Digestion (Biology 20) Flashcards
4 steps in the digestive process
1) ingestion
2) digestions
3) absorption
4) egestion
4 main macromolecules needed to be broken down to micromolecules
1) carbohydrates – broken down to monosaccharides
2) proteins – broken down to amino acids
3) lipids – broken down to fatty acids and glycerol
4) nucleic acids – broken down to sugar, nitrogen bases, and phosphate group.
After the dashmarks are the sub units/building blocks. The body uses them to create its OWN macromolecules.
2 types of digestion used in actual digestion of food
(1) mechanical – chewing, as well as muscular contractions to grind food.
(2) chemical – enzymes, acids, and other chemicals.
4 things affecting enzyme’s work
1) Temperature ~ 37 degrees
2) pH ~ each enzyme functions best at a specific pH
3) concentration of substrates ~ chewing things increases surface area by breaking down large pieces into small pieces, letting enzymes work faster.
4) the use and removal of inhibitors on proteins.
Chemical digestion of carboydrates in mouth
salivary amylase turns polysaccharides into disaccharides.
Chemical digestion of carbohydrates in stomach
n/a
Chemical digestion of carbohydrates in small intestine
pancreatic amylase turns polysaccharides into disaccharides, and carbohydrases turn disaccharides into monosaccharides. (absorbed into capillaries in the villi)
Common macromolecules
1) carbohydrates
2) lipids
3) proteins
4) nucleic acids
Dehydration synthesis
Joining two smaller subunits (molecules) with the removal of water. You remove an OH- group from one subunit, and H+ group from another, resulting in the macromolecule and H2O. The process relies on special enzymes.
Hydrolysis
Used to break these macromolecules. It is done by adding an H2O molecule and breaking the covalent bond formed during dehydration. Also requires special enzymes.
How are simple carbohydrates used?
they are taken to the liver where they are converted to glucose or stored as glycogen.
How are amino acids used?
they are used by cells to build protein molecules for your body, or can be sent to the liver for deamination.
How are lipids used?
they are broken down to glycerol and fatty acids.
Monosaccharide
made from single, simple sugar.
Ex: glucose, fructose.
Disaccharide
made from two simple sugars bonded together.
Ex: sucrose (glucose + fructose), lactose (glucose + galactose)
What happens to excess glucose/glycogen in the liver?
it is converted and stored as fat.
Triglycerides
made of 1 glycerol and 3 fatty acids. (in animals called fat and in plants called oil)
- fats (animal) are classified as:
a) saturated - single bonds between carbon in molecules {bonds are difficult to break} - oils (plants)
b) unsaturated - have one or more double bonds between carbon (polyunsaturated – many double bonds) {double bonds are easily broken}
Phospholipids
made of 1 glycerol, 2 fatty acids, and 1 phosphate molecule
- phosphate molecules are soluble in water, so this makes one end of the lipid chain soluble in water and the other insoluble
- since blood is 90% water, phospholipids allow the cells in the blood (RBC, WBC, platelets) to mix and move freely. The insoluble middle layer acts as a barrier so that organelles in the cell do not move outside and to control what moves inside the cell.
Waxes
- insoluble to water
- coating on leave, fur, and animal feathers
How much more energy do fats contain over carbohydrates or proteins?
2x the amount
Why is saturated fat worse for your health?
they are difficult to break down, so they remain in your cells for longer.
Ingestion
taking in of nutrients
Digestion
breaking down of nutrients ingested into their component molecules
Absorption
absorption and transport of digestive nutrients to body tissues.
Egestion
removal of waste
What taste buds are in which parts of the tongue?
bitter = back sour = back corners (left+right) sweet = right mid-front salty = left mid-front
How long does food remain in the stomach?
2-4 hours
How long does digestion take?
up to 24-33 hours
How much saliva can an adult produce in a day?
as much as 2L of saliva a day!
Salivary glands
produce saliva
Epiglottis
a sphincter that covers your trachea when swallowing