Polarity of the water molecule
Results when a molecule is formed between two molecules that have different electronegativity, or ability to attract electrons ex.
For example, water (a polar molecule) does not mix with oil (a non polar molecule). alcohol
(When ionic bonds break and the atoms dissociate into unattached charged particles).
The formation of charged particles when a molecule formed by ionic bonds dissolves in a solvent. ex.(Na+)
the symbol for the negative logarithm of the H ion concentration p (power) or [H+]10. A system for rating acidity and alkalinity.
pH = -log[H+]
- Molecular groups or accessory molecules that bind to organic compounds.
Example: (R–OH hydroxyl- carbohydrates, alcohol), ( R–COOH- carboxyl- fatty acids proteins, carbonic acids), (R–NH2- amino, protein, nucleic acid)
occurs in the polymerization process when one carbon group gives up an H and the other carbon group gives up an OH, forming water.
large molecules assemble from smaller molecular subunits or building blocks called monomers.
simple molecules that can be linked by chemical bonds to form larger molecules.ex amino acid
Disruption of the native state of a protein through heat, chemicals, acid or other means, making the protein non-functional
- a substance comprising only one kind of atom that cannot be degraded into two or more substances without losing its chemical characteristics. There are 92 naturally occurring elements on Earth.
- molecules that are combination of two or more different elements. H2O
the smallest particle of an element to retain all the properties of that element.
–Each element is made up of only one type of atom.
a distinct chemical substance result from the combination of two or more atom.ex. O2
are elementary particle that carries a positive charge. It is identical to nucleus of the hydrogen atoms. In the nucleus
a negative charge subatomic particle that is distributed around the nucleus in an atom. Surround the nucleus
- positive charged ion.
- negatively charged ion
- form between atoms that share electrons rather than donating or receiving them.CH4. Equal sharing.
- formed when electrons are transferred completely from one atom to another. Opposite charge. Na+ --Cl- to NaCl
- reactions absorb energy
-reactions release energy.
-energy requiring reacton that builds complex organic molecules from simpler ones.
- chemical reaction that releases energy involving the breakdown of complex organic compounds into simpler ones
During synthesis reactions bonds are formed.All synthesis reactions are endergonic. Anabolism is the synthesis of molecules in a cell. S+O2 ----- SO2
Decomposition reaction- reaction bonds are broken. All decomposition reactions are exergonic.Catabolism is the decomposition reactions in a cell. Ex. 2H2O2 à 2H2O + O2
ex.AB → A + B
Covalent bonds form when two atoms share one or more pairs of electrons.H--H to H2.
– weak chemical bond formed by the attraction of forces or atoms- in this case, hydrogen and either oxygen of nitrogen. In this type of bond, electrons are not shared, lost, or, gained.
- simple molecules that can be linked by chemical bonds to form larger molecules. Ex. amino acid
- monomors are bound into chains of various lengths. Ex.protein
molecules that contain the basic framework of the elements of carbon and hydrogen.Simplest: CH4
- does not contain both carbon and hydrogen. Ex
NaCl (Sodium chloride), CO2 (Carbon dioxide)
-A dissolving medium.Water is the most common solvent in natural systems
- A substance that is uniformly dispersed in a solvent.
Ex. Solute-If a salt were dissolved in a liquid, then the salt would be classified as the solute
- solution with the pH value below 7 on the pH scale. An acid is a
substance that dissociates into one or more H+.
ex. HCl---H+ + Cl-
- solution with the pH value above 7on the pH scale. A base is a substance that dissociates into one or more OH-. ex. NaOH---Na+ + OH-
- fear of water. nonpolar molecules such as oils that repel water
- love water. molecules such as salt or sugar that attract water to their surface.
-All carbons in the fatty acid chain are single-bonded to 2 other carbons and 2 hydrogens
- a fatty acid in which at least one double bond exists between carbon atoms
- variety of substances that are not soluble in polar solvents such as water, but will dissolve in nonpolar substances such as benzene and chloroform.
- a class of lipid that compose a major structural component of cell membranes
What is the difference in the concentration of hydrogen ions (H+) between a solution of pH 3 and one of pH 8? Which one is more acidic?
pH 3 is more concentrated than ph8. ph3 is more acidic.
Describe fully one example of how water participates as a reactant in biochemical reactions in living cells.
Four main families of biochemicals: Carbohydrates, Lipids, Proteins, Nucleic acids
Describe how hydrogen bonds form between water molecules.
–Polarity of water allows hydrogen bonds with other molecules
Describe the structure of a phospholipid and diagram how they are arranged in the cell membrane.
–Allows the molecule to form bilayers and membranes
(a) What is a pH buffer?
Buffers are substances present in cells that resist pH change.
- They accept H+ ions when they are in excess.
- They donate H+ ions when they are depleted.
(b) Explain precisely how pH buffers work to regulate the pH of a cell.
Biochemical reactions in cells take place best within a narrow range of pH: 6.8-7.2
(c) Why are they necessary in living cells?
to resist pH change
(d) Explain why proteins make good pH buffers.
- Are essential in cell structure and function.
- Enzymes are proteins that speed chemical reactions.
Transporter proteins move chemicals across membranes
Describe the structure of an amino acid.
- Building blocks of proteins
- Exist in 20 different naturally-occurring forms
- Linked by peptide bonds
- The type, number, and order of amino acids.
Arises when functional groups on the outer surface of the molecule interact with each other. α helix, β pleated sheet, Amino acid chain folds and coils in a regular helix or pleats
- Torsion caused by interaction between functional groups
Covalent sulfide bonds.The tertiary structure occurs when the helix folds irregularly, forming disulfide bonds, hydrogen bonds, and ionic bonds between amino acids in the chain.
- The quaternary structure consists of two or more polypeptides. Ex. Collagen.
State the 3 types of molecules make up a typical nucleotide?
Nitrogen base, Pentose (5-carbon) sugar, Phosphate
List the complementary base pairs found in DNA.
Contains all of the nitrogen bases except uracil. Nitrogen base (A,T,C,G) Thymine, Cytosine, Adenine and Guanine
State three ways in which the DNA molecule differs from the RNA molecule.
DNA- Contains all of the nitrogen bases except uracil
DNA- Nitrogen bases are covalently bonded to deoxyribose
RNA- Contains all of the nitrogen bases except uracil
RNA-Nitrogen bases are covalently bonded to deoxyribose
Describe the structure of ATP and state its function in living cells.
Releases energy when the bond is broken between the 2nd and 3rd phosphates.
Adenine, Ribose, Three phosphate molecules.
Is made by dehydration synthesis.
Is broken by hydrolysis to liberate useful energy
for the cell
State four differences between PrPc and PrPsc. Why does infection with PrPsc lead to disease?
- Normal protein: PrPc: prion protein cellular- Readily destroyed by cellular proteases as they age (normal process)
- Infectious prion: PrPsc: prion protein scrapie- Not easily degraded by cellular proteases
Accumulate in brain tissue
Explain fully how H. pylori a neutrophile, is able to survive and cause infection in the stomach where the pH is 2.
pylori- survive the acidic environment of the stomach by secreting urease, breaks urea into carbon dioxide and ammonia. Ammonia neutralizes stomach acid.