Organic and Inorganic Substances

• Plants produce their own food through photosynthesis
• Most other organisms, including humans, must obtain organic matter from their surroundings

Chemicals of Life

• There are two types of chemicals in cells: organic and inorganic

Organic Substances

• Some are described as chemicals produced by living things
• These do not include carbon dioxide, carbon monoxide, carbonic acid, and salts derived from carbonic acid

Inorganic Substances

• Substances include nitrate, magnesium, calcium, and iron

Inorganic Chemical Constituents of Organisms

• Involved in chemical reactions in the body
• Help keep organisms healthy

Organic Chemical Constituents of Organisms

• Carry information that controls cell activities

Importance of Food

• Food provides substances that organisms use to live, grow, and maintain their bodies
• Food is needed for:
• Providing energy for activities and warmth
• Providing materials for growth and repair of body tissues
• Maintaining overall bodily functions and health

How Humans Obtain Food

• Humans get food from other organisms
• This mode of nutrition is called heterotrophic nutrition

Food Requirements

• Humans need seven types of food substances to stay healthy

Carbohydrates

What They Are

• Carbohydrates are organic, and consist of carbon, hydrogen, and oxygen atoms
• The hydrogen:oxygen ratio in carbohydrates is equal to 2:1

Why They Are Important

• Carbohydrates provide energy for body activities

• Excess carbs are stored as glycogen in the liver and muscles, or converted to fat under the skin and around internal organs

• Cellulose, the main component of plant cell walls, is a type of carbohydrate

• Cellulose acts as an important source of dietary fiber for humans, which keeps us healthy

Kinds of Carbohydrates

• Simplest carbohydrates, like glucose, fructose, and galactose, are sweet, soluble, and provide energy to living cells
• Disaccharides are made of two monosaccharides joined together by a specific reaction
• They can be split into monosaccharides, are sweet, and soluble in water
  • Sucrose is made of fructose + glucose
  • Maltose is made of glucose + glucose
  • Lactose is made of glucose + galactose
• Exmaples: Sucrose (sugar cane), maltose (germinating barley), lactose (milk)
• All common disaccharides possess reducing power, except sucrose.
• Polysaccharides consist of many monosaccharides linked by a reaction, are non-sweet, and insoluble in water
• Examples: Starch, glycogen, and cellulose
• Examples: Rice, noodles, bread and potatoes

Chemical Tests

Clinistix and Diastix Paper Tests

• Chemical tests to detect glucose
• Add a drop of unknown liquid to spotting tile; dip the color end of the paper into the liquid
• Observe any color change

Benedict's Test

• The chemical test to detect reducing sugar
• Label a test tube, add 2mL unknown liquid, 2mL Benedict's solution and mix
• Transfer to the boiling water bath and heat for five minutes
• Remove from the bath; let it sit for 10 minutes and observe

Iodine Test

• A chemical test to detect starch
• Add a drop of unknown liquid to the spotting tile
• Add a drop of iodine solution, and observe any color change.

Lipids

What They Are

• Lipids are organic, contain carbon, hydrogen, and oxygen, and have a low proportion of oxygen atoms to hydrogen
• A lipid molecule consists of glycerol and fatty acids
• Lipids are insoluble in water, but soluble in organic solvents like alcohol
• They exist as solids/semi-solids at room temp (fats) or as liquids (oils)
• Major food sources of lipids are meat, milk, butter, egg yolk, and peanuts

Why They Are Important

• Lipids act as source of energy and are stored
• Lipids act as insulation under the skin or around internal organs
• Lipids make up cell membranes, certain hormones, and help absorb fat-soluble vitamins Functions of lipids in the body:
• Provide long-term energy storage
• Insulate the body to reduce heat loss
• Protecting internal organs

Grease Spot Test

• Physical test for lipids
• Add a drop of the unknown liquid to filter paper; let it sit for 10 minutes
• Hold the paper up to the light and check for translucent spots
• Translucent spots indicates that lipid is present

Proteins

What They Are

• Proteins are organic, consist of carbon, hydrogen, oxygen, and nitrogen

• Some may also contain sulfur and phosphorus

• Proteins are composed of repeating units of amino acids

• 20 kinds of amino acids can combine differently to create many proteins

• Plants can make all amino acids from minerals, such as magnesium

• Animals cannot produce all amino acids; therefore, humans can only produce 12 amino acids

