Life Sciences Grade 12 Paper 2 NSC June 2013 Question Paper

Downloaded from hlayiso.com basic education Department: Basic Education REPUBLIC OF SOUTH AFRICA SENIOR CERTIFICATE EXAMINATION BIOLOGY P2 STANDARD GRADE 2013 MARKS: 150 TIME: 2 hours BIOLOGY SG: Paper 2 3062E 30622E This question paper consists of 18 pages. X@5 VMI Copyright reserved GAUTENG Please turn over |

Downloaded from hlayiso.com Biology/SG/P2 / 2 DBE/2013 SCE INSTRUCTIONS AND INFORMATION Read the following instructions carefully before answering the questions. 1. 2. 10. 11. Answer ALL the questions. Write ALL the answers in the ANSWER BOOK. Start the answer to EACH question at the top of a NEW page. Number the answers correctly according to the numbering system used in this question paper. You will lose marks if answers are not presented according to the instructions of each question. Do ALL drawings in pencil and label them in ink. Draw diagrams and flow charts only when requested to do so. The diagrams in this question paper are NOT necessarily drawn to scale. Do NOT use graph paper. You may use a non-programmable calculator, a protractor and a compass. Write neatly and legibly. Cont sen UNA

Downloaded from hlayiso.com Biology/SG/P2 3 DBE/2013 SCE SECTION A QUESTION 1 1.1 Various options are provided as possible answers to the following questions. Choose the correct answer and write only the letter (A—D) next to the question number (1.1.1—1.1.6) in the ANSWER BOOK. QUESTIONS 1.1.1 and 1.1.2 are based on the apparatus below. Copyright reserved 1 Light rays Which hormone causes this growth response in plants? A Gibberellin B Cytokinin Cc Auxins D Thyroxin In which part of the stem is this hormone produced? A Shadow side B Light side Cc Elongation area D Stem tip Two statements are provided below. STATEMENT | STATEMENT II Stomata are mainly | Water moves as a result of a higher water closed at night. potential in the guard cells to adjacent cells. Which ONE of the following is correct for Statements | and II? A Statement | is true; Statement II is false. B Statement | is false; Statement II is true. Cc Both Statement | and Statement II are true, but Statement II does not explain Statement | correctly. D Both Statement | and Statement II are true, and Statement II explains Statement | correctly. HANNAN} A A finial GAUTENG

Downloaded from hlayiso.com Biology/SG/P2 4 DBE/2013 SCE 1.1.4 The structural unit of the nervous system is the ... A axon. B cell body. C neuron. D_nerve. Ue Which ONE of the following is an advantage of apical dominance? A __ It contributes to better fruit production and growth. B_ Plants take on a form which is better for their environment and reproduction methods. C It causes the abscission of leaves in winter. D __ Ithelps plants to develop adventitious roots. 1.1.6 Which conditions favour guttation most? A __ High root pressure and humid air B High temperature and humid air C Dry air and low root pressure D Wind and dry air (6 x 2) (12) 1.2 Give the correct biological term for each of the following descriptions. Write only the term next to the question number (1.2.1-1.2.5) in the ANSWER BOOK. 1.2.1 The modified epidermal cells of a leaf which contain chloroplasts | The pores found in the margins of some leaves through which liquid water is lost 1.2.3 The gap which exists between two successive or connecting neurons 1.2.4 A chemical regulator produced by endocrine glands 1.2.5 The part of the renal tubule found between the proximal and the distal convoluted tubule (5) Cont end NU LN AN 9s

Biology/SG/P2 Downloaded from hlayiso.com 5 SCE DBE/2013 1.3 Choose a description from COLUMN B that matches an item in COLUMN A. Write only the letter (A-I) next to the question number (1.3.1-1.3.5) in the ANSWER BOOK. COLUMN A COLUMN B 1.3.1 1.3.2 1.3.3 1.3.4 1.3.5 Root pressure Capillarity Root hair Water potential Exosmosis the ability of water molecules to do work by osmosis a structure that allows rapid passage of water molecules but not larger molecules the tendency of a solution to absorb water across a differentially permeable membrane movement of water into the cell pushes water from the xylem of the root to the xylem of the stem movement of water out of a cell the tendency of water to spontaneously rise up in narrow tubes the force of attraction between water molecules an epidermal cell modified for absorption of soil water Copyright reserved (5x 2) LAAN AOA} 0A A Pease turn over (10)

Downloaded from hlayiso.com Biology/SG/P2 6 DBE/2013 SCE 1.4 The diagram below shows a boy sneezing as a result of dust in the air. Answer the questions that follow. The dust in the air made this boy sneeze In this action: 1.4.1 (a) The stimulus is the ... (b) The receptors are found in the ... (c) The response is the ... (d) The response is known as a... (4) 1.4.2 Describe how the structures in the eye change when a person views a distant object after reading a book. (4) (8) 1.5 State and explain the effect of the hormone adrenalin on each of the following: 1.5.1 Pupil size (2) ae Blood supply to the internal organs (2) (4) i la aktd CAT AAA OCA A A Pease tm over

