Cell Structure

• All living organisms are made up of cells, of which there are several different types of cells, some of the sharing some common features.
• A cell is the smallest unit of a living thing, and can be grouped into either eukaryotic or prokaryotic cells.
• What is the smallest unit of a living thing?

  Cell
• What are the two types of cells?

  Eukaryotic and prokaryotic
• Eukaryotes can form multicellular organisms, while prokaryotes cannot.
• In complex multicellular organisms, cells gain specific features, this is called specialisation.
• What is specialisation?

  Where cells in complex multicellular organisms gain specific features
• Specialised cells are organised into groups to perform a function
• A cell specialises because the shape and contents of the cell help it to carry out its function
• What are some examples of cell specialisation?

  • Muscle cells, which are very active and so contain lots of mitochondria in order to produce ATP.
  • Red blood cells have a biconcave shape and no nucleus to maximise space to carry oxygen, they also have lots of haemoglobin
  • Palisade cells have a long, upright shape and contain chlorophyll to absorb light for photosynthesis
• Specialised cells are organised into tissues, tissues into organs and organs into organ systems.
• What type of cells are humans made up of?

  Eukaryotic
• What are eukaryotic cells?

  Cells that contain a nucleus and membrane-bound organelles.
• Eukaryotic cells are defined as cells that contain a nucleus as well as other membrane-bound organelles
• The nucleus is a large organelle that is present in all eukaryotic cells
• What is the nucleus?

  A large organelle present in all eukaryotic cells
• The nucleus controls the cells activity by controlling the transcription of DNA, which contains the instructions to make proteins, these instructions differ depending on the type of cell.
• What is the function of the nucleus?

  It controls the cells activity by controlling the transcription of DNA
• How does the nucleus control cell activity?

  By controlling the transcription of DNA
• What are the structures that make up nuclei?

  Nuclear envelope, nuclear pores, nucleoplasm and the nucleolus
• The nucleus is surrounded by a double membrane called the nuclear envelope
• What is the double membrane surrounding the nucleus called?

  The nuclear envelope
• The nuclear envelope helps to maintain the shape of the nucleus, separates it from the cytoplasm and is consisted of phospholipids, which forms a phospholipid bilayer
• What is the function of the nuclear envelope?

  Helps to maintain the shape of the nucleus, separates it from the cytoplasm and regulates the movement of molecules into and out of the nucleus
• The nuclear envelope assists in regulating the flow of molecules into and out of the nucleus through nuclear pores that bridge the double membranes.
• The nucleoplasm is the gelatinous substance within the nucleus that suspends all the internal structures. The chromatin, nucleolus and linear chromosomes are found here.
• What is the nucleoplasm?

  A gelatinous substance within the nucleus that suspends all the internal structures
• Where are chromatin found in the nucleus?

  The nucleoplasm
• Chromosomes consist of DNA, which contains genetic information and instructions for cell growth, development and reproduction.
• When a cell is not undergoing mitosis, the chromosomes are organised into long entangled structures called chromatin.
• How are chromosomes arranged when a cell isnt undergoing mitosis?


  Long, entangled structures called chromatin
• The nucleolus is a densely stained sphere inside the nucleus, it is not surrounded by a membrane, and is the site of RNA production and the making of ribosomes.
• What is the nucleolus?


  A densely stained sphere inside of the nucleus
• What is the function of the nucleolus?

  The site of RNA production and the making of ribosomes
• Ribosomal RNA is joined together with associated proteins in the nucleolus to assemble ribosomal subunits
• Mitochondria are found in a large number of cells that are very active, and thus require a lot of energy. This energy is gained via aerobic respiration, which produces ATP - an energy carrying molecule that provides the energy to drive many processes inside cells.
• How does mitochondria provide energy to cells?

  ATP production via aerobic respiration
• What is ATP?


  An energy carrying molecule that provides the energy to drive many processes within cells
• What is the structure of mitochondria?

  Inner and outer membrane, cristae and the matrix space
• The inner and outer membranes of the mitochondria are folded to form the cristae, the enclosed space formed inside the inner membrane is called the matrix space