Life Sciences Grade 12 P1 North West June 2024 QP (Eng)

PROVINCIAL ASSESSMENT GRADE 12 LIFE SCIENCES JUNE 2024 MARKS: 150 TIME: 2½ hours This question paper consists of 16 pages. Copyright reserved Please turn over

Life Sciences 2 NW/June 2024 Grade 12 INSTRUCTIONS AND INFORMATION 1. Answer ALL the questions. 2. Write ALL the answers in your ANSWER BOOK. 3. Start the answer to EACH question at the top of a NEW page. 4. Number the answers correctly according to the numbering system used in this question paper. 5. Present your answers according to the instructions of each question. 6. Do ALL drawings in pencil and label them in blue or black ink. 7. Draw diagrams, tables or flow charts only when asked to do so. 8. The diagrams in this question paper are NOT necessarily all drawn to scale. 9. Do NOT use graph paper. 10. You must use a non-programmable calculator, protractor and compass where necessary. 11. Write neatly and legibly. Copyright reserved Please turn over

Life Sciences 3 NW/June 2024 Grade 12 SECTION A QUESTION 1 1.1 Various options are provided as possible answers to the following questions. Choose the answer and write only the letter (A–D) next to the question numbers (1.1.1 to 1.1.9) in the ANSWER BOOK, e.g 1.1.10 D. 1.1.1 Which ONE of the following parts control the amount of light entering the eye by influencing the size of the pupil? A Sclera B Cornea C Retina D Iris 1.1.2 Meiosis is best explained as a process that produce … daughter cells? A two haploid B two diploid C four diploid D four haploid 1.1.3 A list of functions of the brain is provided below: (i) Interpret sensation (ii) Regulates involuntary actions (iii) Controls higher thought processes (iv) Controls voluntary actions Which ONE of the following combinations are the functions of the cerebrum? A (i) and (ii) only B (i), (ii), (iii) and (iv) C (i), (iii) and (iv) only D (i) and (ii) only 1.1.4 During Anaphase II of meiosis, the two chromatids of a chromosome are pulled apart, each moving towards opposite poles at a rate of 1 micrometre per second. The distance in micrometre between the chromatids after 45 seconds is A 15. B 25. C 45. D 90. Copyright reserved Please turn over

Life Sciences 4 NW/June 2024 Grade 12 1.1.5 A red flowering plant is crossed with a white flowering plant. All the offspring have pink flowers. When the two pink flowering plants are crossed, the next generation of flowering plants will have flowers that are … A pink only. B red only. C white only. D pink, red and white. 1.1.6 A sample of DNA has 60 Guanine bases and 30 Adenine bases. How many phosphate molecules would you expect in this sample of DNA? A 30 B 90 C 180 D 270 1.1.7 Grommets may be used in treatment of ... A astigmatism. B cataracts. C middle ear infections. D long-sightedness. 1.1.8 The part of the brain that regulates body temperature is the … A medulla. B cerebrum. C cerebellum. D hypothalamus. 1.1.9 It allows for gaseous exchange in the amniotic egg and forms the placenta in mammals. A Allantois B Chorionic villi C Umbilical cord D Chorion (9 x 2) (18) Copyright reserved Please turn over

Life Sciences 5 NW/June 2024 Grade 12 1.2 Give the correct biological term for each of the following descriptions. Write only the term next to the question numbers (1.2.1 to 1.2.9) in the ANSWER BOOK 1.2.1 Two or more alternative forms of a gene at the same locus 1.2.2 An inheritance disorder where blood fails to clot properly 1.2.3 The structure that the Graafian follicle develops into after ovulation 1.2.4 The structure in a cell that forms the spindle fibre 1.2.5 A branch of the autonomic nervous system that decreases the heartbeat back to normal 1.2.6 A nerve cell that carries nerve impulses from receptors towards the central nervous system 1.2.7 The centre that controls sleep 1.2.8 The organelle found in large quantities in the neck region of a sperm cell 1.2.9 Type of egg where the embryo develops inside the fluid sac which is surrounded by a shell (9 x 1) (9) 1.3 Indicate whether each of the statements in COLUMN I apply to A ONLY, B ONLY, BOTH A AND B or NONE of the items in COLUMN II. Write A only, B only, both A and B or none next to the question numbers (1.3.1 to 1.3.3) in the ANSWER BOOK. COLUMN I COLUMN II 1.3.1 Type of inheritance where both alleles A: Incomplete dominance are expressed equally in the B: Complete dominance phenotype 1.3.2 Reproductive strategy in birds where A: Precocial hatchling are helpless and unable to B: Altricial move and feed themselves 1.3.3 Type of reproduction in vertebrates A: Ovipary where the foetus is attached to and B: Ovovivipary develops inside the uterus (3 x 2) (6) Copyright reserved Please turn over

