When digested, proteins are broken down into _____.
amino acids
When digested, fats are broken down into _____.
both glycerol and fatty acids
Starch is a type of _____.
polysaccharide
Your small intestine can absorb ____ without their being further digested.
fructoses
Which of these enzymes begins the breakdown of starch?
amylase
Starch can be broken down into the disaccharide known as _____.
maltose
Protein digestion begins in the _____.
stomach
What is the main component of gastric juice?
water
What acid is responsible for stomach acidity?
hydrochloric acid
The gastrovascular cavity differs from the alimentary canal in that only the gastrovascular cavity _____.
has only a single opening
Which organ converts fructose to fat?
liver
nutrition
food being taken in, taken apart, and taken up
essential nutrients
preassembled organic molecules and minerals; materials that an animal cannot assemble from simple organic molecules
essential amino acids
amino acids required by animals that must be obtained from food in prefabricated form
essential fatty acids
fatty acids required by animals that must be obtained from food
vitamins
organic molecules that are required in the diet in small amounts
minerals
inorganic nutrients, like iron and sulfur, that are required in small amounts
malnutrition
diet that lacks essential nutrients or consistently supplies less chemical energy than the body requires
golden rice
strain of rice that synthesizes pigment beta caroten to vitamin A
undernutrition
diet that fails to provide adequate sources of chemical energy
4 stages of food digestion
1. ingestion
2. digestion
3. absorption
4. elimination
ingestion
the act of eating or feeding
digestion
food is broken down into molecules small enough for the body to absorb
absorption
the animal cells take up small molecules like amino acids and simple sugars
elimination
undigested material passes out of the digestive system
chemical digestion
enzymatic hydrolysis
extracellular digestion
breakdown of food particles outside the cell
gastrovascular cavity
functions in digestion as well as in distribution of nutrients throughout the body
alimentary canal
a complete digestive tract that allows animals to ingest food while earlier meals are still being digested
4 feeding mechanisms of animals
1. filter feeding
2. substrate feeding
3. fluid feeding
4. bulk feeding
filter feeders
strain small organisms/ food from the surrounding medium (aquatic animals)
substrate feeders
animals that live in or on their food surfaces
fluid feeders
suck nutrient rich fluid from a living host
bulk feeders
most animals that eat large pieces of food
peristalsis
alternations waves of contraction and relaxation in the smooth muscles lining the alimentary canal that helps push food through the digestive system
sphincters
ringlike valves that can close off the alimentary canal to regulate the passage of materials between compartments
oral cavity
the mouth and the first step of digestion
salivary glands
deliver saliva through the ducts to the oral cavity
amylase
an enzyme found in saliva that hydrolyzes starch and glycogen into polysaccharides in maltose
mucus
provides most of the protective effects of saliva
bolus
ball shaped mixture of food and saliva the tongue creates before swallowing
pharynx
throat region that opens to two passage ways:
1. trachea
2. esophagus
epiglottis
flap of tissue that prevents food/water entering the trachea
stomach
stores food and