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B1: Cells - Coggle Diagram

- - - - Osmosis required practical
        
        Method:
        
        Cut cylinders of potato with a cork borer,
        
        Measure them to 3 cm in length with a ruler and cut.
        
        Record the mass of each one on the balance and record it.
        
        Place one cylinder in a test tube with either 10ml of distilled water, one cylinder in 10ml of 1M solution and another in 10ml of 2M solution start the stopwatch.
        
        Time for 30mins
        
        Record the mass again using the balance.
  - - - Factors that affect the rate of diffusion
        
        the difference in concentration (concentration gradient)
        
        surface area of the membrane
        
        temperature
      - Exchange surfaces
        
        Gills: gill filaments and lamella – increase surface area, Good blood supply – to maintain concentration gradient, Thin membranes – short diffusion distance.
        
        Roots: Root hair cells - increase surface area.
        
        Lungs: Alveoli– increase surface area, Good blood supply – to maintain concentration gradient, Thin membranes – short diffusion distance.
        
        Leaves: Large surface area, thin leaves for short diffusion path, stomata on the lower surface to let O2 and CO2 in and out.
        
        Small intestines: Villi – increase surface area, Good blood supply – to maintain concentration gradient, Thin membranes – short diffusion distance.
  - - - This requires energy; gained from respiration in the form of adenosine triphosphate (ATP)
    - - Lumen of the small intestine: transport sugars in, have many mitochondria
      - Root hair cell: bring in mineral ions, have many mitochondria
  - - - SA:V = SA/V :1
- - - - x10^-6
  - - - x10^-9
  - - - x10^-3
  - - - x10^-2
- - - - Cytoplasm
        
        Most chemical reactions occur here, typically controlled by enzymes.
      - Cell Membrane
        
        Controls the movement of substances in and out of the cell; a semipermeable membrane
      - Nucleus
        
        Contains genetic material; including DNA, which controls what happened within the cell
      - Mitocondria
        
        Contains the enzymes for respiration, and where most energy is released in respiration. (aerobic respiration)
      - Ribosome
        
        Where protein synthesis occurs.
    - - Sperm cell
        
        Function: Join with a ovum (egg cell) in a process called fertilisation.
        
        Adaptations
        
        A flagellum (tail) allowing them to swim to the ovum.
        
        Large number of mitochondria to provide the energy needed for swimming.
        
        Enzymes which allow them to digest their way through the outer layer of the ovum.
      - Muscle Cell
        
        Function: contract (get shorter) to allow movement
        
        Adaptations
        
        Many mitochondria to provide energy for muscle contrations
        
        Long tissues
      - Nerve Cell
        
        Function: to send electrical impulses around the body
        
        axon carries the electrical impulses
        
        Adaptations
        
        Myelin sheath around the axon insulating it, speeding up the transmission of nerve impulses; insulating sheath
        
        Synapses on each end of the cell allowing impulses to pass from one nerve cell to another; long branching connections
        
        Dendrites increase the surface area so nerve cells can connect easier
      - Specialised: adaptation which help them carry out their function
  - - - Cell membrane
        
        Controls the movement of substances in and out of the cell; a semipermeable membrane
      - Cell Wall
        
        Strengthens the cell giving it structure - made from cellulose in plant cells. Keep their regular shape
      - Cytoplasm
        
        Most chemical reaction occur here, typically controlled by enzymes
      - Chloroplasts
        
        Contain chlorophyll, absorbs light energy for photosynthesis
      - Ribsomes
        
        Where protein synthesis occurs
      - Mitochondria
        
        Contains the enzymes for respiration, and where most energy is released in respiration. (aerobic respiration)
      - Vacuole
        
        Filled with cell sap (water and other chemicals) to help keep the cell turgid (keep its shape).
      - Nucleus
        
        Contains genetic material, which controls what happened within the cell
    - - Root Hair Cell
        
        Function: Increase surface are of roots so water and dissolved mineral ions can be absorbed more effectively
        
