Plant cell specialisation + Microscopes Flashcards
State some specialised cells in plants
root hair cells, xylem and phloem cells in plants.
State the function of the root hair
The function of the root hair cell is to absorb water and mineral ions from the soil
State the adaptations of the root hair cells
the root hair
Do not contain chloroplasts
Large permanent vacuole
Many mitochondria
Explain how the root hair helps the root hair cell to carry out its function
The root hair increases the surface area available for water to move into the cell by osmosis.
Explain how having no chloroplasts helps the root hair cell to carry out its function
Root hair cells do not contain chloroplasts, because they are underground (photosynthesis requires light)
they are underground
cannot absorb light
cannot photosynthesise (As photosunthesis requires light)
Explain how having a large permanent vacuole helps the root hair cell to carry out its function
Root hair cells have a permanent vacuole that speeds up the movement of water by osmosis from the soil across the root hair cell
Explain how having many mitochondria helps the root hair cell to carry out its function
Root hair cells have many mitochondria that transfer the energy needed for the active transport of mineral ions into the root hair cells.
Where are xylem found in a plant
Xylem are found in the plant’s stem.
What do the xylem cells form
The xylem cells form long tubes.
State the function of the xylem
Xylem is a transport tissue in plants that carries water and dissolved minerals from the roots to the leaves
xylem form long tubes which carries water and dissolved minerals from the roots to the leaves
State the adaptations of xylem cells
Thick walls containing lignin
The end walls between the cells have broken down.
The cells are dead, without any sub-cellular structures.
Explain how having very thick walls containing lignin helps the xylem cells to carry out its function
How do xylem cells die
Xylem cells have very thick walls containing lignin. This provides support to the plant
Because the cell walls are sealed with lignin, this causes the xylem cells to die.
Explains how the end walls between the cells have broken down helps the xylem cell to carry out its function
The end walls between the cells have broken down. This means that the cells now form a long, hollow tube so water and dissolved minerals can flow easily.
Explain how having no sub-cellular structures helps the xylem cell to carry out its function
Xylem cells have got no nucleus, cytoplasm, vacuole or chloroplasts. That makes it easier for water and minerals to flow
State the function of the phloem cell
The function of the phloem is to carry dissolved sugars from the leaves around the plant
carry dissolved sugars up and down the plant
State the two types of cell phloem consists of
Phloem vessel cell
Companion cell
State the adaptation of the phloem cell
cell walls break down to form sieve plates
Phloem cells have companion cells
Explain how the cell walls break down to form sieve plates helps the phloem cell to carry out its function
Phloem vessel cells have no nucleus and only limited cytoplasm
The end walls of the phloem vessel cells have pores called sieve plates. These features allow dissolved sugars to move through the cell interior
Explain how companion cells help the phloem cells to carry out its function
Each phloem vessel cell has a companion cell connected by pores. Mitochondria in the companion cell provide energy to the phloem vessel cell
Label the root hair cell
https://bam.files.bbci.co.uk/bam/live/content/zxqfcdm/small
https://cdn.savemyexams.co.uk/cdn-cgi/image/w=640,f=auto/uploads/2020/01/Root-Hair-Cell.png
Label xylem
https://www.youtube.com/watch?v=yVd9Z3av1Ew&list=PL9IouNCPbCxVU74eQtCcqbaQdYmwzAnlC&index=7
https://cdn.savemyexams.co.uk/cdn-cgi/image/w=640,f=auto/uploads/2020/01/Xylem-Structure.png
Label phloem cell
https://www.youtube.com/watch?v=yVd9Z3av1Ew&list=PL9IouNCPbCxVU74eQtCcqbaQdYmwzAnlC&index=7
https://cdn.savemyexams.co.uk/cdn-cgi/image/w=640,f=auto/uploads/2020/06/1.1.3-Phloem-cells.png
+ sieve plates
https://ds-content.doublestruck.eu/AG_BLG/Q14SIP108_files_Q/img01.png
what is tissue A
Xylem
https://bam.files.bbci.co.uk/bam/live/content/ztmn8mn/large
xylem makes an x
phloem on the outside
State the parts of a light microscope
Stage
Stage clips
Light
Objective lens
Eyepiece
Coarse adjustment knob
Fine adjustment knob
State the function of the stage
The stage is where we place the microscope slide
State the function of the stage clips
The stage has clips to hold the slide in place
State the function of the light
Light from the lamp passes up through the microscope slide
Label the parts of the microscope
https://www.microscopeworld.com/Images/label-microscope.jpg
https://www.microscopeworld.com/Images/label-microscope-answers.jpg
How many objective lenses do microscopes have
What are their magnifications
Most microscopes have three different objective lenses.
