Download June BI5

Candidate Name
Centre Number
WELSH JOINT EDUCATION COMMITTEE
Candidate Number
CYD-BWYLLGOR ADDYSG CYMRU
General Certificate of Education
Advanced
Tystysgrif Addysg Gyffredinol
Uwch
315/01
BIOLOGY BI5
P.M. FRIDAY, 25 June 2004
(2 hours)
For Examiner’s Use Only
Total
Marks
INSTRUCTIONS TO CANDIDATES
Write your name, centre number and candidate number in the spaces at the top of this page.
Answer all questions in sections A and B.
Write your answers in the spaces provided in this booklet.
INFORMATION FOR CANDIDATES
The number of marks is given in brackets at the end of each question or part-question.
You are reminded of the necessity for good English and orderly presentation in your answers.
The quality of written communication will affect the awarding of marks.
No certificate will be awarded to a candidate detected in any unfair practice during the
examination.
VP*(0006/20)
2
Examiner
only
Arholwr
yn unig
SECTION A
1.
Answer the questions in the spaces provided.
(a)
Name the following.
(i)
The tube which connects the epididymis to the urethra in the male reproductive
system of a mammal.
[1]
................................................................................................................................
(ii)
The tiny hole in an ovule through which the pollen tube enters.
[1]
................................................................................................................................
(iii)
One hormone which affects milk release in the mammary glands.
[1]
................................................................................................................................
(iv)
The plant organ that produces microspores.
[1]
................................................................................................................................
(b)
Distinguish between
(i)
Self-pollination and cross-pollination.
[1]
....................................................................................................................................................................................................................
....................................................................................................................................................................................................................
....................................................................................................................................................................................................................
(ii)
Intra-specific competition and inter-specific competition.
[1]
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(Total 6 marks)
(C006/20)
3
2.
Examiner
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The modern system of classification has five Kingdoms.
(a)
Name the five Kingdoms.
[2]
....................................................................................................................................................................................................................................
....................................................................................................................................................................................................................................
(b)
(i)
Write the following taxa in order of size starting with the largest group and ending
with the smallest group.
[2]
order,
genus,
phylum,
class,
family.
....................................................................................................................................................................................................................
....................................................................................................................................................................................................................
(ii)
Give one reason why the tiger is placed in order Carnivora.
[1]
....................................................................................................................................................................................................................
(iii)
Give one reason why the tiger is placed in family Felidae.
[1]
....................................................................................................................................................................................................................
(c)
According to the binomial system, the tiger is named Panthera tigris.
(i)
Which two taxa are used in the binomial system to name a particular organism?
[2]
....................................................................................................................................................................................................................
(ii)
Why is the binomial system important to the international scientific community?
[1]
....................................................................................................................................................................................................................
(Total 9 marks)
(0006/20)
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4
3.
Examiner
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Coat colour in mice (Mus muscularis) is determined by at least three genes.
(a)
One gene has a dominant allele, B, for black fur and a recessive allele, b, for brown fur.
The second gene has a dominant allele, A, for agouti coat, where the pigment is unevenly
distributed along each hair, (see diagram). The recessive allele, a, is for non-agouti coat,
where the pigment is evenly distributed.
hair
Non-agouti, pigment evenly distributed.
hair
Agouti, pigment unevenly distributed.
(i)
In a dihybrid cross, a black agouti mouse was bred with a brown non-agouti mouse.
Some of the offspring were brown and some were non-agouti.
Use a suitable genetic diagram to show the results of the cross.
[7]
Parental phenotypes:
...........................................................
X
...........................................................
Parental genotypes:
...........................................................
X
...........................................................
Possible gametes:
(ii)
...........................................................
X
...........................................................
F1 genotypes:
...........................................................
...........................................................
F1 phenotypes:
...........................................................
...........................................................
In a litter of eight offspring, how many would you expect to have brown, agouti
coats?
[1]
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(C006/20)
5
(b)
A third gene controls the production of the pigment melanin. Mice which are homozygous
for the recessive allele, m, of this gene have white fur and pink eyes. They are said to be
albino.
(i)
Give the genotype of an albino mouse.
[1]
................................................................................................................................
(ii)
By what process might a dominant allele spontaneously change into its recessive
form?
[1]
................................................................................................................................
(iii)
What is the general term applied to agents that increase the frequency of such
changes?
[1]
................................................................................................................................
(c)
In large populations, and in the absence of selection, the proportion of dominant to
recessive alleles for a particular gene will remain constant in the gene pool, from generation
to generation.
(i)
What is meant by the terms
(I)
gene pool;
[1]
......................................................................................................................................................................................................
......................................................................................................................................................................................................
(II)
genetic drift?
