active transport

active transport main points / summary

• movement of molecules - from an area of low concentration to high concentration

• requires energy - uses atp (molecule) to move substances against concentration gradient

• occurs in plants and animals

active transport in animals

• absorption of glucose in small intestine - the concentration of glucose is higher in the small intestine than in the bloodstream, meaning glucose moves into the bloodstream from the intestine via active transport because the glucose concentration is lower in the blood, and this supports energy production in the body

• sodium-potassium pump in nerve cells - there is a higher concentration of sodium ions outside the nerve cell and a higher concentration of potassium ions inside, meaning sodium ions move out and potassium ions move in via active transport, because ions need to move against their concentration gradient, and this helps maintain the electrical charge in nerve cells for nerve impulses

• reabsorption of water in kidneys - the concentration of water in the kidneys is lower than in the bloodstream, meaning water is reabsorbed from the kidneys into the blood via active transport, because the body needs to maintain proper hydration and fluid balance

• absorption of minerals in small intestine - the concentration of minerals (like iron or calcium) is lower in the bloodstream than in the small intestine, meaning these minerals move into the bloodstream via active transport, because the body needs these minerals for various functions such as bone health and oxygen transport

• oxygen transport in red blood cells - the concentration of oxygen is lower in tissues compared to the red blood cells, meaning oxygen is transported into tissues via active transport, because it helps cells receive oxygen needed for cellular respiration, even when oxygen concentration in tissues is low

active transport in plants

• uptake of mineral ions by root hair cells - the concentration of mineral ions (like potassium and nitrate) in the soil is lower than in the root hair cells, meaning mineral ions move into the root hair cells via active transport, because the plant needs these ions for growth and nutrient production

• absorption of water in roots - the concentration of water in the root cells is lower than in the surrounding soil, meaning water is absorbed by the roots via active transport, because the plant needs to transport water against gravity for transpiration and photosynthesis

• transport of sugars from leaves to roots - the concentration of sugars in the leaves is higher than in the roots, meaning sugars move from the leaves into the roots via active transport, because the plant needs to store energy in the roots for growth and survival during non-photosynthetic periods

• movement of potassium ions in guard cells - the concentration of potassium ions is higher inside guard cells than in the surrounding cells, meaning potassium ions are pumped into guard cells via active transport, because this helps control the opening and closing of stomata for gas exchange

• transport of nutrients in xylem - the concentration of essential nutrients in the soil is lower than in the plant’s xylem, meaning nutrients move into the xylem via active transport, helping the plant take up water and nutrients from the soil and distribute them to all parts of the plant