structure of cells

• struc + func of nucleus

  struc:

  • Nuclear pores - Movement of substance to/from cytoplasm
  • Nuclear envelope - outer + inner membrane
  • Nucleolus - MAKES RIBOSOMES (func)
  • func:
  • Site of Transcription (mRNA splicing)
  • Site of DNA replication
• What is an organelle?

  A part of a cell that plays a specific role.
• Name the organelles you might find in an animal cell

  1)Plasma cell surface membrane

  2)Rough/smooth endoplasmic reticulum

  3)nucleus (nucleolus)

  4)lysosome

  5)ribosome

  6)Golgi apparatus

  7)cytoplasm

  8)mitochondrion
• Describe the cell surface plasma membrane.

  Outline the functions.

  
  

  controls the movement of substances in and out of the cell.

  
  

  has receptor molecules to allow membrane to respond to chemicals eg hormones.
• Name the components of the nucleus

  1)nucleolus

  2)nuclear envelope

  3)nucleoplasm

  4)nuclear pores

  5)chromatin
• Describe the nucleus.

  Outline the functions.

  A large organelle surrounded by a nuclear envelope which contains many pores. The nucleus contains chromosomes.

  
  

  The nucleus controls the cell's activities by controlling the transcription of DNA. The pores allow substances to move between the nucleus and the cytoplasm. The nucleolus makes ribosomes.
• Describe mitochondrion.

  Outline the functions.

  They are usually oval-shaped and have a double membrane. The inner membrane is folded to form structures called cristae. Inside is the matrix, which contains enzymes involved in respiration.

  
  

  The site of aerobic respiration, where ATP is produced. They are found in large numbers in cells that are very active and require a lot of energy.
• Describe the structure of the Golgi apparatus.

  Outline the functions.

  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.
• Describe the structure of a Golgi vesicle.

  Outline the functions.

  A small fluid-filled sac in the cytoplasm, surrounded by a membrane, and produced by the Golgi apparatus.

  
  

  Stores lipids and proteins made by the Golgi apparatus and transports them out of the cell via the cell surface membrane.
• Describe the structure of a lysosome.

  Outline the functions.

  A round organelle surrounded by a membrane, with no clear internal structure. It's a type of Golgi vesicle.

  
  

  Contains digestive enzymes called lysozymes, that are kept separate from the cytoplasm by the membrane. They can be used to digest invading cells or the break down worn out components of the cell.
• Describe the structure of a ribosome.

  Outline the functions.

  A very small organelle that either floats free in the cytoplasm or is attached to the rough endoplasmic reticulum. It is made up of proteins and RNA, and is not surrounded by a membrane.

  
  

  It is the site where proteins are made.
• Describe the structure of the rough endoplasmic reticulum. (RER)

  Outline the functions.

  A system of membranes enclosing a fluid-filled space. The surface is covered with ribosomes.

  
  

  They fold and process proteins that have been made at the ribosomes.
• Describe the structure of the smooth endoplasmic reticulum. (SER)

  Outline the functions.

  A system of membranes enclosing a fluid-filled space. The surface is completely smooth.

  
  

  Synthesises and processes lipids.
• How are epithelial cells in the small intestine specialised to absorb food efficiently?

  1)The intestine walls have lots of villi, which increase surface area for absorption

  2)The epithelial cells on the surface of the villi have folds in their cell-surface membrane called micro-villi, increasing SA even more.

  3)They have lots of mitochondria to provide energy.
• What are specialised cells grouped together to form?

  Tissues
• What is a tissue?

  A group of cells working together to perform a particular function. Different tissues work together to form organs, organs make up an organ system.