Life Sciences P1 1 FS/September 2016 PREPARATORY EXAMINATION GRADE 12 LIFE SCIENCES P1 SEPTEMBER 2016 MEMORANDUM MARKS: 150

Transcription

1 Life Sciences P1 1 FS/September 2016 PREPARATORY EXAMINATION GRADE 12 LIFE SCIENCES P1 SEPTEMBER 2016 MEMORANDUM MARKS: 150 This memorandum consists of 11 pages.

2 Life Sciences P1 2 FS/September 2016 PRINCIPLES RELATED TO MARKING LIFE SCIENCES If more information than marks allocated is given Stop marking when maximum marks is reached and put a wavy line and 'max' in the right hand margin. If, for example, three reasons are required and five are given Mark the first three irrespective of whether all or some are correct/incorrect. If whole process is given when only part of it is required Read all and credit relevant part. If comparisons are asked for but descriptions are given Accept if differences/similarities are clear. If tabulation is required but paragraphs are given Candidates will lose marks for not tabulating. If diagrams are given with annotations when descriptions are required Candidates will lose marks. If flow charts are given instead of descriptions Candidates will lose marks. If sequence is muddled and links do not make sense Where sequence and links are correct, credit. Where sequence and links are incorrect, do not credit. If sequence and links become correct again, resume credit. Non-recognised abbreviations Accept if first defined in answer. If not defined, do not credit the unrecognised abbreviation but credit the rest of answer if correct. Wrong numbering If answer fits into the correct sequence of questions but the wrong number is given, it is acceptable. If language used changes the intended meaning Do not accept. Spelling errors If recognisable, accept the answer, provided it does not mean something else in Life Sciences or if it is out of context. If only letter is asked for but only name is given (and vice versa) Do not credit.

3 Life Sciences P1 3 FS/September If units are not given in measurements Candidates will lose marks. will allocate marks for units separately. Be sensitive to the sense of an answer, which may be stated in a different way. Caption All illustrations (diagrams, drawings, graphs, tables, etc.) must have a caption. Code-switching of official languages (terms and concepts) A single word or two that appears in any official language other than the learner's assessment language used to the greatest extent in his/her answers should be credited, provided it is correct. A marker that is proficient in the relevant official language should be consulted. This is applicable to all official languages.

4 Life Sciences P1 4 FS/September 2016 SECTION A QUESTION A C C A C B B D D A (10 x 2) (20) Astigmatism Conjunctiva Neurons Pinna Extinct Allantois Myelin Sheath (7 x 1) (7) A only A only None B only (4 x 2) (8) (a) (b) Centromere Spindle fibre Meiosis I Crossing Over (a) (b) (c) (a) (b) (DNA) Replication DNA (9)

5 Life Sciences P1 5 FS/September Dendrite (a) (b) (c) Synapse Conduction of impulse in unilateral direction Interneuron /connector and motor neuron (MARK FIRST TWO ONLY) (2) SECTION B QUESTION 2 Ventral Root (6) TOTAL SECTION A: (a) A Prostate gland (b) E Urethra (a) C epididymis (2) (b) D testes (2) Spermatozoa still produced in the testes - will be unable to move to the penis during ejaculation - Semen without spermatozoa will still be produced - will not be able to bring about pregnancy in a woman (Any 3) (3) (9) Stem tips - Root tips /Apical tips (MARK FIRST TWO ONLY) (Any 2) (2) A requires a higher concentration/more of the plant growth hormone to stimulate cell elongation OR - Shoot grows faster than normal Concentration of auxin is high in the tip of A/stem - where it is produced - Concentration decreases - because it moves away from the area where it is produced (Any 3) (3) Grow downwards

6 Life Sciences P1 6 FS/September Auxins move downwards /bottom section of root - under the influence of gravity - Concentration becomes higher - Higher concentration in root inhibits cell elongation - Top side of root grows faster Consequently tip grows downwards (Any 4) (4) (11) Hyperthyroidism Decrease in body mass - due to increased basal metabolic rate - especially cell respiration in mitochondria (Any 2) (2) TSH Hypophysis /Pituitary gland is stimulated and - less TSH is secreted - influencing the thyroid gland - to secrete less thyroxin - decreasing the level/concentration of thyroxin - returning it to normal (Any 4) (4) (8) Secretes adrenalin - which causes the blood vessels in the skin to constrict - less blood flows to the surface of the skin (3) The body cannot produce any insulin - high levels of glucose in blood - therefore they have to inject themselves daily to control the blood sugar level (any 2) (2) Hepatic /Liver cells - Muscle cells (MARK FIRST TWO ONLY) (2) Blood - Urine (Any 1) (MARK FIRST ONE ONLY) (5) The hypothalamus is stimulated - impulses are send to the blood vessels in the skin to dilate / vasodilation - consequently more blood flows through the surface of the skin - more heat is lost through radiation from the skin - more sweat is formed because more blood flows to the glands (4) - increased evaporation occurs consequently more heat is lost (Any 4) [40]

