Bellwork 131 Put your phone up Week 128
Bellwork: 1/31 Put your phone up Week 1/28 -2/1 1. Grab your lab notebook
Today: 1. Lab 2. Part 6 Notes 3. Digestion Poster
Materials • Unit Book • Lab Notebook
This Week: • Monday: Lab Notebook Set-Up • Tues/Wed: Fermentation Lab • Thursday: Digestion Notes & Poster • Friday: Poster
Homework • Anaerobic Lab • Due Tomorrow
Today: • Lab Notebook • Graph w/lines of best fit • Data Table #2 based on graph data • Sample Calculation - slope • Summary of Results – 2 sentences • Conclusion – 5 -6 sentences • Reflection – 4 -5 sentences
Unit IV: Cell Energy
Part VI: Nutrition & Digestion
Food We Eat • 75% of the energy obtained from food used for body maintenance • Examples: • Maintain heart pumping blood • To breathe • To maintain body temperature • To digest food
Remaining Energy Used • To do voluntary activities • Examples: • Bicycling • Dancing • Eating • Running • Walking
Measurement of Energy • Energy units are kilocalories, commonly referred to as “Calories” • Average adult needs about 2200 kcal of energy per day. This will vary depending on how active you are
Voluntary Activities • Bicycling (racing) • Eating • Running (7 min/mi) • Walking (3 mph) 514 kcal/hr 28 kcal/hr 865 kcal/hr 158 kcal/hr
Energy Production • Small-energy molecules absorbed & then broken down by cellular respiration • Result: Production of energy either stored as ATP or lost as heat to the surrounding
Metabolic Rate • Amount of energy an organism uses per unit of time • Measured in kilocalories • Determined by: • Amount of oxygen used in cellular respiration • Heat loss per unit time
Basal Metabolic Rate (BMR) • Minimal caloric requirement needed to keep you alive • Equivalent to the amount of energy your body would burn if you slept all day • Adult human averages 1300 -1800 kcal/day BMR • Equivalent to the energy consumption of a 100 watt lightbulb
Factors that Affect BMR • Age – BMR higher in youth • Height – tall, thin people have higher BMR • Body Composition – more lean tissue, higher BMR & more fat tissue, the lower the BMR • Stress- stress hormones raise the BMR • Environmental temperature – heat & cold raise the BMR • Fasting/Starvation – lowers BMR • Malnutrition – lowers BMR
Expenditure of Energy Beyond BMR • Attributed to increased activities – running, walking, studying • Maximum metabolic rates – required for peak activities • Ex. All out running, when running away from predators
Comparison of BMR between Couch Potato & Physically Active Person
Heterotrophs Rely on Organic Compounds in their Food for…. . • Fuel (chemical energy) for respiration • Synthesis of macromolecules • Essential nutrients that the body cannot make • Ex. Essential amino acids (e. g. tryptophan, methionine)
Humans Manage Fuel Supply • Humans have basal energy requirements to sustain self • If take in excess calories, excess store: • Initially in the form of glycogen in the liver & muscles • Further excess stored in fat • If take in too few calories • Breakdown glycogen first, then fat • Starvation persists - breakdown proteins • Result: muscle atrophy & can result in consumption of brain proteins
Overview of Digestion • Four General Steps: • Ingestion – act of eating • Digestion – breakdown of food • Absorption – absorb small energy containing molecules by the body cells • Elimination – excretion of undigested material
Ingestion – Oral Cavity • Both mechanical & chemical digestion begin in the mouth • Teeth – smash & grind food • Increase surface area • Salivary glands – deliver saliva • Purpose: • Protects the mouth from abrasion • Lubricates food for easier swallowing • Breaks down carbohydrates
Ingestion – Oral Cavity • Tongue • Purpose: • Tastes food • Manipulates food during chewing • Shapes the food into bolus making it easier to push food to back of oral cavity
Esophagus • Conducts food to stomach • Occurs by waves of muscular contraction known as peristalsis
Stomach • Location: upper abdominal cavity just below the diaphragm • Function: store food & perform preliminary digestion • Secretes digestive fluid – gastric juices (p. H 2) • Breaks down meat & plant material • Contains pepsin, an enzyme that hydrolyzes proteins • Food becomes nutrient-rich broth known as acid chyme
Small Intestine • In humans more than 6 m in length • Function: food digestion & absorption of nutrients into blood • Anatomy: • First 25 cm – duodenum; acid chyme mixes with digestive juices secreted from pancreas, liver, gallbladder and gland cells found in intestinal wall • Remainder of intestine – jejunum & ileum – involved in absorption
Absorption • Absorption of nutrients enter the body by crossing the lining of the digestive tract • Large folds in the living of small intestine known as villi increase surface area • Core of each villus – set of microscopic blood vessels (capillaries)
Absorption • These blood vessels take absorbed nutrients away from the small intestine • Ultimately, goes to the heart which then directs blood containing the nutrients to the remainder of the body
Energy Costs • Substantial energy cost to processing food • Depending on animal species – absorbing a meal may cost between 3 -30% of chemical energy contained in that meal
Answer the Questions in your Note. Guide
Project • Create a map of the digestive system • Show what happens when you eat your favorite food • Draw a person eating your favorite food • Draw & label the mouth, teeth, tongue, salivary glands, esophagus, stomach, small intestines, duodenum, jejunum, ileum, villi, capillary veins • Label & describe ingestion, digestion & absorption • Color • Project Grade
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