In what way do plant cells differ from animal cells? 

What features do animal cells and plant cells have in common?

Plants (eukaryotic organisms) are multicellular organisms; some of their cells contain chloroplasts which carry out photosynthesis; plant cells have cellulose cell walls; plants can store carbohydrates as starch or sucrose. Common examples include flowering plants, grain cereals like maize and a herbaceous legumes like peas or beans.

Plant cells are much larger than bacterial cells, with important differences from animal cells.

The diagram shows the principal subcellular structures of a plant cell.

Like animal cells, plant and algal cells have:

(1) a cell membrane, (2) mitochondria, (3) cytoplasm, (4) nucleus and (5) ribosomes,

All of which perform the same functions as in animal cells. 

All (1) to (5) are described in part 3 animal cells and a summary on this page in the key points section.

The three extra principal different sub-cellular structures that plant cells have, and animal cells do not are:

(i) a rigid cell wall

(ii) chloroplasts

(iii) a large permanent vacuole - animal cells do NOT have these three features, but some have small vacuoles.

You need to be able to describe the function of the components of a plant cell including chloroplast, large vacuole, cell wall, cell membrane, mitochondria, cytoplasm and nucleus (see diagram and notes below) and know the differences between plant and animal cells.

(i) Plant and algal cells have a more rigid cell wall made of cellulose, which strengthens the cell, supports it and therefore the plant's structure as a whole.

The plant cell wall is effectively an additional layer outside of the cell's inner membrane.

It is made from cellulose fibres that provide strength to the cell and collectively the strength of a whole multicellular plant.

Unlike the cell membrane, the cell wall does not control what materials can enter or leave the cell.

(ii) Chloroplasts the sites of photosynthesis

Chloroplasts (an organelle) has a complex internal membrane structure.

Chloroplasts can absorb light energy to make food via chlorophyll in photosynthesis

The chloroplasts contain green chlorophyll molecules which are involved in the energy absorbing process of photosynthesis. The chlorophyll molecules absorb the light energy from the sun to promote the endothermic reaction below. The chloroplasts must also contain all the enzymes to catalyse the whole series of complex reactions to make sugars - the equation below is a greatly simplified summary!

sunlight energy + carbon dioxide + water ==> sugars (e.g. glucose) + oxygen

6H₂O_(l) + 6CO_2(g) ====> C₆H₁₂O_6(aq) + 6O_2(g)

Therefore chloroplasts are the site of food production for the plant. The sugars may be used directly as a source of energy or converted to starch grains - the plant's food store (and part of our food store as well!).

Chlorophyll absorbs mainly in the violet-blue and orange-red regions of the visible spectrum, hence it appears green, the light NOT absorbed.

(iii) Large permanent vacuole

Most plant cells have a single large permanent vacuole surrounded by a membrane containing cell sap, a dilute solution of mineral salts and sugars. It maintains the internal pressure to support the cell.

The central vacuole is a cellular organelle found in plant cells. It is often the largest organelle in the plant cell.

The central vacuole's membrane's functions is to hold useful materials and wastes.

It also functions to maintain the proper internal pressure within the plant cells to provide structure and support for the growing plant.
 

Other features

Starch grains

Stored food for respiration and from the glucose made by photosynthesis.

Key points - Summary of ideas

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

Revision Notes: Structure and Function of Plant Cells and Algae Cells

Both plant cells and algae cells share structural similarities as they belong to the kingdom Plantae and Protista, respectively.

While algae cells can be unicellular or multicellular, they often resemble plant cells in terms of their organelles and functions.

Structure of Plant Cells

Plant cells are eukaryotic cells with a rigid structure and specialized organelles. Below are key components of plant cells and their functions:

Structure of Algae Cells

Algae cells have similar components to plant cells but may vary depending on their type (unicellular or multicellular).

Key features include:

Key Differences Between Plant and Algae Cells

1. Cell Wall Composition – Plant cell walls are always made of cellulose, while algae cell walls vary (cellulose, silica, glycoproteins).

2. Unicellular vs. Multicellular – Plants are multicellular organisms, while algae can be unicellular (e.g., Chlamydomonas) or multicellular (e.g., seaweed).

3. Locomotion – Some algae have flagella for movement, which plant cells lack.

4. Pyrenoid Presence – Found in some algae chloroplasts, aiding in carbon fixation, but absent in plant cells.

• Learn the functions of each organelle in detail and understand their importance.

• Know the similarities and differences between plant and algae cells.

• Practice drawing and labelling diagrams of both types of cells.

• Familiarize yourself with key terminology and definitions.

• Understand how algae adapt to their environment compared to terrestrial plants.

Summary of learning objectives and key words or phrases for the characteristics of plant cells

Know the typical characteristics of plant cells and the structure and function of their organelles and cell features including chloroplasts, the rigid cell wall large permanent vacuole cell membrane mitochondria cytoplasm nucleus ribosomes vesicle starch granules.

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Index of biology notes on cell structure

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