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Nutrition in Humans. NutrientsPart I. Nutrients are the usable portions of foods What are nutrients used for? Energy Sources Building or Repair of cell structure Regulate metabolic processes. 6 Main Groups. Carbohydrates (bread, pasta, potatoes, candy)

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Nutrition in Humans

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Nutrition in humans

Nutrition in Humans

Nutrients part i

NutrientsPart I

  • Nutrients are the usable portions of foods

  • What are nutrients used for?

  • Energy Sources

  • Building or Repair of cell structure

  • Regulate metabolic processes

6 main groups

6 Main Groups

  • Carbohydrates (bread, pasta, potatoes, candy)

  • Proteins (beef, fish, milk, peas, nuts)

  • Fats & Oils (butter, bacon, vegetable oil)

  • Water (most foods contain water)

  • Minerals (calcium, iron, sodium, chlorine)

  • Vitamins ( A, B1, B2, Niacin, B12, C, D, K)

Which are organic and which are not

Which are organic and which are not?

  • Organic

  • Carbohydrates

  • Proteins

  • Fats N Oils

  • Vitamins

  • Inorganic

  • Water

  • Minerals

What about what we can t digest

What about What we can’t digest

  • Roughage: indigestible food

    Examples: fibrous matter (cell wall) in fruits, vegetables, and whole grains

    Benefit: provides bulk to be worked on by muscles, keeps things moving forward



  • Subunit: Saccharides

  • Monosaccharides:1 (simple sugars, glucose)

  • Disaccharides: 2 (sucrose and maltose)

  • Polysaccharides: 3 or more (Starch in plants and Glycogen in animals)

Regents question

Regents Question

Most of the starch stored in the cells of a potato is composed of molecules that originally entered these cells as

  • (1) enzymes

  • (2) simple sugars

  • (3) amino acids

  • (4) minerals

Why can glucose diffuse through the cell membrane and starch can not

Why can glucose diffuse through the cell membrane and Starch can not?

  • Glucose is a monosaccharide and much smaller than the polysaccharide of Starch



  • Subunit: Amino Acids (NH2 = amino group COOH = carboxyl acid)

Regents question1

Regents Question

Two proteins in the same cell perform different functions. This is because the two proteins are composed of

  • (1) chains folded the same way and the same sequence of simple sugars

  • (2) chains folded the same way and the same sequence of amino acids

  • (3) chains folded differently and a different sequence of simple sugars

  • (4) chains folded differently and a different sequence of amino acids

Regents question2

Regents Question

Which statement concerning proteins is not correct?

  • (1) Proteins are long, usually folded, chains.

  • (2) The shape of a protein molecule determines its function.

  • (3) Proteins can be broken down and used for energy.

  • (4) Proteins are bonded together, resulting in simple sugars.



  • The Human body need 20 different types of Amino Acids

  • 12 of the 20 humans can synthesize (produce)

  • 8 of the 20 humans can not, these 8 are called Essential amino acids (Isoleucine, Leucine,Lysine, Methionine, L-Phenylalanine, Threonine, Tryptophan and Valine)

If proteins come mostly from meat how do vegetarians get the 8 essential

If proteins come mostly from meat, how do vegetarians get the 8 essential?

  • There are 2 types of proteins

  • Complete Protein: contains all essential amino acids

  • Incomplete Protein: missing one or more essential amino acids

  • So to answer the question: a vegetarian can eat a combination of incomplete proteins to provide all essential amino acids (ex. Rice and Beans)

What happens if you are missing one of the essential 8

What happens if you are missing one of the essential 8?

  • You would get a protein-deficiency disease.

    Example: Populations in Africa diet consist of cornmeal (incomplete protein) lacks Tryptophan. These children have a disease called Kwashiorkor (tired and abnormal growth)

Fats lipids

Fats (Lipids)

  • Synthesized in body from Fatty acids and Glycerol

  • Represents stored energy

  • Together with proteins synthesize the cell membrane

Fats lipids1

Fats (Lipids)

Bad fat

Bad Fat

  • Saturated Fat: Usually solid at room temperature, No Double Bonds, lead to cholesterol deposits in blood vessels

Good fat

Good Fat

  • Unsaturated Fat: consists of oils (liquid at room temperature), one or more Double Bonds



  • Important inorganic material (helps in structure of cells and tissues)

  • Calcium (Ca): strong teeth and bones, milk & eggs

  • Iron (Fe): helps in formation of red blood cells (red pigment), liver, meats & vegetables

  • Sodium (Na): needed for proper cell function, table salt



  • Like minerals, perform many functions

  • Especially important growth of children

  • In adults repair and maintain healthy body functions

  • Unable to be synthesized by humans



  • A: healthy eyes & skin, green and yellow vegetables

  • B1: growth and appetite, meats, seafood, milk

  • B12: production of red blood cells, liver & green vegetables

  • C: healthy teeth, gums, and blood vessel repair, fruits

  • D: growth and maintenance of bones, produced in skin exposed to sunlight & fortified milk

  • K: blood clotting, liver function, synthesized by bacteria in body



  • Excellent solvent (dissolves many compounds)

  • Main component of fluid transport (blood)

  • Many chemical reactions take place

  • Lubricant for joints and digestive system

  • Cools body by sweat evaporation

  • Lost by breathing, urination, and elimination

What is a calorie

What is a calorie?

