Active Transport Flashcards
Active transport:
• The net movement of particles from an area of low concentration to an area of high concentration against a concentration gradient across a partially permeable membrane
• This is an active process so therefore requires energy from respiration therefore from mitochondria as they release energy throughout aerobic respiration
Why is active transport needed?
Transport or carrier proteins are needed to get the molecules into the cells and these use energy
What are some cell adaptations for active transport?
• Cells that do active transport contain large numbers of mitochondria. This means that they carry out lots of aerobic respiration to release energy (in the form of ATP (adenosine and triphosphate) to carry out active transport
• Lots of ribosomes as they are the site of protein synthesis and carrier proteins are needed to get these molecules into cells which uses energy.
Biological examples of active transport: Marine fish
Have cells in their gills that can pump salt back into the salty sea water
Biological examples of active transport: Thyroid gland
Cells in the thyroid gland take in iodine to use in the production of hormones
Biological examples of active transport: kidney
Cells in the kidney re-absorb sodium ions from urine
Biological examples of active transport: crocodiles
Have salt glands in their tongues that remove excess salt from their bodies
Biological examples of active transport: villi
Villi in the small intestine absorb glucose and amino acids into the blood
Biological examples of active transport: Active transport in the gut
• When there’s a higher concentration of glucose and amino acids in the gut they diffuse naturally into the blood
• But sometimes there’s a lower concentration of nutrients in the gut than there is in the blood
• Active transport allows nutrients to be taken into the blood, against the concentration gradient
• This is essential to stop us starving
• It means that glucose can be transported in the bloodstream when its concentration in the blood is already higher than in the gut
Biological examples of active transport: Active transport of sugar molecules in the gut:
• Active transports allows sugar molecules to be transported from lower concentrations in the gut into the blood which has a higher sugar concentration
• The glucose can be transported into cells, where it’s used for respiration
Biological examples of active transport: Root hair cells
• Plants need mineral elements from the soil for healthy growth
• It allows mineral ions to be absorbed into plant root hairs from a very dilute solution in the soil
• Minerals enter a plant through its roots
• When plants absorb nitrate ions through the root hairs from the soil water
• The concentration of nitrate ions in soil water is usually less than the concentration of nitrate ions inside the root hair cell
• Nitrate ions naturally diffuse down their concentration gradient, out of the cell and into the soil, but plants transport the nitrates into their soil using active transport which is the movement of particles from a low contraction to a high concentration against a concentration gradient across a partially permeable membrane
the ion concentration the root hair cell in relation to the soil (4). Predict which the ions will move (5/6). Suggest an explanation for this movement (7/8).
• There is a higher concentration in the root hair cell than in the soil
• The ions move from the soil into the root
• Plants need mineral ions to survive e.g. make chlorophyll
• They use energy to move against the concentration gradient by active transport (via carrier proteins)
What does active transport allow in plants?
For plants to take up mineral ions, ions are moved into root hairs, where they are in a higher concentration than in the dilute solutions in the soil.
What does active transport allow in humans?
Examples of active transport include the uptake of glucose in the intestines in humans and the uptake of mineral ions into root hair cells of plants.
