Energy, Nutrition, Calories & Lab 2B

“Focus On” – p. 54

Food and Nutrition

Why do we need food? Energy (catabolism) Building new molecules (anabolism)

Proteins Cell membrane DNA/RNA

Nutrition is the study of food and its effects on the body

Essential Nutrients Water, Vitamins, Minerals, Fats (lipids), Proteins, Carbohydrates

Water

Every cell in the body needs water to complete many of the body’s processes and chemical reactions

Water loss causes problems in all the body systems

Fats (Lipids)

Manufacture cell membranes, produce hormones and store energy

Saturated- contains only single bonds (all possible hydrogens) eg. butter

Unsaturated- contains one or more double or triple bonds eg. olive oil

Trans-fats

Protein

Provide body with material for growth

Make up parts of muscles, skin and internal organs

Enzymes Body can naturally produce

12 of 20 amino acids The other 8 must be obtained

from food Called essential amino acids

Vitamins

Organic molecules that are needed by the body to help perform important chemical reactions

14 essential vitamins 2 types:

fat-soluble (A,D,E,K)- stored in fatty tissues of the body

water-soluble (C,B)- cannot be stored

Minerals

Inorganic nutrients that the body needs Found in periodic table Examples: Ca (bones), Fe (needed for

hemoglobin), Mg (normal function of nerves and muscles)

Lost in sweat, urine and other waste products

Carbohydrates

Major source of energy Two forms:

Simple sugars Complex starches

Broken down into simple sugar in digestive system

Cellulose= fiber (cannot be broken down, helps process food more efficiently)

Food and Energy

Food contains- Carbs, Fat, Protein and Nulceic Acids Which is our main source for energy? Back up source?

Carbs are broken down by the digestive system to the simple sugar, GLUCOSE

Our cells like to use glucose for cell respiration. As a back up fatty acids and even amino acids can be used if necessary

How Much Energy is in the Food We Eat?

CALORIE Measures the amount of energy that is in food Amount of heat energy needed to raise the temp.

of 1 mL of water by 1 degree Celsius On our food labels we see Calories (kilocalorie) 1 Calorie = 1000 calories

1 jelly bean = 3 Calories = 3000 calories! (That’s a lot of energy!)

Food Labels

What are calories? Calories?

calorie = amount of energy required to raise temp of 1 g of water 1ºC (15º-16º)

Calorie = 1 kilocalorie Calories are used

on food labels Why do we use C

rather than calories?

How do we determine caloric content of foods?

Calorimeter Completely combust

food heats up water Measure temperature

change of water Good ones are highly

insulated so all heat goes to water rather than surroundings

Our setup . . .

Calorimetric Calculations

Q = m c ΔT Q = heat in calories m = grams of water in calorimeter (same as mL) c = specific heat of water 1 cal/gºC ΔT = change in temp of water

EX: burning a 0.2 g peanut raises the temp of 10 mL water in the calorimeter from 20º to 37ºC.

(Calories) kcal 0.170 cal 1000 cal 170 C17C g

cal110g Q

100g per Calories 85 kcal/g 0.85 peanut 0.2g kcal 0.170

Foods We Will Test

Potato chips Beef Jerky Marshmallows

Each is primarily one type of food (lipid, protein, carb) Which is which?

“Rule of Thumb” for caloric content: 1g of fat = 9 Calories (9000 cal) 1 g of carb/protein = 4 Calories (4000 cal)

Lab Prep

Create a hypothesis Think: What will the results of the lab be? What samples am I using? Therefore, of the 3 samples, what do I think…

Copy the data table from your book(p703) using the food items provided Leave samples blank for now

Draw flow chart of the experiment

Additional Analysis Questions

A1. One of the foods had a high fat content (chip), high protein content (beef jerky), and high carb content (marshmallow). From your results, what can you conclude about the relative energy content of carbs, proteins, and fats?

A2. What advice would you give to a sports team about their diets?

A3. What’s the difference between “Power Bars” and “Protein Bars”? For what type of physical activity would you recommend eating each type?