(3) Specialised plant cells

 

Root hair cells - are adapted to absorb water and minerals from soil and then through the root system to transport these minerals around the plant. Root hair cells are long and cover the surface of plant roots to create a large surface area to absorb water and minerals.

Xylem cells - are not living cells, but rod-like cells that form hollow tubes that can move water and dissolved minerals from the roots around the plant.

Phloem cells - phloem vessels (columns of living cells) move dissolved sugars, produced during photosynthesis, and other soluble food molecules from the leaves to growing tissues (e.g. the tips of roots and shoots) and storage tissues (e.g. in the roots).

Palisade leaf cells - their structure is adapted to support the sites of photosynthesis.

Their tall and thin shape allows lots of light to be absorbed and have a large surface area for absorbing carbon dioxide. Palisade cells contain lots of chloroplasts, subcellular structures that contain the chlorophyll needed for photosynthesis and the shape allows lots of them to be packed together on the top side of a leaf for maximum exposure to light - essential for photosynthesis.  See diagram below.

Guard leaf cells - can open and close the pores (stomata) in leaves and allow oxygen and carbon dioxide to pass in and out.  See diagram above.

---

For more details on plant cell evolutionary adaptations see

Transport and gas exchange in plants, transpiration, absorption of nutrients, leaf & root structure

and Photosynthesis, importance explained, limiting factors affecting rate, leaf adaptations

---

Key points

Based on the syllabus-specifications for students taking the AQA, Edexcel and OCR GCSE level biology examinations (~US grades 9-10).

Summary of ideas

Certainly! Specialised plant cells have adaptations that allow them to perform specific functions efficiently.

Below are detailed revision notes on key examples to study,  excluding meristem cells which are dealt with in section 7.

Specialised Plant Cells

These specialised cells play crucial roles in plant survival and are excellent examples to study.

Root Hair Cells

Function: Absorb water and minerals from the soil efficiently.

Adaptations:

• Long, thin extensions (root hairs) increase surface area for maximum absorption.

• Thin cell walls allow easy passage of water and minerals.

• Large vacuole speeds up osmosis by maintaining a low water potential inside the cell.

• Many mitochondria provide ATP for active transport of minerals.

Xylem Cells

Function: Transport water and minerals from the roots to the rest of the plant and provide structural support.

Adaptations:

• Hollow, dead cells (lumen) form long tubes for uninterrupted water flow.

• Thickened walls with lignin strengthen the vessel and prevent collapse.

• No cytoplasm or organelles reduces resistance to water movement.

• Pits in the cell walls allow water to move between vessels and to surrounding cells.

Phloem Cells

Function: Transport sugars (e.g., sucrose) and other nutrients throughout the plant via translocation.

Adaptations:

• Sieve tube elements (living cells) contain pores for easy transport of substances.

• Companion cells provide ATP for active transport via their many mitochondria.

• Few organelles in sieve tube elements allow efficient movement of sugars.

• Plasmodesmata (tiny channels) connect sieve tube elements and companion cells for communication.

Palisade Mesophyll Cells

Function: Carry out photosynthesis efficiently.

Adaptations:

• Packed with chloroplasts (contains chlorophyll) for maximum light absorption.

• Column-shaped and tightly packed to increase light capture.

• Thin cell walls allow rapid diffusion of gases (CO₂ and O₂).

• Large vacuole helps keep the cell turgid, ensuring optimal position for light capture.

Spongy Mesophyll Cells

Function: Allow gas exchange within leaves.

Adaptations:

• Loosely packed with air spaces to facilitate diffusion of gases.

• Contain some chloroplasts for photosynthesis, though fewer than palisade cells.

• Moist surfaces to allow gases to dissolve and diffuse efficiently.

Guard Cells

Function: Control the opening and closing of stomata, regulating gas exchange and water loss.

Adaptations:

• Uneven cell wall thickness (thicker inner wall, thinner outer wall) causes the cell to bend when turgid, opening the stomata.

• Respond to environmental changes (light, CO₂ levels) to optimise gas exchange.

• Contain chloroplasts to produce energy needed for active transport of ions.

• Can accumulate potassium ions to lower water potential and trigger water uptake by osmosis.

---

Summary of learning objectives and key words or phrases

Be able to describe the structure and function of specialised plant cells and their evolutionary adaptations.

They are all dealt with in more detail on the various pages on plant biology.

---

WHAT NEXT?

TOP OF PAGE

Index for biology notes on stem cells, cell differentiation and cell specialisation

INDEX of all my BIOLOGY NOTES

HOME PAGE of Doc Brown's Science website

UK KS3 Science Quizzes for KS3 science students aged ~11-14, ~US grades 6, 7 and 8

Biology * Chemistry * Physics UK GCSE level students aged ~14-16, ~US grades 9-10

Advanced Level Chemistry for pre-university age ~16-18 ~US grades 11-12, K12 Honors

Find your GCSE/IGCSE science course for more help links to all science revision notes

email doc brown - comments - query?

---

Doc Brown's school biology revision notes: GCSE biology, IGCSE  biology, O level biology,  ~US biology science grade 8, grade 9 and grade 10 school science courses or equivalent for ~14-16 year old students of biology IGCSE AQA GCSE Biology Edexcel GCSE Biology IGCSE OCR Gateway Science Biology OCR 21st Century Science Biology  Some of these biology revision notes might be suitable for UK KS3 Science-Biology courses for ages 12-14 (~US biology science grades 6, grade 7 and grade 8) Explaining the importance of function of specialised plant cells in GCSE level biology, What you need to know about function of specialised plant cells for GCSE level biology, Explaining the use of function of specialised plant cells knowledge in GCSE level biology, Examples of function of specialised plant cells explained when studying GCSE level biology, What is the significance of function of specialised plant cells in GCSE level biology, describing and explaining the theory of function of specialised plant cells when studying GCSE level biology, revision notes for function of specialised plant cells in exams, online help for understanding function of specialised plant cells, exam revision notes for function of specialised plant cells, what do I need to learn about function of specialised plant cells? revision summary for function of specialised plant cells, learning notes for function of specialised plant cells, help to pass the function of specialised plant cells topic in an exam question, how to prepare for questions on function of specialised plant cells in a GCSE biology examination? Based on the syllabus-specifications for students taking the IGCSE/GCSE level biology examinations summary revision notes and key points on function of specialised plant cells for students taking the AQA igcse/gcse biology notes on function of specialised plant cells, Edexcel gcse biology notes on function of specialised plant cells,  OCR 21st century GCSE biology notes on function of specialised plant cells, OCR gateway GCSE biology notes on function of specialised plant cells, WJEC gcse biology notes on function of specialised plant cells, CCEA gcse biology notes on function of specialised plant cells for students taking CIE Cambridge igcse biology, or any other GCSE or IGCSE level biology exams notes on function of specialised plant cells, useful for US grade 9-10 biology courses

---

SITEMAP Website content © Dr Phil Brown 2000+. All copyrights reserved on Doc Brown's biology revision notes, images, quizzes, worksheets etc. Copying of website material is NOT permitted. Exam revision summaries and references to science course specifications are unofficial.