Chapter 6 - Protein

Front 1

Essential Amino Acid

Back 1

Amino acids that the body cannot make at all or cannot make enough of to meet physiological needs.

Front 2

Nonessential Amino Acid

Back 2

Amino acids that the body can make if supplied with adequate Nitrogen.

Front 3

Peptide

Back 3

Strands of protein formed by amino acids links in specific sequences.

Front 4

Peptide Bond

Back 4

The bond between 2 amino acids formed when a carboxyl (-COOH) group of one amino acid joins an amino (-NH2) group of another amino acid, releasing water in the process.

Front 5

Denature

Back 5

An unfolded polypeptide chain that lacks biological activity.

Front 6

Pepsin

Back 6

Begins protein digestion

Front 7

Protease

Back 7

Enzymes that break down protein into peptides and amino acids.

Front 8

Trypsin/chymotrypsin

Back 8

Activated proteases that break down polypeptides into smaller peptides.

Front 9

Trypsin

Back 9

protease produced by the pancreas that is converted from the inactive proenzyme form (trypsinogen) to the active form (trypsin) in the small intestine.

Front 10

Chymotrypsin

Back 10

inactive proenzyme form (chymotrypsinogen) to active form (chymotrypsin) in the small intestine.

Front 11

Protein Turnover

Back 11

The constant synthesis and breakdown of proteins in the body

Front 12

Urea

Back 12

The main nitrogen-containing waste product in mammals. Formed in liver cells from ammonia and carbon dioxide, urea is carried by the bloodstream to the kidneys, where it is excreted in the urine.

Front 13

Vegan

Back 13

No animal-based foods.

Front 14

Lacto-ovo vegetarian

Back 14

Use animal products such as milk, cheese, and eggs, but abstain from eating the flesh of animals.

Front 15

Ovo-vegetarian

Back 15

Excludes all animal-based foods except for eggs.

Front 16

Protein Energy Malnutrition

Back 16

A conditions resulting from long-term inadequate intakes of energy and protein that can lead to wasting of body tissues and increased susceptibility to infection.

Front 17

Most Americans eat…

Back 17

as much or more protein than they need, even vegetarians

Front 18

Although we are mostly made of proteins, why are our dietary needs for protein relatively low?

Back 18

- The human body is very efficient in using protein making our needs relatively small

- Recycled and a lot of proteins can be made 12/20

Front 19

How does the structure of proteins allow them to be more diverse than other organic compounds?

Back 19

- Very large molecules.

- Chains of linked amino acids twists, fold, or coil into unique shapes.

- The body combines amino acids in different sequences to for a nearly infinite variety of proteins.

Front 20

Protein digestion & absorption

Back 20

Digestion of proteins begin in the stomach:

- Stomach acid unfolds proteins, exposing them to digestive enzymes. Pepsin begins protein digestion.

Small intestine:

- Enzymes break down protein to individual amino acids and small peptides (2-3 amino acids in length)

Absorption:

- Intestinal cells absorb amino acids and peptides. These cells finish splitting peptides into individual amino acids. Amino acids are absorbed into the capillaries of the villi.

- Amino acids travel in the bloodstream to tissues as needed, and the liver can use amino acids to manufacture a variety of important substances.

Front 21

What happens to amino acids when they are absorbed, the separate ‘fates’ of the carbon skeletons and the nitrogen component 6.17

Back 21

- Carbon turns into acetyl CoA

- Nitrogen becomes urea

Front 22

What does it mean to be in a positive or negative nitrogen balance, provide examples

Back 22

Positive: Nitrogen intake exceeds the sum of all sources of nitrogen excretion.

Ex. Growing children, pregnant women, people recovering from protein deficiency or illnesses

Negative: Nitrogen intake is less than the sum of all sources of nitrogen excretions.

​Ex. People who are starving, on extreme weight-loss diets, or people who suffer from fever, severe illnesses, infections

Front 23

Protein: Structural and Mechanical Functions

Back 23

- Structural and Mechanical

o Collagen and Keratin help structures such as bones, skin, and hair

o Motor proteins – proteins that turn energy into mechanical work

▪ Ex. Muscle contraction, cell division, sperm swimming

Front 24

Proteins: Enzyme Function

Back 24

o Catalyze chemical reactions without being destroyed in the process

▪ Ex. during digestion enzymes help break down carbohydrates, proteins, and fats into monosaccharides, amino acids, and fatty acids for absorption into the body

Front 25

Proteins: Hormone Function

Back 25

o Chemical messengers that are made in one part of the body but act on cells in other parts of the body.

▪ Ex. insulin

Front 26

Protein: Immune Function

Back 26

o Responsible for fighting invasion and infection by foreign substances

▪ Ex. Antibodies – blood proteins that attack and inactivate bacteria and viruses that cause infection

Front 27

Protein: Fluid Balance Function

Back 27

o The interior and exterior fluid levels must stay in balance for body processes to work properly

Front 28

Protein: Acid-base balance function

Back 28

o We can only tolerate small blood pH fluctuations without disastrous physiological consequences.

▪ Proteins serve as buffers, they pick up extra hydrogen ions when conditions are acidic, they donate hydrogen ions when conditions are alkaline

Front 29

Protein: Channels and pumps/transport function

Back 29

o Many cells pass in and out of cells via proteins that act as channels and pumps

▪ Ex. Sodium – potassium pumps, proteins control cell volume and nerve impulses

o Proteins act as carriers, transporting many important substances in the bloodstream for delivery throughout the body

Front 30

Protein: Source of energy and glucose function

Back 30

o Proteins when completely metabolized in the body yields 4 kilocalories of energy for every gram consumed.

Front 31

Categories of people who have relatively high needs for protein intake

Back 31

- Infants: have the highest protein needs relative to body weight of any time of life

o Protein is needed to support rapid growth during infancy

- Pregnancy and lactation increase a women’s need for proteins

- Older adults

o Proteins can provide immune status, wound healing, blood pressure, and bone health

Front 32

Benefits of vegetarian diets

Back 32

- A vegetarian diet that is high in fiber and phytochemicals and low in processed food and foods containing saturated fat and cholesterol has been shown to provide benefits for prevention and treatment of chronic health conditions.

o Obesity, cardiovascular disease, diabetes, cancer, and osteoporosis.

- Vegetarian diets contain less fat, saturated fat, and cholesterol and more magnesium and folate.

- Vegetarians emphasize fresh fruits and vegetables that provide higher amounts of antioxidants.

Front 33

Risks of vegetarian diet

Back 33

- Miss out on essential nutrients and may compromise their health

- May develop unhealthy or disordered eating patterns (eating disorder)

- Must be planned carefully for periods of rapid growth: infants and young children, pregnant women, breastfeeding women, and elderly

Front 34

Possible risks of excessive protein in the diet

Back 34

- High protein intake can strain kidney function and is harmful for people with kidney disease or diabetes

- High proteins intake increases calcium excretion, which can result in bone mineral losses

- Obesity, high protein foods are high in fat

- Heart disease, animal protein can lead to high blood cholesterol levels and c=increased risk of heart disease, stroke, cancer, and diabetes.

- Cancer, strong link between animal protein and colon cancer

- Gout