NUTRITION

How Organisms Obtain Nutrition

AUTOTROPHSExamples are green plants, algae, some microorganisms• Most are photosynthetic

Using sunlight, CO2, water food

Are called phototrophs• Some bacteria are chemosynthetic

Using energy from chemical reactions

to produce food Are called chemotrophs

How Organisms Obtain Nutrition

HETEROTROPHS

• All animals

• Some microorganisms

Energy content of food

• Energy is provided to the organisms by the chemical breakdown of carbo’s, fats, and proteins

• Energy is released and stored as ATP in certain molecules during the process of cellular respiration

• The measure of this energy released by cellular respiration is in calories

• Energy released by 1 gram of a carbohydrate = 4 kilocalories

• Energy released by 1 gram of a protein = 4 kilocalories

• Energy released by 1 gram of a fat = 9 kilocalories

Humans need 6 nutrients

1. Proteins

2. Carbohydrates

3. Fats

4. Vitamins

5. Minerals

6. Water

See page 5 and 6 in your packet

Four (five) basic food groups

1. Milk and cheese2. Meat, poultry, fish, beans

Legumes – plants that have seeds w/ podsBeans, peas, peanuts are high in proteins

3. Fruit, vegetables4. Bread and cereals5. Sweets

Fiber •bulky indigestible materials including cellulose from the cells walls of fruits, vegetables, and grains

fiber stimulates the digestive musclesdecreases the risk of colon cancer

Mechanical breakdown vs. chemical breakdown of

food

• Mechanical breakdown = foods are broken, crushed into smaller pieces with out being changed chemically. This gives the materials a greater surface area so that the digestive enzymes can work more efficiently on them.

Mechanical breakdown vs chemical breakdown of

food

• Chemical breakdown (digestion) = carried out by digestive enzymes breaking down large molecules into smaller and smaller ones by chemical reactions.

• Example: hydrolysis

Nutrition in an Ameba

• Has pseudopods “false feet”• Surrounds food when it contact

with it• The cell membrane forms a food

vacuole• Food vacuole joins with a

lysosome and digestive juices break down the food particle

• Small particles diffuse out of the vacuole into the cytoplasm

• Indigestible materials remain in the vacuole until the contents are expelled from the cell

Nutrition in an Ameba

Ameba ingestion

http://www.youtube.com/watch?v=W6rnhiMxtKU

Nutrition in a paramecium• Cilia sweep food particles down

the oral groove• Into the gullet which pinches off

to form a form a food vacuole• Food vacuole joins with a

lysosome and digestive juices break down the food particle

• Usable materials diffuse into the cytoplasm

• Indigestible materials are discharged from the cell through the anal pore

Nutrition in a paramecium

http://www.youtube.com/watch?v=saLYHUs6cWk

Nutrition in a hydra• Performs intra- and extracellular digestion• Threads in the tentacles wrap and poison prey• Captured food is pushed into the oral groove• Endoderm cells secrete digestive enzymes into the

gastrovascular cavity (extracellular digestion)• Nutrients are absorbed into the cells forming food vacuoles

(intracellular digestion)• Wastes can diffuse two ways:

– Out the ectoderm into the outside environment

– Out the endoderm into the gastrovascular cavity and out the mouth

Nutrition in a hydra

http://www.youtube.com/watch?v=zkF_1r6ll54&feature=related

Nutrition in an earthworm• Digestive tube called an

alimentary canal• Food is sucked into the

mouth by a muscular pharynx to

→Esophagus to→Crop for storage to→Gizzard for grinding

(mechanical digestion)→To the intestine for

chemical digestion and absorption

→Indigestible material pass out through the anus

Nutrition in an earthworm• A typhlosole is a fold in the digestive wall

• It increases surface area

• Therefore increases absorption

Nutrition in a grasshopper→Mechanical digestion by mouth parts→Salivary glands (saliva) secrete digestive enzymes→To the esophagus to the crop (storage)→To the gizzard (mechanical digestion)→To the stomach (chemical digestion and absorption)→Indigestible (dry) materials go through the intestine out

the anus→Water is absorbed in the rectum

Grasshopper eating a leaf

http://www.youtube.com/watch?v=F3JJFSsVUBg

Organism

AdaptationsOr

Specialized structures

FunctionOr

Special structures

Protists

(ameba)

Protests

(paramecium

Hydra

Earthworm

Grasshopper

Cilia•Cilia sweep food into oral groove•Gullet pinches off into vacuole•Vacuole fuses with lysosome

Pseudopod

(false feet)

•Contact and surround food•Membranes join•Food vacuole forms•Vacuole fuses with lysosome

Special stinging cells

Wrapping Treads out of tentacles

•Poisons prey•Tentacles capture food and push it into the mouth•Exrtacellular digestion in gut•Absorption into the endoderm

Alimentary canal

Typhlosole

(↑ surface area)

Mouth – pharynx-esophagus-crop (storage)–gizzard (mech dig) – intestine (chem dig and absorption)

Tube in a tube digestive system

Mouth parts (mech dig) –salivary glands (chem dig) – esophagus – crop (storage) – gizzard (mech dig) – stomach (chem dig and absorption) – intestine – rectum (water absorption) – anus (dry waste)

The Human Digestive System

• Complete the diagram on page 14 in your note packet

The Human Digestive System

1. Mouth2. Tongue3. Salivary glands4. Epiglottis5. Esophagus6. Liver7. Stomach8. Pancreas9. Large intestine10. Small intestine11. Appendix12. Rectum13. Anus

Accessory organs

14. Stomach (not seen here)

15. Pancreas

16. Gallbladder

17. Liver

18. (Common) Bile duct

19. Duodenum

20. Pancreatic duct

The Human Digestive System(in more detail)

