Unit 1. Energy Production and Transport

1. Unit 1. Energy Production and Transport

2. Energy C6 H12 O6 + O2 CO2 + H2 O Digestion Respiration Digestive System Respiratory System Transport Cells

3. food O2 ATP What do animals need to live? • Animals make energy using: • food • oxygen • Animals build bodiesusing: • food for raw materials • amino acids, sugars, fats, nucleotides • ATP energy for synthesis mitochondria

4. digestion What happens to the food we eat?

5. How do animals get their food? filter feeding living in your food fluid feeding bulk feeding

6. Different diets; different lives • All animals eat other organisms • Herbivores • eat mainly plants • gorillas, cows, rabbits, snails • Carnivores • eat other animals • sharks, hawks, spiders, snakes • Omnivores • eat animals & plants • cockroaches, bears, raccoons, humans • humans evolved as hunters, scavengers & gatherers

7. Digestive systems Everybody’s got one!

8. When we eat a meal, the food passes through the gut in a series of processes: • Ingestion: eating the food • Digestion: chemical and physical reactions that break down food into smaller pieces • Absorption: the mass of small food molecules from the digestive system into the blood or lymphatic vessels. • Transport: the circulatory system delivers the small molecules into your body cells. • Assimilation: the small molecules are used in your body cells to build new and larger molecules.

9. Structure of The Digestive System

10. Human digestive system

11. The wall of the alimentary canal is made of living tissues which include: • Muscle fibers: circular and longitudinal • Secretory cells • A single layer of epithelium • Associated glands

12. Glands • Gastric juices are released into the gut by various glands: • Salivary glands • Stomach wall • Pancreas • Small intestine wall

13. Enzymes in digestion.- • Enzymes are chemical catalizers, helping to speed up the process of digestion. Enzymes are sensitive to temperature, pH and substrate concentration. Most enzymes are highly specific, but digestive enzymes tend to act on a broader range of substrates. • Enzymes of digestion are all made in glands and are secreted into the gut, where they mix the food.

15. Mouth • Functions • mechanical digestion • teeth • break up food • chemical digestion (saliva) • amylase enzyme • digests starch • mucus • protects soft lining of digestive system • lubricates food for easier swallowing • buffers • neutralizes acid to prevent tooth decay • anti-bacterial chemicals • kill bacteria that enter mouth with food

17. Esophagus • Epiglottis • flap of cartilage • closes trachea (windpipe) when swallowing • food travels down esophagus • Peristalsis • involuntary muscle contractions to move food along

18. Stomach • Functions • disinfect food • hydrochloric acid = pH 2 • kills bacteria • food storage • can stretch to fit ~2L food • digests protein • pepsin enzyme But the stomach is made out of protein! What stops the stomach from digesting itself? mucus secreted by stomach cells protects stomach lining

20. Small intestine • Functions • digestion • digest carbohydrates • amylase from pancreas • digest proteins • trypsin & chymotrypsin from pancreas • digest lipids (fats) • bile from liver & lipase from pancreas • absorption • nutrients move into body cells by: • diffusion • active transport

21. Small intestine • Functions • Gland • Produces enzymes to digests other substances (ex.nucleases) • Protection • Areas in the wall of the small intestine called Peyer’s patches contain lymphocytes that detect pathogens in food to help in the production of antibodies against them

22. Absorption in Small Intestines • Absorption through villi & microvilli • finger-like projections • increases surface area for absorption

23. Liver & Gall Bladder • Produces bile • breaks up fats • gallbladder only stores bile • that’s why you can have your gall bladder removed bile contains colors from old red blood cells collected in liver = iron in RBC rusts & makes feces brown

24. Assimilation • Filters harmful substances and bacteria in blood. • After blood has passed through, it is pumped to the lungs and then to the rest of the body where cells absorb substances. • The process by which cells use this substances to build new macromolecules is called assimilation.

25. Pancreas • Produces digestive enzymes • digest proteins • trypsin, chymotrypsin • digest starch • amylase • digest lipids • lipase • Buffers • neutralizes acid from stomach smallintestine pancreas

27. Large intestines (colon) • Function • re-absorbs water • use ~9 liters of water every day in digestive juices • if don’t reabsorb water would die of dehydration • > 90% of water re-absorbed • not enough water re-absorbed • diarrhea • can be fatal! • too much water re-absorbed • constipation • reabsorb by diffusion

28. You’ve got company! • Living in the large intestine is a community of helpful bacteria • Escherichiacoli:E.coli • digest cellulose • digests fruits & vegetables • produce vitamins • vitamin K & B vitamins • BUT generate gases • by-product of bacterial metabolism • methane, hydrogen sulfide

29. Appendix Vestigial organ

30. Rectum • Last section of large intestines • eliminate feces • what’s left over? • undigested materials • mainly cellulose from plants • called roughage or fiber • keeps everything moving & cleans out intestines • masses of bacteria

31. mouth break up food digest starch kill germs moisten food stomach kills germs break up food digest proteins store food liver produces bile - stored in gall bladder break up fats small intestines breakdown food - proteins - starch - fats absorb nutrients pancreas produces enzymes to digest proteins & carbs large intestines absorb water appendix

32. Sources: • Regents Biology (2012 – 2013) Animal Nutrition, Human Digestion. (On Line) http://www.westlake.k12.oh.us/whsteachers/crist/2012_2013/Bio/digestion_35.pdf. PPT modified from this source. • Allot, Andrew and Mindorff, David (2010) Biology Course Companion, (2nd ed.). Oxford University Press, New York, 212 – 218 • Damon, Alan; McGonegal, Randy; Tosto, Patricia; and Ward, William. (2007) Biology Higher Level, Pearson Baccalaureate, London, 151 – 156