Unit 7: Chemical and Physical Changes & Balancing The Digestive System

Amazing Facts  We make 1-3 pints of saliva a day. The average male will eat about 50 tons of food to sustain weight of 150 pounds A horse’s intestines are about 89 feet long

How is the digestive system like a post office?

ANALOGY The digestive system is like a post office it receives mail which is like the food in the digestive system, gets processed, and then is sent out.

Function of the Digestive System To Convert large complex molecules (FOOD) into simpler molecules (nutrients) that get absorbed into the body, then move the leftover food/waste out of the body. It takes anywhere from 12-72 hours to digest food completely, depending on what the food is.

used for cell activities What is being released when food is broken down into smaller molecules? ENERGY used for cell activities

Major/Accessory Organs work together to break down food.

Two types of Digestion Mechanical digestion (physical change) Chemical digestion (chemical change)

Chemical or Physical change? Mouth (teeth): chewing and grinding Salivary enzymes (amylase) break down amylose (starch) into disaccharides (sugars) ; the Esophagus moves broken down food into the stomach. Stomach: Pepsin with help of HCl break down proteins Small intestine: Nutrients are absorbed into Villi in the small intestine; Bile (“detergent” from liver) physically breaks down Lipids into smaller fats Other enzymes further break down Lipids into fatty acids , carbs into simple sugars, & proteins into amino acids Lactase breaks down lactose into glucose and galactose Large intestine: absorbs water Liver: Catalase breaks down H2O2 (toxin) into water and oxygen physical chemical chemical physical physical chemical Digestion take place through the interactions of enzymes, stomach acid, hormones, bile from the liver, and a network of nerves and muscles. chemical physical chemical

Catalase in the Liver Remember when we were talking about enzymes? Here’s the video on how the enzymes in the liver break down H2O2.

Some people cannot consume dairy products, such as milk, without their stomach becoming upset. Explain. They lack the enzyme lactase, which breaks down lactose (sugar) into simple sugars during digestion.

Where in the body are biomolecules digested? amylase Carbohydrates disaccharides sugars Proteins Amino acids pepsin Lipids fatty acids

If you ate a meal of spaghetti and meatballs, where would chemical digestion of the pasta and meat begin? Mechanical digestion: pasta and meatballs Chemical digestion: Pasta (starch) with amylase Chemical digestion: Proteins with pepsin

Why do systems interact? To maintain homeostasis

How does digested food get to cells?

Interactions with Circulatory system The circulatory system carries absorbed nutrients (small intestine) in the bloodstream to all the body cells.

In cells, nutrients are broken down into even smaller parts by lysosomes (bags of digestive enzymes and acids). Ex. Glucose that can be used by mitochondria to make ENERGY.

Interactions with Muscular system The muscles help chew and swallow food. The smooth muscles of stomach contracts to push food through.

Interactions with Endocrine system Makes the hormone insulin to regulate blood sugar. (When we digest carbohydrates, they are converted into sugars, then the endocrine system yields the hormone, insulin, to control how much sugar is in the blood flow and the amount at a certain time)

Interactions with Excretory system Digested system breaks down food into nutrients that are absorbed in a small intestine  blood  transported to all the cells in the body. Cells produce waste  enter the blood stream  travel to kidneys  kidneys filter it out  turns into urine

Interactions with Nervous system Recieves cellular energy (ATP) from nutrients Sends messages to the digestive system when body is hungry and when body is full. Signals peristalsis (Physical movement) in the digestive tract. Signals hydrolytic enzymes/hormones to be distributed.

Interactions with Respiratory system Recieves carbs for cellular respiration Provides oxygen for the process of cellular respiration to take place in the mitochondria to convert glucose into ATP.

Enzymes are proteins that act as biological catalysts. Enzymes Review Enzymes are proteins that act as biological catalysts. Without enzymes, chemical reactions will not occur fast enough to sustain life processes.

Enzymes Review The ACTIVE SITE is the area of the enzyme that attaches to the chemical (substrate) undergoing change.

Enzyme Review Enzymes lower or decrease the activation energy needed to start a chemical reaction; therefore, enzymes speed up reactions.

Enzyme Review Enzymes are specific to the chemical reaction they catalyze. They have unique structures and functions. The enzymes remain unchanged when a reaction is complete and can assist with the same reaction over and over again.

Summarize your Cornell Notes