Downloaded from hlayiso.com Biology/SG/P2 1.6 7 SCE The diagram below represents water balance in the human body. Gained Lost ¢ Chemical reactions 400 cm® Drink 1500 cm* Skin Breathing 400 cm Urine 1500 cm N Nee” > Water balance in the body 1.6.1 1.6.2 1.6.3 Copyright reserved What volume of water is lost in faeces? What volume of water is lost (in cm>) by sweating? GAUTENG DBE/2013 Calculate the total volume of water gained. Show all workings. Please turn over (2) (3) (2) (7)

Downloaded from hlayiso.com Biology/SG/P2 8 DBE/2013 SCE 7 Study the apparatus below which was set up in an investigation and answer the questions that follow. The apparatus has been set up incorrectly. Ys plastic bag twig cork stopper water Apparatus used in an investigation 1.7.1 If the apparatus were set up correctly, what would the learner be investigating? (1) 1.7.2 State ONE way in which the learner could improve the accuracy of the apparatus. (2) 1.7.3 State ONE advantage of the process being investigated. (1) (4) TOTAL SECTION A: 50 Cotsen AN |e on

Downloaded from hlayiso.com Biology/SG/P2 9 DBE/2013 SCE SECTION B QUESTION 2 7 Learners prepared four cell models by using dialysis tubing containing the same blue solution. Each of the cell models originally weighed 10 grams. Each cell model was placed in a beaker containing a different concentration of water. After 24 hours, the learners recorded the mass of the cell models as shown in the table below. CONCENTRATION OF WATER MASS OF CELL MODEL SURROUNDING THE CELL MODEL (%) AFTER 24 HOURS (g) 100 12 90 11 80 10 70 9 2.1.1 Why did the cell model that was placed in 100% water increase in mass? 2.1.2 What was the concentration of the water in the original blue solution? State evidence in support of your answer. 2.1.3 How can you ensure that the results of this investigation are reliable? 2.2 Study the diagram below of a container of water and two different kinds of molecules, A and B, separated into two chambers by a membrane through which only water and molecule A can pass. membrane B BoB > Bee A container showing the distribution of molecules A and B before net movement 2.2.1 Which process is illustrated in this diagram? 2.2.2 Give a reason why molecule B will not diffuse through the membrane. | Draw a similar diagram in your ANSWER BOOK and indicate the distribution of molecules A and B after the net movement of molecules stops. Coy sen ANA) or (2) (3) (2) (7) (1) (1) (5) (7)

Biology/SG/P2 10 DBE/2013 SCE 2.3 Study the diagram below that shows a wet mount of red onion cells as seen Downloaded from hlayiso.com through a microscope. Answer the questions that follow. 2.3.1 2.3.2 A wet mount of red onion cells Identify structure A. Which diagram below best illustrates the technique that would most likely be used to add salt to these cells? Write only the letter (A—D) next to the question number. Diagram B Diagram C Diagram D Techniques that could be used to add salt to the cells 2.3.3 2.3.4 Copyright reserved Which process takes place in the cell after the addition of salt? Draw a labelled diagram that shows what a red onion cell, as illustrated above QUESTION 2.3.1, would look like some time after the addition of the salt. FITMENT Pease un over GAUTENG (1) (1) (1) (4) (7)

Downloaded from hlayiso.com Biology/SG/P2 11 DBE/2013 SCE 2.4 Study the diagram below that shows an investigation of osmosis and answer the questions that follow. The letter A represents a sugar solution and B is water. B A <C> An investigation of osmosis Explain why the: 2.4.1. Dialysis tube must be tied tightly (2) 2.4.2 Dialysis tube must be washed after filling and before being placed into the beaker (2) (4) [25] Coo om LEAN HAAN)

Downloaded from hlayiso.com Biology/SG/P2 12 DBE/2013 SCE QUESTION 3 3.1 The diagram below shows a section through the human skin. Study the diagram and answer the questions that follow. A B A section through human skin 3.1.1 Name parts A, B and C. (3) 77 Explain the role of part C in the regulation of body temperature. (4) 3.1.3 Give a reason for the rich blood supply to part C. (2) 3.1.4 Name ONE poor conductor of heat shown on the diagram. (1) 3.1.5 Will the skin blood capillaries be dilated or constricted on a hot day? (1) 3.1.6 Explain your answer to QUESTION 3.1.5. (3) (14) Copyright reserved Please turn over

Downloaded from hlayiso.com Biology/SG/P2 13 DBE/2013 SCE C7 Explain ONE way in which the skin of a marine mammal such as a dolphin or seal is insulated against heat loss. (2) 3.3 The blood test results of a woman show that her levels of thyroxin are below normal levels. 3.3.1 Name the gland in the body that produces thyroxin. (1) 3.3.2 Where in the human body will you find the gland named in QUESTION 3.3.1? (2) 3.3.3 State TWO functions of thyroxin. (4) 3.3.4 The woman is advised to include sea salt in her diet. Sea salt is rich in iodine. Give a reason for this advice. (2) (9) [25] Cop roe OANA!

