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Chapter 2: Chemical (Bio166)

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What is the charge, location, and mass of a proton?
Positive; in atomic nucleus; 1 Dalton
What is the charge, location, and mass of a neutron?
No charge; in atomic nucleus; 1 Dalton
What is the charge, location, and mass of an electron?
Negative; in electron cloud; 1/2000th Dalton
What are e-s in valence shell called?
Valence e-s
Atoms want _______ shell filled?
Valence
Atoms with an incomplete valance shell are?
Reactive
Atoms with a complete valance shell are?
Unreactive
What are chemical bonds?
An attraction between two atoms by the sharing or transferring of valence electrons.
What is the term for any chemical structure consisting of atoms held together by shared electrons?
Molecule
What is the term for a pure chemical substance made up of atoms of two or more different elements in a fixed proportion, regardless of the type of chemical bond joining them?
Compound
Cations have what type of charge?
Positive
Anions have what type of charge?
Negative
What is an ionic bond?
A bond created by the electrical attraction between cations and anions. A transfer of e-s from one atom to another.
What is a covalent bond?
A bond between two atoms that involves the sharing of electrons.
Nonpolar covalent bonds involve?
Equal sharing of electrons.
Polar covalent bonds involve?
Unequal sharing of electrons.
In Ionic bonds, a highly ________ atom "strips" e- from another atom.
Electronegative
What is a covalent bond?
Sharing a pair of e-s between two atoms (forms molecule).
What is the most stable (strongest) bond?
Covalent bonds
What is electronegativity?
The attraction of a particular kind of atom for e-s of covalent bond. A measure of the tendency of an atom to attract a bonding pair of electrons
The two types of covalent bonds are?
Nonpolar and polar
What consists of a nonpolar covalent bond?
The equal sharing (generally occuring between atoms with same electronegativity) and pulls with the same amount of force.
What consists of a polar covalent bond?
The unequal sharing of e-s and it is between atoms with different electronegativity.
What is a hydrogen bond?
A bond between H atom of one polar covalent bond and N or O of another polar covalent bond. These bonds are weak.
What are chemical reactions (Rxns)?
The making or breaking of chemical bonds that leads to changes in composition of matter.
We cannot _______ or ______ matter, we can only rearrange _______ and ______.
create or destroy; atoms and bonds.
What are reactants?
Starting materials
What are products?
Resulting materials
What is metabolism?
All of the rxns in the cells/tissues of the body at a given moment.
What is a catabolic reaction?
The breaking down of molecules. (Ex: AB --> A + B
What is another name for catabolic reaction?
Decomposition
What is Hydrolysis reaction?
Catabolic rxn splits water and adds H and OH to products.
What is an anabolic reaction?
Build up molecules
What is another name for an anabolic reaction?
Synthesis
What is dehydration synthesis reaction?
Anabolic rxn forms water by removing H and OH from reactants.
What is another name for dehydration synthesis?
Condensation
What is stability measured by?
Measured by how much energy it takes to break the bond.
What are enzymes?
Proteins that selectively speed up chemical rxns without being changed.
What do enzymes do to chemical rxns?
They lower the activation energy (Ea) and once started can release or absorb E (usually in form of heat).
If E is released from an enzyme, what is it called?
Exergonic or exothermic
If more E is absorbed within an enzyme, what is it called?
Endergonic or endothermic
The reactants in enzymatic rxns are called?
Substrates
The substrate must bind to a special region of the enzyme called a(n)?
Active Site
Although enzymes are are proteins, any ________ or ________ compound that will bind to the active site can be a substrate.
Organic; inorganic
Describe enzyme structure and function?
Substrates bind to the enzyme at its active site and that produces an enzyme-substrate structure, produces a temporary reversible change in the shape causing the product formation, and then product is released and frees up the enzyme. Then it can repeat the process.
What is a cofactor?
An ion or molecule that must bind to an enzyme before substrates can also bind.
Without a cofactor, the enzyme is?
Intact but nonfunctional
What are examples of ionic cofactors?
Calcium and magnesium
What are coenzymes?
Nonprotein organic molecules that function as cofactors.
What is denaturation?
A change in tertiary or quaternary structure that makes it nonfunctional.
What is pepsin and what environment does it work best in?
An enzyme that breaks down food proteins in the stomach. It works best in a strongly acidic environment.
What is trypsin and what environment does it work best in?
An enzyme that attacks proteins in your small intestine. It works best in a weak basic/alkaline environment.
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