Winter Teacher Doc LFSC Grade 12 2023 Final

CURRICULUM GRADE 10-12 DIRECTORATE NCS (CAPS) TEACHER SUPPORT DOCUMENT WINTER CLASSES GRADE 12 LIFE SCIENCES STEP AHEAD PROGRAMME 2023

Life Sciences Grade 12 Winter Classes 2023 CONTENTS No. TOPIC PAGE NO. 1. Genetics 2 - 11 2. Nervous System 12 -14 3. Eye 15 4. Ear 16 - 17 5. Endocrine and Homeostasis 18 – 21 1

Life Sciences Grade 12 Winter Classes 2023 Topic: Genetics Activity 1 Give the correct biological term for each of the following descriptions. No. Description Biological Term 1.1 The position of a gene on a chromosome Locus 1.2 Undifferentiated cells that may be stimulated to develop into any Stem cells type of body cell 1.3 Mendel's principle which states that an organism possesses two Mendel’s law of factors which separate so that each gamete contains only one of segregation these factors 1.4 The biotechnological production of genetically identical Cloning offspring. 1.5 The genetic crossing of two organisms in which two pairs of Dihybrid contrasting characteristics are studied. 1.6 Individual having two alleles that influence a characteristic in Heterozygous different ways 1.7 The physical and/or functional expression of a gene Phenotype 1.8 An allele that expresses itself only when in the homozygous Recessive condition 1.9 A sex linked disorder that affects the photoreceptors in the eye Colour-blindness 1.10 The insertion of a gene from one organism into the genetic Genetic material of another organism engineering 1.11 The number , shape and arrangement of all the chromosomes Karyotype in the nucleus of a somatic cell 1.12 A genetic disorder resulting in the non-production of the clotting Haemophilia factor in blood 1.13 A sudden change in the structure of a gene or chromosome Mutation 1.14 Disorder caused by the presence of an extra copy of Down syndrome chromosome 21 1.15 Characteristics controlled by alleles that are located on the Sex linked gonosomes disorder Activity 2 2.1 Spotted back  (1) 2.2 Spotted frogs produced offspring without spots OR The spotted offspring were three times more than offspring without spots / ratio spotted offspring to offspring without (2) spots is 3:1 2

Life Sciences Grade 12 Winter Classes 2023 (9) Activity 2 2.1 Spotted back  (1) 2.2 Spotted frogs produced offspring without spots OR The spotted offspring were three times more than offspring without spots / ratio spotted offspring to offspring without (2) spots is 3:1 3

Life Sciences Grade 12 Winter Classes 2023 (9) Activity 3 3 3.1 Incomplete dominant (1) 3.2 - The pink flower is an intermediate phenotype / a blend of red and white (1) - indicating that neither of the alleles is dominant 4

Life Sciences Grade 12 Winter Classes 2023 3.3 (2) (15) Activity 4 4 4.1 954 000 (1) 4.2 1800 000 – (954 000 + 180 000 + 54 000) = 612 000 people OR 1 800 000 – 1 188 000 = 612 000 people OR 34 x 1 800 000 = 612 000 100 (3) 4.3 - The allele for blood group A / IA is inherited from one parent and (3) - the allele for blood group B / IB is inherited from the other parent therefore - the child has blood group AB / genotype IAI (7) 5

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Life Sciences Grade 12 Winter Classes 2023 Activity 5 5 5.1 One /1 (1) 5.2 Mrs Thomas (1) 5.3 -The child has the genotype ii / is homozygous recessive and - if both parents are heterozygous  / have the genotypes IAi or IBi - she inherits one recessive allele from each parent (3) 5.4 Three  / 3 (1) (6) Activity 6 6 6.1 (2) 6

Life Sciences Grade 12 Winter Classes 2023 6.2 (10) Activity 7 7 7.1 Dihybrid (1) 7.2 TTrr (2) 7.3 TR, Tr, tR, tr (4) 7.4 (7) Activity 8 8 8.1 Round shape , red flower (2) 8.2 DE , De, dE, de 7

