Cell questions

2019-04-03T15:02:15+03:00[Europe/Moscow] en true What are the 3 main conversions for units?, What is meant by the term 'resolution'?, What is meant by the term 'magnification'?, What are the main features of a light microscope?, What are the main features of a scanning electron microscope (SEM)?, What are the main features of a transmission electron microscope (TEM)?, What are the main features of a laser scanning confocal microscope?, What is florescence?, What is the magnification equation triangle?, What are the main features of a light microscope?, What are the main features of an electron microscope?, What are artefacts?, Describe a eukaryotic cell structure, Describe a prokaryotic structure, What is the role of the nucleus?, What is the role of the nuclear envelope?, What is the role of the nuclear pores?, What is the role of the nucleolus?, What is the role of the the mitochondria?, What is the role of the vesicles?, What is the role of the lysosomes?, What is the role of the cytoskeleton?, What three components make up the cytoskeleton?, What is the role of the microfilaments in the cytoskeleton?, What is the role of microtubules in the cytoskeleton?, What are spindle fibres composed of?, What is the role of the intermediate fibres in the cytoskeleton?, What is the role of the centrioles?, What is the role of the centrosome?, What is the role of stationary cilia?, What is the role of mobile cilia?, What is the endoplasmic reticulum?, What is the role of the smooth ER?, What is the role of the rough ER?, What is the role of the ribosomes?, What is the role of the golgi apparatus?, What are the steps to protein production?, What are the differences between an animal and plant cell wall?, What are the properties of cellulose cell walls?, What is the role of the vacuoles?, What is the tonoplast?, What is the role of the chloroplasts?, What is the structure of chlorplasts?, What is the stroma?, What are thylakoids?, What is a granum?, How is strach produced by photosynthesis stored?, What are extremophiles?, How does the flagella of a prokaryote differ from a eukaryote?, What form is DNA in a prokaryote?, What form is DNA in a eukaryote?, How is DNA organised in a prokaryote?, How is DNA organised in a eukaryote?, What are prokaryote cell walls made out of?, What are eukaryote cell walls made out of?, What size are ribsomes in prokaryotes?, What size are ribsomes in eukaryotes?, How do prokaryotes reproduce?, How do eukaryotes reproduce?, How would you describe the cell type of a prokaryote?, How would you describe the cell type of a eukaryote? flashcards Cell questions
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  • What are the 3 main conversions for units?
    1. 1cm = 10mm 2. mm x 1000 = micrometres 3. micrometres x 1000 = nanometres
  • What is meant by the term 'resolution'?
    The ability to distinguish between two seperate points and see them as seperate entities.
  • What is meant by the term 'magnification'?
    The number of times larger an image is compared with the real size of the object.
  • What are the main features of a light microscope?
    1. Resolution of 200nm or 0.2 micrometres 2. Can view live specimens 3. Uses glass lenses to focus light 4. Images need to be stained
  • What are the main features of a scanning electron microscope (SEM)?
    1. Resolution of around 3-10nm 2. Magnification of x100 000 3. A beam of electrons is sent across the surface of a specimen and the reflected electrons are collected. 4. The inside of the microscope is a vaccum to ensure the electron beams travel in straight lines.
  • What are the main features of a transmission electron microscope (TEM)?
    1. Resolution of upto 0.5 micrometres 2. Magnification of x500 000 3. Uses electrons fired at the object which is focused by electromagnets 4. Images are always black and white 5. Samples are stained with heavy metals e.g. uranium or lead 6. Electrons can't pass through denser parts of an object, so they appear dark
  • What are the main features of a laser scanning confocal microscope?
    1. Uses florescent dyes and lasers 2. Moves a single spot of focused light across a specimen 3. The specimen has been treated with a florscent dye beforehand 4. When focused on the specimen it causes florscence 5. The emitted light is filtered through a pinhole aperture
  • What is florescence?
    The absorption and re-radiation of light
  • What is the magnification equation triangle?
    IAM
  • What are the main features of a light microscope?
    1. Cheap to purchase and operate 2. Low resolution and magnification 3. Uses light 4. Specimens can be either dead or alive 5. Focused by lenses 6. Natural colour can be observed 7. Portable 8. Preparation of materials are quick 9. Image formed on retina
  • What are the main features of an electron microscope?
    1. Expensive to purchase and operate 2. High resolution and magnification 3. Focused by magnets 4. Specimens are dead 5. All images are black and white 6. Operated in special rooms 7. Preparation of materials is lengthy 8. Image formed on computer
  • What are artefacts?
    Visible structural details caused by processing a specimen and is not one of the features of them.
  • Describe a eukaryotic cell structure
    Made up of multi-cellular organisms. Complicated internal structures containing a membrane-bound nucleus and cytoplasm
  • Describe a prokaryotic structure
    Single-celled organisms with a single internal area called the cytoplasm - composed of cystol which contains water and salts
  • What is the role of the nucleus?
    Responsible for containing all of the genetic information of the cell in the form of DNA and directs protein synthesis.
  • What is the role of the nuclear envelope?
    Protects the DNA from damage in the cytoplasm and contains nuclear pores
  • What is the role of the nuclear pores?
    Allows molecules to move into and out of the nucleus
  • What is the role of the nucleolus?
    Responsible for producing ribosomes. Composed of proteins and RNA, which are used to produce rRNA which combines with proteins to form ribosomes.