These usually have a magnification of x4, x10 or x40
State the function of the eyepiece
Eyepiece - This is where we look through to see the specimen
What does the eyepiece contain
What is the magnification of it.
The eyepiece contains the eyepiece lens which has a magnification of x10.
State the function of the course and fine adjustment knobs
To focus the (image/cells)
Describe how to use a light microscope to look at a prepared slide
To use a light microscope
Place the slide onto the stage. Use the clips to hold the slide in place.
Select the lowest-powered objective lens.
Use the coarse adjustment knob to move the stage up to just below the objective lens.-without looking down the eyepiece- (It is important to look at the microscope from the side while the position of the stage is being adjusted) -so that we do not damage the slide
Look down the eyepiece and use the coarse adjustment knob to move the stage downwards until the image is roughly in focus.
Adjust the focus with the fine adjustment knob, until a clear image of the cells is visible.
To see the cells with greater magnification, swap to a higher-powered objective lens and refocus
A magnification scale must be included.- in the drawing
How to calculate the total magnification (using a light microscope)
To calculate the total magnification.
Multiply the magnification of the eyepiece lens by the magnification of the objective lens.
Calculate the total magnification that a student viewed a specimen.
The eyepiece lens is x10
The low-powered objective lens is x4
Total magnification =
10 x 4 = x40
Describe how to prepare a slide
If you want to look at a speciment (plant or animal cells) under a light microscope, you need to put it on a microscope slide first.
A slide is a strip of clear glass or plastic onto which the speciment is mounted
To prepare a slide
Add a drop of water to the middle of a clean slide
(Cut up an onion and seperate it out into layers - a thin layer to help see individual cells. Use tweezers to peel off some epidermal tissue from the bottom of one of the layers)
Using the tweezers, place the epidermal tissue into the water on the slide
Add a drop of iodine solution/stain. Iodine solution is a stain
Stains are used to highlight parts of a cell by adding colour to them.
Place a cover slip (a square of thin, transparent plastic or glass) on top by standing it upright on the slide, next to the water droplet, then carefully tilting and lowering it so it covers the specimen without trapping any air bubbles
(air bubbles obstruct the view of the specimen)
What are stains used for
Stains are used to highlight objects in a cell by adding colour to them
Name two pieces of laboratory equipment the student could have used to prepare
cells to view using a microscope.
microscope slide
* cover slip
* dye / stain
* pipette / dropper
tweezers
State some hazards to preparing a slide
Iodine solution is an irritant
Sharp knife
State the risk of the hazard of iodine solution and the plan to minimise risk - when preparing the slide
Risk:
May cause an allergic reaction or a skin rash
Plan to minimise risk:
Wash skin immediately (after contact)
Wear gloves
Clean up spils
State the risk of the hazard of using a sharp knife when preparing the slide and the plan to minimise the risk
Risk:
The knife may cut you, someone/skin
Plan to minimise risk:
Cut away from the body
Cut on a chopping board
Keep fingers away from blade when cutting
Carry knife safely
Why is a thin layer of onion epidermis used - for preparing to look at onions on a microscope
To help see individual cells
(or so light can penetrate)
Why is iodine solution added to the onion epidermis
To stain/see the parts of the cell
Why is the cover slip lowered onto the onion epidermis at an angle
Prevent/reduce air bubbles
State the rules of drawing cells
Include magnification/scale
Use continuous lines/ ensure no gaps in lines
Do not draw overlapping cells
Draw cell walls
Do not shade
Draw all cells present
Draw correct cell shapes
Do not have gaps between cells
Draw nuclei in correct location
Label cell parts
Give two ways onion cells would look different when seen using an electron microscope
The cells would look more magnified/bigger
_____________
Cell would have more detail
Cell would be at a higher resolution
More sub-cellular structures would be seen