Life Sciences 6 NW/June 2024 Grade 12 1.4 In human, long finger (F) and continuous hairline (H) are dominant over short finger and widow’s peak. A man and a woman, both heterozygous for the two characteristics, plan on having a child. Gametes FH Fh fH fh FH FFHH FFHh FfHH FfHh Fh FFHh FFhh FfHh Ffhh fH FfHH FfHh ffHH ffHh fh FfHh Z ffHh ffhh 1.4.1 State the genotype at Z. (1) 1.4.2 Give the: (a) Genotype of the parents (2) (b) Number of genotypes that could result in offspring with long finger and a continuous hairline (1) (c) Alleles for continuous hairline (1) (d) Phenotype of a child who is homozygous recessive for both characteristics (2) (7) 1.5 Human blood groups are controlled by multiple alleles. 1.5.1 How many alleles control blood groups? (1) 1.5.2 Which TWO alleles are codominant in the inheritance of blood groups? (2) 1.5.3 A man is heterozygous for blood group A and marries a woman who has blood group O. Use a genetic cross to show the phenotypic ratio of their offspring. (7) (10) TOTAL SECTION A: 50 Copyright reserved Please turn over

Life Sciences 7 NW/June 2024 Grade 12 SECTION B QUESTION 2 2.1 A mutation has occurred on the last codon of an mRNA molecule as shown below. Original sequence AUG GAA AUA CCG CCA GGA Mutated sequence AUG GAA AUA CCG CCA GGC 2.1.1 Name the type of mutation that has occurred. (1) 2.1.2 Give a reason to your answer in QUESTION 2.1.1 (2) 2.1.3 The table below shows some mRNA codons and amino acids that they code for. mRNA codons Amino Acid AUA Isoleucine AUG Methionine CCA Proline CCG Proline CUG Leucine GAC Glutamic acid GGA Glycine (a) State the number of different amino acids coded for by the original sequence of the mRNA molecule given above. (1) (b) Give the anticodon on tRNA molecule that carries the amino acids Methionine and Leucine. (2) (c) Use the information in the table to describe the effect of the mutation on the protein formed. (4) 2.1.4 Describe the process of transcription in protein synthesis. (5) (15) Copyright reserved Please turn over

Life Sciences 8 NW/June 2024 Grade 12 2.2 Read the extract below about a medical condition in male babies called cryptorchidism. Cryptorchidism occur in new-borns when one or both of the testes do not descent into the scrotal sac at birth, but remain inside the abdominal cavity. Cryptorchidism occur in approximately 3 to 5% of full-term male infants while approximately one third of premature male babies are born with this condition. If the testes do not descent naturally by the age of one, treatment is needed. Treatment may involve administering testosterone, but the most common treatment is surgery. If cryptorchidism is not resolved, it may lead to infertility when both testes do not descent and increased the risk of testicular cancer by the age of 30 to 40 years. 2.2.1 State ONE function of testosterone not mention in the extract above. (1) 2.2.2 According to the extract, state TWO ways in which cryptorchidism is treated. (2) 2.2.3 What percentage of premature male babies are born with cryptorchidism? (1) 2.2.4. From the extract, give ONE reason, other than infertility, why cryptorchidism needs to be treated if the condition is not resolved naturally. (1) 2.2.5 Explain why undescended testes may lead to infertility in young males. (2) (7) Copyright reserved Please turn over

Life Sciences 9 NW/June 2024 Grade 12 2.3 One type of deafness in humans is carried on a single allele. The diagram below shows the inheritance of deafness in a family. 2.3.1. How many: (a) Generations are represented in this pedigree diagram (1) (b) Children of Tom and Pearl are able to hear (1) 2.3.2 Which genotype is dominant? (1) 2.3.3 Use the offspring of Neo and Jane to explain your answer to QUESTION 2.3.2. (4) 2.3.4 Use the letter ‘A’ to represent the dominant allele and a letter ‘a’ for recessive allele to give ALL the possible genotype for a hearing individual. (2) (9) Copyright reserved Please turn over

