond
monounsaturated
- just one double bond in the hydrocarbon chain, has just one
polyunsaturated
has more than one double bond in the hydrocarbon chain and it contains more than one kink.
triglycerides
consists of two types of building blocks: a single glycerol molecule and three fatty acid molecules.
Monounsaturated fats
- contain triglycerides that mostly consist of monounsaturated fatty acids
- Olive oil, peanut oil, canola oil, most nuts, and avocados are rich in triglycerides with monounsaturated fatty acids
- decrease the risk of heart disease
Polyunsaturated fats
- contain triglycerides that mostly consist of polyunsaturated fatty acids.
- Corn oil, safflower oil, sunflower oil, soybean oil, and fatty fish (salmon, tuna, and mackerel) contain a high percentage of polyunsaturated fatty acids
- decrease the risk of heart disease
phospholipids
- have a glycerol backbone and two fatty acid chains attached to the first two carbons.
- In the third position, however, a phosphate group links a small charged group that usually contains nitrogen (N) to the backbone.
- This portion of the molecule (the “head”) is polar and can form hydrogen bonds with water
- amphipathic molecules, having both polar and nonpolar regions
amphipathic
Molecules that have both polar and nonpolar parts are said to be
Amphipathic phospholipids
line up tail‐to‐tail in a double row to make up much of the membrane that surrounds each cell
Steroids
have four rings of carbon atoms
sterols
cholesterol, estrogens, testosterone, cortisol, bile salts, and vitamin D
Cholesterol,
which is synthesized in the liver, is the starting material for the synthesis of other steroids in the body.
Proteins
are large molecules that contain carbon, hydrogen, oxygen, and nitrogen
Enzymes
are proteins that speed up most biochemical reactions
amino acids
The monomers of proteins
Body proteins
contain 20 different amino acids, each of which has a unique side chain.
Amino acids
are the monomers used to build proteins.
Proteins level of Organizational structure
primary
secondary
tertiary
quaternary
the primary level of structure for a protein
- primary structure is the unique sequence of amino acids that are linked by covalent peptide bonds to form a polypeptide chain
- A protein’s primary structure is genetically determined, and any changes in a protein’s amino acid sequence can have serious consequences for body cells
- The primary structure is the sequence of amino acids in the polypeptide.
enzymes
- most catalysts are protein molecules
- Some enzymes consist of two parts—a protein portion, called the apoenzyme (ā′‐pō‐EN‐zīm), and a nonprotein portion, called a cofactor
Nucleic acids
so named because they were first discovered in the nuclei of cells, are huge organic molecules that contain carbon, hydrogen, oxygen, nitrogen, and phosphorus. Nucleic acids are of two varieties.
deoxyribonucleic acid (DNA)
forms the inherited genetic material inside each human cell.
Ribonucleic acid (RNA),
the second type of nucleic acid relays instructions from the genes to guide each cell’s synthesis of proteins from amino acids.
Nucleotides
are the repeating units of nucleic acids. Each nucleotide consists of a nitrogenous base, a pentose sugar, and a phosphate group.
