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Why do we eat?.

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Presentation on theme: "Why do we eat?."— Presentation transcript:

1 Why do we eat?

2 Food Type Use Carbohydrate Fat Protein Sugars Long term energy
Protecting organs and long term energy store Making muscle, enzymes, skin, hair Fast energy Brainstorm 4 main food types and where they come from Fat and protein meat, fish Sugars fruit, sweet things Crbs from pasta, potatoes etc

3 Food tests Food type Test Protein Sugar Fat Carbohydrate
Biuret turns purple if protein is present Benedicts turns from blue to red/brown if sugar is present Greaseproof paper gets an oily residue Iodine turns blue/black if starch is present KOH and CuSO4 Biuret Expt H/O whats in our foodtest a variety of foods

4 Carnivore Only eats meat
E.g. Spider, lion Its survival is dependent on finding and catching prey What happens in times of famine, turn on each other, strong survive Hunt in packs or individually (dogs , spider – what are the benefits of each? Sharing in times of need idea of love and family helps share the bounty – mutualism (communism) Top predator – Nothing eats him!

5 Carnivore Teeth Adaptation
What do you notice? Crocodile and shark continue to grow new teeth Why doesn’t it chew for a long time?

6 Herbivore Only eats plants Depends on a large supply of plant matter.
E.g. Cow, aphid Depends on a large supply of plant matter. Longer gut as less energy available in their food. Much bigger than t rex scales and tail for defence, tend to be herd animals for defence in numbers like african zebra Slow moving not as much energy in the food and plants don’t run away! What if there is a drought? What happens to the carnivores?

7 Herbivore Teeth Adaptation
How does the sheep teeth differ from carnivore? What are the ridges on the elephant tooth for? GRINDING – cellulose is hard to digest due to cell wall so needs to chew for a long time Gap in teeth for rechewing grass, no canine. What about the muscle strength Rabbit teeth continualy grow and are eroded by the hard plant material they eat Why so many molars?

8 Omnivore Eats a mixture of plants and animals
E.g. Pigs, humans Increased chance of survival as they are not restricted to one diet. Oviraptor Still dependent on plants but will take any opportunity to feed

9 Decomposers Breaks down and recycles dead material.
E.g. Bacteria, fungi Have survived for millions of years, always plenty of dead things

10 Primary Producers (Plants)
Plants can make their own food using Sunlight Chlorophyll Water Carbon dioxide How are all the consumers and producers linked? What happens if one factor is missing – plant dies What is the effect on herbivores and carnivores Dinosaur extinction theory, asteroid hits dust and volcanic explosion block out sun for several years… What about the fly trap – tops up its nutrition with protein rich flies! H/O Food chains cut out pics

11 Definitions Trophic level Producer Consumer
– feeding group in food chain (eg Herbivore) – makes own food – eats other organisms for food What are the trophic groups in this diagram (all consumers) Assume the little fish feeds on algae then there is a herbivore, series of carnivores and a top predator

12 Food Chain Shark Fish Zooplankton Phytoplankton
Consumers Shark Top Predator Fish Carnivore Zooplankton Herbivore Important to draw the arrows to indicate direction of food flow Phytoplankton Producer Label the trophic levels as herbivore, carnivore, producer, top predator. Indicate which are consumers.

13 Food webs can get very complex
EXERCISE – Rose bush food web

14 Food Chains Food chains describe how organisms gain______ from eating each other in a community. Plants are called _______ because they make glucose using energy from the ______ _________ must eat other organisms for their _______ and nutrients. Food Producers H/O food chain Qs Sun Consumers Energy

15 Energy Pyramids Only about 10% of energy passed on between trophic levels Few Carnivores More Herbivores Most is lost through the organisms living processes Name the trophic levels (producer, herbivore, carnivore) Why is it a good idea to eat from the bottom of the pyramid/? Poisons accumulate, energy decreases so need to eat more, don’t need to be as active plants don’t run All supported by energy from producers

16 Let’s find out what happened to your breakfast today!
The Digestive System (Breaking food down into smaller pieces) Let’s find out what happened to your breakfast today! Mouth Oesophagus Stomach Small Intestine Liver Large Intestine Gall Bladder Pancreas Rectum Anus H/O anticipation guide digestion and absorption H/O vocab square digestion H/O game structure of digestive system Stretch out person until intestine is straight they are 8m long, HORSE 30M! shine torch Ingestion Digestion Absorbtion Egestion

17 Mouth Teeth (mechanical breakdown) Saliva (chemical breakdown)
Incisors used for cutting Canines used for stabbing and holding Molars large surface area used for grinding Saliva (chemical breakdown) Enzyme (speeds up reactions in the body) Breaks down carbohydrate Masseter muscle zygomatic arch, cranial ridge = carnivore Herbivore – diastema plate for incisors to press against Epiglotis prevents food going down the wrong way

18 Oesophagus Approximately 25cm long
Moves food from the throat to the stomach Muscle movement called peristalsis If acid from the stomach gets in here that’s heartburn. A good way to describe peristalsis is an ocean wave moving through the muscle. These diagrams don’t separate the esophagus from the mouth functions, you might want to talk about what happens in the mouth too.

19 Stomach Stores the food you eat
Chemically breaks it down into tiny pieces Mixes food with digestive juices Acid in the stomach kills bacteria The stomach takes around 4 hours to do it’s job on the food, depending on what kinds of food are digested. Digestive juices HCL and pepsin (protein breakdown)

20 Small Intestine Small intestines are roughly 6 metres long.
Enzymes and bile are added. Villi increase the surface area to help absorbtion. Nutrients from the food pass into the bloodstream through the small intestine walls. Enzymes breakdown large molecules. Villi look like little fingers Blood system is in close proximity to carry nutrients away around the rest of the body

21 Liver Directly affects digestion by producing bile
Bile is an enzyme that helps dissolve fat Processes nutrients in the blood, filters out toxins and waste. Is often called the body’s energy factory Livers can regenerate missing pieces if necessary. Is one of the largest organs in the body.

