Plant cell specialisation + Microscopes Flashcards by A A

State some specialised cells in plants

root hair cells, xylem and phloem cells in plants.

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State the function of the root hair

The function of the root hair cell is to absorb water and mineral ions from the soil

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State the adaptations of the root hair cells

the root hair
Do not contain chloroplasts
Large permanent vacuole
Many mitochondria

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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.

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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)

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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

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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.

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Where are xylem found in a plant

Xylem are found in the plant’s stem.

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What do the xylem cells form

The xylem cells form long tubes.

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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

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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.

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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.

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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.

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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

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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

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State the two types of cell phloem consists of

Phloem vessel cell
Companion cell

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State the adaptation of the phloem cell

cell walls break down to form sieve plates
Phloem cells have companion cells

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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

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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