7 Life Sciences P1 7 FS/September 2016 QUESTION Paper Source of food /nutrients available for bacteria/decomposers X 58,56 tons (3) Glass takes long to decompose - Danger it has if thrown at people/broken (2) Attract pests /rats, mice, flies that spread disease - Decomposition of solid waste generates an acidic liquid that leaches into, poisoning soil water and freshwater resources - Landfill actions and decomposition creates dust and odours polluting the environment /causing allergic reactions (Any 1 x 2) (2) (MARK FIRST ONE ONLY) Pollution/dumping is reduced as more scrap materials will be used - Less waste go to landfills therefore fewer landfill sites would be required - Cost effective /economical since decreased need for new raw materials - Create jobs therefore more recycling plants will be established - Reduce exploitation of natural resources because it lowers the dependence on raw materials (Any 2 x 2) (4) (MARK FIRST TWO ONLY) (13) Urbanisation - Agricultural needs - Wood as a source of fuel - Serve as timber and mining material - Medicinal uses (Any 2) (2) (MARK FIRST TWO ONLY)

8 Life Sciences P1 8 FS/September Loss of habitat - results into the death /migration/extinction of organisms - Balance between oxygen and carbon dioxide is disturbed - fewer plants to photosynthesise - Food chains are disturbed - species die out /migrate - Degradation of habitat (4) - leading to more erosion (Any 2 x 2) (MARK FIRST TWO ONLY) (6) (a) Diameter of the pupil (b) Distance between the eye and the bulb Between 7 and Diameter of pupil is the widest /6mm wide open - to allow the maximum amount of light to enter the eye - to fall on the retina /yellow spot - enabling the woman to see during the lower light intensities (Any 3) (3) To allow the eye/pupil to adjust - to the darkness of the room and - to ensure validity before the next reading is taken (Any 2) (2) Repeat the investigation Increase the sample size (Any 1) (10) C Cochlea B Cristae Cerebrum Vibrations from the tympanum - will not be transmitted to the oval window - consequently no hearing will be registered /person will be deaf (3) (6)

9 Life Sciences P1 9 FS/September Consist of cranial and - spinal nerves - Cranial nerves may be sensory, motor or mixed - Sensory nerves conduct impulses from the receptors to the CNS - Motor nerves conduct impulses from the CNS to effectors - Neurons are found outside the CNS - Paired cranial nerves carry impulses directly to and from the brain - Paired spinal cord nerves - carry impulses from receptors to the spinal cord and from the spinal cord to the effectors Autonomic nerves transmit impulses from CNS to involuntary muscles and glands (Any 5) (5) [40]

10 Life Sciences P1 10 FS/September 2016 SECTION C QUESTION 4 Development of Graafian Follicle - The hypophysis /pituitary gland - secretes FSH - which stimulates the development of a primary follicle - in one of the ovaries - Only one follicle develops to full maturity in every cycle - into a mature Graafian follicle - Around day 14 - the Graafian follicle is fully developed - The mature Graafian follicle moves to the surface of the ovary - forming a slight swelling - There is a sharp increase in the concentration of LH - The wall of the ovary ruptures - The ovum /haploid secondary oocyte is released - which is known as ovulation - After ovulation the remains of the Graafian follicle develop - into a mass of yellow cells the corpus luteum (Any 9) Oogenesis - A diploid cell/2n - in the ovary - undergoes meiosis /meiosis I to - form a primary oocyte - reducing the number of chromosomes to haploid /n - Only one cell develops into an ovum (Any 4) Prevention of follicle development - Progesterone levels are high - being secreted by the placenta - It inhibits - the secretion of FSH - Therefore preventing the stimulation of development of primary follicle (Any 4) Content: Synthesis: (17) (3) (20)

11 Life Sciences P1 11 FS/September 2016 ASSESSING THE PRESENTATION OF THE ESSAY Criterion Elaboration Mark Relevance (R) Logical sequence (L) Comprehensive (C) All information provided is relevant to the question Ideas are arranged in a logical/cause-effect sequence Answered all aspects required by the essay in sufficient detail Only information with regard to development of the Graafian follicle until corpus luteum is formed, oogenesis and the prevention of follicle development during pregnancy. The sequence of events in development of the Graafian follicle until corpus luteum is formed, oogenesis and the prevention of follicle development during pregnancy is correct. Development of the Graafian follicle until corpus luteum is formed (7/9) oogenesis (3/4) and the prevention of follicle development during pregnancy (3/4) TOTAL SECTION C: GRAND TOTAL: