Cells and Tissues
Plant and animal tissues
Name the three meristems and the permanent tissues they become, match each plant and animal tissue to its job, and tell the joints and muscle types apart by what they do.
A tissue is a group of similar cells doing one job together. Plants and animals need different ones because they live differently: a plant is rooted to the spot and has to hold itself up, so it builds stiff walled tissues, while an animal moves and so builds flexible ones. A plant also grows from a few small zones of dividing cells rather than over its whole body.
Three meristems, three kinds of growth
Apical meristem at the tips of roots and shoots lengthens the plant. Lateral meristem, a ring inside the stem, thickens it. Intercalary meristem, down at the base of an internode, is why a mown lawn comes back. Cells that leave a meristem lose the ability to divide and specialise — that is differentiation, and what it produces is permanent tissue.
Have a play
Three simple permanent tissues, side by side and each one named.
Tap any part of the picture.
Worked example
Two onion bulbs sprout roots in water. On day 3 the tips of one bulb's roots are snipped off. Over the next four days the untouched roots lengthen and the snipped ones do not. What does that show?
Notice what was removed: a centimetre of root tip, and nothing else about the two jars differed.
One change between two otherwise matching set-ups is what lets the result be pinned on that change.
Try it together
Now work out how much of a body's weight is bone and muscle.
Take a student of 40 kg. Bone is about 12 per cent of body weight here and muscle about 40 per cent. Answer with a bare number each time.
1.First the bone. What is 12 per cent of 40 kg, in kg?
Have a go
Have a go on your own. An adult weighs 50 kg and their skeleton is 14 per cent of that. What does the skeleton weigh, in kg? Answer with a number.
Ready to practise?
Eight questions on what you have just read. Nothing is timed, and you can play as many times as you like.