Digestive System

Flashcards about the Digestive System and related concepts.

Four main groups of organic chemicals used

Carbohydrates, Lipids, Proteins, Nucleic acids + inorganic molecules (water, ions…)

Condensation

Large molecules (Polymers) are formed by the buildup of smaller molecules (Monomers) through the removal of water

Hydrolysis

Large molecules (Polymers) are broken down into smaller ones (Monomers) by the addition of water

Monomer

Small basic unit of the molecule.

Polymer

Complex re-arrangement of monomers.

Carbohydrates

Main function is short-term energy; other uses include structure/support; found in sugar and starch (breads, pastas, fruits, veggies); made of C, H, O.

Monomer of Carbohydrates: Monosaccharides

Single sugar molecules, e.g., Glucose, Galactose, Fructose.

Polymer of Carbohydrates: Polysaccharides

Large molecules formed by monosaccharides, e.g., Starch, Glycogen, Cellulose.

Energy Storage of Carbs

4 calories/milligram. First thing your body breaks down for energy.

Lipids

Main function is long-term energy storage; other uses include cushioning organs, insulation, hormones, cell membrane; found in fats, oils, phospholipids, steroids; made of C, H, O.

Polymer of Lipids

Fats, oils, phospholipids, steroids, hormones.

Monomer of Lipids

No “true” monomer, but mostly Fatty Acids; 9 calories/milligram - body breaks down to get energy when it runs out of carbs

Phospholipids

Structure = 2 fatty acids, a phosphate and a glycerol. Found making up the plasma membrane of cells.

Proteins

Most diverse macromolecule, makes up 50% of cell's biomass, runs your body.

Functions of Proteins

Control the rate of chemical reactions, regulate cell processes, form bones and muscles, transports substances, help fight diseases, and are a food source.

Proteins

Found in meats, nuts, Greek yogurt, etc. Examples in your body include hemoglobin and insulin. Made of C, H, O, N, P and S.

Monomer of Proteins

Amino Acids

Polymer of Proteins

Polypeptide - amino acids are linked together by a peptide bond.

Nucleic Acids

Store & transmit hereditary or genetic information; examples include DNA, RNA.

Composition and Source of Nucleic Acids

Made of C, H, O, N, and P; you get them from your parents not your food!

Monomer of Nucleic Acids

Nucleotides - Ex. A, G, T, C, U. Includes a 5-carbon sugar, Phosphate group, and Nitrogenous base.

Polymer of Nucleic Acids

DNA and RNA

Energy Storage of Nucleic Acids

0 cal/mg – Nucleic Acids are NOT EVER broken down for energy!!

Macromolecules

Large organic molecules (meaning they contain carbon) used for various functions in living things.

Salivary Glands

Moistens food into a bolus and begins polysaccharide digestion.

Oesophagus

Transports food to stomach.

Liver

Detoxifies certain molecules, stores vitamins, iron, glycogen, and synthesizes bile.

Gall Bladder

Stores/concentrates bile.

Small Intestine

Absorbs nutrients.

Rectum / Anus

Stores and expels faeces.

Stomach

Stores and churns food and begins protein digestion.

Pancreas

Releases digestive enzymes and hormones (e.g. insulin).

Large Intestine

Absorbs water and ions.

Ingestion

Taking food into the body.

Digestion

Breaking down food.

Absorption

Moving food into cells.

Assimilation

Making food part of cell.

Elimination

Removing unused food.

Propulsion

Swallowing (oropharynx) and Peristalsis (esophagus, stomach, small intestine, large intestine).

Mechanical Digestion

Chewing (mouth), Churning (stomach), and Segmentation (small intestine).

Absorption during Digestion

Nutrients and water to blood vessels and lymph vessels (small intestine); water to blood vessels (large intestine).

Physical Digestion

Food is chewed in the mouth and churned in the stomach and further broken down through peristalsis.

Peristalsis

A series of wave-like muscle contractions that move food through the digestive tract.

The Stomach

Gastric juice makes the stomach very acidic, the mucus protects the stomach, and pepsin is an enzyme found in the stomach. The food that reaches the stomach turns into Chyme through churning.

Small Intestine

The chyme reaches the small intestine, passing through the duodenum which is 1 meter. Ducts connected to the pancreas (enzymes) and liver(bile) help in the digestion of the chyme.

Chemical Digestion

Bile emulsifies fat globules into smaller droplets and pancreatic juice contains digestive enzymes, like lipase. Sodium bicarbonate molecules are released from the pancreas to neutralize stomach acids (intestinal pH is ~ 7).

Villi

Increase the surface area of absorption of mineral ions and vitamins.

Blood capillaries

Absorb glucose & amino acids (smaller molecules).

Lacteal

Absorb fatty acids & glycerol (larger molecules).

Amylase

Enzyme produced in saliva, but also in the pancreas.

Bile

Breaks fat up in smaller droplets.

Lipase

Enzyme that can digest the lipid molecules in the small intestine.

Food Scientists

People who research and improve the food products you buy at the grocery store.

Serving Size Influence

The size of the serving influences the number of calories and nutrient amounts. Ask yourself, 'How many servings am I consuming?'

Calories

Calories provide a measure of how much energy you get from a serving of this food. 400 Calories or more is considered high.

Problem related to Consuming too much Calories

Eating too many calories per day is linked to overweight and obesity.

Nutrients to be eaten in limited amounts

Fats (saturated and trans fat), cholesterol, and sodium.

Health risks linked to excessive consumption of Certain components

Eating too much fat, saturated fat, trans fat, cholesterol, or sodium may increase your risk of certain chronic diseases, like heart disease, some cancers, or high blood pressure.

Health benefits of Calcium

May reduce the risk of osteoporosis.

Health benefits of Dietary fiber

Promotes healthy bowel function.

Health benefits of Fruits, vegetables, and whole grains

May reduce the risk of heart disease.

Balanced Diet

Provides all the nutrients in the correct amounts needed to sustain life; eating the right type of food with the right nutrients for our body.

Carbohydrates used for

Energy through respiration, muscle contraction, manufacturing of large biological molecules, excess can be stored as fats and glycogen.

Carbohydrates digestion

Digested in the mouth and the intestine and absorbed as glucose.

Lipids used for

Electrical insulation, thermal insulation, Formation of cell membrane.

Lipids digestion

Digested in the small intestine and absorbed as fatty acids and glycerol.

Proteins used as

Catalysts(enzymes), transport molecules(haemoglobin), structural material(muscles) , hormones(insulin), Defence against deseases (antibodies).

Proteins digestion

Digested in the stomach and small intestine and absorbed as amino acids.

Fibers used in

Bulk of faeces, Stretches the muscles of the gut wall and helps in pushing the food (peristalsis).

Water used in

Two thirds in cells and cytoplasm, One third in tissue fluid and blood plasma.