Life Processes

Step 1: Reabsorption returns water to blood. Step 2: If it decreases more water passes into urine. Step 3: This can increase urine volume and water loss.

Step 1: Kidneys help in filtration and body balance. Step 2: Dialysis mainly removes waste substances from blood. Step 3: So it supports but is not the same as all kidney functions.

Step 1: Excretion removes wastes made by body chemical reactions. Step 2: Urea is such a waste. Step 3: Undigested food leaves the digestive tract so it is egestion.

Step 1: Urine forms in the kidney. Step 2: The ureter carries it to the urinary bladder. Step 3: A blockage will stop this path.

Step 1: Plants do not have kidneys like animals. Step 2: They can store some wastes in special parts or substances. Step 3: Resins and gums can be such stored waste materials.

Step 1: The surface of a unicellular organism directly contacts the environment. Step 2: In large organisms many cells are inside. Step 3: Therefore a transport system is needed to deliver substances.

Step 1: Breathing is movement of air in and out. Step 2: Cellular respiration breaks food inside cells to release energy. Step 3: Faster air movement increases energy only if cells can use the materials.

Step 1: A cell needs energy for every activity. Step 2: Breakdown of food in mitochondria releases energy. Step 3: Therefore mitochondria are called the powerhouse.

Step 1: Digestion provides nutrients. Step 2: Blood circulation carries them and oxygen to cells. Step 3: If circulation stops cellular respiration is affected.

Step 1: Cells need food and oxygen. Step 2: Cells also produce wastes. Step 3: The transport system moves substances in both needed directions.

Step 1: Carbon dioxide is a waste of cellular respiration. Step 2: Lungs remove it during exhalation. Step 3: Its accumulation means trouble in removing gaseous waste.

Step 1: Active tissues need more energy. Step 2: Good oxygen supply is needed for energy. Step 3: Mixing of blood can make oxygen supply less efficient.

Step 1: The heart pumps blood forcefully into arteries. Step 2: Elasticity of arteries helps handle pressure. Step 3: Reduced elasticity can disturb blood flow and pressure control.

Step 1: The trachea carries air to the lungs. Step 2: A blockage reduces air reaching alveoli. Step 3: With less air gas exchange decreases.

Step 1: Bile breaks fat into small droplets. Step 2: Pancreatic juice has many digestive enzymes. Step 3: Without both digestion in the small intestine becomes weak.

Step 1: Kidneys filter soluble nitrogenous wastes from blood. Step 2: Lungs remove gaseous waste carbon dioxide. Step 3: Thus both help excretion in different ways.

Step 1: Plants can store some wastes in old parts. Step 2: When old leaves fall those wastes are removed too. Step 3: Therefore leaf fall can also be linked with excretion.

Step 1: Nutrition provides materials. Step 2: Transport delivers materials and respiration releases energy. Step 3: Excretion removes wastes so failure of one can affect the whole system.

Step 1: Aerobic respiration needs oxygen along with glucose. Step 2: Without oxygen complete breakdown will not occur. Step 3: Some cells may get less energy through anaerobic respiration.

Step 1: An organism needs materials energy and waste control. Step 2: Each life process fulfils a different part of this need. Step 3: Together these processes keep the organism alive.