Life Sciences Grade 12 Winter Classes 2023 8.3 (10) Activity 9 9 9.1 (a) RRLL (1) (b) Red fruit and spiny leaves (2) 9.2 (3) 9.3 -rrLL (2) OR - One parent is rrLL and the other parent is rrLl (8) Activity 10 10 10.1 High yield  Short stem  (2) 10.2 hT  (1) 10.3 HHtt , Hhtt  (2) 10.4 The plant breeder must cross plants of variety A (HHtt) with plants (2) of variety A (HHtt) (7) 8

Life Sciences Grade 12 Winter Classes 2023 Activity 11 11 11.1 - Embryo - Umbilical cord - Bone marrow (Mark first THREE only) (3) 11.2 - Stem cells are undifferentiated  - and have the potential to develop into any type of cell - to replace affected / defective cells causing a disorder  Any (2) 11.3 - Heart disease - Spinal injuries (Mark first ONE only) Any (1) (6) Activity 12 12 12.1 -The manipulation of genetic material (2) -to produce a genetically different / identical organism / repair tissues and organs OR - The manipulation of genetic material  - to produce something of benefit to humans / society 12.2 - A plasmid / circular DNA is removed from the bacteria cell (4) - it is cut using enzymes - The insulin gene is removed from a human cell and - inserted into the plasmid to form the recombinant DNA 12.3 - Bacteria reproduce very rapidly (2) - forming many copies of the gene in a short period of time OR - Bacteria reproduce asexually / by mitosis, - forming identical copies of itself OR - The bacteria DNA is in the form of a plasmid - for easy insertion of genes OR - Bacteria exist everywhere, - So they can be obtained with no difficulty / expense OR - Bacteria are simple organisms , - so their use is unlikely to raise ethical issues (Any 1x 2) 12.4 - Expensive / research money could be used for other needs (3) - Interfering with nature / immoral - Potential health impacts -Unsure of long-term effects  (Any 3) (Mark first THREE only) (11) 9

Life Sciences Grade 12 Winter Classes 2023 Activity 13 13 13.1 Males (2) 13.2 (a) 3 / Three (b) 3 / Three 13.3 (a) T U (2) (b) XHXh  (2) (7) Activity 14 14 14.1 3 /Three (1) 14.2 (a) H (1) (b) Rr (1) (c) C and F (2) (5) Activity 15 15 15.1 Incomplete dominance (1) 15.2 (a) RR (2) (b) RW (2) (c) WW  (2) (7) Activity 16 16 16.1 - Decide on the sample size - Decide on the sample selection - Get permission from the school to conduct the investigation - Decide on the appropriate time / day / venue to conduct the investigation - Decide on how to record the results of the investigation - Ask permission from participants (Mark the first THREE only) (3) 16.2 -Same person counted - Equal number of boys and girls (2) 16.3 To ensure / increase the reliability of the investigation (1) 16.4 (4) Boys Girls Tongue rollers 260 220 Non tongue rollers 15 55 Marking Criteria Columns heading (C) 1 Rows heading (R) 1 Data correct in the table (T) 1: 1-3 correct 2: All correct (10) 10

Life Sciences Grade 12 Winter Classes 2023 Activity 17 17.1 • Glyphosate resistance increased • from 2009 to 2015 • and remained constant in 2016  (3) 17.2 45 〉  x 100  20 =225  (3) 17.3 • The glyphosate will not kill the maize • A greater yield of maize • Means greater profit OR • Application of the glyphosate does not have to be selective • this will save on labour / time / costs which • means greater profit (3) 17.4 (6) (10) 11

