Life With Carbon

Chapter 7 Section 3

• Nutrients – substances that provide energy and raw materials for an organisms to stay alive

4 Classes of Organic Molecules in Living Organisms

• Carbohydrates

• Lipids

• Proteins

• Nucleic Acids

3 Carbohydrate categories:

Monosaccharides

Disaccharides

Polysaccharides

• Lets look first at Carbohydrates.

Monosaccharide: Simple sugars (3 to 7 C atoms)

Very soluble in water.Important as fuel for cells

Ex.:Glucose

Isomers - have same molecular formula but different shape

Ex.: Glucose, Galactose and Fructose

All have 6 C atoms

Disaccharide: Composed of two Monosaccharides bonded together

Disaccharide: Very sweet.

Very water soluble

Ex.: Sucrose (cane sugar)

- composed of glucose and fructose

Polysaccharide:More than 2 Monosaccharides bonded togetherAlso called Complex Carbohydrates

Starches: the form that plants store glucose inGlucose based polysaccharides Readily digested

Glycogen: Animal starch -composed of glucose molecules bonded

together- Not soluble in water- Manufactured and stored by liver and muscle

Cellulose – one form that man can not digest!Cell walls of plants

Glycogen: Animal starch

Also composed of glucose molecules

Lactose Intolerance

• Condition caused by inadequate production of lactase to break down lactose fast enough

• This causes increased water retention and general upset stomach feeling

Storage of Glucose as Glycogen

• The liver stores limited amounts of excess glucose in the form of glycogen in the liver.

• The liver can then break down the glycogen and release the glucose into the blood stream when it is needed.

Maintaining glucose levels• Glucose levels in the blood should be

maintained at a constant homeostatic level for optimum health.

• Insulin – a hormone is secreted into the blood to when blood glucose levels rise.– Insulin causes cell to increase their uptake of

glucose to get it out of the blood

Glucagon – another hormone secreted by the pancreas when blood glucoses fall triggering the liver to break down glycogen releasing glucose into the blood

Diabetes

• Type 1- less common type in which the pancreas does not make enough insulin resulting in high blood glucose levels

• Type 2 – more common and mostly caused by obesity. In this instance, cells do not respond to the adequate amounts of insulin being produced

Dental Caries

• What causes cavities?

• High sugar foods serve as nutrients for bacteria living in your mouth.

• The bacteria become very active producing higher amounts of waste products which are acidic

• It is the acidic waste that causes cavities.

What are fats?

• The term fat refers to a group of nutrients called Lipids which include the following:

– Triglycerides (fats and oils)– Phospholipids– Sterols

Fatty Acids – the building blocks of all fats

• Fatty acids are organic compounds that are capable of storing significant amounts of energy.

• They are made from chains of carbon atoms with a methyl group at one end and an acid group at the other.

Fatty Acids

• The length of these fatty acids vary between 6 and 24 carbons.

• Most fatty acids in foods are around 18 carbons long.

Saturated and Unsaturated

• Saturated Fatty Acids are fully loaded with hydrogen atoms and no double bonds between the carbon atoms.

• Unsaturated Fatty Acids are missing 2 or more hydrogen atoms causing one or more double bonds to form between carbon atoms.

Mono or Polyunsaturated

• Monounsaturated Fatty Acids are missing 2 hydrogen atoms causing one double bond to form between two carbon atoms

• Polyunsaturated Fatty Acids are missing 4 or more hydrogen atoms causing 2 or more double bonds to form in the fatty acid

Triglycerides

• Triglycerides are organic molecules made of three fatty acids attached to one glycerol molecule.

• They are the major fat found in our diets and also the major storage form of fat in the body.

• Compare firmness and stability of saturated and unsaturated fats.

• Hydrogenation refers to the process by which hydrogen atoms are added to unsaturated fats to make them take on characteristics of saturated fats.

• Trans fatty Acids have hydrogen atoms next to the double bond on opposite sides of the chain.

Phospholipids

• Phospholipids are made of a glycerol and phosphate backbone with two fatty acids attached.

• Fatty acids are used in our foods as an emulsifier because phospholipids are both water soluble and fat soluble.

• Fatty acids are also the major component in the membrane of all cells.

Sterols

• Sterols are ring shaped molecules an include cholesterol, some hormones and bile acids in the body.

Proteins

• Proteins are another category of organic molecule made of carbon, hydrogen, oxygen and nitrogen which is where they get the amino name.

• Proteins are made by putting together long chains of smaller molecules called amino acids. There are 20 different amino acids used to make proteins.

• All of the amino acids are alike with the exception of the side group.

• These amino acids are put together in a very specific order based on the type of protein being made.

• Proteins have specific functions based on their shape.

• Proteins can denature, or change shape if exposed to changes in the environment such as temperature or pH.

Nucleic Acids

• Two types of nucleic acids are– DNA – deoxyribonucleic acid– RNA – Ribonucleic Acid

Nucleic acids are made of smaller building blocks called nucleotides which are put together to form very large chains.