The mouth and pharynx

1. teeth - mechanical digestion2. tongue - moves and shapes the

food mass3. 3 pair of salivary glands secrete

saliva– thin saliva wets food– thick saliva sticks food together into

a bolus• contains digestive enzymes for

chemical digestion• salivary amylase breaks down starch

to maltose (a polysaccharide to a disaccharide)

4. tongue pushes food into the pharynx - starts swallowing reflex

Action of the epiglottis

The esophagus

• flap of tissue called epiglottis prevents food from going down the trachea instead of the esophagus

• peristalsis - alternating relaxation and contraction of the muscular walls

• sphincter (ring of muscle) where the esophagus opens to the stomach called the cardiac sphincter

The stomach

• mechanical digestion by contractions of stomach walls

• chemical digestion by glands in stomach lining– pyloric glands - mucus

to protect the stomach lining– gastric glands - acidic

gastric juices• kills bacteria• contains pepsin to break down

large proteins into polypeptides• solids form soupy liquid called

chyme

• pyloric sphincter opens to the small intestine

The small intestine• chemical digestion

– pancreatic juice from the pancreas

– bile from the liver– intestinal juice from glands in the

walls• absorption

– simple sugars, amino acids, vitamins, minerals absorbed through villi into the blood stream

– increased surface area• very long• many folds• villi and microvilli

– fatty acids and glycerol absorbed into lymphatic system

Intestinal villi

• Intestinal villi (singular: villus) are tiny, finger-like projections that come out from the wall of the small intestine and have additional extensions called microvilli (singular: microvillus) which protrude from epithelial cells lining villi. They increase the absorptive area and the surface area of the intestinal wall. It is important that the food is absorbed at a considerably fast rate so as to allow more food to be absorbed. (If the process is too slow, the concentration of the blood in the blood vessels and the food will be equal, thus, diffusion will not occur.) Digested nutrients (including sugars and amino acids) pass into the villi through diffusion. Circulating blood then carries these nutrients away.

Intestinal villi

Blood capillaries absorb amino acids, glucose, vitamins and minerals into the blood

The lacteals absorb fatty acids and glycerol into the lymphatic system

peristalic movement

• squeeze chyme through intestine

• mix chyme with digestive juices

• breaks down mechanically

• speed absorption by pushing chyme against walls

pancreas• hormones from the stomach stimulate pancreas to

secrete pancreatic juices and enzymes into the small intestine (duodenum)– pancreatic juice neutralizes stomach acid– pancreatic enzymes

1. amylase breaks down starch to maltose

2. proteases break down proteins

3. lipase breaks down fats

Gall bladder

• stores bile made in the liver

• bile travels from liver to gallbladder (storage) into bile duct to duodenum (small intestine)

• bile emulsifies fat - bile has no enzymes

Large intestine

• small pouch where large and small intestine join is the appendix

• undigested and unabsorbed materials pass through large intestine

• reabsorption of water from the food mass

• absorbs vitamins produced by bacteria here

• elimination - removal of undigested material (feces)

• feces stored in the rectum and then defecated out the anus

Digestive glands

• glands that secrete substances that aid in digestion

• the food mass never passes through these glands

Digestive glands:the liver

1. produces bile

2. bile emulsifies fat

3. stores excess carbohydrates in the form of glycogen

4. bile is slightly basic and assists in neutralizing acid chyme from the stomach

5. bile stored in the GALLBLADDER

6. bile travels:

GALLBLADDER BILE DUCT DUODENUM (small intestine)

Digestive glands:the pancreas

1. produces pancreatic juices

2. aids in digestion of– proteins– starch– fats

3. pancreatic juices are basic and neutralize the acid chyme from the stomach

The small intestine is slightly basic (pH ~ 8)

Human nutrition

page 20 in your packet

Organ Chief function

1.

2.3.4.5.6.7.8.9.

Salivary glands1. Begins chemical digestion of starch2. Wets food3. Sticks food together

esophagus Transports food to the stomach

stomach 1. Begins chemical digestion of protein2. Mechanical digestion

liver 1. Produces bile2. Stores extra starch as glycogen

pancreasProduces pancreatic juice that aids in chemical

digestion of all food groups

Gall bladder Stores bile

Small intestine 1. Completes chemical digestion2. Absorption of nutrients

Large intestine1. reAbsorption of water2. Production and absorption of vitamins

rectum Storage of feces

Which organs have a “S” on them?

1. Salivary glands

2. Stomach

3. Liver

4. Pancreas

5. Small intestine

Which organs have a “ D” on them?

1. Mouth (not shown)

2. Stomach

3. Small intestine

Digestive juice Secreted byWhich acT

upon(substrate)

Saliva

Gastric juice(contains HCl)

bile

Pancreatic juice

Intestinal juice

Salivary glands

starch

glands in stomach walls

proteins

pancreas fats, starch, proteins

liver emulsification of fats

glands in the intestinal wall

fats, starches proteins

1. The end products of the digestion of carbohydrates are

2. The end products of the digestion of proteins are

3. The end products of the digestion of lipids are

simple sugars or monosaccharides

amino acids

3 fatty acids and 1 glycerol

Turn to page 21 in your packet

Digestive juice

Secreted by

Contains enzymes

Acts uponEnd

products

saliva

Gastric acid(hcl)

Bile

Pancreatic juice

Intestinal juice

salivary glands

salivary amylase

starch or polysaccharides

maltose disaccharide

stomach pepsin proteinssmall amino acid chains

activates pepsin

liver none fatsEmulsifies fats in to droplets

pancreastrypsin →amylase → lipase →

proteins → starch → fats →

peptides maltose f. a. + glycerol

glands in the

intestinal wall

peptidase → lactase → maltase → sucrase →

peptides → lactose → maltose → sucrose →

amino acids glucose glucose glucose