5.5 Plant and animal responses OCR ExamBuilder

1 Answer all the (a).Fig. is a flow diagram that shows the sequence of events in the body once a threat is perceived. Theresponse is often described as the fight or flight response as it prepares the body to respond physically to thethreat in the short-term. (i)Identify two signalling molecules named in Fig. OCR 2018. You may photocopy this of 31 Created in ExamBuilder12[1](ii)Adrenaline acts on a variety of cell types with a variety of the table by stating the effects of stimulating each target cell. The first one has been completed cellResponseRole in the fight or flight responseSmooth muscle in bronchiolesMuscle relaxesBronchioles dilate and allow moreoxygen to reach bloodSino-atrial nodeLiver cellErector muscle in skin[6](iii)Describe the sequence of actions that occur once adenylyl cyclase is activated in the target liver cells.

2 [2](iv)The response in Fig. also occurs when a person is subjected to stress. However, the body does notneed to respond physically to the stimulus and so, for example, the bronchioles do not the information given and your own knowledge, suggest the long term adverse effects of continuedexposure to stress on body function.[2] OCR 2018. You may photocopy this of 31 Created in ExamBuilder (b).Athletic sprinters require large amounts of energy in short periods of time. Many elite sprinters can run 100 metreraces in under 10 normal conditions, exercise requires an increased rate of breathing. It has been observed that some of thebest sprinters only take one breath at the start of the race and do not inhale again until the end of the how these sprinters can expend so much energy without needing to carry out aerobic respiration.

3 [2] OCR 2018. You may photocopy this of 31 Created in have evolved response mechanisms to a variety of abiotic and biotic plants respond to changes in the length of day. The advantage of this response is that these plantsbegin to flower only when environmental conditions are Hamner studied the effect of exposure to light and darkness on flowering in cocklebur plants . He placedcocklebur plants in darkness for different periods of time. Some of his results are shown in Table of darkness (h)Flash of light during the periodof darkness?Flower light after 6 light after 6 hours, followed bya flash of far red flashes of far red lightYesTable what conclusions can be drawn from the results in Table about the effect of exposure to light anddarkness on flowering in cockleburs.

4 [3] OCR 2018. You may photocopy this of 31 Created in ExamBuilder3.* The orange tree, Citrus sinensis, is an important crop applied the following treatments to commercial orange trees: Gibberellins were applied at various stages of were applied during development and to mature orange treated orange trees were compared to untreated orange trees. Scientists observed that the treated trees:had slightly shorter rootsgrew tallerall began to grow within two days of each otherhad fewer and shorter side branchesretained their fruit and leaves for explanations for each of these observations.[6] OCR 2018. You may photocopy this of 31 Created in ExamBuilder4(a).

5 Flowering plants often produce one hormone that promotes the ripening of fruit. [1] (b).State two responses that some plants use to defend themselves from herbivory. [2] OCR 2018. You may photocopy this of 31 Created in work in a number of different ways. (i)Some herbicides, known as phenoxy herbicides, mimic the action of the auxin, indoleacetic acid (IAA).What is the normal action of IAA in Plant cells?[1](ii)The herbicide atrazine works by disabling plastoquinone, one of the proton pumps in photosystem how atrazine would kill a susceptible Plant .[5] OCR 2018. You may photocopy this of 31 Created in way that humans try to maximise food production is to manipulate the transfer of energy number of methods can be used to increase energy transfer through agricultural ecosystems and other foodproduction methods include.

6 Aartificial selectionBrecombinant DNA technologyCgrowing microorganisms in a fermenterDuse of immobilised enzymesEcontrol of Plant physiology with synthetic planthormonesFmanipulation of the nitrogen the letters A F, select the most suitable method that could be used to achieve each of the aims shownin the table may select each letter more than soil that is low in nutrients for the growing of wheatpreventing the spoilage of fruits after pickingreducing the impact of a fungal disease on yields from cucumber plantsproducing strawberry plants that grow quicker and fruit earliermaking sugar syrup from waste starchproducing large amounts of a fungus for food[6] OCR 2018.

7 You may photocopy this of 31 Created in student setting up an experiment to investigate the effect of light on cress Plant seedlings accidentally shonethe bright light onto one side of the face of another student. He noticed that the student immediately respondedby raising her hand to shield her eye from the response of the cress seedlings to light shining from one direction was slower, but after 24 hours the cressseedlings had grown towards the the mechanisms that produced the responses to light in the cress seedlings and in the seedlingshuman[7] OCR 2018. You may photocopy this of 31 Created in ExamBuilder8(a).

8 Animals and plants respond to changes in their respond to changes in their environment using chemicals known as Plant hormones or Plant student carried out a two-part experiment to identify the contents of two unlabelled bottles, J and K. One bottlecontained auxin and the other contained Part 1 of the experiment, 30 seedlings had their shoot tips removed. The 30 seedlings were then divided intothree groups of 10 and treated as shown in Table and Fig. GroupTreatment1no treatment applied2solution of J applied to cut stem at apex of seedling3solution of K applied to cut stem at apex of seedlingTable the seedlings were then exposed to light from all directions and left for seven Part 2 of the experiment, 30 coleoptiles had their tips removed.

9 They were then divided into three groups of 10coleoptiles and treated as shown in Table and Fig. GroupTreatment4no treatment applied5solution of J applied to cut tip of coleoptile6solution of K applied to cut tip of coleoptileTable OCR 2018. You may photocopy this of 31 Created in ExamBuilderFig. coleoptiles in groups 4, 5 and 6 were then exposed to light from one direction, as shown in Fig. , and leftto grow for two days. (i)Identify three variables that must be controlled in this experiment to produce valid [3](ii)Groups 1 and 4 were controls in this why these controls were necessary.[1] OCR 2018. You may photocopy this of 31 Created in ExamBuilderThe observations at the end of each part of the experiment are shown in Table in stem length of 10 mm and growth of lateral buds2J on cut stem apexno growth of lateral buds3K on cut stem apexincrease in stem length of 40 mm and growth of lateral buds4nonevertical growth of the coleoptiles5J on cut coleoptile tipgrowth of the coleoptiles towards the light source6K on cut coleoptile tipvertical growth of the coleoptilesTable (iii)Using the information from Table , identify the contents of bottles J and K and give reasons for [3] OCR 2018.

10 You may photocopy this of 31 Created in ExamBuilder (b).As mammalian muscle uses energy to contract, it needs an energy the following passage by choosing the best term to fill each ATP for muscle contraction is generated by aerobic respiration in organellescalled _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . Most of this ATP is produced by the stage of aerobicrespiration called _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ .If the oxygen supply is insufficient, ATP can also be obtained from anaerobic respiration, in which pyruvate isconverted to the toxic product _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.