Biology for CAPE Unit 1 Chapter 12 Answers



There is document - Biology for CAPE Unit 1 Chapter 12 Answers available here for reading and downloading. Use the download button below or simple online reader.
The file extension - PDF and ranks to the School Work category.


239

views

on

Extension: PDF

Category:

School Work

Pages: 8

Download: 60



Sharing files


Tags
Related

Comments
Log in to leave a message!

Description
Download Biology for CAPE Unit 1 Chapter 12 Answers
Transcripts
    Biology for CAPE Original material © Cambridge University Press 2011 1   12 Answers to end-of-chapter questions 1 B [1] 2 A [1]  3 C [1]  4 B [1]  5 B [1]  6   A  [1] 7   A  [1] 8   B [1] 9 A [1] 10 C [1] 11 A [1] Structured questions 12 a   i • Characterised by a large, fluid-filled antrum   •   Secondary oocyte pushed to one side   •   Thin layer of theca cells / granulosa cells on the periphery 3–4 points [2] •   The corona radiata surrounds the oocyte 1–2 points [1] ii I – corona radiata / granulosa cells [1] II – theca [1] III – antrum [1] IV – secondary oocyte [1] iii Magnification = size of scale bar / actual size = 20 000/50 Complete calculation [2] = × 400 Partial [1] b corona radiata zona pellucida lipid droplets haploid nucleus nucleolus cortical granules / lysosomes mitochondrion first polar body cytoplasm Good drawing [1] 5–6 labels [3] 3–4 labels [2] 1–2 labels[1]    Biology for CAPE Original material © Cambridge University Press 2011 2   c • Only meiosis I has been completed with the production of 1st polar body   •   Meiosis II is not completed / arrested in metaphase II •   It is only completed when the sperm enters the oocyte 3–4 points [2] •   Completion of meiosis II produces 2nd polar body and ovum 1–2 points [1] d I – oestrogen II – progesterone III – LH 3–4 correct [2] IV – FSH 1–2 correct [1] 13   a I – chorion II – amnion III – cavity of uterus IV – umbilical cord V – allantois 8–9 correct [5] VI – yolk sac 6–7 correct [4] VII – placenta / chorionic villi 4–5 correct [3] VIII – amniotic fluid 2–3 correct [2] IX – foetus 1 correct [1] b • amnion •   chorion •   yolk sac 3–4 correct [2] •   allantois 1–2 correct [1] c • To protect the foetus or embryo from physical shock and mechanical damage; it acts as shock absorber    •   The foetus can move freely / allows development of the skeleton and muscles and lung development •   Provides a sterile environment hence prevents infection •   Supports the foetus so it floats •   Maintains a constant temperature in the foetus •   Acts as a receptacle for waste eg exfoliations, secretions, urine from foetus •   The foetus swallows the amniotic fluid and therefore develops Any 1 point [1] swallowing reflex [max 3] d Smoking   •   IGUR / slow / stunted growth / underweight baby •   Carbon monoxide binds irreversibly to form a stable compound with haemoglobin in red blood cells of foetus •   Carbon monoxide has a higher affinity for haemoglobin than oxygen •   Reduces oxygen transport •    Nicotine constricts / narrows / reduces blood flow in arteries •   Reduces transport of nutrients •   Increases foetal heart rate •   Small placenta •   Both carbon monoxide and nicotine reduce the foetus’s growth in uterus •   Increased risk of miscarriage / prenatal mortality / stillbirth •   Baby might be premature / have respiratory illness Any 1 point [1] •   immature lungs / size of lungs reduced by 30% [max 5] Drawing showing the detailed structure of a secondary oocyte    Biology for CAPE Original material © Cambridge University Press 2011 3   Alcohol   •   Foetal alcohol syndrome •   Slows nervous system and brain development •   Heart defects •   Cleft palate •   Poor muscle tone Any 1 point [1] •   Abnormal limb development [max 2] 14 a i I – acrosome   II – nucleus III – mitochondrion 3–4 correct [2] IV – axial filament 1–2 correct [1] ii I    –    contains hydrolytic enzymes which are released during fertilisation and are used to digest a path into the female gamete [1]   •   II    –    contains the haploid number of chromosomes and carries the male genetic material; fuses with female gamete to keep the chromosome number constant [1]  iii • III produce large amounts of ATP in aerobic respiration [1]   •   ATP required by the microtubules of IV to move relative to each other in order to bring about the wavelike movements of the tail,  producing the swimming movements used to take the spermatozoan to the female gamete [1]  b 3 labels [2] 2 labels [1]  Drawing showing a section through middle Correct drawing [2]  piece of the human sperm   Partial [1] [max 4]  plasma membrane mitochondrion 9 + 2 microtubules