Digestive System Quiz Flashcards
What are the three main biological molecules we eat?
Carbohydrates, lipids and proteins
What are carbs the source of?
All energy that we have available
What are the simplest sugars called?
Monosaccharides (glucose, fructose)
What is sucrose?
Disaccharide (made of two monosaccharides)
Sucrose made of glucose and fructose
What are the two roles of polysaccharides?
Store energy (like amylose)
Storing energy as structures (cellulose)
What is the source of all carbs?
The sun
What can’t lipids dissolve in?
Water
What are lipids made of?
Glycerol and 3 fatty acids
What is the difference between saturated and unsaturated fats?
Saturated: all bonds are single bonds with hydrogen
Unsaturated: can have double bonds or triple bonds
What roles do proteins play in the body?
Affects antibodies, enzymes and hormones
What are proteins made of?
Amino acids
What are polypeptides?
Long chains of amino acids
What are essential amino acids?
The 9 amino acids our body can’t make on its own
Where do we get energy? Where do we store it? (6)
- from good we eat
- sugars (carbs) are broken down into energy through cellular respiration
- don’t use all energy produced every day so it’s stored as glycogen (glucose polymer)
- found in liver and muscle cells (use it first)
- stores as fat is glycogen is full and energy is still being produced
- when fewer calories are being produced than are being burned, fuel is taken out of glycogen and digested
Explain how to get proteins if on a vegetarian diet?
Need to make sure you’re still getting enough protein
Out of 20 amino acids, 8 must be eaten
- grains (like corn) have 6 but are missing 2
- beans have 6 but are missing a different 2
What happens if you’re missing too much of a nutrient?
A deficiency disease like scurvy (vitamin c) rickets (vitamin D) anemia (iron or B12)
What does digestion of cellulose have to do with diet?
Cellulose is more difficult to digest so that governs the life strategies of herbivores but you need sugars which you can get from cellulose
Cows digest cellulose well so there’s no need for supplemental sugars
Gorillas need other sugars because they can’t digest cellulose
What are the differences of teeth in different diets? What about the length of the digestive system? Why are these different?
Carnivore: teeth are sharp and ripping; short system (protein is easier to digest)
Herbivore: wide grinding teeth; longer system (more time to digest cellulose; symbiotic bacteria in gut which helps digest cellulose)
Omnivores: have combinations of both
What are the functions of the digestive system?
- Ingest (take in nutrients)
- Digest (break down organic molecules into smaller pieces)
- Absorb (take digested molecules into cells and transport to body and tissues)
- Egest (remove waste materials from body)
What are the processes of digestion?
Mechanical digestion- the breakdown of food into smaller parts (chewing)
Chemical digestion- the breakdown of the food into chemical parts
Absorption- the body taking in the nutrients from food
Describe the function of the tongue? (4)
- Positions food on teeth for chewing
- pushes food to back of mouth for swallowing
- the bolus (chewed food) passed into esophagus
- has cone shaped projections (papillae); house taste buds
What role does saliva play in digestion? (4)
Produced by 3 glands (parotid, sublingual and submandibular glands)
Empty secretions into mouth through short ducts
Contains water, amylase and mucus
Lubricates food so it’s easy to swallow
Explain more about the esophagus. (3)
- muscular tube connecting mouth and stomach
- transports food and mucus to stomach
- food moves through peristalsis (contractions in esophagus, small intestine, large intestine, and rectum)
Explain the role of the stomach. (3)
- muscular bag that stretches as it fills with food
- 3 sets of muscles contract rhythmically the mix food with gastric juices produced in stomach (juices contain HCl which turns pepsinogen into pepsin which digests most proteins)
- mechanical and chemical digestion
Explain the role of the small intestine. (3)
- Majority of digestion occurs in first 25 cm (duodenum)
- entire thing is 7m long, with other parts being jejunum and ileum
- ball of food that leaves stomach (chyme) has stomach acid which causes production of secretin (hormone) which triggers pancreas to release bicarbonate ions to reduce Ph and not damage intestine
Explain the role of the large intestine. (2)
- about 5cm wide and 1.5m long
* store waste materials long enough that water can be reabsorbed back into the body
Describe egestion. (3)
- cellulose can’t be egested so it is most of what is egested
- bowel movements allow potentially toxic waste to be removed
- those who don’t eat enough cellulose can develop colon cancer from toxic waste build up
Explain the purpose and complications from the liver.
- produces bile which helps break down food in the stomach
- detoxifies substances from the body
- stores vitamin A, B12 and D
Problems: jaundice, cirrhosis
Explain more about the gallbladder.
Stores bile
Needed when stomach is empty and digestion isn’t occurring
Problems: gallstones
Describe the purpose of the pancreas.
Produces insulin (regulates sugar concentration in the blood)
Produces digestive enzymes (trypsin)
