micro ch2

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1

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

2

Ionization

(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+)

3

PH

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+]

4

Functional group

- 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)

5

Dehydration synthesis

occurs in the polymerization process when one carbon group gives up an H and the other carbon group gives up an OH, forming water.

6

Macromolecule

large molecules assemble from smaller molecular subunits or building blocks called monomers.

7

Monomers

simple molecules that can be linked by chemical bonds to form larger molecules.ex amino acid

8

Protein denaturation

Disruption of the native state of a protein through heat, chemicals, acid or other means, making the protein non-functional

9

Elements

- 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.

10

Compound

- molecules that are combination of two or more different elements. H2O

11

Atom

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.

12

Molecule

a distinct chemical substance result from the combination of two or more atom.ex. O2

13

Proton

are elementary particle that carries a positive charge. It is identical to nucleus of the hydrogen atoms. In the nucleus

14

Electron

a negative charge subatomic particle that is distributed around the nucleus in an atom. Surround the nucleus

15

Cation

- positive charged ion.

16

Anion

- negatively charged ion

17

Covalent bond

- form between atoms that share electrons rather than donating or receiving them.CH4. Equal sharing.

18

Ionic bond

- formed when electrons are transferred completely from one atom to another. Opposite charge. Na+ --Cl- to NaCl

19

Endergonic

- reactions absorb energy

20

Exergonic

-reactions release energy.

21

Anabolic

-energy requiring reacton that builds complex organic molecules from simpler ones.

22

Catabolic

- chemical reaction that releases energy involving the breakdown of complex organic compounds into simpler ones

23

Synthesis reaction

During synthesis reactions bonds are formed.All synthesis reactions are endergonic. Anabolism is the synthesis of molecules in a cell. S+O2 ----- SO2

24

Decomposition reaction

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

25

Covalent bond-

Covalent bonds form when two atoms share one or more pairs of electrons.H--H to H2.

26

Hydrogen bond

– 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.

27

Monomers

- simple molecules that can be linked by chemical bonds to form larger molecules. Ex. amino acid

28

Polymer

- monomors are bound into chains of various lengths. Ex.protein

29

Organic

molecules that contain the basic framework of the elements of carbon and hydrogen.Simplest: CH4

30

Inorgancic

- does not contain both carbon and hydrogen. Ex

NaCl (Sodium chloride), CO2 (Carbon dioxide)

31

Solvent

-A dissolving medium.Water is the most common solvent in natural systems

32

Solute

- 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

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Acid

- 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-

34

Base

- 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-

35

Hydrophobic

- fear of water. nonpolar molecules such as oils that repel water

36

Hydrophilic

- love water. molecules such as salt or sugar that attract water to their surface.

37

Saturated fat

-All carbons in the fatty acid chain are single-bonded to 2 other carbons and 2 hydrogens

38

Unsaturated fat

- a fatty acid in which at least one double bond exists between carbon atoms

39

Lipid

- variety of substances that are not soluble in polar solvents such as water, but will dissolve in nonpolar substances such as benzene and chloroform.

40

Phospholipid

- a class of lipid that compose a major structural component of cell membranes

41

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.

42

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

43

Describe how hydrogen bonds form between water molecules.

–Polarity of water allows hydrogen bonds with other molecules

44

Describe the structure of a phospholipid and diagram how they are arranged in the cell membrane.

–Allows the molecule to form bilayers and membranes

45

(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.
46

(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

47

(c) Why are they necessary in living cells?

to resist pH change

48

(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

49

Describe the structure of an amino acid.

    1. Building blocks of proteins
    2. Exist in 20 different naturally-occurring forms
    3. Linked by peptide bonds
50

Primary structure

- The type, number, and order of amino acids.

51

Secondary structure

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

52

Tertiary structure

- 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.

53

Quaternary structure

- The quaternary structure consists of two or more polypeptides. Ex. Collagen.

54

State the 3 types of molecules make up a typical nucleotide?

Nitrogen base, Pentose (5-carbon) sugar, Phosphate

55

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

56

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

57

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

58

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

59

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.