basic education
Department:
Basic Education
REPUBLIC OF SOUTH AFRICA
NATIONAL
SENIOR CERTIFICATE
[
~/4,, ii
GRADE 12 ]
....... ~~~~~~~~~~ ~~~ ~~ ~ ~~~~~~~~~~~~~ ~ ~ ~~.
ii ii ii ii ii ii - - - - - - -
II
II
II
II
ll
LIFE SCIENCES P2
II
II
II
II
NOVEMBER 2022
II
~~~~~~~·········
---------~~~~~~~~~~~~ ----------~~~~- -----~~
MARKS: 150
TIME: 2½ hours
-
ii
!!!!
ii
!!!!
----
This question paper consists of 15 pages.
Copyright reserved
!!
Please turn over
lif e Sclences/P2
2
DBE!Nov9mt'Jr 1,,,i/ ,/
NSC
INSTRUcr ,
N
ONS AND INFORMATIO
.
ctio
Read the fo llo wi ng instru ns carefully before answering th e qu es tions
1
·
tions.
An sw er AL L th e qu es
·
OK.
s in the ANSWER BO
er
th
sw
an
e
L
AL
e
rit
W
2
3.
4.
5.
6.
7.
8.
9.
10.
11 .
W page.
tion at the top of a NE
es
qu
CH
EA
to
s
er
S ar t th e an sw
m used in this
to the numbe rin g syste
ing
rd
co
ac
y
ctl
rre
co
Nu m ~e r the answers
qu es tion pa pe r.
estion.
instructions of each qu
the
to
ing
rd
co
ac
s
er
Pr es en t yo ur answ
in blue or black ink .
pencil and label them
in
s
ing
aw
dr
L
AL
Do
asked to do so .
or flow charts only when
les
tab
s,
am
gr
dia
Dr aw
wn to scale .
are NO T necessarily dra
r
pe
pa
n
tio
es
qu
s
thi
Th e diagrams in
t
per.
Do NO T use graph pa
mpass,
, protractor and a co
tor
la
lcu
ca
le
ab
m
m
ra
n-prog
Yo u m us t use a no
wh er e necessary.
y.
W rite neatly and legibl
j
V
I
Please turn
ove r
3
NSC
Life Sciences/P2
DBE/November 202?
SECTION A
QUESTION 1
1.1
Various options are provided as possible answ
ers to the follo wing 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 ANS WER BOO K,
e.g. 1.1.10 D.
1.1.1
The scientist who discovered the fossil 'Kara bo'
(A sediba):
A Robert Brown
B Lee Berger
C Raymond Dart
D Ronald Clarke
1.1 .2
Which ONE of the following is a source of varia
tion that occurs
during normal meiosis?
A
B
C
D
1.1.3
1.1.4
How many sex chromosomes does a normal huma
n fema le inherit
from her mother?
A
1
B
2
C
D
23
46
During which phase of meiosis does the
nuclear membrane
disappear?
A
B
C
D
1.1.5
Metaphase
Telophase
Prophase
A naph ase
-
Which ONE of the fol lowing is an example
of disco ntinu ous
variation in humans?
A
B
C
D
Copyright reserv ed
Random mating
Random arrangement of chromosomes
Chromosomal mutations
Cloning
Heig ht
Heart rate
Gend er
Weight
Please turn over
li1e Sciences/P2
4
DBE /November 202
NSC
1 .1 .6
2
For a particular characteristic,
the offs prin g inh erit s .. .
A
one allele from the mo the r and
one allele from the fath er.
B both alleles from the fath er
.
C both alleles from the mother.
D the alleles from either the mo
the r or the fath er ran dom ly.
1.1 .7
Which ONE of the following is
CORRECT for speciation thro ugh
geographic isolation?
A The populations undergo phe
notypic changes only.
B Each population undergoes
natural selection independently
.
C The conditions on each side
of the geographic barrier are the
same.
D The new species formed are
genotypically the same as the
orig inal species .
1.1.8
Below is a list of events that occ
ur during
(i)
(ii)
(iii)
cell division .
Homologous chromosomes line
up at the equator of the cell.
Chromatids are pulled to opposit
e poles of the cell.
Chromosome pairs arrange the
mselves randomly at the
equator of the cell.
Individual chromosomes line up
at the equator of the cell.
(iv)
Which ONE of the following com
binations occur in both meiosis
and mitosis?
A
B
C
D
1 .1.9
(ii), (iii) and (iv) only
(i) and (iv) only
(i), (iii) and (iv) only
(ii) and (iv) only
A short piece of DNA, containing
19 nucleotides in each strand ,
was analysed. The number of
some of the different nitrogenous
bases in each strand is shown belo
w.
