Building blocks of life Lesson 2: year 7 life processes

Living things are made up of tiny building blocks called cells. Each cell respires, takes in food, gets rid of wastes, grows, reproduces and dies. A living thing can be just one cell or millions of cells. Big living things don’t have bigger cells they just have more cells.

Amazingly, the human body has more than 10,000,000,000,000 (that’s 10 million million) cells! Think about the size of your little toe. It has about 2 or 3 thousand million cells! That’s a lot of cells to make one toe, so cells must be very, very, very small. How do we know about cells if they are so small?

Every living thing – from an elephant to an ant, from a tree to a daisy, from your left toe to right earlobe – is made of cells. Microscopes allow us to magnify cells revealing their shape and structure. This is a typical animal cell. Do animal and plant cells look the same?

TEACHER’S NOTES Click on the forward button to reveal a diagram of a typical animal cell. Move the cursor over the labels beneath the cell diagram to reveal descriptions of the parts of the cell.

TEACHER’S NOTES Click on the forward button to reveal a diagram of a typical plant cell. Move the cursor over the labels beneath the cell diagram to reveal descriptions of the parts of the cell.

Compare a typical animal cell and a typical plant cell. TEACHER’S NOTES - get students to draw up table listing all possible parts of cell and tick/cross in column for animal cell and plant cell. - lead into consideration of why do plant cells and animal cells have different structures? Which parts of a plant cell are the same as an animal cell? Which parts of a plant cell are not found in an animal cell?

What could you do if you were one cell? Not much! You’d be a blob, with lots of pieces floating around inside of you! Keeping you alive is a big job. So your body is made of millions of cells that have to be very organised. Your body has organs that each carry out specific jobs to keep you alive. How many organs can you name?

Identify the organs labelled in the diagram. brain eye ear tongue heart skin lung stomach intestines muscle

Similar cells that do the same job work together to make tissue. Muscle cells make muscle tissue. What type of cells are nerve tissue and blood tissue made from? muscle tissue Cells are the building blocks of all living organisms.   Different cells do different jobs. How do the millions of cells in your body work together? muscle cell Different tissues work together to make an organ.   Muscle tissue, nerve tissue and blood tissue make up the stomach. Organs work together to make an organ system. What organ system is the stomach part of? stomach TEACHER’S NOTES mention other types of blood cells and tissues formed e.g. nerve

Name a cell that would be suitable for each job. TEACHER’S NOTES Answers: Job No1 – Nerve cell Job No2 – Egg cell Job No3 – Palisade cell Job No4 – Root hair cell Job No5 – Red blood cell