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Free Edexcel Maths Past Papers. GCSE Style Maths Past Papers 1MA0 Arranged by Topic Trying to revise using past papers usually means going from one topic to another and not covering any of them in detail. The following FREE booklets contain most of the question types asked since 2006, but arranged by topic so you can get lots of practice concentrating on one topic at a time. Great for revision. These papers have been carefully written in the style Edexcel use for their 1MA0 Maths papers. The A* booklets cover topics that come up less often. Edexcel Past Papers Archive This page and the past papers on it are now hosted by Wayback Machine and there lots of FREE Edexcel 1380 Maths past papers for you to download. Model Answers Improve your grade.
Get all 25 Model Answer booklets BUY Get all 25 Model Answer booklets £22 BUY International GCSE style Maths Past Papers 4MB0 This part of the site will include the topics not covered in the UK papers, but needed for IGCSE. Home Resources AQA. Cardiovascular System. Exercise & Cellular Respiration. Cellular respiration includes the reactions in the cells of your body when they convert the food you eat into a molecule of energy called adenosine triphosphate, or ATP, a form your cells can use. Light household activities or sitting down to watch TV requires a steady supply of ATP.
When you transition from daily activities to exercise or when you have to carry laundry up several flights of stairs, your body needs a rapid burst of ATP. Your cellular respiration or cellular metabolism can be aerobic or anaerobic. These are processes in which energy is converted from the food you eat into energy molecules that the cells of your body can use. Aerobic respiration occurs in the presence of oxygen, while anaerobic metabolism occurs in the absence of oxygen. Anaerobic respiration takes place at the onset of exercise for up to 90 seconds.
Anaerobic respiration occurs in the watery fluid inside the cell. The anaerobic process relies solely on carbohydrates to make energy. Digestion: Digestive System, Enzymes, Absorption in the Small Intestine. Digestion Digestive System The diagram to the left is of the alimentary canal also known as the digestive tract and also shows other organs of the digestive system like the liver. After being swallowed, the food travels down the Oesophagus or esophagus, this is continually being damaged by the friction of food, so the epithelium is a few cells thick and secretes mucas to lubricate the food's passage. The muscularis externa is also much larger to give more force to peristalsis. The next place it enters is the stomach this is a temporary store, mixes the contents up and also is the site for a bit of digestion. The mucosa are folded to allow for expansion as more food is added. Into the small intestine opens the pancreatic and bile ducts: opening into the duodenum.
Food is moved thorugh the digestive system by a process called peristalsis. Enzymes For more information about enzymes see Enzymes Enzymes are what digest, or break up the food. Human Gut Wall The Villi Digestion of Triglycerides. Digestive System. TSR Wiki > Study Help > Subjects and Revision > Revision Notes > Biology > Digestive System The Digestive system - A-level Biology Revision notes What is the digestive system? The digestive system consists of a tube which leads from mouth to anus. The digestive system is made up of the oesophagus, the stomach, small intestine and large intestine. File:Peristalsis.JPG The muscles above the bolus in the digestive tract contract while those in front of it relax, this gradually causes the movement of the bolus through the digestive system. What is the structure of the digestive tract? The general structure of the digestive tract goes as follows: Mucosa – This is involved in the secretion of digestive juices and the absorption of digested food.
Parts of the Digestive System Stage 1 - The Mouth Food first enters the digestive system in the mouth. Stage 2 - The Oesophagus This is a tube which connects the mouth to the stomach, food travels down this tube by peristalsis. Stage 3 - The Stomach Comments. The Digestive System - Biology Innovation. Digestion is the breaking down of chemicals in the body to a form that can be absorbed and used. Digestion begins, in mammals, with the saliva in the mouth.
The Mouth This is the buccal cavity in a human and is where mechanical digestion and mastication (chewing) takes place.Saliva in the mouth consists of mucin (binds food together), salivary amylase (digests starch to maltose) and mineral salts (regulates pH around 7, neutral). Oesophagus Peristalsis of the circular muscle contracts and relaxes to push food down.The upper part of the oesophagus is under conscious control until a point when it becomes involuntary.It usually takes between 4 and 8 seconds for food to travel from mouth to stomach. Stomach Chyme is the word we use to describe the semi-liquid food which is now all mixed together. Duodenum (early small intestine) Liver Pancreas Brunner’s gland Located in the wall of the duodenum.Secretes alkaline juices (which help maintain the correct pH) and mucus (for lubrication and protection). The Digestive System - Biology Innovation. Acidosis/Alkalosis. Acidosis and alkalosis are terms used to describe the abnormal conditions when a patient’s blood pH may not fall within the healthy range.
Measuring the pH of blood is a way of finding out how acidic or alkaline the blood is. Normal blood pH must be within a narrow range of 7.35-7.45 so that the body’s metabolic processes can work properly and can deliver of the right amount of oxygen to tissues. Many diseases or and other conditions can cause a patient’s blood pH to fall outside of these healthy limits. In the human body, normal metabolism generates large quantities of acids that must be removed to keep a normal pH balance. Disruption of this balance can be caused by a build-up of acid or Alkali (base) or by an increased loss of acid or base (see the diagram of ‘taps and drains’ below).
The major organs involved in regulating blood pH are the lungs and the kidneys. Figure 1: Taps and Drains Acid-base disorders are divided into two broad categories. Cardiovascular System.