A
Strand 1
Strand 2
8
-
Number of nitrogenous bases
T
G
-
3
8
C
4
How many nucleotides contain
ing thymine (T) were present
in
strand 1?
A
B
C
D
Cop yrig ht rese rved
8
4
6
2
(9 X 2)
Please turn over
(1 8)
Life Sciences/P2
1.2
5
NSC
DBE/November 2022
G'
the correct biological term for each
of the follo wing des criptions.
only the term nex t to the question num
bers (1 .2.1 to 1.2.9) in the
ANSWER BOOK.
~~i~e
1.2.1
The process of change in the characte
ristics of biological spe cies
over time
1.2.2
The type of bonds between nitrogenous
base s in a DNA mole cule
1.2.3
The structure that joins two chromatids of
a chromosome
1.2.4
The division of the cytoplasm of a cell durin
g cell division
1.2.5
The process during meiosis where there
is an exchange of genetic
material between chromatids
1.2.6
The structures in animal cells that give rise
to spindle fibres during
cell division
1.2.7
Similar structures that are inherited from
a common ancestor and
are modified for different functions
1.2.8
The phase in the cell cycle during which DNA
replication takes place
1.2.9
1.3
The organelle where translation occurs durin
g protein synthesis
(9 X 1)
Indicate whether each of the descriptions
in COLUMN I applies to A ONLY,
B ONLY, BOTH A AND B or NONE of the
items in COLUMN 11. 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.
1.3.1
1.3.2
1.3.3
Copyright reserved
COLUMN I
COLUMN II
Type of evolution characterised A: Artif
icial selection
by long periods of little or no
B: Punctuated equilibrium
change alternating with short
periods of rapid change
A plant with white flowers that is A:
Incomplete dominance
crossed with a plant with red
B: Complete dominance
flowers and produces offspring
with pink flowers
The separation of alleles during A: Law of Dom
inance
gamete formation
B: Principle of Segregation
(3
(9)
--
i ii
X 2)
Please turn over
(6)
.. 'e Sc ence s D~
1lli l /Novornber
1()11
G
NSC
Mo, amoya 1s a
\ allele (R ). Th is
d1so1de1 rB used
di so rd er
by 8 cloininan
oama9e$ \he Rr
te, ,es supplying
bl oo d \o \l\ c:
br ai n
1•~c t"C"u gr('>P dm~1
al
,1rn below s\~ow
s \\~ c 1nhcn\ance Moyamoya in a family .
- -A
- - -- - - -
B
-i
G
H
J
KEY
\□
U n affected m al
e
Affected male
• L,
2
•
Unaffected fem
ale
Affected femal
e
H ow m an y ge ne
ra tio ns are repr
esented in the di
agram?
G ive the .
(a )
l b)
(c)
Co py rig ht reserv
ed
0
LE TT E R (S ) of un
affe cted m al es
G en ot yp e of indi
vidual A
(1 )
(1 )
LE TT E R (S ) of
indi viduals not bi
ologically re late
d to A and B
Pl e>nse turn ove1
(1)
,2 )
l5)
7
LIie Scie nces/P2
1.5
DBE/November 2022
NSC
Th e diagram bel ow rep res
ent s par t of an ab no rm al
hu ma n kar yot ype .
21
22
23
AAA AA ~ A
'\ .5.'\
How ma ny autosomes are
sho wn in the dia gra m?
( 1)
'\ .5.2
Name the type of chr om oso
me s rep res ent ed by pai r 23
.
(1)
1.5 .3
1 .5.4
1.6
Name the :
(a)
Disorder represented in the
diagram
(b)
Process during anaphase
of meiosis tha t resulted
in the
abnormal number of chrom
osomes in this karyotype
(1)
State the gender of the per
son represented in this kar
yotype .
In rabbits , brown fur (B)
is dominant to white fur (b)
and long ears (E) is
dom ina nt to short ears (e) .
( 1)
( 1)
(5)
A rab bit, that is heterozyg
ous for both characteristics
, is crossed with a white
rab bit wit h short ears.
1.6 .1
Na me the type of cross rep
resented .
1.6 .2
Giv e the :
( 1)
(a)
Phenotype of a rabbit that is
dominant for both characteri
stics
(b)
Genotype of the white rabbit
with short ears
' '
(c)
(2)
(2)
Ge not ype of the gametes of
a heterozygous brown rabbit
with
sho rt ears
(2)
(7)
TOT AL SECTION A:
Copyright reserve d
Please tum ove r
50
-------
---
!!!!!!
