Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
17 Cards in this Set
- Front
- Back
|
What is active transport? |
The movement of large or water soluble substances across the membrane via carrier proteins. Active transport will occur down or against a concentration gradient and requires ATP. |
|
|
What are 4 facts about active transport? |
Molecules may move against a concentration gradient. Molecules have kinetic energy ATP is required Protein carriers are present |
|
|
How do the carrier proteins work? |
They act as pumps. Their shape is specific and complements the shape of the molecule they carry. They carry larger or charged particles through the membrane as they can't diffuse through the bilayer. They change shape to allow the molecule through. |
|
|
How is a one way flow ensured? |
ATP changes the shape of the carrier protein, so on one side of the membrane the shape will complement the molecule to be transported.Once energy has been used by the carrier, it changes shape and releases the molecule ensuring a one way flow. |
|
|
How does a substance which inhibits ATP production affect active transport? |
It will stop the moevement of molecules by active transport and cause death. |
|
|
Which molecules are actively transported by carrier proteins? |
Non-lipid soluble molecules Large molecules Large and water soluble molecules |
|
|
What is the ileum? |
The final part of a mammal's small intestine |
|
|
What happens in the co-transportation and abosorption of glucose in the ileum? |
Glucose is absorbed into the blood stream in the ileum. The concentration of glucose is too low to diffuse out into the blood, so glucose is absorbed from the lumen of the ileum by co-transporters. They're a type of carrier protein which bind 2 molecules at a time. The concentration gradient of 1 molecules is used to move the other against it own gradient. |
|
|
Which moecules are involved? |
Sodium ions- which move from a high concentration in the cell to a low concentration in the blood Glucose- which moves from a low concentration to a high concentration |
|
|
What lines the ileum? |
Epithelial cells which have microvilli to increase surface area. They also have an increased number of channel and carrier proteins in their membranes. |
|
|
What occurs in step 1of sodium and potassium ion co-transport? |
Sodium ions are actively transported out of epithilial cells in the ileum into the blood by the sodium potassium pump. This creates a concentration gradient and there's a higher concentration of Na+ in the ileum's lumen than in the cell. |
|
|
Step 2 |
This causes sodium ions to diffuse from the lumen of the ileum into the epithilial cell, down the concentration gradient. They do this via sodium-glucose co-transporter proteins. This causes glucose concentration inside the cell to increase to. |
|
|
Step 3 |
Glucose diffuses out of the cell,into the blood, down the concentration gradient through a channel protein by facilitated diffusion. |
|
|
What is bulk transport? |
The movement of bulk substances |
|
|
What are the two types of bulk transport? |
Endocytosis and exocytosis |
|
|
What happens in endocytosis? |
The bulk transport of substances into the cell. It uses ATP to move the plasma membrane around a substance. This forms a vesicle which contains the substance as it enters the cell. |
|
|
What happens in exocytosis? |
The bulk transport of substances out of the cell. It uses ATP to move the vesicle and allow it to fuse with the plasma membrane, allowing substances to leave the cell. |