22 Gall Bladder Stores bile from the liver
Delivers bile when food is digested Fatty diets can cause gallstones Explain to students that removing the stones typically means removing the gallbladder, but that the body eventually adjusts to not having the bile stored.

23 Pancreas Produces compounds to digest fats and proteins
Neutralizes acids that enter small intestine Regulates blood sugar by producing insulin Explain the difference between the two types of diabetes. In type 1, the pancreas fails to produce enough insulin. In type 2, the body stops responding properly to the insulin it creates. Enzymes for breakdown of protein, cbh, sugar

24 Large Intestine About 1.5 metres long
Accepts what small intestines don’t absorb. Absorbs water and minerals from the waste matter. Absorption means taking into the body via the blood stream. Depending on the maturity of the group, you can talk about the feces leaving via the anus. Mention the appendix at the bottom of the ascending colon and that it might have been used long ago but is not today Mention the portions of the large intestine, ascending, transverse, descending, sigmoid, and rectum (last one if the audience is mature enough)

25 Rectum and Anus Rectum Anus About 15cm long
Stores waste before egestion. Anus Muscular ring that controls egestion. H/O game word play

26 Write the name of each colored organ:
Green: Red: Pink: Brown: Purple: Yellow:

27 Answers Green: Oesophagus Red: Stomach Pink: Small Intestine
Brown: Large Intestine Purple: Liver Green: Gall Bladder Yellow: Pancreas H/O in teams complete 69 the digestive system then use it to Draw full size body and position organs

28 Cells Cells are the building blocks of life
All cells have the following in common: Nucleus Cytoplasm Mitochondria Cell membrane Plant cells also have a cell wall and chloroplasts Why do we need these nutrients from food? H/o match up Plant and animal cell components

29 Function of cell organelles
Nucleus largest organelle control centre Instructions for the whole body Cell membrane Controls the entry and exit of material Cytoplasm Liquid containing cell parts and nutrients Mitochondria Powerhouse (burns energy from food) Anticipation guide microscope Expt view cheek cell, onion cell, hay infusion – scientific drawing practise

30 Turning food into energy
Respiration is the conversion of glucose into energy Glucose is “burnt” with oxygen It takes place in the Mitochondria C6H12O6 + 6O CO2 + 6H2O + ENERGY Carbon Dioxide Water We burn coal in oxygen to give us energy in powewrstations Factory analogy lorries bring reactants represent blood, factory is mitochondria, co2 h2o are waste products, energy is used for growth, reproduction, movement etc How does body transport blood (oxygen, glucose, co2 etc) pumped via heart H/O Energy in food Expt burn variety of foods ENERGY Glucose Oxygen

31 Circulatory System What is it for ?
Anticipation guide transport in the body lorry need to transport oxygen and food BRAINSTORM PARTS Pump 2 = right side of heart pump blood to oxygen plant (lungs) Return to pump 1 sends blood to factory (rest of body) Heart = pump Vessels like tree branches We need 2 pumps because 1 would not have enough energy to push blood through the lungs and then around the body.

32 Anatomy of the Heart Oxygenated blood LHS thicker Deoxygenated blood
To the body LHS thicker Deoxygenated blood To the lungs Video? (major organs H/O) Discuss flow of blood Oxygenated, deoxygenated, 2 pump, left thicker, artery leave heart, veins return, valves Complete heart H/O Dissection of heart Elephant beat 25/min Mouse 600/min Baby 120/min Us 70/min How many beats in a lifetime? Same for mouse? Heart jigsaw in teams EXPT Measure pulse before and after exercise Why does the pulse rate go up? Muscles need more oxygen therefore blood needs to be pumped quicker. Who had lowest rate = fittest ALSO who’s returned to normal quickest.

33 Blood Vessels Blood vessels laid out = Km round the earth 2x

34 Structure of Arteries Oxygenated blood leaving heart High pressure
Thick muscular walls Exception pulmonary artery Atherosclerosis thickening of artery wall fat deposits hard work for blood to be pumped, finally blocked stroke, heart attack blood flow to heart is blocked and muscle dies SMOKING increase pulse rate (heart beats)15 bpm , Increase blood pressure so heart works harder Increase fats so vessels narrow Increased clotting thick blood harder to move Wbc anaesthetised get more infections PULSE RATE EXPT can feel high pressure in arteries

35 Structure of Capillaries
Carry blood to cells Remove waste Deliver oxygen Deliver food Single file r.b.c. Very thin walls (single cell thick) H/O diagram of capillary O2, CO2 and food can pass into/ out of capillaries X =O2 Y= CO2 Z = sugars

36 Structure of Veins Deoxygenated blood returning to heart Thin walls
Low pressure Valves – allow flow of blood in one direction Muscle contraction Exception pulmonary vein Harvey EXPT tie arm drain vein

37 Blood Plasma Red Blood Cells White Blood Cells Platelets
Liquid carries other components Nutrients Waste like carbon dioxide Red Blood Cells Carry oxygen and carbon dioxide White Blood Cells Fight disease Platelets Clotting Round the room exercise Blood (5 reading workstations) Blood 50% water, 50% RBC life span 120 days made in bone marrow, rbc like donut, no nucleus 25 trillion Recap H/O circulatory system then provide letter home to Mum H/O

38 Made By Hussain Ashoor Mahdi Harake

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