  • What is the role of the the mitochondria?
    The powerhouse of the cell and the site of ATP synthesis. Also the site of the final stages of cellular respiration. The number of mitochondria present in a cell is a direct reflection of how much energy it uses.
  • What is the role of the vesicles?
    Membrane sacs that have storage and transport roles. Consist of a single membrane with fluid enclosed.
  • What is the role of the lysosomes?
    Specialised forms of vesicles that contain hydrolytic enzymes which are responsible for breaking down the waste materials in cells. Plays an important role in the immune system
  • What is the role of the cytoskeleton?
    A network of fibres necessary for the shape and stability of a cell. Controls cell movement and the movement of organelles within cells.
  • What three components make up the cytoskeleton?
    1. Microfilaments 2. Microtubules 3. Intermediate fibres
  • What is the role of the microfilaments in the cytoskeleton?
    Formed from actin and is responsible for cell movement and cell contraction during cytokenesis
  • What is the role of microtubules in the cytoskeleton?
    Made of globular proteins and determines the strucutre of a cell. They also act as tracks for the movement of organelles, including vesicels around the cells.
  • What are spindle fibres composed of?
    Microtubules
  • What is the role of the intermediate fibres in the cytoskeleton?
    Provides mechanical strength and helps maintain integrity.
  • What is the role of the centrioles?
    Component of the cytoskeleton and is composed of microtubules. Two centrioles form the centrisome.
  • What is the role of the centrosome?
    Involved in the assembly and organisation of the spindle fibres during cell division.
  • What is the role of stationary cilia?
    Present on the surface of many cells and have an important role in sensory organs e.g. the nose
  • What is the role of mobile cilia?
    Beats in a rhythmic manner, creating a current and causing fluids to move.
  • What is the endoplasmic reticulum?
    A network of fibres enclosing flattened sacs called cisternae. It is connected to the outer membrane of the nucleus.
  • What is the role of the smooth ER?
    Responsible for lipid and carbohydrate synthesis and storage.
  • What is the role of the rough ER?
    Contains ribosomes bound to its surface and is responsible for the synthesis and transport of proteins.
  • What is the role of the ribosomes?
    Either free floating or attached to the rough ER and is the site of protein synthesis.
  • What is the role of the golgi apparatus?
    Formed of cisternae and modifies proteins and packages them into secretory vesicles or lysosomes if they are to stay in the cell.
  • What are the steps to protein production?
    1. DNA containing the instructions for proteins leaves the nucleus via the nuclear pores as mRNA. 2. Proteins produced on the ribosomes bind to the rough ER. 3. It passes into the cisternae of the rough ER and packaged into transport vesicles. 4. Moves towards the golgi apparatus via the transport function of the cytoskeleton (microtubules) 5. The vesicles fuse with the golgi apparatus and the proteins enter. They are structurally modified before leaving the gologi in packaged vesicles. 6. Secretory vesicles carry proteins to the cell surface membrane to fuse with it and release its contents by excocytosis. Some proteins are packagd into lysosomes which contains enzymes for use in the cell.
  • What are the differences between an animal and plant cell wall?
    Plant cells are rigid and have a cell wall surrounding the cell-surface membrane. The cell wall is made out of cellulose.
  • What are the properties of cellulose cell walls?
    1. They are freely permeable so substances can diffuse in and out. 2. Gives the plant its shape 3. The contents of the cell presses against the cell wall making it rigid (turgor pressure) 4. Acts as a defence mechanism as a barrier to pathogens
  • What is the role of the vacuoles?
    Membrane lined sacs in the cytoplasm containing cell sap and is important in the maintenance of turgor pressure.
  • What is the tonoplast?
    The membrane of a vacuole. It is selectively permeable.
  • What is the role of the chloroplasts?
    Responsible for photosynthesis
  • What is the structure of chlorplasts?
    They have a double-membrane structure, similar to mitochondria.
  • What is the stroma?
    The fluid enclosed in the chloroplast
  • What are thylakoids?
    Membranes which form flattened sacs
  • What is a granum?
    Several thylakoids stacked together. They are joined by membranes called lamellae.
  • How is strach produced by photosynthesis stored?
    As starch grains present in the chloroplast.
  • What are extremophiles?
    Cells adapted to living in extremes of salinity, pH and temperature. e.g. some forms of bacteria living in deep sea vents.
  • How does the flagella of a prokaryote differ from a eukaryote?
    Thinner, doesn't have the 9+2 arrangement and the energy to move it is supplied from chemisosmosis rather than ATP.
  • What form is DNA in a prokaryote?
    Circular
  • What form is DNA in a eukaryote?
    Linear
  • How is DNA organised in a prokaryote?
    Proteins fold and condense DNA.
  • How is DNA organised in a eukaryote?
    Associated with proteins called histones
  • What are prokaryote cell walls made out of?
    Peptidoglycan
  • What are eukaryote cell walls made out of?
    1. Fungi = Chitin 2. Plants = Cellulose
  • What size are ribsomes in prokaryotes?
    70s
  • What size are ribsomes in eukaryotes?
    80s
  • How do prokaryotes reproduce?
    Binary fission
  • How do eukaryotes reproduce?
    Assexual or sexual reproduction
  • How would you describe the cell type of a prokaryote?
    Unicellular
  • How would you describe the cell type of a eukaryote?
    Unicellular or multicellular