Life Sciences 10 NW/June 2024 Grade 12 2.4 Some mine workers are constantly exposed to loud noise for long periods. This can destroy the hair cells in the Organ of Corti and damage the auditory nerve, resulting in hearing loss. A survey was conducted in Marikana Mines from 2010 to 2015, to establish the number of mine workers who suffered from hearing loss. The results are shown in the table below. NUMBER OF MINE WORKERS YEARS WITH HEARING LOSS 2010 1500 2011 5000 2012 8000 2013 10000 2014 11000 2.4.1 Name the location of the Organ of Corti. (1) 2.4.2 Calculate the percentage increase in the number of mine workers with hearing loss between 2010 and 2014. (3) 2.4.3 Suggest ONE reason for the increase in the number of mine workers with hearing loss caused by exposure to loud noise in this mine. (1) 2.4.4 Draw a bar graph to represent the data in the table. (6) (11) Copyright reserved Please turn over

Life Sciences 11 NW/June 2024 Grade 12 2.5 The diagram below show a phase during meiosis in an animal cell. 2.5.1 Identify part C. (1) 2.5.2 Part B represents homologous chromosomes. What are homologous chromosomes? (1) 2.5.3 Name and describe the phase prior to the phase illustrated above. (3) 2.5.4 Describe the results at the end of meiosis, if the chromosomes at part B failed to separate. (3) (8) [50] Copyright reserved Please turn over

Life Sciences 12 NW/June 2024 Grade 12 QUESTION 3 3.1 Joel and Monique have three children. One of the three children was adopted. A DNA profile for each member of the family was prepared to determine if Joel is the father of all three children (Junia, Cynthia and Cyril). The DNA profiles are given below. 3.1.1 Which ONE of the children has been adopted? (1) 3.1.2 Explain your answer to QUESTION 3.1.1. (2) (3) Copyright reserved Please turn over

Life Sciences 13 NW/June 2024 Grade 12 3.2 The diagram below represents a part of the female reproductive system. B A C D 3.2.1 Identify part C. (1) 3.2.2 State TWO functions of part D. (2) 3.2.3 Name the hormone secreted by part A that stimulates puberty. (1) 3.2.4 State how the hormone named in QUESTION 3.2.3 influences the endometrium. (2) 3.2.5 Explain how reproduction will be affected if part B has a blockage on both sides. (3) 3.2.6 Explain ONE way in which part C is structurally suited for gestation. (2) 3.2.7 Describe the process of oogenesis in part A. (5) (16) Copyright reserved Please turn over

Life Sciences 14 NW/June 2024 Grade 12 3.3 Read the extract below. ALZHEIMER’S DISEASE AND EXERCISE Age and family history are the known risk factor for Alzheimer’s disease. The most common symptom of Alzheimer’s disease is a worsening ability to remember new information. Regular exercise may help to reduce the risk of developing Alzheimer disease because it can improve blood flow to the brain and help to maintain the volume of the hippocampus. The hippocampus is located deep inside the cerebrum and plays a major role in learning ability and orientation. Scientist conducted an investigation to determine if regular exercise reduces risk of Alzheimer’s disease in humans. They:  Used 37 female participants between the ages of 65 and 75 in an exercise programme  Used participants that did not show symptoms of Alzheimer disease at the start of the investigation  Conducted the investigation three times a week for three months. The results showed an improvement in higher-order thinking abilities and an increased blood flow to the cerebrum. 3.3.1 From the extract state: (a) Age group of female participants (1) (b) ONE function of the hippocampus (1) 3.3.2 State the aim of this investigation. (2) 3.3.3 Explain why this investigation cannot be used to conclude that exercise reduces the risk of getting Alzheimer’s disease. (3) (7) Copyright reserved Please turn over

Life Sciences 15 NW/June 2024 Grade 12 3.4 The diagram below represents part of the human ear with middle-ear infection. 3.4.1 Identify part: (a) A (1) (b) D (1) 3.4.2 State the function of the round window. (1) 3.4.3 Explain how middle ear infection could affect hearing. (2) 3.4.4 Describe the role of auditory nerve. (2) 3.4.5 Which hearing defect is caused by hardening of tissues of part B? (1) 3.4.6 Name the treatment for the hearing defect mentioned in QUESTION 3.4.5. (1) 3.4.7 Describe how part C is involve in maintaining balance when there is change in the speed and direction of movement of the head. (4) (13) Copyright reserved Please turn over

Life Sciences 16 NW/June 2024 Grade 12 3.5 The diagram below represents a type of visual defect. 3.5.1 Identify part B. (1) 3.5.2 Name the visual defect shown in the diagram above. (1) 3.5.3 Name and describe the visual defect that occurs when part G is uneven. (3) 3.5.4 Name the TWO muscles found in part A. (2) 3.5.5 Describe how the muscles mentioned in QUESTION 3.5.4 will regulate light while driving back from the stadium at 19h30 in summer. (4) (11) [50] TOTAL SECTION B: 100 GRAND TOTAL: 150 Copyright reserved