Eukaryotic Cells and Organelles

• Cell surface membrane

  • The membrane found on the surface of animal cells and just inside the cell wall of other cells mainly made of lipids and protein
  • Regulates the movement of substances into and out of the cell. It also has receptor molecules on it, which allow it to respond to chemicals like hormones
• Nucleus

  • A large organelle surrounded by nuclear envelope, which contains many pores. The nucleus contains chromosomes called a nucleolus
  • The nucleus controls the cells activities - DNA contains instructions to make proteins. The pores allow substances to move between the nucleus and cytoplasm. The nucleolus makes ribosomes
• Mitochondrion

  • They're usually oval shaped. They have a double membrane - the inner one is folded to form structures called cristae. Inside is the matrix, which contains enzymes involved in respiration
  • The site of aerobic respiration. Aerobic respiration produces ATP - a common energy source in the cell
• Chloroplast

  • A small, flattened structure found in plant cells and algal cells. It’s surrounded by a double membrane, and also has membranes inside called thylakoid membranes. These membranes are stacked upin some parts of the chloroplast to form grana. Grana are linked together by lamellae — thin, flat pieces of thylakoid membrane.
  • The site where photosynthesis takes place. Some parts of photosynthesis happen in the grana, and other parts happen in the stroma
• Golgi apparatus

  • A group of fluid-filled membrane-bound flattened sacs. Vesicles are often seen at the edges of the sacs
  • It processes and packages new lipids and proteins. It also makes lysosomes
• Golgi vesicle

  • A small fluid-filed sac in the cytoplasm surrounded by a membrane produced by the Golgi apparatus
  • Stores lipids and proteins made by the Golgi apparatus and transports them out of the cell
• Lysosome

  • A round organelle surrounded by a membrane,with no clear internal structure. It's a type of Golgi vesicle.
  • Contains digestive enzymes called lysozymes. These are kept separate from the cytoplasm by the surrounding membrane, and can be used to digest invading cells or to break down worn out components of the cell
• Ribosome

  • A very small organelle that floats free in the cytoplasm or is attached to the rough endoplasmic reticulum. Its made up of proteins and RNA. Its not surrounded by a membrane
  • The site where proteins are made
• Rough endoplasmic reticulum

  • A system of membranes enclosing a fluid-filled space. The surface is covered with ribosomes
  • Folds and processes proteins that have been made at the ribosomes
• Smooth endoplasmic reticulum

  • Similar to rough endoplasmic reticulum but with no ribosomes
  • Synthesises and processes lipids
• Cell Wall

  • A rigid structure that surrounds cells in plants, algae and fungi. In plants and algae its mainly of the carbohydrate cellulose. In fungi its made of chitin
  • Supports cells and prevents them from changing shape
• Cell vacuole

  • A membrane-bound organelle found in the cytoplasm. It contains cell sap - a weak solution of sugar and salts. The surrounding membrane is called tonoplast
  • Helps to maintain pressure inside the cell and keep the cell rigid. This stops plants wilting. Its also involved in the isolation of unwanted chemicals inside the cell
• Sperm cells

  Sperm cells contain a lot of mitochondria to provide the large amounts of energy they need to propel themselves towards an egg
• Red blood cells

  • Red blood cells are adapted to carry oxygen around the body. They have no nucleus to make more room for the oxygen carrying compound haemoglobin
• Epithelial cells

  • The walls of the small intestine have a lot of villi that increase surface area for absorption
  • The epithelial cells on the surface of the villi have folds in their cell-surface membranes, called microvilli. Microvilli increase surface area even more.
  • They also have lots of mitochondria — to provide energy for the transport of digested food molecules into the cell
• In multicellular eukaryotic organisms, specialised cells are grouped together to form tissues. A tissue is a group of cells working together to perform a particular function. Different tissues work together to form organs. Different organs make up an organ system.