Presentation on theme: "Proteins Carbohydrates Lipids Water Edited by Janet A Renshaw School of Biological Sciences."— Presentation transcript:
Proteins Carbohydrates Lipids Water Edited by Janet A Renshaw School of Biological Sciences
Introduction Carbohydrates Proteins Lipids Water Questions and Answers EXIT
They are all based on the chemical elements carbon, hydrogen and oxygen. Proteins can also contain the elements nitrogen, sulphur and phosphorous The three main organic molecules are carbohydrates, proteins and lipids. These molecules are very important in living organisms, they can be used as building blocks for cells and also for energy
The structures of these molecules are of key importance to their functions Carbohydrates Proteins Lipids Water is a very important molecule, it makes up between 45- 75% of the body mass of most organisms and without it life on earth would not have evolved.
Carbohydrates have roles in all forms of life and make up most of the organic matter on earth. Monosaccharides are the basic monomer units of which carbohydrates are composed. The most common monosaccharide is glucose starches cellulose glycogen sugars carbon hydrogen oxygen Carbohydrate molecules consist of 3 elements
H in the form the OH is here OH HO OH H H O H 2 COH H This has a great effect on the property of molecules made when glucose molecules link together. in the form the OH is here H OH Glucose Glucose can exist in two forms, the form and the form. The two forms of glucose have the same properties. The only difference between them is the position of one of the OH groups.
Disaccharides When 2 monosaccharides join together they form a larger disaccharide molecule. The linkage is via a glycosidic bond where they share an oxygen molecule and a water molecule is eliminated. Monosaccharide Removal of H 2 0 Disaccharide share oxygen Two monosaccharides can become linked by a condensation reaction.
H2OH2O Glycosidic Bond Condensation Reaction between 2 glucose monomers
Examples of Disaccharides Maltose Formed from 2 glucose molecules, formed in germinating seeds from the breakdown of starch, providing energy Sucrose Formed from 1 glucose and 1 fructose molecule and is the form in which carbohydrates are transported in the phloem in plants Lactose Formed from 1 glucose and 1 galactose molecule, it is an energy source found in the milk of nearly all mammals
Polysaccharides Carbohydrates which are made from many linked monosaccharide monomers form long chain-like molecules called polymers. - made from glucose monomers polysaccharides cellulose glycogen starch
Starch Starch The other form is amylopectin which consists of branched chains of glucose, this forms a branched compact brush. One form is amylose which consists of un-branched chains of glucose,this coils into a helical compact structure Found in two forms, which are both made up of glucose
Starch is the main storage carbohydrate in plants. Hydrolysis reaction:- A chemical process whereby a compound is cleaved into two or more simpler compounds along with the uptake of water Amylase (enzyme) Breaks down maltose glucose sources of energy Starch H2OH2O
It is the main storage carbohydrate in mammals found in liver and muscle cells. It is more branched in structure than amylopectin. The more branched the molecule, the quicker it can be made and broken. Glycogen A polymer of glucose monomers.
Is a polymer of glucose monomers. It is an important component of plant cell walls. It does not spiral as with glucose glucose consists of chains that are straight and long, they lie parallel to each other bound together by hydrogen bonds. Cellulose
Proteins have many roles in living organisms and are extremely important. There are many different types of proteins with different functions, for example, Antibodies are protective proteins and as part of the immune system they help fight disease Biological molecule with enzyme Biological molecule with enzyme Biological molecule with enzyme Enzyme Enzymes are proteins which speed up the rate of biological reactions Haemoglobin is a protein that transports oxygen in the blood. ANTIBODIES DISEASE
The R group can contain hydrogen and/or carbon and sometimes oxygen, sulphur and nitrogen. This is the basic structure of an amino acid. Proteins are polymers made up of monomers called amino acids. There are 20 different amino acids, amino acids can join in any order to produce an infinite number of different proteins. The only thing that changes between different amino acids is the R group
A condensation reaction joins two amino acids together forming a dipeptide. The bond formed between them is called a peptide bond H2OH2O Peptide Bond A chain of many amino acids linked by peptide bonds is called a polypeptide. A protein can consist of one or more polypeptides. Proteins can get broken down by hydrolysis reactions into polypeptides, dipeptides and amino acids.
The primary structure :- this is the sequence of amino acids in the polypeptide formed from many condensation reactions Protein Structure There are four different levels of protein structure. amino acid amino acid amino acid amino acid amino acid amino acid amino acid amino acid amino acid amino acid H2OH2OH2OH2OH2OH2OH2OH2OH2OH2OH2OH2OH2OH2OH2OH2OH2OH2O
The secondary structure :- where the polypeptide chains can fold into stable 3D regular shapes. One secondary structure is the -helix where the chains fold into a helical shape. Another structure is the strand -helix structure
The tertiary structure :- this is when further folding occurs and this is the overall shape of the polypeptide chain. This is the tertiary structure of the alpha chain of the protein, haemoglobin. This 3D shape is maintained by a series of weak interactions which are mostly hydrogen bonds.
