Year 8 Science

• Plant cell


  • Chloroplasts
  • Cell wall
  • Large Vacuole
• Animal cell


  Very small vacuoles
• Same (Found in both Plant & Animal Cells)

  • Cell membrane
  • Nucleus
  • Cytoplasm
  • Mitochondria
• Mitosis


  • Is the process of making new cells for growth and repair
  • The daughter cells are identical to each other and the parent cell
  • PMATC
  • Mitosis makes me heal and grow, from my head to my toes (helps you to remember the difference between mitosis and meiosis)

  
• Meiosis


  • The type of cell division that occurs only in the gonads to produce 4 gametes (either eggs or sperm) ready for sexual reproduction
  • Not identical
  • Meiosis makes me

  
• Muscle cells


  • Have a lot of mitochondria in them to give them energy
• Types of muscles in your body

  • Smooth muscle cells- involuntary muscles eg muscles that help you breath
  • Striated muscle cells - eg biceps
  • Cardiac muscle cells- your heart
• Nerve Cells


  • Carry signals throughout the body
  • Nerve cells are called neurons
  • Help you to sense touch, and to taste
  • Contain very long fibres that allow the cells to carry the messages throughout the body
• Blood Cells


  • Red blood cells carry oxygen - no nucleus
  • White blood cells help the body fight diseases - they do have a nucleus
• Fat Cells


  • Help to keep you warm
  • Store energy
  • Brown fat cells are used to produce heat and white fat cell are used to store energy
• Cell


  • Function
  • Special Features
  • Why special feature is useful
• Levels of Organisation


  • Cells
  • Tissues
  • Organs
  • Systems
• The heart is the organ which pumps the blood around your body
• Parts of the Heart

  • Right Atrium
  • Right Ventricle
  • Left Atrium
  • Left Ventricle
• Flow of blood from the heart —> lungs —> heart —> body


  Superior/Inferior Vena Cava → Right Atrium → Tricuspid Valve → Right Ventricle → Pulmonary Valve → Pulmonary Artery → Lungs → Pulmonary Vein → Left Atrium → Mitral Valve → Left Ventricle → Aortic Valve →Aorta → Rest of the body

  
• Types of Blood Vessels

  • Arteries
  • Veins
  • Capillaries

  
• Arteries


  • Carry blood away from the heart (think Arteries = Away)
  • When the heart beats, the blood moves along the arteries under pressure
  • The walls of the arteries are thick and elastic, which expand and contract with every heartbeat
• Veins


  • Carry the blood back to the heart
  • The pressure in the veins is low so the walls are thinner and have valves, which open when the blood is flowing upwards, and close when the blood flows downwards
  • The blood is pumped back up to the heart by the body's muscle contractions pressing against the veins
• Capillaries


  • Are the finest of the blood vessels and extend throughout the body
  • They reach nearly every cell of the body
  • The walls are only one cell thick which allows the dissolved materials to pass through them
• Oxygen dissolves on the moist surface of the alveoli and moves through the cells and into the capillaries through a process called diffusion. The reverse happens with the carbon dioxide that is produced as a waste during cellular respiration
• Cell


  The building block of living organisms
• Eukaryotic cell


  • A complex cell that contains a nucleus and membrane-bound organelles
• Prokaryotic cell


  • A primitive single-celled organism that has no nucleus
• Organelles


  A structure within a cell that has a specific function
• Nucleus


  • An organelle that contains genetic material (DNA) and controls the processes of the cell
• Mitochondrion


  • An organelle in cells where energy is produced
• Ribosome


  • A cell organelle where protein production takes place
• Chloroplast


  • An organelle found in plant cells that transforms solar energy into chemical energy
• Cell membrane


  • A structure that helps form the shape of the cell and controls what enters and leaves the cell
• Mitosis


  The type of cell division that produces two identical daughter cells and is used to repair the body
• DNA


  Deoxyribonucleic Acid - the molecule that contains the genetic information of a person
• System


  A collection of organs and structures that have a specific function within the body
• Heart


  • An organ that continuously pumps blood through the body
• Arteries


  • A type of blood vessel that takes blood under pressure away from the heart
• Veins


  • A type of blood vessel that brings blood back to the heart, they have valves in them
• Capillaries


  • The smallest of the blood vessels with a wall only one cell wall thick to allow for gas exchange and the movement of wastes and nutrients
• Circulatory System


  The organ system that controls the flow of blood throughout the body
• Respiratory System


  The organ system that controls the inhalation of oxygen and the exhalation of carbon dioxide gases
• Lungs


  • The organs that extract oxygen from the air and allow gas exchange to occur
• Alveoli


  • Very small structures in the lungs where the process of gas exchange occurs