2 Macronutrients Free Online FlashCards

How much energy do carbohydrate, protein, and fat provide per gram?

Digestible carbohydrate and protein provide about $4\ \text{kcal/g}$, while fat provides about $9\ \text{kcal/g}$. These values describe energy, not overall nutritional quality.

What are the three main types of carbohydrates?

Carbohydrates include sugars, starches, and dietary fiber.

How do single sugars differ from double sugars?

Sugars contain one or two sugar units. Glucose and fructose are single sugars; sucrose and lactose are double sugars.

How does the body use and store glucose?

Cells use glucose for energy, and the body can store it as glycogen in the liver and muscles.

Why does dietary fiber resist digestion?

Fiber is carbohydrate that human digestive enzymes do not fully break down; some passes through largely intact.

What are two effects of dietary fiber in the digestive tract?

Some fiber is fermented by microbes in the large intestine, producing compounds the body can use. Fiber also contributes to stool bulk and regularity.

Where does carbohydrate digestion begin, and where does it continue?

Carbohydrate digestion begins with salivary amylase in the mouth and continues with pancreatic amylase and intestinal-surface enzymes in the small intestine.

What is the basic structure of a triglyceride?

Most dietary fat is in triglycerides, each made of a glycerol backbone attached to three fatty acids.

How do saturated, monounsaturated, and polyunsaturated fats differ?

Saturated fatty acids have no carbon–carbon double bonds; unsaturated fatty acids have one or more. Monounsaturated fats have one, while polyunsaturated fats have more than one.

Name two important functions of dietary fat besides supplying energy.

Fat supplies concentrated energy, forms part of cell membranes, helps protect organs, and supports absorption of vitamins A, D, E, and K.

What do bile and pancreatic lipase each do in fat digestion?

Bile disperses fat into small droplets but is not a digestive enzyme. Pancreatic lipase breaks triglycerides into smaller molecules that can be absorbed.

What are proteins made of, and how are their building blocks linked?

Proteins are chains of amino acids joined by peptide bonds and folded into specific shapes.