Acids, bases, energy levels and chem reactions WK 1

Question 1

Differ between acids and bases

Answer 1

Acid :proton donor (release H+)
Base: proton acceptor(accept H+)

Question 2

Define pH. When is it acidic, acidic, neutral

Answer 2

measure derived from molarity of H+ on logarithmic scale
-pH 7=neutral (H=OH)
-pH of less than 7=acidic
-pH more than 7=basic

Question 3

Describe ratio of change between pH and H+ conc

Answer 3

change in one number on Ph scale=10 fold change in H+ conc
e.g. pH 4 is 10x more acidic than pH 5

Question 4

Describe buffers

Answer 4

chemical solution that resists changes in pH

Question 5

How do H atoms become H+ ions

Answer 5

lose and electron

Question 6

When is something extremely reactive

Answer 6

can break chem bonds and disrupt cell function

Question 7

Define energy

Answer 7

capacity to do work
-all body activities are forms of work

Question 8

Define chem energy, potential energy, kinetic, activation and free energy

Answer 8

chem: potential energy in molecular bond

potential: energy stored in an object (not currently working)

free: potential energy available in system to do work

kinetic: energy of motion, doing work

activation: energy required to start chemical reaction

Question 9

Differ between exergonic and endergonic

Answer 9

Energy releasing process-exergonic
Energy conserving process endergonic

Question 10

Define chem reaction and chem equation

Answer 10

reaction: process in which covalent or ionic bond is formed or broken

equation: symbolises course of a chemical reaction

Question 11

Describe/define the three classes of chemical reactions. Provide e.g. equation structure for each

Answer 11

synthesis: two or more smaller molecules combine to form larger
(A + B—> AB)
decomposition: large molecule breaks down into two or more smaller ones
(AB—> A + B)
exchange: two molecules exchange atoms or group of atoms
(AB+CD–>ABCD–AC + BD)

Question 12

Define metabolism

Answer 12

all chem reactions in body

Question 13

Describe/define catabolism

Answer 13

releasing energy (exergonic) decomposition reactions
-break covalent bonds
-produce smaller molecules

Question 14

Describe/define anabolism

Answer 14

energy-storing (endergonic) synthesis reactions
-requires energy input
-productions of protein or fat

Question 15

What is the connection between anabolism and catabolism

Answer 15

inseparably linked.
-anabolism is driven by energy released by catabolism

Question 16

Describe/define oxidation reactions

Answer 16

chem reaction where molecule gives up e and release energy
-molecule oxidised in process
-e acceptor (base) molecule is oxidising agent (reduced)

Question 17

Describe/define reduction reactions

Answer 17

chem reaction where molecule gains e and energy
-molecule reduced when accepting e
-molecule donating e (acid) is reducing agent (oxidised)

Question 18

Describe what is meant by oxidation-reduction reactions

Answer 18

oxidation of one molecule accompanied always by reduction of another
-e are transferred as H atoms
-reactions catalysed by enzymes (H removed-dehydrogenases, were O added-oxidases)

Question 19

Describe the 4 types of chem reactions

Answer 19

Decomposition=catabolism(release energy)
Break bonds between large complex molecules=smaller fragments (absorbed)

Hydrolysis=Decomp. involving water, components of water molecule join new fragments

Synthesis=anabolism (requires energy)
Assembles smaller into larger molecules

Dehydration synthesis= condensation-complex molecules formed by removal of H2O

Question 20

How are H atoms removed from metabolic intermediates

Answer 20

in pairs
-2x proteins and 2xe-
-transfer to co-enzymes (become temporary carriers of energy extracted)
-NAD^+ (nicotinamide adenine dinucleotide, derived from niacin (B vitamin)
NAD^++2 H→NADH+H^+
-FAD (flavin adenine dinucleotide, derived from riboflavin)
FAD+2 H→FADH_2