Life Sciences Grade 12 Winter Classes 2023 Topic: Nervous System Activity 1 No. Description Biological Term 1.1 The functional gap at which a nerve impulse passes from neuron Synapse to another 1.2 A disease characterised by the degeneration of brain cells and Alzheimer memory loss 1.3 Type of neurons that joins sensory and motor neurons Interneuron /connector neuron 1.4 Part of a neuron which contains the nucleus Cell body 1.5 Fluid around the brain and spinal cord that aids in protection Cerebro-spinal fluid 1.6 The part of the skull that protects the brain Meninges (1 x 6) (6) Activity 2 2.1 Reflex arc  (1) 2.2 (a) B Motor neuron /efferent neuron (1) (b) C Interneuron /connector neuron (1) (c) E Sensory neuron /efferent neuron (1) 2.3 (a) F  (1) (b) A  (1) 2.4 (a) D Synapse (2) (b) G  Myelin sheath (2) (10) Activity 3 3 3.1 The pathway along which nerve impulses are carried from a receptor to an (2) effector to bring about a reflex action. 3.2 A person would be able to feel the sensation but is unable to react to the (1) stimuli. 3.3 Multiple sclerosis (2) (5) Activity 4 4 4.1 Smooth muscles  Heart muscle Glands  (Mark first TWO only) (2) 4.2 - Every organ/gland are controlled by two sets of nerves  - that act antagonistically  Autonomic nervous system is divided into - Sympathetic nerves  and 12

Life Sciences Grade 12 Winter Classes 2023 - Parasympathetic nerves  - Sympathetic nerves stimulate  - fight of flight function  in emergency situations - Parasympathetic inhibits  a response and - restores the body to normal  (5) (7) Activity 5 5 5.1 (a) Myelin sheath  (2) (b) Axon  5.2 (a) A  (2) (b) C 5.3 D Synapse (2) (6) Activity 6 6 brain 6.1 Corpus callosum (1) 6.2 - It controls vital processes/heartbeat/breathing (2) - which will stop when it is damaged 6.3 (a) Spinal cord (1) (b) - The impulses from the cerebrum (2) - are not transmitted to the skeletal muscles (6) Activity 7 7 7.1 Africa (1) 7.2 - Not all brain injuries are recorded (2) - due to poor health facilities 13

Life Sciences Grade 12 Winter Classes 2023 7.3 (9) Activity 8 8 8.1 - From the dendrite ✓ (2) - to the axon ✓ 8.2 0 to 1 ✓ µm ✓ / 0 to 0.9 µm (2) 8.3 As the axon diameter increases the speed of impulse increases ✓✓ OR (2) As the axon diameter decreases the speed of impulses decreases ✓✓ 8.4 - The speed of the impulse will decrease ✓ - resulting in taking longer for impulses to reach the effectors ✓ - and the person will react more slowly ✓ (3) (9) 14

Life Sciences Grade 12 Winter Classes 2023 Topic: Eye Activity 1 No. Description Biological Term 1.1 The type of vision where both eyes are used to focus on an object Binocular Vision 1.2 The visual defect characterised by a cloudy lens Cataracts 1.3 The nerve that transmits impulses from the eye to the brain Optic nerve 1.4 The protective membrane covering the cornea of the eye Conjunctiva 1.5 A visual defect caused by the uneven curvature of the cornea Astigmatism 1.6 The area of the retina that contains the highest concentration of cones Yellow spot/Fovea (1 x 6) (6) Activity 2 2 2.1 B – Sclera ✓ (1) G – Iris ✓ (1) I – Cornea ✓ (1) 2.2 (a) H ✓ – Pupil ✓ (2) (b) F✓ – Optic nerve ✓ (2) (c) A ✓ – Eyelid ✓ (2) 2.3 (a) It contracts ✓ (1) (b) It slackens ✓/loosens (1) (c) Becomes more convex ✓/more rounded (1) 2.4 (a) Concave lenses ✓/ Concave Glasses/(Laser) surgery (1) (b) Surgery ✓/synthetic lens (1) (14) Activity 3 3 3.1 (a) Different light conditions✓ (1) (b) Diameter of the pupil✓ (1) 3.2 Only one person ✓ participated in the experiment/small sample size The experiment was not repeated ✓/only done once (2) 3.3 (3) 3.4 Iris✓ (1) 3.5 Pupil mechanism✓ (1) 3.6 Circular muscles of the iris relax✓ Radial muscles of the iris contract✓ Pupil diameter increases✓ (3) 3.7 (a) 5✓mm (1) (b) 3✓ (1) (14) 15