  • The amount of heat needed to raise 1mL of water by 1 C0

  • Unit of measurement for energy value in food

  • Calorimeter: tool used to measure calories in foods

Food additives

Food Additives

  • Saccharin: artificial sweetener

  • Nitrites: protect food from bacterial decay and provide red color, found in bacon hotdogs, and deli meats

  • Monosodium glutamate (MSG): flavor enhancer

The digestive system partii

The Digestive System PartII

What is the digestive system

What is the Digestive System?

  • The alimentary canal (coiled tube which ingested materials move in one direction) and digestive glands make up the digestive system

  • Hydrolysis

What are the functions of the digestive system

What are the functions of the Digestive System?

  • There are 3 main functions of the Digestive system

  • Ingest foods (eat)

  • Breakdown foods so nutrients can be absorbed

  • Eliminate (egestion) what can not be digested

Regents question3

Regents Question

Which order of metabolic processes converts nutrients consumed by an organism into cell parts?

  • (1) digestion → absorption → circulation →diffusion → synthesis

  • (2) absorption → circulation → digestion →diffusion → synthesis

  • (3) digestion → synthesis → diffusion →circulation → absorption

  • (4) synthesis → absorption → digestion →diffusion → circulation

When does digestion start

When does digestion start?

  • As soon as we place food in our mouth.

  • Mechanical and Chemical digestion occurs

  • Mechanical digestion = Chewing

  • Chemical digestion= Saliva

Digestion in the mouth

Digestion in the Mouth

  • Mucus Glands: lubricant for food in the form of mucus (allows food to travel smoothly)

  • Saliva Glands: contains amylase (enzyme) which breakdown starch into maltose

    Polysaccharide (starch) to a Disaccharide (maltose)

From your mouth to your esophagus

From your mouth to your Esophagus

  • Swallowing: coordinated reflex action that moves food to the esophagus

  • During swallowing the trachea (windpipe) moves upward against the epiglottis (flap)



  • Food is moved from the mouth to the stomach

  • The movement is called Peristalsis: muscle contractions and relaxations (moves in waves, like pushing a tube of toothpaste)



  • Muscular organ that churns food and initiates protein digestion (balloon like, expands when full and shrinks when empty

Stomach gastric juices

Stomach (Gastric Juices)

  • Gastric Glands: located on the inner lining of the stomach

  • Contains peposinogen and hydrochloric acid HCl (keeps pH at 2 and kills off bacteria)

  • Acidic environment favorable for pepsin (enzyme) to breakdown proteins

  • Rennin: an enzyme that changes liquid proteins into a solid state (curdles milk proteins)

Stomach final product

Stomach (final product)

  • The process takes about 2 to 24 hours (depending of the foods present)

  • Chyme: mixture of saliva, gastric juices, and water

Which organs of the digestive system never in contact with food

Which organs of the digestive system never in contact with food?

  • Liver: secretes bile (aids in digestion of fats) emulsification (makes small globules of fat from large ones)

  • Gallbladder: bile is stored here and transport to small intestine via bile duct

  • Pancreas: pancreatic juices (enzymes)

  • Proteases= protein digestion

  • Amylase= carbohydrate digestion

  • Lipase= fat digestion

Liver gallbladder pancreas

Liver, Gallbladder, & Pancreas

Small intestine

Small Intestine

  • Longest part of digestive tract (7m)

  • Called small because of diameter (6.5 cm)

  • Most digestion and absorption occurs here

Absorption in small intestine

Absorption in Small Intestine

  • Villi: tiny projectiles on the inner surface of small intestine

  • There are enough villi in your small intestine to cover a tennis court (large surface area)

How do the nutrients leave the small intestine

How do the nutrients leave the Small intestine?

  • Diffusion

  • Villi only 1 cell thick

  • Amino acids and simple sugars enter capillaries

  • Fats enter lacteal (lymph vessel)

Small intestine is an excellent example of adaptation

Small Intestine is an excellent example of adaptation

  • Muscles contract to mix liquids and bring them to villi

  • Great length and folds provide large surface area for absorption

  • Villi provides large surface area (ten times greater than skin)

  • Thin membrane allows for easy diffusion of nutrients

Large intestine

Large Intestine

  • No digestion occurs here

  • Water absorption

  • Contains bacteria which produce vitamins

  • Eating yogurts help replenish lost bacteria

Time of digestion

Time of Digestion

  • Mouth: 5-10 sec

  • Esophagus: 10 sec

  • Stomach: 2 to 24 hours

  • Small Intestine: 3 to 4 hours

  • Large Intestine: 18 hours to 2 Days

Elimination egestion

Elimination (egestion)

  • Feces or waste is stored in the rectum (lower part of large intestine)

  • Feces leaves our body through the anus

Problems in digestion

Problems in Digestion

  • What do you call a hole in your stomach?

  • Ulcer: occurs when HCl (hydrochloric acid) and pepsin are in direct contact with the stomach lining. (little to no Mucus present)

Why can t i poop

Why can’t I Poop?

  • Constipation: occurs in the Large intestine, happens when too much water is absorbed and the feces hardens

  • What is the opposite of constipation?

  • Diarrhea: Not enough water in absorbed in the Large intestine and the feces remains soft and watery (may be a symptom of infection or stress)



  • Inflammation of the appendix (located where the small intestine meets the large intestine)

  • Symptoms: abdominal pain, nausea, and fever

  • Surgery usually needed to remove before rupture



  • Harden deposits that form in the gallbladder (deposits may block the bile duct, causing pain)

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