Cell structure

• What does the flagella do in a prokaryotic cell?

  It is thinner than eukaryotes and does not have the 9+2 arrangement. It is attached to the membrane by a basal body and is rotated by a molecular motor.
• What is the cell wall like in a prokaryotic cell?

  They are made from peptidoglycan.
• What are the ribosomes like in prokaryotic cells?

  They are smaller at 70s. This is due to making simpler proteins as they are unicellular.
• What is the DNA structure like in a prokaryotic cell?

  They have circular DNA. The chromosomes are typically grouped into operons.
• What is the structure of prokaryotic cells?

  They are unicellular with circular DNA.
• Why are prokaryotic cells extremeophiles?

  They are found in hydrothermal vents and in salt lakes.
• What is the history of a prokaryotic cell?

  It is the earliest form of life. First appeared 3.5 billion years ago.
• What does the chloroplast do?

  It is responsible for photosynthesis. It has a double membrane and has a fluid enclosed known as the stroma. They have flattery sacs called thylakoids and serval thylakoids makes up a granum. There are lamellae which joins the granas together.
• What does the vacuole do?

  It is a membrane lined sac where it contains the cell sap. It helps maintain the turgor pressure. The membrane of the vacuole is tonoplast. It is selectively permeable.
• What does the cellulose cell wall do?

  It gives the cell the shape and helps withstand the pressure. It acts as a defence mechanism to help protect it from the pathogens.
• How are proteins synthesised?

  Proteins are synthesised on the ribosomes on the RER then is transported in a transport vesicle to the golgi apparatus where it gets modified and packaged into a secretary vesicle where it will be released from the cell surface membrane by exocytosis.
• What is the golgi apparatus?

  It has a cisternae structure and has no ribosomes. it helps modify and package the proteins into the vesicles.
• What is the ribosome?

  They are free floating in the cytoplasm or attached to the RER. They are made from RNA and is the site for protein synthesis.
• What is the rough ER for?

  It has ribosomes attached to the surface and helps synthesis and transport proteins.
• What is the smooth ER for?

  It synthesises lipids and carbohydrates
• What is the endoplasmic reticulum?


  It is a network of membranes which enclose to form flattened sacs known as the cisternae.
• What is the structure of cilia?

  It contains 2 central mircotubles surrounded by 9 pairs of mircotubles which is arranged in a wheel shape. This is known as the 9+2 arrangement. The pairs of parallel mircotubles slide over each other causing the cilia to move in a beating motion.
• What is cilia?

  Tiny hairlike structures that propel substances along the surface of the tissue (Like in your throat/esophogus). They can be mobile or stationary.
• What is flagella?

  Long, thin whip-like structure that helps organisms move through moist or wet surroundings.
• What is a centriole?

  Made of mircotubles which is involved in the assembly of spindle fibres during cell division.
• What are the components of the cytoskeleton?

  Micro filament which are responsible for cell movement and contraction in cytokinesis, microtubules which determine the shape of the cell, intermediate fibres which gives mechanical strength and maintains the integrity.
• What is the cytoskeleton?

  Present throughout the cytoplasm and is a network of fibres which holds the shape and stability of the cell. It controls movement within the cell.
• What is a lysosome?

  Specialised vesicle that has hydrolysis enzymes that is responsible for breaking down waste material in the cells. They play an important role in the immune system as it breaks down pathogens ingested by the phyocytic cells
• What is a vesicle?


  They are membranous sacs that have storage and transport roles. It is used to transport materials inside the cell.
• What is the structure of mitrocondria?

  It has a double membrane. The inner membrane is highly folded known as the cristae and there is a fluid interior known as the matrix. It also contains mtDNA
• What is the mitochondria?

  It is the site for aerobic respiration where ATP is released.
• What is the nucleolus?

  It is where ribosomes are made. It is made from proteins and RNA. RNA is used to make rRNA which is needed for protein synthesis.
• What is the structure of the nucleus?

  It has a double membrane known as the nuclear envelope. to help protect it from the cytoplasm. The nuclear envelope has nuclear pores which will allow molecules to move in and out.
• What is the nucleus?

  contains the genetic information in DNA. It helps synthesise proteins.
• What is metabolism?

  sum of all chemical reactions in the body. It takes place in the cytoplasm.
• What is a eukaryotic cell?

  It has more complex structures such as membrane bound organelles like the nucleus and mitochondria.
• What is a prokaryotic cell?

  Single cel organisms with a simple structure.
• What is a laser scanning confocal mircoscope?


  It moves a spring spot of focus light and causes the fluorescent and labels with a dye.
• How are artefacts created?

  Trapped air bubbles when placing the cover slip. When using electron microscope you have to change the specimen so organelles may get damaged so there. at be entry spaces where artefacts can form.
• What is scanning electron microscope?

  beam of electrons across the the surface of a specimen and creates a 3D image of the speciemen. Has a resolution of 3-10nm.
• What is transmission electron microscope?

  Uses beam of electron to transmit through a specimen. It is similar to a light microscope but it has the best resolution of 0.5nm.
• What are the 2 types of electron microscopes?

  transmission and scanning
• What is a disadvantage of an electron microscope?

  Very expensive, cannot be used on live specimens, problems with artefacts due to complex preparation process.
• What is an electron microscope?

  A microscope that uses magnets to aim a beam of electrons at a cell to produce an image. This microscope magnifies images up to 500,000 times the actual size.
• How is magnification calculated?

  magnification = image size/actual size