• The other 8 amino acids need to be supplied from food

• Many proteins are soluble in water but are denatured & insoluble at high temperatures

• Excess amino acids are broken down, removing the nitrogen-containing component

• The nitrogen-containing compound is then converted to urea for excretion

• Foods containing mostly protein are meat, fish, egg white, milk, and beans

Why They Are Important

Functions of proteins in the body:

• Components of membranes and enzymes

• Raw material for growth and repair

• Energy, hormones and antibodies

• Excess proteins and amino acids are not stored

• A lack of protein may lead to kwashiorkor, whose symptom is a swollen belly due to tissue fluid accumulation

Albustix Paper Test

• Chemical test for proteins
• Add a drop of unknown liquid to a spotting tile
• Dip a paper into the liquid, wait one minute, and observe any color change

Water

What it is

• Water is an inorganic compound
• Exists as a liquid at room temperature
• It is the major substance in the bodies of living organisms

Why it is Important

• As a solvent: Dissolves substances for reactions such as blood for nutrient/waste/gas around the body
• As a cooling agent: Used in sweating in mammals to remove heat
• As a reactant: Used in photosynthesis
• Providing support and structure to plants
• Helping organisms keep afloat in water

Vitamins

What They Are

• Organic food substances required in small amounts
• They do not provide energy but are essential for bodily functions

Why They Are Important

• They're involved in metabolic processes

• Deficiency in vitamins leads to many diseases

• Vitamin A sources: Fish-liver oil, milk, green vegetables and carrots

• Lack of Vitamin A causes night blindness and drying up of the cornea and skin

• Fresh vegetables and fruits are Vitamin C sources

• Lack of Vitamin C leads to scurvy and is important for growth and repair of cells

• Vitamin D sources include fish-liver oil and dairy products

• Lack of vitamin D causes rickets and is important to maintain bones and to promote the uptake of calcium or phosphate ions from food

DCPIP Test

• Chemical test for Vitamin C
• Add DCPIP solution into a test tube
• Add the unknown liquid in drops
• Observe if the DCPIP solution is decolonized

Minerals

What they are

• Minerals are inorganic
• Minerals have no energy value
• They regulate metabolic reactions and build body tissues

Why they are important

• Functions: help maintain body structure and help bodily processes
• Without the proper amount of minerals, health problems stem

Functions of Minerals Include:

• Calcium is the major component of bones, and helps with blood clotting/muscle contraction
• Lack of calcium results in rickets or osteoporosis; sources include dairy products and green vegetables
• Iron forms hemoglobin in red blood cells

Dietary Fiber

What it is

• Dietary fiber comes from plant cell walls
• Also known as roughage

Why it is important

• It adds bulk to food to stimulate the gut wall; and helps it move through the intestine
• Deficiency leads to constipation and other digestive problems

Balanced Diet

What it is

• A balanced diet is when the correct amounts of the seven food groups (carbohydrates, proteins, fats, vitamins, minerals, water and fibre) are supplied to the body
• Needed for nutrition and varies from individual to individual

Why it is Important

• When too much food is eaten, fat is stored
• When too much protein is removed, the body suffers
• When too much vitamin is lacking, the body suffers
• Proper portions of fats, dairy, meat, eggs, vegetables, fruit, and grains are considered
• Balanced diet can be designed with a food guide pyramid

Nutrient Content

• Different foods have nutrients in different ratios
• Carbs and proteins have similar kJ
• Lipids have twice carbs

Special Dietary Requirements

• Depend on age, gender, activity level

Diet and Health

Obesity

• Taking in more energy than what the body needs
• Results in overweight
• Common risk factor for high blood pressure, heart disease, and type 2 diabetes

Deficiency Diseases

• Insufficient iron> anemia
• Insufficient calcium> osteoporosis
• Insufficient vitamin A> night blindness
• Insufficient vitamin C> scurvy
• Insufficient vitamin D> rickets
• Insufficient dietary fibre> constipation
• Insufficient protein> kwashiorkor

Anorexia Nervosa

• Anorexia is the disease of undereating
• When someone is so sick of putting on weight that they don’t eat proper