_______,....----~-~
DBE/Nov8rnbF'>r
) ();';
8
Life Sciences/P2
NSC
SECTION B
QUESTION 2
2.1
.
is
. . during protein synthes .
The diagram below represents transcription
Adenine
DNA
mRNA
2 .1.1
Name the part of the cell where this process occurs .
2.1.2
(1)
Identify:
(a)
Sugar X
(b)
Nitrogenous base Y
( 1)
( 1)
2.1.3
Tabulate
replication.TWO
differences
between
transcription
and
DNA
(5)
(8)
Copyright reserved
Please turn over
Life Sciences/P2
2.2
9
NSC
DBE/Nove mber 2022
A mutation has occurred on a section of an mRNA molecule as shown below.
Oriqinal sequence
1 Mutated sequenc e
2.2.1
2.2.2
2.2.3
AU G GAA AUA CCG CCA GGA
AUG GAA AUA CUG CCA GGA
Name the type of mutation that has occurred .
(1 )
Give a reason for your answer to QUESTI ON 2.2.1.
(1)
The table below shows some mRNA codons and the amino acids
that they code for.
(a)
(b)
(c)
mRNA codon
Amino acid
AUA
AUG
CCA
CCG
CUG
GAA
GGA
lsoleucine
Methionine
Praline
Praline
Leucine
Glutamic acid
Glycine
State the number of different amino acids coded for by the
original sequence of the mRNA molecule given above.
(1)
Give the anticodon on the tRNA molecule that carries the
amino acid isoleucine.
(1)
Use information in the table to describe the effect of the
mutation on the protein formed .
(4)
(8)
Please tum over
Copyright reserved
l 1ft'
S C'll111l'l'SIP 2
1l)
N~C
2.3
The nu111be1 of cl1ro111osomes i11 the soi 1111tlc
' culls f'
' 1jc•rrw tJlff,,w from
u or~J,H
"
'
species lo species
The graph below shows the 11u111ber of, chromosomes I , .~
n 8iJC 11 u•·c1rnc:1tic c;tJI I uf
TH REE different species.
The numb er of chrom osom es in the soma tic cells
of
three differ ent spec ies
81 60 ..--- - - - - -- - - - - - - -E
~
0
50 -+---- -- -- - - - - -- - - - - - -
E 40 + - - -- - - - - o
30 - t - - -
.c
(J
....0
...
Q)
.c
20
10
E 0
~
z
Giraffe
Mouse
Pineapple plant
Species
2.3.1
How many chromosomes will be present in:
(a) Mouse cells during Telophase II of meiosis
( 1)
(b) A leaf cell of a pineapple plant
(1)
2.3.2
Explain why the sperm cell of a giraffe has 15 chromosom
es.
(4)
2.3.3
Name the phase of meiosis where the halving of the chrom
osome
number begins.
2.3.4
Describe the events in the phase named in QUESTION
2.3.3.
Copyright reserved
Please turn over
( 1)
(3)
(10 )
Life Sc1ences/P2
DBE/November 2022
11
NSC
2.4
•
.
.
.
The table below shows ·111f ormatIon
about blood groups in a certain population .
BLOOD
GROUP
0
A
B
AB
PERCENTAGE OF
THE POPULATION
NUMBER OF
PEOPLE
954 000
X
180 000
54 000
53
34
10
3
2.4 .1
How many people have the genotype ii?
2.4 .2
The population size is 1 800 000.
(1)
(3)
Calculate the value of X. Show ALL working.
2.4.3
2.5
Describe how a child inherits the blood group represented by
3 per cent of this population .
The diagram below represents the DNA profiles of three children and their
parents. Only two of the children are their biological children and one is
adopted .
Mother
2.6
(3)
(7)
Father
Heila
Priya
Leo
2.5.1
Identify the TWO biological children.
(2)
2.5.2
Explain your answer to QUESTION 2.5.1.
(2)
2.5.3
State THREE other uses of DNA profiling.
(3)
(7)
Brown enamel of the teeth is a sex-linked trait. A dominant allele on the
X chromosome causes brown teeth in humans.
2.6.1
Explain why more males than females have white teeth.
2.6.2
A man with brown teeth married a woman with white teeth .
(4)
Use a genetic cross to show the possible phenotypic ratios of their
8
children. Use X for brown teeth and Xb for white teeth.
(6)
(10)
[50]
Copyright reserved
Please turn over