1Specialised cells
In a multicellular organism, cells have different jobs. A specialised cell has a shape and parts that suit its job.
multicellularspecialised cell
Lesson 1.5 notes
From cells to organisms
See how specialised cells make up tissues, organs, organ systems and whole organisms.
2Animal cells for the job
A red blood cell has no nucleus, leaving more room to carry oxygen. A nerve cell is long, to carry electrical messages. Ciliated cells have tiny hairs that sweep mucus along.
3More special cells
A sperm cell has a tail to swim and lots of mitochondria for energy. A root hair cell's long hair gives a big surface to absorb water. Leaf cells are packed with chloroplasts.
4Cells make tissues
A tissue is a group of similar cells working together to do one job. Muscle cells join to make muscle tissue, which contracts.
tissue
5Tissues make organs
An organ is several tissues working together. The stomach has muscle tissue to churn food, gland tissue to make digestive juices, and lining tissue covering it inside and out.
organ
6Organs make systems
An organ system is a group of organs working together. In the digestive system, the mouth, gullet, stomach and intestines break food down and pass it into the blood.
organ systemdigestive system
7Systems make an organism
Organ systems work together to make an organism. Your digestive, circulatory and gas exchange systems all depend on each other. Plants have organs too: roots, stems and leaves.
organism
Explore: Zoom lab
Zoom from a whole person or plant down to a single cell, through an organ system, an organ and a tissue.
Common mistake: An organ is made of several different tissues
A tissue is a group of similar cells doing one job. An organ, like the stomach or the heart, is several different tissues working together.
Remember
- Multicellular organisms are organised: cells, then tissues, organs, organ systems and the whole organism.
- A tissue is a group of similar cells. An organ is several tissues working together. An organ system is several organs working together.
- Specialised cells have shapes and parts that suit their jobs, like a nerve cell's long fibre or a root hair cell's hair.
Going further at GCSE
GCSE: Cells, tissues and organs → GCSE: Specialised cells → GCSE: The digestive system →