Note that your final mark will not be saved in the system.
Plant and animal responses Typeit
Type the correct answers into the spaces. Fill all the spaces before clicking ‘Check Answers!’
The main way that plants respond to change is via tropisms controlled by plant . The uneven distribution of causes cells in certain parts of roots or shoots to elongate - it can cause shoots to bend towards light in positive , or away from the effect of gravity, known as negative geotropism. can prevent leaf loss and promote growth of buds, which is why they are commonly used in tissue culture. Plants also have other responses to stresses - many plants may display chemical responses, such as the release of chemicals called from the leaves to deter herbivores with their bitter taste, or from the roots, where they are toxic to microbes.
Rapid, involuntary nervous responses in animals are called . They involve three types of neurone - a sensory neurone, a relay neurone in the nervous system, and a motor neurone - and they have a protective effect. Slower, longer-lasting responses are usually controlled by hormones. Hormones which cannot pass through the cell membrane, but bind to receptors on the surface and trigger an effect inside the cell, are called .
Neurotransmitters are used at synapses, as well as at junctions between motor neurones and muscle fibres to transmit an impulse to cause contraction. Contraction in muscle fibres, also called , takes place according to the model. This describes how heads form cross bridges with filaments, pulling them along their length. The energy for this comes from the hydrolysis of , so it is important that cells in endurance muscles have many , which are the site of respiration.