7.1 Hormones

 A chemical substance  Produced in an endocrine gland  Carried in the blood  Alters the activity of the target organ(s)  Destroyed by the liver Copy and complete this table using p152 fig Do not use adrenaline as an example HormoneGlandAction hormones

 Produced by the adrenal glands (above the kidneys)  Prepares the body for action: Effect on muscles Adrenal glandsFight or flight ActionReason Increases blood glucose level for muscles to use to produce ATP energy for contraction Increases heart rate to transport more glucose and oxygen to the muscle cells Dilates airways so more air reaches alveoli for increased gas exchange Dilates blood vessels in brain and muscles to deliver more glucose and oxygen to these cells Constricts blood vessels in gut and other organs allowing blood to be diverted to muscles

7.2 Tropic responses

 Plants grow towards or away from stimuli  The growth response is called a tropism gravity light Shoots will grow towards light – a positive tropism Shoots will grow against gravity – a negative tropism

 Phototropism is the growth response towards or away from light  Geotropism is the growth response with or against gravity geotropism phototropism

 Complete this table: ResponseTropism Shoots growing towards sunlight Positive phototropism Shoots growing against gravity Negative geotropism Roots growing away from sunlight Negative phototropism Roots growing with gravity Positive geotropism

 A hormone called auxin is made in the tip of the shoot  Auxin causes shoot cells to enlarge  When light is directly overhead, auxin diffuses equally down the shoot  The shoot grows straight up light

 When light is directional, the auxin moves to the shaded side of the shoot  The cells on the shaded side elongate more than the cells on the lighted side  The shoot grows towards the light light Auxin at work

gravity shoots grow up roots grow down negative geotropism positive geotropism

 Auxin is made in the shoot and root tips  Auxin causes slowed growth in root cells  When a plant is laid on its side, auxin collects in the lower cells  The lower cells in the shoot elongate and the shoot grows upwards  The lower cells in the root slow in growth and the roots grow down Phototropism and geotropism

 Complete the following summary questions:  P153 exercise 1  P155 exercises 1, 2 and 3  Complete the following exam-style questions:  P156 question 4