[1]
......................................................................................................................................................................................................
......................................................................................................................................................................................................
(ii)
Explain how owls might reduce the frequency of the allele m (albino) in the gene
pool of a mouse population in a wood.
[1]
....................................................................................................................................................................................................................
....................................................................................................................................................................................................................
(iii)
Explain how hawks, which hunt in daylight, might also reduce the frequency of allele
B in the mouse population.
[1]
....................................................................................................................................................................................................................
....................................................................................................................................................................................................................
(iv)
Explain why, over many generations, the allele B might completely disappear from
the gene pool, but the allele m will always be present even if in very low numbers. [2]
....................................................................................................................................................................................................................
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(0006/20)
(Total 17 marks)
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6
4.
(a)
Examiner
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Arholwr
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The diagram shows a process that occurs in the testes of male mammals.
Germinal epithelium cell
D
Growth
C
B
A
Differentiation
Spermatozoa
(i)
Name the process.
[1]
..................................................................................
(ii)
Name the equivalent process that occurs in the ovaries of female mammals.
[1]
..................................................................................
(iii)
(0006/20)
Name the cell types labelled A, B, C, and D on the diagram.
A
.............................................................................................
B
.............................................................................................
C
.............................................................................................
D
.............................................................................................
[2]
7
(b)
Examiner
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Arholwr
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The drawing below shows a cross section through a seminiferous tubule.
Germinal epithelium cell
..................................................
..................................................
..................................................
..................................................
Spermatozoa
X
(i)
Use letters A, B, C and D to show on the diagram which of the labelled cells would
be the types you identified in part (a).
[2]
(ii)
Name the cell labelled X in the diagram.
[1]
...............................................................................................................................................
(iii)
What is the function of the cell labelled X in the diagram?
[1]
....................................................................................................................................................................................................................
....................................................................................................................................................................................................................
(c)
The cell labelled C in part (a) is shown undergoing cell division.
(i)
State the type of cell division this cell would be carrying out.
[1]
...............................................................................................................................................
(0006/20)
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(ii)
Draw a labelled diagram to show how two homologous pairs of chromosomes would
be arranged at the equator of cell C, at metaphase I.
[3]
(iii)
What is the significance of cells like cell C carrying out this type of cell division? [2]
....................................................................................................................................................................................................................
....................................................................................................................................................................................................................
(Total 14 marks)
5.
Answer one of the following questions.
Any diagrams included in your answer must be fully annotated.
Either,
(a)
Describe the positions and outline the functions of the following main parts of
the human brain: the cerebral hemispheres, hypothalamus, cerebellum, and
medulla oblongata.
[10]
Or
(b)
Give an account of the steps involved in cloning plants and mammals.
Describe one advantage and one disadvantage of these techniques.
[10]
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(0006/20)
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9
Examiner
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(0006/20)
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(Total 10 marks)
(0006/20)
11
BLANK PAGE
(0006/20)
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12
Examiner
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SECTION B
Answer all questions.
6.
The diagram shows the arrangement of protein filaments in a muscle fibril.
X
P
Q
(a)
Name the functional sub-unit of a muscle fibril labelled X in the diagram.
[1]
..................................................................................................................................................
(b)
(c)
Name the proteins of which the filaments are made.
(i)
Thick filament
...............................................................................
(ii)
Thin filament
...............................................................................
(i)
Name the regions labelled P and Q on the diagram.
P
Q
(ii)
Q
(i)
[1]
...............................................................................
...............................................................................
If the muscle fibre contracted, how would the appearance of regions P and Q compare
with the diagram?
[1]
P
(d)
[1]
...............................................................................
...............................................................................
What is meant by the primary structure of a protein molecule?
[1]
....................................................................................................................................................................................................................
(ii)
Name the specific, three dimensional, spiral shaped, secondary structure of muscle
fibril protein molecules.
[1]
....................................................................................................................................................................................................................
(iii)
How do the structures of muscle fibril proteins differ from the structure of enzyme
molecules?
[1]
....................................................................................................................................................................................................................
(0006/20)
Total 7 marks
13
7.
(a)
Examiner
only
Arholwr
yn unig
The diagram below shows part of a kidney nephron.
D
Peritubular capillary
C
B
A
Branch of renal artery
Proximal
convoluted tubule
Branch of renal vein
Loop of Henle
Name the parts labelled A, B, C, D.
(0006/20)
A
...............................................................................
B
...............................................................................
C
...............................................................................
D
...............................................................................
[2]
Turn over.
14
(b)
(i)
Examiner
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Arholwr
yn unig
Complete the diagram below to show how the capillary epithelial cells and the
podocytes would be arranged on the basement membrane of the opposite wall of the
capsule.