Life Sciences Grade 12 Winter Classes 2023 Topic: EAR Activity 1 No. Description Biological Term 1.1 A structure in the ear that absorbs excess pressure waves from inner ear Round window 1.2 Part of the ear that equalises pressure on the either side of the tympanic membrane Eustachian tube 1.3 A structure in the ear that absorbs excess pressure waves from Round window the inner ear 1.4 Receptors in the semi-circular canals that are sensitive speed cristae and direction 1.5 Structure inserted to the tympanic membrane to allow air to pass Grommets into the middle ear 1.6 The structure within the cochlea responsible for picking up the Organ of Corti stimulus of sound (1 x 6) (6) Activity 2 2 2.1 Cochlea ✓ (1) 2.2 (a) Absorbs excess pressure waves/releases pressure from the inner ear/ prevents an echo (1) (b) It converts stimuli/pressure waves into impulses (1) 2.3 Part A ✓/tympanic membrane will not be able to vibrate/vibrate freely (2) 2.4 - Middle ear infections cause fluid build-up in the middle ear - which can block the Eustachian tube - The grommet will release the pressure that will build up in the middle ear/ drain the fluid from the middle ear - The pressure on either side of the tympanic membrane is equalised - preventing the tympanic membrane from rupturing and - allowing the ossicles to vibrate freely Any (4) 2.5 - The cristae are stimulated and - convert the stimuli into impulses - The impulses are sent via the auditory nerve - to the cerebellum - which interprets the information and - sends impulses to the skeletal muscles to restore balance Any (4) (13) Activity 3 3 3.1 (a) Semi-circular canals✓ (1) (b) Auditory canal ✓ (1) 3.2 (a) E✓ - Oval window✓ (2) (b) D✓ - Round window✓ (2) 16

Life Sciences Grade 12 Winter Classes 2023 3.3 (a) Cerebellum✓ (1) (b) Hair cells/Organ of Corti✓ (1) 3.4 -The pinna of the ear traps sound waves✓ -The auditory canal directs the sound waves to the tympanic membrane✓ -causing the tympanic membrane to vibrate✓ -which causes the ossicles to vibrate✓and -pass the vibrations to the oval window✓/ amplify the vibrations -(Pressure) waves are set up in the inner ear✓ / perilymph/endolymph -The organ of Corti is stimulated✓ -and converts the stimuli into impulses✓ -which are transmitted by the auditory nerve✓ -to the cerebrum✓ for interpretation Any (7) (15) 17

Life Sciences Grade 12 Winter Classes 2023 Topic: Homeostasis and Endocrine Systems Activity 1 No. Description Biological Term 1.1 Joint linking and working together of systems and activities within Coordination the body to bring about a harmonious response. 1.2 A system responsible for chemical co-ordination and regulation of Endocrine system various activities in the body 1.3 Organic chemical messengers secreted directly into the blood by Hormones an endocrine gland. 1.4 Organs which respond to specific hormones received through the Target organs bloodstream 1.5 It is the process of maintaining a constant internal environment Homeostasis Within narrow limits, despite changes that take place internally and externally. 1.6 When there is an increase from normal, a corrective mechanism Negative feedback causes a decrease and vice versa to maintain a balanced system. mechanism 1.7 Regulation of water balance in the internal environment Osmoregulation 1.8 To work in opposite ways; if one hormone causes an increase of Antagonistically a substance, the other hormone will cause a decrease of that substance. (1 x 8) (8) Activity 2 2 2.1 Thermoregulation ✓ (2) 2.2 − As the environmental temperature increases − the hypothalamus is stimulated ✓ − and sends impulses to the blood vessels ✓ of the skin − Blood vessels dilate /blood vessels become wider/vasodilation occurs − More blood flows to the surface of the skin ✓ − More heat radiates from the skin ✓ − (So average heat released/lost increases) (Any 3) (3) 2.3 − As the environmental temperature increases above/beyond body temperature ✓ − the average heat released/lost through radiation reaches its maximum ✓ /levels out/no gradient for radiation of heat − therefore, increased sweating will occur ✓/sweat glands become more active − As the sweat is evaporated ✓ − it allows the body temperature to decrease ✓/more cooling of the skin will occur (Any 4) (4) 18

