WORDSWORTH HIGH SCHOOL
LIFE SCIENCES
GRADE 12
JUNE 2015
EXAMINER: MRS. L. SEDDON
MODERATOR: MRS. L. ANDERSON
TIME: 2 ½ HOURS
MARKS: 150
Instructions:
1. Answer ALL the questions.
2. Start each new answer on a new line.
3. Number the answers correctly according to the numbering system used in this question paper.
Numbers must be AGAINST the margin and NOT in the middle of the page.
4. Rule off after each COMPLETE question.
5. All drawings / graphs should be done in pencil and labelled in blue ink, using lower case print.
6. Draw diagrams and flow charts ONLY when requested to do so.
7. Non-programmable calculators, protractors and compasses may be used.
8. If answers are NOT presented according to the instructions of each question, candidates will
lose marks.
SECTION A:
QUESTION 1: MULTIPLE CHOICE
Various possible answers are provided to the following questions. Choose the
correct or best answer and write only the letter (A – D) next to the question number.
1.1)
Cells with an endocrine function in the testis are:
A – Cowper’s cells
B – Cells of Leydig
C – Cells of Schwann
D – Cells of Sertoli
1.2)
Which of the products in the table below is the result of meiotic division of the
primary spermatocyte (diploid number = 2n)?
Number of spermatozoa produced
Ploid number of each sperm
A1
N
B4
N
C4
2n
D2
n
1.3)
Which method will prevent the embryo from developing into a foetus?
A – Male condom
B – Morning after pill
C – Female condom
D – Birth control pill
Questions 1.4 – 1.6 are based on the diagram below which represents a longitudinal
section through the cerebrum.
1.4)
Which of the following combinations shows the parts that consist of fatty
myelinated nerve fibres?
A – 8 only
B – 8 and 13
C – 7 and 12
D – 6 and 9
1.5)
Numbers 6 and 10 are the ___________.
A – central sulcus and a gyrus
B – longitudinal sulcus and a gyrus
C – gyrus of Rolando and a sulcus
D – aquaduct of Sylvius and the dura mater
1.6)
The fluid that occurs in no. 3 is also found in _____________.
A – no. 6 and contains ammonia
B – no. 9 and removes metabolic waste products
C – no. 8 and acts as a cushion against shock
D – no. 9 and dries out the cells of the central nervous system
1.7)
Otoliths are found in the ____________.
A – ampulla
B – cupula
C – maculae
D – semi-circular canal
1.8)
A worker walks into a factory and a sharp smell causes him to cover his nose.
The receptors functioning in this area are ____________.
A – organs of Corti in the ear, which are bipolar neurons in the scala media
section.
B – olfactory cells in the nose, which are bipolar neurons in the turbinate
bones.
C – olfactory cells in the nose, which are monopolar neurons in between the
glands of Bowman.
D – olfactory cells in the nose, which are bipolar neurons in between the
glands of Bowman.
1.9)
The pathway of a nerve impulse through the eye at noon is as follows:
A – Cones bipolar neuron
ganglion cell
optic nerve
optic
chiasma
occipital lobe of cerebrum
B – Rods
cones
bipolar neuron
ganglion cell
optic nerve
optic chiasma
occipital lobe of cerebrum
C – Cones
ganglion cell
bipolar neuron
optic nerve
optic
chiasma
occipital lobe of cerebrum
D – Cones
bipolar neuron
ganglion cell
optic chiasma
optic nerve
occipital lobe of the cerebrum
1.10) Which one of the following glands functions as both an exocrine gland and an
endocrine gland?
A – Adrenal gland
B – Pancreas
C – Hypophysis / Pituitary gland
D – Thyroid gland
1.11) Which one of the following is not a property of hormones?
A – Hormones are secreted by ductless glands.
B – Most hormones are steroids.
C – Hormones have a very short life.
D – Hormones are chemicals which stimulates target cells.
1.12) Which hormones will the pancreas secrete if the blood sugar level is too high?
A – Glucagon
B – Insulin
C – Adrenaline
D - Calcitonin
1.13) Which method of contraception will be the most efficient?
A – The Pill
B – Withdrawal
C – Intra-uterine device
D – Vasectomy and the legation of the Fallopian tubes.
1.14) Which method of contraception will prevent pregnancy as well as HIV / AIDS?
A – The Pill (Oral contraception)
B – The condom
C – The intra-uterine device
D – The diaphragm
1.15) Blood from the placenta to the foetus carries ___________.
A – metabolic waste products.
B – nutrients and oxygen.
C – carbon dioxide and nutrients.
D – metabolic waste and carbon dioxide.
1.16) The hormone responsible for female secondary sex characteristics is ______.
A – prolactin
B – testosterone
C – progesterone
D - oestrogen
1.17) The spermatozoa contains _______________.
A – 22 chromosomes and an X or a Y chromosome.
B – 44 chromosomes and XX chromosomes.
C – 44 chromosomes and XY chromosomes
D – 24 chromosomes.
1.18) The developing spermatids in the seminiferous tubules are nourished by
______.
A – Sertoli cells
B – Leydig cells
C – Interstitial cells
D – Seminal vesicles
[18]
QUESTION 2: TERMINOLOGY
Provide the correct term / phrase for the descriptions / definitions that follow:
2.1) Maintenance of the constant internal environment of any cell in the body.
