Plant Cell Structure

Laura Armstrong & Joe Wolfensohn

Teachers

Laura Armstrong Joe Wolfensohn

Recall Questions

This topic requires prior knowledge of animal cell structure and the concept of eukaryotic cell organisation. You can test your knowledge on these below.

What is the function of the mitochondria?

Produces ATP (energy carrier) via aerobic respiration.

What is the function of the golgi body?

Processes and packages proteins and lipids.

What is the nuclear envelope?

Double membrane surrounding the nucleus, with nuclear pores. Made of phospholipid bilayers.

Topic Explainer Videos

Check out this @JoeDoesBiology video that explains plant cell structure or read the full notes below. Once you've gone through the whole note, try out the practice questions!

Plant Cell Organelles & Their Functions

 

Cell Wall

  • Made of cellulose, provides strength and support.
  • Prevents the cell from bursting due to osmotic pressure (also known as turgor pressure).
  • Fully permeable to water and solutes.

Chloroplasts

  • Site of photosynthesis.
  • Contains chlorophyll, which absorbs light for photosynthesis.
  • Chloroplast envelope - a double membrane made up of phospholipid bilayers.
  • Thylakoids - Disc like structures that stack into grana. These discs are surrounded by the thylakoid membranes which have a large surface area. Stage one of photosynthesis - the light dependent reaction - occurs here.
  • Stroma - This is the fluid filled centre of the chloroplast. It contains the chloroplasts own circular DNA, ribosomes (the smaller 70S size) and starch grains for storage of glucose. Stage two of photosynthesis - the light independent reaction - occurs here.

Large, Permanent Vacuole

  • Large central vacuole surrounded by a membrane (tonoplast).
  • Contains cell sap (water, enzymes, nutrients, and waste products).
  • Provides turgor pressure, maintaining the cell shape.

Plasma Membrane (Cell surface membrane)

  • Composed of a phospholipid bilayer with embedded proteins.
  • Function: Partially permeable - controls the movement of substances in and out of the cell via diffusion, osmosis, active transport, and facilitated diffusion.

Cytoplasm

  • Site of many metabolic reactions.
  • Contains enzymes and nutrients.

Mitochondria

  • Have a double membrane; the inner membrane is folded into cristae to increase the surface area for ATP production.
  • The matrix contains enzymes for aerobic respiration.
  • Mitochondria have their own circular DNA and their own 70s ribosomes.
  • Function: Produces ATP (energy carrier) via aerobic respiration.

Ribosomes

  • Small organelles composed of RNA and protein, found either free-floating in the cytoplasm or attached to the rough endoplasmic reticulum (RER).
  • Function: Site of protein synthesis.

Endoplasmic Reticulum (ER)

Rough ER:

  • A 3D system of sheet-like membranes spreading through the cell.
  • The membranes form a series of flattened sacs called cisternae.
  • The Rough ER has ribosomes attached to its surface.
  • The RER provides a large surface area to synthesise proteins.
  • It also transports proteins and packages them into vesicles before they move to the golgi body.

Smooth ER

  • A 3D system of sheet-like membranes spreading through the cell.
  • The membranes form a series of flattened sacs called cisternae.
  • Similar to the RER but with no ribosomes attached.
  • The SER synthesises, stores and transports lipids and carbohydrates.

Golgi Apparatus

  • A series of flattened sacs (similar to the endoplasmic reticulum but more compact) that modify, sort, and package proteins and lipids into vesicles for secretion.
  • Function: Modifies and processes proteins and lipids.

Plasmodesmata

  • Cytoplasmic channels connecting plant cells, allowing exchange of substances.

Key Terms

  • Cellulose: Structural carbohydrate forming the cell wall.
  • Chloroplast: Organelles for photosynthesis.
  • Plasmodesmata: Channels between plant cells.
  • Turgor Pressure: Pressure exerted by the vacuole against the cell wall.
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Exam Tip

AQA exams often ask how structure relates to function. Be prepared to explain why cell walls are strong or how chloroplasts are adapted for photosynthesis.

No answer provided.

Identify structures found in plant cells that are not present in animal cells and describe the function. (3 marks)

Cell wall: Provides structural support and maintains the shape of the cell; made of cellulose, it prevents the cell from bursting when water enters by osmosis.

Chloroplasts: Site of photosynthesis; contain chlorophyll, which absorbs light energy for the production of glucose.

(Large) permanent vacuole: Stores nutrients, waste products, and water; helps maintain turgor pressure.

Practice Question

Try to answer the practice question from the TikTok on your own, then watch the video to see how well you did!