IBDP Biology: Plant Cell Structure

Plant Cell Structure

February 20, 2022

In this topic of IBDP Biology, we will learn about Plant Cell Structure.

Plant Cell Structure

When it comes to IBDP Biology, plant cells are eukaryotic.
- As are animals, fungi and protoctists.
They contain a nucleus and other membrane bound organelles:
- Mitochondria, ER, generally one Golgi.
However, there are fundamental differences between plant cells and animal cells.

Structure in plant cells not animal cells

Cell wall
- Thick layer outside the cell membrane to give strength and rigidity.
- Major component is cellulose.
- When it comes to IBDP Biology, cell wall allows movement of water through and along it.
- Have channels called plasmodesmata which connect the cytoplasms of adjacent cells.
- Primary cell wall – made of cellulose;
- Secondary cell wall – produced in some plant cells when fully developed, eg xylem.
  - Contains cellulose and can contain lignin which makes it impermeable

Chloroplast
- Site of photosynthesis, only found in plants and algae.
- 5 to 10 micrometers long.
- Double membrane – chloroplast envelope.
- Thylakoids
  - Membranous discs
  - Photosynthetic pigments are embedded in the membrane.
  - Stacked into grana
  - These are linked by intergranal lamellae.
- Fluid filled matrix is called stroma.
  - This also contains starch grains, ribosomes, and circular DNA.

Vacuoles
- Membrane–bound sacs = tonoplast
- Contain cell sap:
  - Sugars, amino acids, pigments, mineral salts.
  - Aqueous solution
- Stores food.
- Help keep cell rigid and turgid.

Specialised plant cells

Water uptake – root hair cells:
- Form the piliferous laer around the root.
- Long cytoplasmic processes called root hairs.
- Increase the surface area for water transport.

This is the end of this topic