        Adaptations
        
        Do not have chlorophyll as they are underground
        
        hair like projections to increase the surface area
      - Xylem
        
        Found in plant cell and form long tubes
        
        Function: carry water and dissolved mineral ions from the roots to the leaves; TRANSPIRATION
        
        Adaptations
        
        Have thick walls containing lignin, supporting the plant
        
        As they are sealed with lignin the xylem is dead
        
        End walls between cells have broken down: this allows the cells to form a long tube so water and dissolved minerals can flow easily
        
        Have no internal structures (e.g cytoplasm nucleus vacuole chloroplasts) meaning water can flow more easily
        
        Flow in one direction
      - Phloem
        
        Function: Carry dissolved glucose up and down the plant
        
        Adaptations
        
        Consist of two types of cell
        
        Phloem vessel cells have no nucleus and limited cytoplasm
        
        End walls have pores called sieve plates allowing dissolved sugars to move through the cell interior.
        
        Have companion cells connected by pores, mitochondria provide energy to the phloem vessel cells
      - To become specialised - differentiation
  - - - Can be cloned and made to differentiate into most cell types
      - Moral and Ethical issues in using them
    - - Can form many types of human cells e.g. blood cells
      - Found in bone marrow
    - - Found in roots and buds
      - Can differentiate into any plant cell type
        throughout the life of the pant.
      - Can be used to produce clone of a plant
- - - - Disadvantages:
        
        Limited resolution (200nm)
        
        Limited magnification (x1500)
      - Advantages:
        
        Cheap
        
        Portable
        
        Can look at live cells
        
        Colour
      - Uses light
    - - Advantages:
        
        Greater magnification (x2,000,000)
        
        Greater resolution (0.5nm)
      - Disadvantages:
        
        Large
        
        Expensive
        
        Examine specimen within a vacuum - specimen has to be dead or dried in water
        
        Requires specialised knowledge to operate
        
        Black and white
      - Uses Electron Beams
  - - - Stage: Flat part upon which the specimen is placed.
      - Eyepiece lens: Look through this lens to see the specimen.
      - Mirror: This reflects light up through the specimen, both lenses then into your eye.
      - Course focus: Moves the stage up and down to focus on the specimen.
      - Fine focus: Used to focus on the specimen to show finer detail.
      - Objective lens: set of lenses used to magnify the specimen. Usually there are three.
    - - Place on slide using forceps.
        
        Add a drop of iodine using a pipette.
        
        Lower the coverslip on to the slide using the forceps or mounted needle. (to avoid the formation of air bubbles).
        
        Blot excess stain with filter paper.
        
        Secure to the stage of the microscope using the clips.
        
        Start on the lowest objective lense, focus using the focussing wheels.
        
        1 more item...
- - - - DNA Loop
        
        controls the function of the cell
        
        Plasmid
        
        Contains additional genes
        
        Small loops of DNA
        
        Flagellum
        
        Used for movement
        
        Cell Wall
- - - - Most types of animal cells differentiate at an early stage. In mature animals, cell division only really happens to replace and repair damaged cells.
        
        In mature animals, cell division is mainly restricted to repair and replacement. As a cell differentiates it acquires different sub-cellular structures to enable it to carry out a certain function. It has become a specialised cell.
      - Plant cells keep the ability to differentiate throughout the life of the plant.
    - - Within the nucleus there are chromosomes made from DNA
        
        Body cells contain two of each type of chromosomes
        
        Human cells contain 23 pairs of chromosomes
        
        Chromosomes contain many genes which are sections of DNA that determines many characteristics
      - The cell cycle
        
        Before the cell divides- DNA replicates, cell grows bigger, more organelles such as ribosomes & mitochondria are made.
        
        Mitosis- one copy of each chromosome moves to opposite sides of the cell
        
        Division- cytoplasm and cell membrane divide and the cell becomes two identical daughter cells.
      - When Mitosis Occurs
        
        growth, repair, replacement of cells.
        
        Asexual reproduction