Phosphocreatine and ATP – Muscles Ep 3

Muscle contraction requires a large amount of energy, meaning that a constant source of ATP is needed. In this article we will look at the three sources of ATP which muscle fibre cells can use. Phosphocreatine ATP has to be made by adding a phosphate group (Pi) to ADP. In the ATP-phosphocreatine system, the phosphate... Continue Reading →

Muscle Contraction – Muscles Ep 2

Muscle contraction is a tricky bit of A-Level biology. There are lots of new terms to learn and a complex process to get your head around. Make sure to review it regularly so that it sticks in your brain. Before beginning this article, make sure you are happy with the different parts of a muscle... Continue Reading →

Anaerobic Respiration and RQs – Respiration Ep 4

Anaerobic respiration happens when there isn't enough oxygen present for aerobic respiration to continue. Different types of organism use different pathways - lactate fermentation or alcoholic fermentation. For both pathways, the amount of ATP produced is much lower than in aerobic respiration because the only ATP produced comes from glycolysis (2ATP per glucose molecule). You... Continue Reading →

Oxidative Phosphorylation – Respiration Ep 3

We've reached the final stage of aerobic respiration - oxidative phosphorylation. This step takes place using proteins in the inner mitochondrial membrane. Now we will find out what all the reduced NAD and reduced FAD produced in glycolysis, the link reaction, and the Krebs cycle is used for. Oxidative phosphorylation The coenzymes NAD and FAD... Continue Reading →

The Krebs Cycle – Respiration Ep 2

The Krebs cycle has many names. Sometimes it is called the tricarboxylic acid (TCA) cycle or the citric acid cycle. But whatever name you give it, it's an important part of aerobic respiration. In the last article we covered the first two stages of aerobic respiration (glycolysis and the link reaction). We ended the link... Continue Reading →

ATP – Biological Molecules Ep 5

Today we are looking at adenosine triphosphate, often just abbreviated to ATP because as with most scientific terms, it's a bit of a mouthful. This molecule is very important in providing a quick source of energy for processes in cells. Let's have a closer look at its structure and function. Structure of ATP ATP is... Continue Reading →

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