Downloaded from hlayiso.com Biology/SG/P2 14 DBE/2013 SCE QUESTION 4 4.1 Study the diagram below of a longitudinal section through a human kidney and answer the questions that follow. Longitudinal section of a human kidney 4.1.1 Identify parts D, E and F. 4.1.2 Why is region B darker in colour in an actual specimen compared to region C? 4.1.3 Identify part A and state ONE function thereof. 4.1.4 State the role of the fatty tissue surrounding the kidney. 4.2 A middle-aged man has been suffering from headaches. He visited his doctor for a health check. His blood pressure, at 155/98 mm Hg, was higher than it should have been. 4.2.1 Name the hormone that normally regulates the re-absorption of water by the kidneys. 4.2.2 Which gland secretes this hormone? 4.2.3 Explain how this hormone causes a rise in a person's blood pressure. Copier AA A A Pesotum ovr (3) (2) (3) (1) (9) (1) (1) (2) (4)

Downloaded from hlayiso.com Biology/SG/P2 4.3 15 SCE DBE/2013 The table below shows the average amount of urine, sweat and salt (sodium chloride) excreted by a person on a normal, cold and hot day. Assume that the same amount of food and drink are taken in for each day. URINE SWEAT SALT EXCRETED PER | EXCRETED PER (SODIUM CHLORIDE) DAY (cm*) DAY (cm*) EXCRETED PER DAY In urine (g) | In sweat (g) Normal day 1500 500 18,0 1,5 Cold day 2 000 0 19,5 0 Hot day 375 2.000 13,5 6,0 4.3.1 Calculate the total amount of salt excreted on a normal day. Show all workings. (3) 4.3.2 Why does a person excrete more urine on a cold day than on a hot day? (3) 4.3.3 Why is urine always excreted, regardless of the weather conditions? (2) 4.3.4 On which day (hot or cold) will the urine be more concentrated? (1) 4.3.5 Explain your answer to QUESTION 4.3.4. (3) (12) [25] Connesened A 0 oar

Downloaded from hlayiso.com Biology/SG/P2 16 DBE/2013 SCE QUESTION 5 a The graph below shows the average height of boys and girls from birth to age 18. Study the graph and answer the questions that follow. A graph showing the average height of boys and girls from birth to age 18 | i boys 180 {jt —— aan | Seam 160 : Jorn zrhes gE = |! H girls | = 140 t _— = ao = 120 fei itt tl = a | o® — S ci 5 100 , es i — a > ~ el rr] 80 i cl i 60 | _ | —_ Pit | T T T 1 2 4 6 8 40°12 14° 16 (18 Age in years 5.1.1 What is the average height of girls at age 8? (2) ae State an age when girls are taller than boys. (2) _ What is the average height of a baby at birth? (2) 5.1.4 What is meant by the term growth in humans? (2) 5.1.5 State ONE way, other than height, that could be used to measure growth. (2) (10) Coma end LAA AN) nr

Downloaded from hlayiso.com Biology/SG/P2 17 DBE/2013 SCE 5.2 A class compared reaction times in people of different ages and sexes. They tested 5 people in each category. A one-meter ruler was dropped in between the fingers of each person. The persons would catch it as quickly as possible once they saw it being dropped. A reading was taken from the ruler at the point where it was caught. The greater the distance the ruler fell, the slower the reaction time. Meter ruler 30 35 40 45 80 58 boil Iona Take reading here A ruler used to test reaction time The results are shown in the table below. AVERAGE POINT AT WHICH THE RULER WAS AGE IN YEARS CAUGHT (cm) MALES FEMALES 10 23 23 15 20 19 20 18 18 30 20 25 40 24 26 50 32 34 60 44 36 5.2.1 Give the average point in cm at which the ruler was caught by a 30-year-old male. 5.2.2 Give ONE conclusion you can make from the results of the experiment. 5.2.3 Which female group has the fastest reaction time? 5.2.4 State ONE way in which the reliability of the results in this experiment could be improved. 5.2.5 Which sense organ detects that the ruler is being dropped? Conritesened ALI 00 0 Pee um vr (1) (2) (1) (2) (1) (7)

Downloaded from hlayiso.com Biology/SG/P2 18 DBE/2013 SCE 5.3 Study the diagram below and answer the questions that follow. A B c D E Longitudinal section through a human eye 5.3.1 Identify part C. (1) 5.3.2 Write the letter (A—G) of the part of the eye that: (a) Responds to light intensity (1) (b) Helps the eye to maintain its shape (1) (c) Prevents internal reflection of light (1) (d) Is transparent and plays an important role in accommodation (1) (e) Causes the lens to change its shape (1) 5.3.3 Identify part G and state its function. (2) (8) [25] TOTAL SECTION B: 100 GRAND TOTAL: 150 Conwirocoves NANT TL