Back to AI Flashcard MakerBiology /Biology IB HL - 6.1 Digestion Part 9
What is the first step of amino acid transportation, what transports them?
Specific amino acid co-transport proteins (a type of carrier protein) are found within the cell-surface membrane of the epithelial cells lining the ileum
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Term
Definition
What is the first step of amino acid transportation, what transports them?
Specific amino acid co-transport proteins (a type of carrier protein) are found within the cell-surface membrane of the epithelial cells lining the il...
When can amino acids be transported?
They transport amino acids only when there are sodium ions present
How do the sodium ions diffuse into the cell and how many amino acids accompany them?
For every sodium ion that is transported into the cell, an amino acid is also transported in This occurs via facilitated diffusion, which requires the...
How do amino acids pass into capillaries?
Amino acids diffuse across the epithelial cell and then pass into the capillaries via facilitated diffusion
What maintains the sodium ion concentration gradient?
The concentration gradient of sodium ions from the lumen of the ileum into the epithelial cell is maintained by the active transport of sodium ions ou...
Why can glucose (monosaccharide) not move via diffusion?
Glucose is polar so cannot pass into the blood by diffusion
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| Term | Definition |
|---|---|
What is the first step of amino acid transportation, what transports them? | Specific amino acid co-transport proteins (a type of carrier protein) are found within the cell-surface membrane of the epithelial cells lining the ileum |
When can amino acids be transported? | They transport amino acids only when there are sodium ions present |
How do the sodium ions diffuse into the cell and how many amino acids accompany them? | For every sodium ion that is transported into the cell, an amino acid is also transported in This occurs via facilitated diffusion, which requires the movement of molecules down their concentration gradient |
How do amino acids pass into capillaries? | Amino acids diffuse across the epithelial cell and then pass into the capillaries via facilitated diffusion |
What maintains the sodium ion concentration gradient? | The concentration gradient of sodium ions from the lumen of the ileum into the epithelial cell is maintained by the active transport of sodium ions out of the cell and into the blood via a sodium-potassium pump at the capillary end of the cell |
Why can glucose (monosaccharide) not move via diffusion? | Glucose is polar so cannot pass into the blood by diffusion |
What aids the transport of glucose? What is it similar to? | The glucose carrier proteins in the cell-surface membrane of the small intestine work in a similar way to the amino acid carrier proteins |
What moves alongside glucose into the epithelial cells? What process? | Sodium ions and glucose molecules are co-transported into the epithelial cells via facilitated diffusion |
Is the transport of glucose passive or active? | This is a passive process but depends on the concentration gradient of sodium ions from the lumen of the ileum into the epithelial cell |
What makes the passive transport of glucose active? | The gradient is maintained by the active transport of sodium ions out of the cell and into the blood via a sodium-potassium pump at the capillary end of the cell |
How does glucose enter the capillary? | The glucose molecules diffuse across the epithelial cell and enter the capillary by facilitated diffusion through a glucose channel protein |
What are the products of lipid digestion? | The products of lipid digestion are fatty acids, monoglycerides, and glycerol |
Are lipids absorbed in the same way as amino acids/monosaccharides? | NO | Absorption of these products is different from the absorption of monosaccharides and amino acids |
How can fatty acids and monoglycerides enter epithelial cells? | Fatty acids and monoglycerides can enter the epithelial cell by simple diffusion |
Why do fatty acids use simple diffusion? | They are non-polar molecules so they can diffuse through the phospholipid bilayer of the cell surface membrane |
Apart from simple diffusion, how can fatty acids be transported? | Fatty acids also move by facilitated diffusion through fatty acid transport proteins |
How do fatty acids not diffuse back into the lumen? | Inside the epithelial cell, fatty acid chains recombine with monoglycerides or glycerol to form triglycerides, which are unable to diffuse back into the lumen |
What is done with the triglycerides? How are they now transported? | The triglycerides are packaged up with cholesterol and encased in phospholipids and proteins to form lipoproteins |
How do lipoproteins enter capillaries/lacteal? | These droplets then enter the lacteal or capillaries via exocytosis |