Lesson starter Give one similarity and one difference between diffusion and osmosis Explain why water is described as a polar molecule.

Answers Both are involved in movement from an area of high concentration to an area of low concentration / are passive / do not require ATP Osmosis refers to water molecules only, but diffusion refers to many different molecules and ions. 2. It has different areas of positive and negative charges.

Learning question: Why is glucose an important molecule? Title: Blood Glucose 17 September 201817 September 2018 Learning question: Why is glucose an important molecule? Homework: Homework due Wednesday 15th October LP9

Key words Monosaccharides Disaccharides Polysaccharides Glycogen Glycosidic bond Glucose Glucose oxidase

Aims from specification outline how the concentration of glucose is measured in human blood describe the basic structure of carbohydrates, with reference to monosaccharides, disaccharides and polysaccharides; describe, with the aid of diagrams, the structure of the ring form of alpha glucose; outline the role of glucose as a respiratory substrate; describe the formation of glycogen by condensation reactions to form glycosidic bonds; describe how the structure of the glycogen molecule adapts it to its function as an energy store in liver and muscle;

Task 1 - Measuring blood glucose concentrations Read the section “Measuring blood glucose concentration” on page 22 Summarise how blood glucose is measured Include the equation for the reaction that takes place Write down 4 key words on your whiteboard to share with the class

Measuring blood glucose concentrations Blood glucose meters are becoming more commonly used to measure the concentration of glucose in the blood, especially for sufferers of diabetes mellitus. The test strip on the metre contains an enzyme – glucose dehydrogenase or glucose oxidase. The following reaction occurs: a small electrical current is initiated, which is detected by the test strip. Within 15-30 seconds, a reading is given out Glucose glucose oxidase/dehydrogenase gluconolactone

Measuring blood glucose concentrations To obtain a reading, the user must wash their hands thoroughly and swap the area to be tested with alcohol. A sterile lancet is used to prick the skin on top of their finger A small drop of blood is placed on a clean glucose test strip. This is then placed into the glucose test meter.

Questions…write in sentences! Why is the normal level for blood glucose given as a range? Why should blood glucose levels be lower before a meal and higher after? Why would a doctor expect blood glucose levels to fall 90 minutes after a meal? What health risks would you associate with elevated blood glucose levels after a meal? Justify your answer by explaining why you think this. Be like the cat – stretch yourself…

Measuring blood glucose concentrations Blood glucose is measured in millimoles per litre (mmol dm-3) 1. Normal blood glucose = 4-8 mmol dm-3 2. Before meals = 4-7 mmol dm-3 3. Less than 10 mmol dm-3 90 minutes after a meal – insulin stimulates glucose storage as glycogen in liver and muscle cells 4. Diabetes mellitus is assoicated with high blood glucose levels. Elevated blood glucose indicates that insulin secreting cells are becoming non-responsive

outline how the concentration of glucose is measured in human blood

Simple Sugars - Monosaccharides Read the section on monosaccharides and summarise in no more than 4 sentences/bullet points

LO: describe, with the aid of diagrams, the structure of the ring form of alpha glucose;

Monosaccharides Simple sugars that can be used as respiratory substrates. This means that is can be broken down directly during aerobic respiration to synthesise ATP. Glucose is very soluble, so it is easily transported in the blood plasma Alpha glucose is an example of a monosaccharide sugar that is found in blood

LO: describe, with the aid of diagrams, the structure of the ring form of alpha glucose;

Draw a diagram of alpha glucose without looking at your notes LO: describe, with the aid of diagrams, the structure of the ring form of alpha glucose; outline the role of glucose as a respiratory substrate; Draw a diagram of alpha glucose without looking at your notes Number the carbon atoms

Task 2 - Disaccharides Read the section on disaccharides and summarise in no more than 4 sentences/bullet points LABELLED diagrams are a good idea! Key words Condensation reaction Glycosidic link Maltose Fructose OH and H groups

Condensation reaction A condensation reaction is a reaction in which two molecules are joined together by removing a hydrogen atom from one molecule and OH from the other molecule. Condensation reactions are a key type of anabolic or “build up” reaction

Disaccharides Two monosaccharides joined up together make a disaccharide. Two glucose molecules joined make the sugar maltose. Glucose and fructose joined together make the sugar sucrose, which we commonly use in tea etc. These monosaccharides join together by condensation reactions and a glycosidic link is created.

describe the formation of glycogen by condensation reactions to form glycosidic bonds;

Polysaccharides Key words Condensation reaction Glycosidic link OH and H groups Glucose Glycogen Insoluble Branched

Polysaccharides When many monosaccharides join together, a polysaccharide is formed (poly = many) In humans, many alpha glucose molecules joining up together forms the storage molecule glycogen A glycogen molecule looks branched because one glucose molecule (residue) can form glycosidic links with 3 other glucose molecules

1,6 glycosidic bond Glucose monomer

Task 3 - Explain why these 3 factors are important to the human body. Polysaccharides Glycogen is used for storage of energy. It is well suited to this role because: Insoluble Compact Branching structure Task 3 - Explain why these 3 factors are important to the human body.

describe how the structure of the glycogen molecule adapts it to its function as an energy store in liver and muscle;

Plenary - Exam questions

Exam questions Be like the cat – stretch yourself…

Exam answers

How did you do? The exam questions are a self assessment tool. If you found these questions difficult, you have not understood (or done) the pre-reading/textbook questions. Be honest with yourself – are you working as hard as you can?!