These seven original questions follow the four lessons in the chapter. Write your answer first, then open the model answer.
Questions
Question 1. State the difference between a tendon and a ligament.
Answer
A tendon joins a muscle to a bone. A ligament joins a bone to another bone at a joint.
Question 2. Explain why a muscle cannot push a bone.
Answer
A muscle can only contract and shorten, and shortening pulls on the bone it is attached to. It cannot lengthen itself by force, so it cannot push.
Question 3. A student straightens the arm to put a book on a shelf. State which muscle contracts and which relaxes.
Answer
The triceps contracts and the biceps relaxes. The contracting triceps pulls the forearm straight.
Question 4. Explain why the arm needs two muscles to bend and straighten.
Answer
Muscles can only pull, so one muscle moves the bone in one direction only. A second muscle, the antagonistic partner, contracts to pull the bone back. The two work in opposite ways, so when one contracts the other relaxes.
Question 5. State two differences between the support of an earthworm and of a grasshopper.
Answer
- An earthworm has a hydrostatic skeleton of body fluid inside the body, but a grasshopper has a hard exoskeleton outside the body.
- The earthworm grows without shedding its support, but the grasshopper must shed its exoskeleton in stages to grow.
Question 6. Explain why a lettuce leaf becomes limp when it is left without water.
Answer
The cells lose water, so their turgor pressure falls and they become flaccid. Herbaceous plants depend on turgid cells for support, so the leaf loses its firmness and becomes limp.
Question 7. A diagram shows a forearm raised toward the shoulder with an arrow pointing upward. Name the muscle that is contracting, and describe what the other muscle of the pair is doing.
Answer
The forearm moves toward the shoulder, so the biceps is contracting and pulling the forearm up through its tendon. The triceps is relaxing, so it does not resist the movement.
If you got these wrong
Question 1 points to relating bones, joints and muscles. Questions 2 to 4 use explaining antagonistic muscle action.
Questions 5 and 6 need comparing support in selected organisms. Question 7 comes from interpreting movement diagrams.
Log each slip in the mistake log and paper-error review, then build a timed set with the timed original practice session builder. For a teacher to go through your answers, see online one-to-one Biology tuition.