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Higher Biology Revision Exercise Unit 3 Control and Regulation.

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Presentation on theme: "Higher Biology Revision Exercise Unit 3 Control and Regulation."— Presentation transcript:

1 Higher Biology Revision Exercise Unit 3 Control and Regulation

2 Plant Growth/Growth Patterns 1. Growth is the ___________ increase in the mass of an organism irreversible 2. In plants growth is restricted to regions called __________.meristems 3. ________ plant growth occurs at ______ meristems (root and shoot tips) where newly formed cells become elongated, vacuolated and ____________. Primaryapical differentiated 4. __________ growth occurs in a perennial plant at a _______ meristem called _________. Secondarylateral cambium

3 5. Cambial activity produces annual ______ of secondary xylem and phloem. Each ring of secondary ______ contains a region of large vessels called _______ wood and a region of smaller vessels called ________ wood. rings xylem spring autumn 6. ________ do not possess meristems. Instead growth occurs all over a developing animal’s _____. Animals body 7. __________ plants (angiosperms) have extensive powers of _____________ whereas mammals have only _______ powers. Flowering regenerationlimited 8. Investigations into growth often involve measuring a variable factor such as fresh weight, _______, length etc. height

4 9. A graph of the results normally takes the form of a ________ (S-shaped) growth curve. sigmoid 10. Growth ________ vary from one type of organism to another.patterns

5 Genetic Control 1. The characteristic features of a cell are controlled by its______.genes 2. To prevent __________ being wasted, some genes can be switched on and off as required. resources 3. The operon (______________) hypothesis states that a structural gene remains switched off while its ________ gene is combined with a __________ from a regulator gene. The structural gene becomes switched on and codes for its protein when an ________ prevents the repressor combining with the operator gene. Jacob-Monod operator repressor inducer

6 4. All the chemical processes that occur in a living organism are known collectively as its ___________. metabolism 5. Each stage in a metabolic _________ is controlled by an enzyme. pathway 6. Production of each ________ is controlled by a particular gene (or group of genes). enzyme 7. A ________ gene is unable to code the information needed to produce its enzyme. Lack of this enzyme may lead to an inborn _____ of metabolism such as _____. mutated errorPKU 8. During ____________, cells become specialised to perform specific _________. differentiation functions

7 9. Within a differentiated cell, only certain genes continue to ________ and the other genes are switched _____. operateoff 10. In some cases genes that were switched off can be switched ___ again bringing about a ________ of differentiation. onreversal 11. Two categories of genes exist: the genes that code for vital ___________ (and are switched on in all cells); the genes that code for ________ characteristic of a particular type of cell ( and are switched on only in that type of _____. metabolites proteins cell

8 Hormonal influences on growth 1. The pituitary gland produces both ______________ (which promotes human growth) and _______________________ (TSH). growth hormone thyroid stimulating hormone 2. The ______ gland responds to TSH by producing ________ which controls metabolic processes. thyroidthyroxine 3. The auxins make up a group of plant growth substances (hormones). The most common ______ is called indole acetic acid (____). auxin IAA

9 4. IAA is produced in root and shoot tips and promotes cell ________, cell _________ and differentiation of cells. 5. Low concentrations of auxin which stimulate ____ elongation have little effect on shoots. ______ concentrations of auxin which stimulate shoot elongation ______ root elongation. 6. Unequal distribution of auxin causes shoots to _____ producing __________ movements. 7. Apical buds exert apical __________ by producing high concentrations of auxin which inhibit growth of ______ buds. divisionelongation root Higher inhibit bend phototropic dominance lateral

10 8. Auxin prevents leaf and fruit _________ and promotes fruit formation. 9. Synthetic auxins act as _________ by disrupting growth of broad-leaved ______ more than grass-like plants which absorb less through their ______ leaves. 10. Synthetic auxins stimulate formation of __________ roots on stem cuttings. 11. The __________ make up a second group of plant growth substances. The most common gibberellin is called _____________ (GA). abscission herbicides weeds narrow adventitious gibberellins gibberellic acid

11 12. GA promotes cell division and elongation in _______. 13. GA reverses genetic ________ by promoting stem ________ elongation. 14. GA induces production of _________ in cereal grains and breaks ________ in winter buds. stems dwarfism internode a-amylase dormancy

12 Physiological Homeostasis 1. Nitrogen, __________, potassium and __________ are four macro-elements needed by plants for healthy growth. 2. A plant grown in a water culture experiment lacking one essential macro-element displays certain ________ symptoms. 3. _____ inhibits the action of certain enzymes, It is poisonous to humans and may have a detrimental effect on the __________ of children. 4. Iron is essential to humans for the formation of ___________. phosphorusmagnesium deficiency Lead intelligence haemoglobin

13 5. ________ is essential to humans for the formation of healthy bones and _____. 6. _________ is needed to promote the uptake of calcium ions by bone and prevent ______. 7. Drugs such as _______, alcohol and __________ harm a developing human ______. 8. A plant grown in darkness develops a weak ____ stem and small curled leaves and is said to be ________. Calcium teeth Vitamin D rickets foetus nicotinethalidomide long etiolated

14 9. Green plants show positive ____________ by growing towards a source of _____ from one direction. 10. In order to flower, long day plants require a number of hours of light ______ a critical level. Short day plants need a critical number of hours of ________. Such a response by an organism to a photoperiod of a certain length is called _____________. 11. Seasonal gonadal activity in many birds and mammals is stimulated by the arrival of daily ___________ of a certain length. phototropism light above darkness photoperiodism photoperiods

15 12. Small mammals with short gestation periods tend to be ____ day breeders. Large mammals with long gestation periods tend to be _____ day breeders. long short 13. Breeding is timed so that the young are born in ______ when the conditions are favourable. spring

16 Homeostasis/Populations/Succession 1. To function efficiently, many aspects of the human body’s ______ environment must be maintained within tolerable _____. 2. Physiological ___________ is the name given to this maintenance of the internal environment despite changes in the _______ environment. 3. Homeostasis operates on the principle of ________ feedback control. By this means a change in the internal environment is detected by _________ which send messages to ________. These trigger responses which negate the deviation from the norm and return the internal environment to its _________. internallimits homeostasis external negative receptorseffectors set point

17 4. Population ________ is the study of population changes and the factors which cause them. 5. A population increases until it reaches the _______ capacity of the environment and then it remains relatively ______. 6. A _________ is prevented from increasing in size indefinitely by several factors known collectively as environmental _________. 7. Some of these factors affect the growth of the population in a manner ___________ of population density. Other factors operate in a _______________ manner. dynamics carrying stable population resistance independent density-dependent

18 8. In a natural ecosystem, a population is kept relatively stable by density-dependent factors effecting negative _________ control (homeostasis). 9. The population numbers of many wild plants and animals are __________ by humans. 10. This provides data which helps humans to manage species used for _____, to control ____ species, to assess pollution levels using ________ species and to protect and ___________ endangered species. feedback monitored foodpest indicatorconserve

19 11. The change which involves a regular progression from a _______ community of plants to a climax community is called __________. 12. During succession each community enjoys a period of short- term stability during which time it ________ the habitat. In doing so it makes the habitat less __________ to itself and more favourable to its seccessor. 13. The ______ community is the final product of succession whose nature is determined by soil and _______ factors. It enjoys stability and is not ________ by another community. pioneer succession modifies favourable climax climatic replaced

20 14. Compared with a pioneer community, a climax community possesses a more diverse range of species, a higher ________ and a more complex set of food _____. webs biomass

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