2.2) The abnormality in children which result from hyposecretion of thyroxine.
2.3) The mucous layer lining the uterus.
2.4) Contraction of the blood vessels in the skin during sympatheric stimulation.
2.5) The area of the central nervous system where nerve fibres between the spinal
cord and the brain cross over.
2.6) The breakdown and shedding of the endometrium of the uterine wall as well as
blood.
[6]
QUESTION 3: ANSWER RELEVANCE
Indicate if the descriptions in COLUMN B are applicable to the items in COLUMN A.
Indicate if the applicability translates to only A, only B, both A and B, or neither.
COLUMN A
3.1) Protects skin against mechanical injury
and entry of germs
3.2) Causes an increased sweat production
3.3) Play(s) a role in the osmoregulation of the
kidney
3.4) Connects the cerebellum to other parts of
the brain
3.5) Controls the biological drive of aggression
COLUMN B
A – Melanin
B – Ceratin
A – Lowering of environmental temperature
B – Diarrhoea
A – ADH and Aldosterone
B – Sodium ions
A – Vermis
B – Corpus callosum
A – Hypothalamus
B - Thalamus
[5]
QUESTION 4: SHORT QUESTIONS
The following diagrams represent certain human organs or parts thereof. Write the
name of the structure which has a circled number next to the correct number on your
folio paper. Use the numbers as from the diagrams, do NOT renumber your
answers.
Continued on next page
[9]
QUESTION 5: SHORT QUESTIONS
5.1) The following diagram illustrates the different types of neurons in the human
body.
5.1.1) No. 1 in the diagram represents certain types / kinds of receptors in the
human body. The function of receptors is to convert stimuli to impulses.
Write down the receptors that will be stimulated when you are exposed
to the following stimuli:
a) Being tickled by a feather.
b) Holding an ice pack to your sprained ankle.
c) Testing the temperature of a hot iron with your finger.
(3)
5.1.2) a) Where in the body can number 2 and 3 be situated respectively?
b) Identify structure 4 and name one function of this structure.
5.1.3) a) Name the types of neurons represented by numbers 3 and 5.
5.1.4) a) What is represented by no. 6?
b) Name TWO types of organs that fulfil the function of no. 6.
(2)
(2)
(2)
(1)
(2)
[12]
TOTAL SECTION A: 50
SECTION B: LONGER QUESTIONS
QUESTION 6:
6.1) The number of ova in every ovary is already determined at birth. Therefore a girl
is born with a specific amount of oogonia in her ovaries. Give a schematic
representation of the Oogenesis process from the time a girl reaches puberty
until ovulation.
(8)
6.2) Draw a labelled diagram of an ovum just before fertilization.
(5)
6.3) Study the diagram of the female reproductive system and answer the questions
that follow:
6.3.1) Discuss multiple pregnancies in humans with reference to the provided
Diagram only.
(5)
6.3.2) Name the hormones that play a role in ovulation and lactation
respectively, as well as their location of formation.
(6)
6.4) Discuss the importance of antenatal care during pregnancy by referring to a the
role of a healthy diet.
(3)
[30]
QUESTION 7:
7.1) Discuss the autonomic nervous system by referring to the two subsystems of
the autonomic system and how they function.
(7)
7.2) a) Which effector has the greatest impact on the autonomic system?
b) Explain your answer to question 7.2 (a) above.
(1)
(4)
7.3) The following diagrams represent the human eye. Study them and answer the
questions that follow:
7.3.1) Write down the numbers of three structure that protect the eye against
mechanical injuries.
(3)
7.3.2) Discuss the process that takes place at number 6 when one is looking
at a bright light.
(3)
7.3.3) Provide the number of the structure that experiences a problem when
suffering from:
a) Astigmatism
b) Cataracts
c) Dust scratching your eye.
(3)
7.3.4) Identify the structures that are responsible for creating tears and the
sand-like particles after you have been asleep, respectively. Write only
the structure numbers as your answers.
(2)
7.4) The diagrams below represent an exocrine and an endocrine gland. Study the
diagrams and answer the questions that follow:
7.4.1) Explain the terms ‘exocrine’ and ‘endocrine’ by referring to the function
of the pancreas at number 1 and 2 respectively in Diagram A.
(6)
7.4.2) Discuss the role of the alpha cells in Diagram B in the process of
glycogen breakdown.
(6)
7.4.3) Provide three characteristics of hormones.
(3)
7.4.4) Give one example of another exocrine gland and provide the name of
the secretion that is released from it.
(2)
[40]
TOTAL SECTION B: 70
SECTION C:
QUESTION 8:
8.1) Study the diagram below and identify structures as indicated below:
a)
b)
c)
d)
e)
f)
g)
h)
i)
j)
1
5
6
8
9
11
12
13
15
Heading
(10)
8.2) Carefully read the scenario below and answer the question that follows:
A whole life in a single paragraph
Peter is a human male, currently 26 years old. He has grown since birth,
successfully crossed through puberty and navigated numerous stimuli from his
environment. He participated in sport such as cricket, where he proved to be a very
useful wicket keeper.
Write a biological essay in which you explain the processes that have governed the
major activities in Peter’s life (as indicated in the scenario).
(17)
Synthesis (3)
(20)
TOTAL Section C: 30
TOTAL for Exam - 150