Life Sciences Grade 12 Winter Classes 2023 2.4 (6) (14) Activity 3 3 3.1 Thyroxin ✓ (1) 3.2 Regulates the rate of: − Respiration ✓/energy production − Energy consumption ✓/metabolism − Heat production ✓ − Heart rate ✓ Mark first TWO only (2) 3.3 − Fat ✓ − (Muscle) protein ✓ Mark first ONE only (1) 3.4 Glycogen✓ (1) 3.5 − Blood glucose level decreased below normal ✓ − The pancreas/islets of Langerhans will be stimulated ✓ 19

Life Sciences Grade 12 Winter Classes 2023 − Glucagon is secreted ✓ − which is transported via blood ✓ − to the liver ✓ − and muscle cells ✓ − which converts glycogen ✓ into glucose − increasing blood glucose levels ✓to normal (Any) (6) (11) Activity 4 4 4.1 Negative feedbackmechanism (1) 4.2 (a) Thyroid (1) (b) TSH/thyroid stimulating hormone (1) (c) Thyroxin (1) 4.3 Goitre (1) 4.4 Hormone A (1) (6) Activity 5 5 5.1 Insulin (1) 5.2 (a) Pancreas (1) (b) Islets of langerhans (1) 5.3 Negative feedback reaction (6) - The glucose concentration in the blood drops below normal  - The alpha cells/islets of Langerhans/pancreas detect the drop and secretes glucagon  - in the blood  - which is transported to the liver /muscle cells - Glucagon stimulates the conversion of glycogen to glucose  - The glucose concentration in the blood returns to normal (9) Activity 6 6 6.1 (a) Wearing of a facemask  (1) (b) Carbon dioxide levels in blood  (1) 6.2 -Age  -Healthy  individuals (Mark first TWO only) (2) 6.3 150 volunteers were used  (Mark first ONE only) (1) 6.4 - To allow the carbon dioxide levels in the blood to go back to normal  - so that each phase will have the same carbon dioxide level as a starting point  (2) 6.5 - To act as a control /baseline - To see if it is the facemask that affects the carbon dioxide levels and not the physical activity  Any (1) 6.6 - Receptors in the carotid artery are stimulated  and - impulses are sent to the medulla oblongata 20

Life Sciences Grade 12 Winter Classes 2023 - The medulla oblongata stimulates the heart  - to beat faster  causing - more carbon dioxide to be taken to the lungs  - The breathing muscles /intercostal muscles and diaphragm - contract more actively  and - the rate/ depth of breathing increases  - More carbon dioxide is exhaled  - The carbon dioxide level in the blood decreases  /returns to normal Any (7) (15) Activity 7 7 7.1 71.53 – 34.72 = 36.81ml/h (2) 7.2 - The high level of ADH at night - Increases the permeability of the renal tubules/collecting duct/distal convoluted tubules in the kidney - More water is re-absorbed/less water is excreted - Less urine is produced (4) 7.3 - Less urine produced/more water is retained (2) - A person will not need to urinate often/ will not be thirsty/sleep will not be interrupted 7.4 - Water will not be reabsorbed from the renal tubules - The volume of water in the blood will be low - The pituitary gland will be stimulated - to release more ADH all the time Any 3 (3) (11) 21