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Questions and Answers
What type of linkages are found in cellulose?
What type of linkages are found in cellulose?
- α-1,6 linkages
- β-1,4 linkages (correct)
- δ-1,3 linkages
- γ-1,5 linkages
Which polysaccharide is primarily made of fructose and is good for digestion?
Which polysaccharide is primarily made of fructose and is good for digestion?
- Starch
- Glycogen
- Inulin (correct)
- Cellulose
Which organism relies on symbiotic gut microflora to digest cellulose?
Which organism relies on symbiotic gut microflora to digest cellulose?
- Humans
- Most multicelled animals (correct)
- Fish
- Bacteria
Which transporter is responsible for transporting fructose into the cell?
Which transporter is responsible for transporting fructose into the cell?
How do termites reconstitute their gut flora?
How do termites reconstitute their gut flora?
Which is crucial for the absorption of carbohydrates at the brush border?
Which is crucial for the absorption of carbohydrates at the brush border?
What change occurs to the villi in the gut of animals during high digestion periods?
What change occurs to the villi in the gut of animals during high digestion periods?
Where does the majority of the biotransformation of phenylephrine occur?
Where does the majority of the biotransformation of phenylephrine occur?
What happens to the absorption of monomers after digestion in the small intestine?
What happens to the absorption of monomers after digestion in the small intestine?
Which of the following is NOT a carbohydrate transporter at the brush border?
Which of the following is NOT a carbohydrate transporter at the brush border?
Flashcards
Cellulose
Cellulose
A complex carbohydrate composed of many glucose molecules linked together by β-1,4 glycosidic bonds.
Inulin
Inulin
A type of polysaccharide made up of fructose molecules. It's found in some plants and is good for digestion.
Vertebrate digestion of cellulose and inulin
Vertebrate digestion of cellulose and inulin
Most multicellular animals lack the necessary enzymes to break down cellulose and inulin.
Symbiotic gut microflora
Symbiotic gut microflora
Microorganisms living in the gut that help break down complex carbohydrates that the host's digestive system can't.
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Absorption
Absorption
The process by which nutrients are absorbed from the digestive tract into the bloodstream.
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Absorption of carbohydrates at the brush border
Absorption of carbohydrates at the brush border
The process by which sugars are transported across the intestinal wall.
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SGLT1
SGLT1
A protein that helps transport glucose and sodium into the intestinal cells.
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GLUT5
GLUT5
A type of protein that helps transport fructose across the intestinal wall.
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Post-absorption processing
Post-absorption processing
The process by which the body breaks down and modifies absorbed molecules.
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Sulfate conjugation
Sulfate conjugation
A chemical process in which a sulfate group is added to a molecule.
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Other Polysaccharides
- Cellulose is a poly-glucose molecule with β-1,4 linkages.
- Inulin is a poly-fructose molecule found in some plants instead of starch. It aids digestion, promotes satiety, and is difficult for the body to break down.
- Vertebrates lack enzymes to break down cellulose and inulin.
- They rely on symbiotic gut microflora, a process that occurs in the large intestine, not the small intestine.
- This results in gas production.
Symbiotic Gut Flora
- Symbiotic protists aid termites in digesting cellulose and lignin.
- Termites must shed their exoskeletons (moult) to grow.
- The lining of the digestive tract is also molted during this process.
- To replenish the gut flora, termites consume the feces of nestmates.
Absorption of Carbohydrates at the Brush Border
- The Na+/K+ pump maintains a sodium gradient, driving sodium from the lumen into absorptive cells.
- SGLT1 co-transports sodium and glucose into the cell.
- Fructose enters the cell via the GLUT5 transporter, moving down its concentration gradient.
- Glucose, galactose, and fructose are transported into interstitial fluid by facilitated diffusion, moving down their concentration gradient.
- Other sugars follow a similar transport pathway.
- Gut surface area can be increased by extending villi, especially during periods of high digestion, such as summer, then reduced during winter or hibernation.
Post-Absorption Processing
- Phenylephrine is rapidly metabolized (typically by conjugation to a sulfate group) primarily in the intestinal epithelium.
- This leaves little active phenylephrine in circulation, limiting its systemic effects.
- The small intestine is a crucial site for absorption.
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