OCR A Level Biology Respiration Test Questions With Solved Solutions 2024.

Site of glycolysis - Answer Cytosol NAD - Answer Nicotinamide adenine dinucleotide Main steps in glycolysis - Answer Phosphorylation lysis phosphorylation dehydrogenation formation of ATP What happens in the first step of glycolysis (Phosphorylation)? - Answer 2 ATP molecules are hydrolysed to release two phosphates, both attached to a glucose molecule, forms hexose bisphosphate What happens in the second step of glycolysis (Lysis)? - Answer Phosphorylation destabilises the molecule, splits into two triose phosphate molecules What happens in the third step of glycolysis (Phosphorylation)? - Answer Inorganic phosphate group is added to a triose phosphate molecule to form two triose diphosphate molecules What happens in the fourth step of glycolysis (Dehydrogenation and formation of ATP)? - Answer Two triose bisphosphate molecules are oxidised by the removal of hydrogen atoms, forms two pyruvate molecules, NAD coenzymes accept the removed hydrogens and are reduced to form two reduced NAD molecules, 4 ATP molecules are produced using phosphates from the triose bisphosphate molecules What is the kind of phosphorylation done in glycolysis? - Answer Substrate level phosphorylation What happens in the link reaction? - Answer Pyruvate enters the mitochondrial matrix by active transport by carrier proteins, pyruvate is dehydrogenated and decarboxylated, hydrogen atoms given to NAD to form NADH, resulting two carbon acetyl group is bound to coenzyme A to form acetylcoenzyme A