The quaternary structure :- polypeptides can associate with other polypeptides and they way in which they bind together to form the molecule is the quaternary structure. Quaternary Structure taken by means of rasmol (www.dkfz-heidelberg.de)
Globular proteins, for example enzymes, form roughly a spherical shape and most of them are soluble in water. Proteins fit into two subgroups, globular proteins and fibrous proteins. The function of a globular protein is determined by its shape, so its shape is vital. The usual function for this subgroup is a chemical function. Molecular representation of an enzyme Substrate Protein Subgroups
Fibrous proteins do not form a spherical structure they form long chains and they are insoluble. Fibrous proteins have structural roles, like giving strength or elasticity to certain tissues. Muscle Fibre (www.uoguelph.ca)
Proteins can become denatured causing their shape to change therefore affecting their function. Example shows an enzyme becoming denatured and losing hold on a substrate A protein can vibrate due to an increase in temperature, which can cause it to become denatured, causing the weak bonds holding the tertiary or quaternary structure together to break.
Lipids are insoluble. They are important dietary constituents as they are full of energy, contain certain vitamins and have a major role in cell membranes. Two major types of lipids are triglycerides and phospholipids. fats oils steroids waxes carbon hydrogen oxygen Unlike carbohydrates and proteins, lipids do not form polymers. Lipid molecules consist of 3 elements
The formula for fatty acids is R-COOH, where the R, which is the hydrocarbon chain can be saturated or unsaturated. They are formed from a glycerol molecule linked by ester bonds to three fatty acids. Ester bond:-This is formed from a condensation reaction where the carboxyl group of a fatty acid and an OH group from the glycerol join and water is lost so they share an oxygen atom. Triglycerides This group of lipids are the fats and oils.
Glycerol 3 saturated fatty acids ester bond 3H 2 O Triglyceride Molecule
The phosphate group is soluble in water, it is water loving, which is termed hydrophillic. The fatty acids are insoluble in water, they repel water, which is known as hydrophobic. Due to these properties phospholipids form cell membranes when in water Phospholipids Fatty acid glycerol phosphate water glycerol fatty acids phosphates
Simplified structure of a phospholipid molecule used in diagrams of membranes Phospholipid Bilayer formed in water H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O
Water is an inorganic substance. It has many essential properties, it has these properties because of the way in which the molecules in water bond together. The biological importance of water is dependent on its physical properties.
Some Important Properties of Water Solvent Properties Water is a polar molecule and it’s polarity makes it an excellent solvent for other polar molecules. There is a whole range of other polar molecules, which include small organic units such as glucose and amino acids, also ions like calcium,potassium and sodium. Non-polar substances do not dissolve in water.
Specific Heat Capacity Water has a high specific heat capacity, which means it has temperature stability. It takes a large amount of heat (energy) to raise the temperature of water measurably. Due to this water containing organisms are stable thermally.
Latent Heat of Evaporation Due to the high specific heat capacity, water resists evaporation into gas better than other liquids do. This is significant to humans and other animals as we rely on the evaporation of water from our body surface as a cooling device.
Now go to the next page to start testing your knowledge. This section is to test your knowledge on what has been covered in this package. To get the answer click on the answer button You will need paper and a pen to help you answer some of the questions
Question 1 What is the name of this carbohydrate monomer ? Question 2 Draw a diagram to show how two of these monomers form a disaccharide and label the bond CARBOHYDRATES Click here for answer Click here to see diagram
Question 4 What are the two forms of the polysaccharide starch ? Question 5 What are the differences between the two forms ? Question 3 What is the name of the disaccharide formed ? Click here for answer
PROTEINS Question 6 What three elements can be found in proteins but not in carbohydrates and lipids ? Question 7 There are two subgroups of proteins, globular proteins and fibrous proteins. Which subgroup - a) is soluble in water ? b) has structural roles ? c) form long chains ? d) is spherical in shape ? Click here for answer Click here for answers
Question 8 What type of reaction occurs to join amino acids together? Question 9 What is the name of the bond formed between amino acids in a protein ? Click here for answer
LIPIDS Question 10 What are the two major types of lipids? Click here for answer Question 11 How is an ester bond formed in a triglyceride? Click here for answer
Question 12 The phosphate group of a phospholipid is soluble in water, what is the term used for this type of molecule Question 13 Fatty acids are insoluble in water, what is the term used for this type of molecule? Click here for answer
Question 14 Name two important properties of water. WATER Question 15 Water is a polar molecule do Non-polar substances dissolve in water? Click here for answer
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Q1 Answer Answer This carbohydrate monomer is glucose