Plants, Tissues + Microscopy Flashcards
(24 cards)
What are the benefits of an electron microscope to a light microscope?
- can be used to study cells in finer detail
- enable scientists to see and understand many more sub cellular structures
What is the function of a leaf?
- site of photosynthesis
What are the layers of a leaf?
Upper epidermis
Palisade mesophyll
Spoungy mesophyll
Lower epidermis
What is the purpose of the stomata and how is it adapted?
- where CO2 diffuses into leaf
- have guard cells to control opening and closing of the stomata to maximise CO2 absorption while minimising water loss
- guard cells sensitive to light so close at night
What happens to the guard cells when there is a high concentration of water in the leaf?
- guard cells become turgid (cell vacuole fills up) which causes stomata to remain open to maximise CO2 absorption, opposite when not enough water
What is meristem tissue? And where is it in a plant?
Plant stem cells , grows at tips of roots and shoots
How is a lead adapted to prevent water loss?
- waxy cuticle (thin waterproof lipid layer prevents water escaping)
- guard cells
What is the purpose of the palisade mesophyll and how is it adapted?
- site of photosynthesis
- lots of chloroplasts in palisade cells
How is the upper epidermis adapted for its function?
- needs to let in sunlight for photosynthesis so is almost transparent
What is the purpose of xylem and how is it adapted for its purpose?
- xylem tissues transport water and mineral ions from the roots to the stems and leaves
- composed of hollow tubes strengthened by lignin
What is the purpose of phloem cells and how is it adapted?
- transport dissolved sugars from the leaves to rest of plant (for immediate use or storage)
- made of tubes of elongated cells (has pores in cell walls for cell sap to travel through)
How is spoungy mesophyll adapted for its function?
- has lots of space so gases can diffuse / move around leaf to the palisade layer
What is a eukaryotic cell?
- animal or plant cell (multicellular organism
What occurs in mitochondria?
- reactions for aerobic respiration
What subcellular structures do plant cells have which animal cells dont?
- cell wall made of cellulose
- permanent vacuole
- chloroplasts
What is the purpose of ribosomes?
Where proteins are made (site of protein synthesis)
What is a small ring of DNA called?
Plasmid
What are the steps of using a light microscope?
- clip the slide onto the stage
- select the lowest magnification lens
- use the coarse adjustment knob on the side to move the stage up to just below the objective lens
- look down the eyepiece and lower the stage downwards until the image is less blurry
- adjust the focus using the ‘fine adjustment knob’ until there is a clear image
What are the two adjustment knobs called and what do they do?
- coarse adjustment knob (moves the stage)
- fine adjustment knob (increases the focus)
What are the steps of preparing an onion cell for viewing under a microscope?
- add a drop of water to the middle of a clean slide
- cut up an onion and separate it out into layers
- using tweezers, peel off some of the epidermal tissue form the bottom of one of the layers
- using tweezers place the epidermal tissue into the water on the slide
- add a drop of iodine solution
- place a clover slip on top
What is the purpose of xylem and what is the purpose of phloem?
To transport water (xylem)
To transport food (phloem)
What is trasnpiration?
The loss of water from a plant
What is translocation?
Transporting food substances in both directions (through phloem)
What apparatus is used to estimate transpiration rates? How do you conduct the experiment? And why does it work?
- Potometer
- setting up the apparatus as given in a diagram, set a stopwatch and record the distance moved by the bubble to the right per unit time.
- works because you can assume water uptake by the plant is directly related to water loss by the leaves (transpiration)
