eukaryotic cells

• what is the structure of a nucleus?

  It has a nuclear envelope which is a double membrane. It contains nuclear pores to allow substances to enter/exit. It contains nucleoplasm, a granular and jelly like substance. It also contains a nucleolus which is the site of rRNA production to make ribosomes.
• what is the function of the nucleus?

  Site of DNA replication and transcription. Contains genetic code for each cell. Site of ribosome synthesis.
• what is the function of the flagella?

  Its used for mobility, sometimes used for sensory purposes for chemical stimuli
• describe hte structure of the cilia?

  Hair like projections outside of the cell
• What is the purpose of the cillia?

  They can be mobile or stationary. The mobile cilia help more substances in a sweeping motion. Stationary cilia are used in sensory organs like the nose.
• what is the structure of centrioles?

  They are made of microtubules. Centrioles appear in pairs to form a centrosome.
• What is the function of a centriole?

  they are involved in the production of spindle fibers and the organization of chromosomes in cell division.
• describe the structure of the cytoskeleton?

  A network of fibres found within the cytoplasm of over a cell. They consist of microfilaments, microtubules and intermediate fibers.
• What is the function of the cytoskeleton?

  Provides mechanical strength

  helps maintain the shape

  Many organelles are bound to the cytoskeleton

  Microfilaments are responsible for cell movement.

  Microtubules are responsible for creating a scaffold like structure

  Intermediate fibres provide mechanical strength
• describe the structure of the endoplastic reticulum?

  They are a series of folded membranes called cisternae. Rough endoplastic reticulums have ribosomes on their cisternae.
• what is the purpose of the rough endoplastic reticulum?

  Synthesis of protein
• What is the purpose of the smooth endoplastic reticulum?

  Synthesis and storage of carbohydrates and lipids
• What is the structure of the golgi apparatus?

  Folded membranes making cisternae
• What are the functions of the golgi apparatus?

  Adds carbohydrates to proteins to make glycoprotiens

  Produces secretory enzymes

  Secretes carbohydrates

  Transports, modifies and stores lipids

  Forms lysosomes

  Molecules are labelled with a destination

  Transports finished products to cell surface
• what is the structure of lysosomes?

  They are bags of digestive enzymes, containing about 50 types of enzymes
• What is the function of lysosomes?

  They hydrolyse phagocytic cells

  They do autolysis, breaking down dead cells

  Exocytosis, releasing enzymes to the outside of the cell to destroy material

  Digest worn out organelles for the recycling of materials
• Describe the structure of the mitochondria?

  It has a double membrane, the inner membrane is called the cristae. It has a fluid centre called the mitochondrial matrix. Has a loop of mitochondrial DNA
• What is the function of the mitochondria?

  Site of aerobic respiration

  Site of ATP production

  DNA is used to code for the enzymes needed in respiration.
• Describe the structure of a ribosome?

  Small, made up of two sub-units of protein and RNA.
• What are the two types of ribosome?

  80s and 70S
• What is the structure of an 80s ribosome and where is it found?

  Its a larger form of ribosome, found in eukaryotic cells
• What is the structure of the 70S ribosome, and where is it found?

  It is the smaller version, found in prokaryotic cells, mitochondria and chloroplasts
• what is the purpose of the mitochondria?

  Site of protein synthesis
• what is the structure of a chloroplast?

  It has a double membrane, containing thylakoids. It has a stroma filled with fluids which contain enzymes for photosynthesis. Only found in plants
• What is the purpose of the chloroplast?

  Site of photosynthesis
• what is thecell wall in plants made of?

  Microfibrils of the cellulose polymer
• What is the cell wall in fungi made of?

  Chitin, nitrogen containing polysaccharide
• what is the purpose of a cell wall?

  Provides structural strength to the cell