supplying the cell

• Diffusion - the net movement of particles from an area of higher concentration to an area of lower concentration (down the concentration gradient)
• Osmosis - diffusion of water particles from an area of higher water potential to an area of lower of water potential through a selectively permeable membrane.
• Active Transport - net movement of ions from and area of lower concentration to and area of higher concentration against the concentration gradient using ATP released during respiration
• Amino acids, glucose, water and oxygen can diffuse through, not bigger particles like starch and carbohydrates
• Plants use active transport to gain minerals from the soil.
• How does temperature affect the rate of diffusion?

  higher temperature means there is more kinetic energy because it causes the particles to move faster. more kinetic energy equals a higher rate of diffusion.
• Factors affecting the rate of diffusion

  1. concentration gradient
  2. temperature
  3. surface area
• Factors affecting the rate of diffusion - concentration gradient

  the greater the difference in concentration, the faster the rate of diffusion. this is because more particles are moving down the the gradient than moving against it.
• Factors affecting the rate of diffusion - temperature

  the higher the temperature, the faster the rate of diffusion. this is because a hotter temperature results in more kinetic energy which means that the particles move quicker and have more collisions.
• Factors affecting the rate of diffusion - surface area (of the membrane)


  the more surface area, the more space for particles to move through resulting in a faster rate of diffusion
• red blood cells


  contains haemoglobin, a red protein which binds with oxygen (making oxyhaemoglobin). it has no nucleus, creating extra space for haemoglobin. has a biconcave disk shape, increasing the surface area for oxygen to be absorbed. they are felxible so they can fit through narrow blood vessels.
• • Blood consists of four main components: red blood cells, white blood cells, platelets, and plasma.
• • White blood cells are vital for immune defense against infections.
• white blood cells

  • Antibody production: targeting pathogens for destruction.
• • Platelets are cell fragments without nuclei that play a critical role in clotting by patching wounds to prevent excessive bleeding and infection.
• • Plasma makes up over half the blood volume; it is a pale yellow liquid that facilitates flow and carries various substances including:
  • nutrients (glucose, amino acids)
  • waste products (carbon dioxide, urea)
  • hormones and proteins
• Significant loss of blood due to injury or surgery can lead to insufficient oxygen delivery to tissues. lack of oxygen means less effective aerobic respiration, or anaerobic respiration, not providing enough energy for the body.
• • Artificial blood substitutes primarily consist of salt water; they add volume but do not contain red blood cells, limiting their effectiveness in transporting oxygen.
• plasma is the liquid part of the blood.
• white blood cells form part of the immune system, for example making antibodies.
• white blood cells contain a nucleus, which contains dna. which encodes the instructions which the white blood cells need to do their job.
• platelets are tiny fragments of cells which help the blood to clot.
• platelets prevent and stop bleeding for cuts or wounds. they clump together to form a clot that helps stop bleeding. [loss of blood = loss of oxygen being transported around the body = less aerobic respiration = less energy]