f214 respiration

F214 Module 4 - Respiration

a. Outline why plants, animals and microorganisms need to respire, with reference to active transport and metabolic reactions

·         All living organisms need energy so as to undergo their biological processes, of which all of the reactions are known altogether as metabolism.

·         Metabolic reactions:

Those that build large molecules are anabolic.

Those that break large molecules into smaller ones are catabolic.

Active transport is when ions and molecules are moved across a membrane against the concentration gradient. A lot of an organisms energy is used for this.

Secretion is when large molecules in some cells are removed via exocytosis.

Endocytosis is the movement of large molecules into the cell.

Synthesis of large molecules from smaller ones.

Replication of DNA and synthesis of organelles.

Movement e.g. cilia

Activation of chemicals.

b. Describe the structure of A.T.P

Adenosine = Ribose and Adenine.

Adenosine Monophosphate = Phosphate and Ribose and Adenine.

Adenosine Diphosphate = Phosphate and Phosphate and Ribose and Adenine.

Adenosine Triphosphate = Phosphate and Phosphate and Phosphate and Ribose and Adenine.

c. State that A.T.P provides the immediate source for biological processes

A.T.P is a universal energy currency because it is in every living organism in cells, and energy can be created by losing a phosphate group and can be added to the molecule by adding a phosphate.

Each phosphate released releases 30.6Kilo joules of energy.

A phosphate is released by hydrolysis of A.T.P.

d. Explain the importance of coenzymes in respiration, with reference to N.A.D and coenzyme A

Coenzymes help to carry out the oxidation reactions of respiration as enzymes are not very good at these.

N.A.D: It is an organic non-protein molecule.

It helps dehydrogenase enzymes to carry out oxidation reactions.

It is made up of two linked nucleotides, each having a ribose and an adenine.

When N.A.D has accepted two hydrogen atoms with their electrons it becomes Reduced N.A.D.

When it loses the electrons it is oxidised.

It is used in glycolysis, the link reaction, Krebs cycle as well as during the anaerobic ethanol and lactate pathways.

·         Coenzyme A (Co.A)

It is made from panthotheic acid, adenosine, three phosphate groups and cysteine.

It carries ethanoate (acetate) groups made during the link reaction from pyruvate to the Krebs cycle.

It can also carry acetate groups made from fatty acids or from some amino acids into the Krebs cycle.

e. State that glycolysis takes place in the cytoplasm

·         Glycolysis is the first stage in respiration.

·         It takes place in the cell’s cytoplasm as this is where the enzymes required are.

f. Outline the process of glycolysis beginning with the phosphorylation of glucose to hexose bisphosphate, splitting of hexose bisphosphate into two triose phosphate molecules and further oxidation to pyruvate producing a small yield of ATP and Reduced N.A.D

·         Phosphorylation

One ATP molecule is hydrolysed to release 30.6Kj of energy to start off the reaction.

The released phosphate group joins to the 6 carbon


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