Chemical Compounds in Cells and in Our Food pp 52-55 & pp 505-517

Review of basic chemistry

• Element – any substance that cannot be broken down into a simpler substance– Ex – carbon, nitrogen, oxygen, hydrogen

• Atom – smallest unit of an element• Compound – two or more elements chemically

combined – Ex – water, sugar, starch

• Molecule – smallest unit of most compounds– Ex – H2O, C6H12O6, O2, CO2

Inorganic Compounds

• Don’t contain Carbon, Hydrogen, and Oxygen– Ex – water (H2O), salt (Sodium chloride), CO2

Organic Compounds• Contain Carbon, Hydrogen and Oxygen

– Includes: Carbohydrates

ProteinsLipids

Nucleic Acids

Proteins

• Contain C, H, O, N and sometimes Sulfur

• Found in many foods

• In the cell, used as: part of cell membranes

structures of organelles

muscles in the body

Structure of Proteins• Made of amino acids

– There are 20 different amino acids in living things

• These aa’s link together to form a large molecule of 50-3000 aa’s in one protein.

• Change one aa, changes whole protein

Protein

Enzymes• Special kinds of proteins

• Chemicals that speed up chemical reactions in the body without being used up themselves.

• Here the enzyme helps break a large molecule into 2 smaller ones. Some enzymes join two small molecules to make one larger one.

Carbohydrates• Energy rich

• C, H, and O

• Simple sugars - glucose

• Complex carbohydrates – made up of many simple sugars attached to each other– Starch– Cellulose – make up plant cell walls

Found in cell membranes, other cell parts, and store energy

Lipids

• Fats, oils, waxes

• Store energy

• Made of C, H, and O

• Contain more energy

than carbs

Nucleic Acids

• DNA = deoxyribonucleic acid

• RNA – ribonucleic acid

• Made of C, H, O, N, and Phosphorus

• Contain instructions for cells to carry

out all their functions.

Water

• Makes up about two thirds of your body.

• Most chemical reactions occur in water.

• Essential for all life.

Food and Digestion-pp 504-530

• Why do we need food?– Material for growth, repair– Energy– Allows body to maintain homeostasis

• Carbohydrates

• Fats

• Proteins

• Vitamins

• Minerals

• Water

Nutrients – substances in food that provides body with raw materials and energy to carry out essential processes

Energy

• Carbs, fats and proteins provide body with energy

• Amount of energy in food measured in calories– One calorie is the amount of energy to raise the

temperature of 1 gram of water 1 degree Celsius

Calorie or calorie?

• Calorie – used to measure energy in foods.

• 1 Calorie = 1000 calories– Ex – 1 apple contains 50 Calories or 50,000

calories. – The more calories a food has, the more energy

it contains.

Amount of Calories needed?

• Depends on physical needs and age of the person– Very active people need more– Infants and small children need more– Older people need fewer

Carbohydrates

• 1 gram carbohydrates provides 4 Calories of energy

• Provide raw materials to make cell parts

• Two groups:– Simple carbohydrates– Complex carbohydrates

Simple Carbohydrates = Sugars

• Found in fruits, vegetables, milk

• Glucose (C6H12O6) – major source of energy for your cells.

• Another simple sugar = fructose in fruits

Complex Carbohydrates• Made of many simple sugars connected

• Starch – found in potatoes, wheat, rice, corn

• Fiber (Cellulose) – found in plants, but cannot be digested and passes through your digestive system - helps keep things moving along.

How much carbohydrates do you need?

• 50-60% of Calories should come from carbs.• Complex carbs are better to eat than simple carbs –

sugars give a quick burst of energy, but starches are a longer, more even energy source.

• Foods high in complex carbs usually have other useful nutrients

• Foods with lots of sugar usually have fewer other useful nutrients

FATS

• Contain more than 2x

the energy of carbohydrates

• Store energy

• Parts of cells

• Protect internal organs

• Insulate the body

Types of Fats

• Unsaturated Fats– Liquid at room temprerature

– Oils

– Considered good for you

• Saturated Fats– Solid at room temperature

– From animals; a few plants –

coconut palm

– Bad for you

Cholesterol

• Saturated fat found in meat, eggs, cheese, etc

• Necessary for cell membranes in animals

• Not needed in diet; liver makes all that is needed.

• Can clog arteries and lead to heart attack

How much fat do we need?

• Should have no more than 30% of Calories in diet from fat

• Should particularly limit intake of saturated fats and cholesterol

• Read labels – look for palm or coconut oil, hydrogenated or partially hydrogenated oils – these are bad for you and you should avoid them if you can

Proteins in the diet• For tissue growth and repair

• Enzymes speed up chemical reactions

• Can be used for energy, but not usually

• About 12% of your daily Calorie intake should be protein

Amino Acids• The body makes about half the amino acids it

needs• Rest come from food• Complete proteins -contain all of the essential amino acids

– Meat and eggs

• Incomplete proteins – missing one or more essential amino acid

– Beans, grains, and nuts

Vitamins

• Act as helper molecules for a variety of chemical reactions in the body.

• The body makes some – K is made by bacteria in intestine

• The rest come from foods – eating a wide variety of foods provides all the vitamins needed.

Types of vitamins – chart p 511

• Fat soluble vitamins– Dissolve in fatty tissue and are stored there.– Includes vitamins A, D, E and K

• Water soluble vitamins– Dissolve in water and not stored in body– Needed in diet every day. – Includes vitamins B and C

Minerals• Nutrients not made by living things

• In soil and absorbed by plants

• Includes calcium and iron

• See chart - 512

Water • People die within days of not having water• Makes up about 65% of your body weight• The body’s most important functions take place in

water• Makes up most of the body’s fluids• Nutrients are dissolved in water in blood and

transported around the body • Perspiration• Need about 2 liter s of water per day

– Need more if weather is hot or your are exercising

Food Guide Pyramid

• Classifies food into

6 groups and indicates

how many servings

from each group

should be eaten per day

Food Labels

• Allow you to evaluate a single food as well as compare the nutritional value of two foods.

• Tells: – Serving size– Calories from fat– % daily value of one serving– ingredients

THE END