• process that changes or transforms one set of chemicals into another

• the elements or compounds that enter into a chemical reaction

• Elements or compounds produced by a chemical reaction

• chemical reactions always involve changes in chemical bonds that join atoms and compounds

• reactions that release energy often occur spontaneously
• reactions that absorb energy need a source

• proteins that act as biological catalysts
• speed up the rate of chemical reactions in the cells

• lower the activation energy, which has a dramatic effect on how quickly reaction is completed

• the reactants of enzyme catalyzed reactions

• site on an enzyme where the enzyme and substrates bind together

• small molecules needed in some enzyme reactions to help the reaction work properly

• reduce or destroy the activity of an enzyme
• two types: competitive and non-competitive 

• bind with the active site of an enzyme (compete with the  substrate for the site and block it
• many are released from active site so enzyme can be regenerated; the higher the concentration of the substrate, the less effect inhibitor has

• doesn't bond to active site, binds with a different part of the enzyme, which distorts the shape of enzyme so it can't function properly
• not released from enzyme molecule so enzyme can't be regenerated
• even a low concentration of a non-competitive inhibitor can be dangerous

• they lower the activitation energy, which dramatically affects the rate of a chemical reaction

• the process of breaking down food into small molecules that can be passed to the cells that need them
• Chemical: breaking down macromolecutles into subunits
• Mechanical: physical breakdown of food into smaller  pieces

• Mouth
• Salivary glands 
• Pharnyx
• Esophagus
• Stomach
• Small intestine
• Large Intestine
• Gallbladder
• Pancreas
• Rectum
• Anus

• Beginning of digestive system
• Mechanical -Tears and grinds food into pieces small enough to swallow
• Chemical-saliva for moisture,cleaning tasting AND Starch Disgestion begins with salivary amylase

• release saliva, which moistens food an helps to swallow; contains amylase, which breaks down starches

• food and air passes through pharnyx

• Digestion
• Absorption-molecules absorbed into blood carried to cells in body
• Elimination-wastes are are removed from body

• j shapedmuscular pouch (empty: 50ml, full: 4000ml)
• mechanical digestion - churn and mix food via contractions until a mixture called chyme (kym) flows into ....
• chemical digestion - hydrochloric acid makes the contentsof the stomach very acidic and Pepsin enzyme, whose precusor is the secretion pepsinogen, works to begin the digestion of protein, both secreted via glands in the stomach (NB amalyse is stopped and carbs are not digested again until the small intestine)

• pushed through the pyloric valve to where almost all digestive enzymes enter this 20 ft. long tube-like structure
• most of chemical digestion and absorption of nutrients occurs here
• Chem. Digest.:
• Carbs: maltase, sucrase, lactase enzymes break down remaining diaccharides into monsaccharides
• Proteins: Proteinases or peptidase enzyme breaks down dipeptides into amino acids

Helper Organs to Small Intestine: Liver, Gallbladder, Pancreas

NB: crucial function BUT food never enters them

Liver: produces bile which separates(emulsifies) fat molecules which makes it possible for enzymes to break down smaller fate molecutels. Bile stored in Gallbladder.

The Pancreas neutralizes stomach acids and secretes sodium bicarbonate and produces 3 enzymes:

• amylase breaks down starch
• trypsinogin in the gastric juice is actived by enzyme into trypsin that breaks down protein
• Lipase breaks down of fat

• 5ft long
• food remains 12-24 hours
• Job: Remove Water from undigested material that is left (big blow dryer)
• Many bacteria live in colon, some secrete Vitamin K
• absorb too little water: diarrhea, too much: constipation these are digestive system disorders along with ulcers

The undigested food would then be moved on to the last muscular part of the large intestine

The muscle process contracting and expanding called peristalsis moves undigested food to this last temorary holding place

• enzyme in saliva that breaks chemical bonds in starches and releases sugars

• produced by glands in stomach, makes stomach acidic
• activates pepsin

• dissolves and disperses droplets of fat in fatty foods
• makes it possible for enzymes to reach the smaller fat molecules and break them down

• enzyme that begins digestion of protein 
• works best under acidic conditions in the stomach

• continues breakdown of protein

• breaks down fat

• continues the breakdown of starch

• Break down remaining disaccharides into monosaccharides

• Breaks down dipeptides into amino acids