Year 7 & 8 TOC

Building Blocks

Cells

Distinguishing plant cells from animal and fungal cells

Scientists have identified cells as the basic building blocks of life. You would have read on the previous page that animals, plants & fungi are all eukaryotic and mostly (except for fungi) multicellular organisms. Multicellular means, they an organism is made up of many different types of cells. However, while they are similar in some aspects, they are very different on a cellular level!

Animals

Cells are microscope. You can’t see or hold them, but if we enlarged an animal cell so you could hold it, you would notice that feels like a water balloon.

You’d also notice some tiny little structures floating around in it. These little structures are called ‘organelles‘ and they help keep the cell alive. These organelles are floating in a thick solution called cytoplasm.

Red blood cells are some of the smallest cells in the human body. These have a diameter of 0.008 mm, meaning a line of 125 red blood cells is only 1 mm long. Scroll over the images below to magnify them. Notice the shapes and structures inside these white and red blood cells.

Red & white blood cells

White blood cells under an electron microscope

There are many different type of organelles in cells and each one serves a specific function. Scroll over each of the information points in the diagram below to learn more about a few key organelles.

Plants

Plants mostly have the same organelles as animals, with a few extra parts. These extra organelles make plants unique and help them survive.

Like animal cells, plant cells have cell membranes, cytoplasm, mitochondria, ribosomes and a nucleus. Vacuoles, while present in animal cells, they are much larger in plant cells. Plant cells also have a cell wall which goes around the cell, outside the cell membrane. Most plants have an organelle which helps them create food. This food comes in the form of glucose and is a product of photosynthesis. Photosynthesis uses the sunlight to chemically combine water and carbon dioxide to create glucose and oxygen.

Photosynthesis occurs in organelles called chloroplast, which are filled with green substance chlorophyll.

Fungi

Fungi cells have a combination of plants and animals. Fungal cells have cell walls like plant cells, however, unlike plant cells, fungal cell walls are made of chitin not cellulose.

Like animal cells, fungal cells are heterotrophs, meaning they must consume other organisms for their food. Fungi produce substances that digest the material they are growing on. They then absorb the digested materials into their cells.

Try the drag and drop exercise below. Sort them into their correct category.

Inside a cell

Before continuing, watch the video below. This video is a 3D animation of inside a cell. While there are some processes that you might not be aware of it is interesting to see how a cell operates on the inside. At certain points you will be promoted to attempt a question. Do your best, you can replay this video as many times as you want.