[2]
Lumen of capillary
Epithelium of capillary
Basement
membrane
Podocyte
Capsular space
Basement
membrane
(ii)
The filtration barrier is believed to be the basement membrane, which does not show
the typical lipid-protein structure. Name a membrane shown in the drawing of a
podocyte that would have the fluid mosaic structure.
[1]
....................................................................................................................................................................................................................
(iii)
(0006/20)
Draw a labelled diagram to show the arrangement of proteins and phospholipids in
this membrane.
[3]
15
(c)
Examiner
only
Arholwr
yn unig
In experiments some globular proteins will pass through the filtration barrier into the
glomerular filtrate. The table shows how much of each protein passes into the glomerular
filtrate (with glucose for comparison), along with the radius of each molecule.
Molecular radius (Å)
Percentage in filtrate
3.6
100
Myoglobin
19.5
75
Egg albumin
28.5
33
Serum albumin
35.5
< 0.01
Substance
Glucose
(i)
Use the information in the table to describe how the size of its molecules affects
whether the substance passes into the glomerular filtrate.
[1]
....................................................................................................................................................................................................................
....................................................................................................................................................................................................................
(ii)
Explain how the presence of pores in the basement membrane might cause the effect
you described in part (i).
[1]
....................................................................................................................................................................................................................
....................................................................................................................................................................................................................
....................................................................................................................................................................................................................
(iii)
From the information given in the table, suggest what the radius of such pores might
be.
[1]
.............................................................................................
(0006/20)
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16
Examiner
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The graphs below show how the hydrostatic and osmotic pressures change in the blood
supply to a nephron.
(d)
120
100
Pressure/mm Hg
Hydrostatic Pressure
80
Osmotic Pressure
60
40
20
(i)
R
ve ena
in l
R
ve ena
nu l
le
s
E
ar ffer
te en
rio t
le
s
P
ca erit
pi ub
lla u
rie lar
s
G
ca lom
pi e
lla ru
rie lar
s
A
ar ffe
te re
rio nt
le
s
Re
na
la
rte
ry
0
Through which type of blood vessel is the greatest drop in hydrostatic pressure?
[1]
............................................................................................................
(ii)
What causes the drop in hydrostatic pressure as the blood flows into the peritubular
capillaries?
[1]
....................................................................................................................................................................................................................
(iii)
The walls of the capillaries are permeable to fluids. In which of the capillaries named
in the graph will fluid move out?
[1]
............................................................................................................
(iv)
Using the terms hydrostatic pressure and osmotic pressure explain why fluid moves
out of these vessels.
[1]
....................................................................................................................................................................................................................
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(Total marks 15)
(0006/20)
17
8.
Examiner
only
Arholwr
yn unig
“Acetylcholine (ACh) is a simple molecule synthesized from choline and acetyl-CoA through the
action of choline acetyltransferase. Neurones that synthesize and release ACh are termed
cholinergic neurones. When an action potential reaches the terminal button of presynaptic neurone
2+
a voltage-gated calcium channel is opened. The influx of Ca stimulates the exocytosis of
presynaptic vesicles containing ACh, which is thereby released into the synaptic cleft. Once
released, ACh must be removed rapidly in order to allow repolarization to take place; this step,
hydrolysis, is carried out by acetylcholinesterase.
+
The activation of ACh receptors by the binding of ACh leads to an influx of Na into the cell and
+
an efflux of K , resulting in a depolarisation of the postsynaptic neurone and the initiation of a new
action potential.”
(a)
Name the junctions between neurones to which the passage refers.
[1]
.............................................................................................................................
(b)
Identify the following chemicals, which are named in the passage:
(i)
[2]
two enzymes;
....................................................................................................................................................................................................................
(ii)
three ions.
....................................................................................................................................................................................................................
(c)
Draw a diagram to illustrate how the process of exocytosis releases the transmitter
substance in one of the structures.
[3]
(d)
Explain why the presence of a myelin sheath would speed up the transmission of the nerve
impulse in the post-synaptic neurone.
[2]
....................................................................................................................................................................................................................................
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(0006/20)
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18
(e)
Examiner
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yn unig
“Donepezil is an oral medication used to treat Alzheimer’s disease, a progressive disease of
the brain that leads to nerve cell death and in turn, causes deficits in the neurotransmitters. It
belongs to a class of drugs called cholinesterase inhibitors, because it acts as a competitive
inhibitor of acetylcholinesterase.”
(i)
Suggest why donepezil might alleviate some of the symptoms of Alzheimer’s disease.
[1]
....................................................................................................................................................................................................................
....................................................................................................................................................................................................................
(ii)
Explain the mechanism of competitive inhibition.
[3]
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(Total 12 marks)
(0006/20)