PPSC BIO-DEMO TEST (SMART INSTITUTE)
01- Which one of the following always contains DNA?
Centriole
Golgi apparent
Lysosome
Mitochondrion
02- Which one of the following would exocrine cells be expected to contain as a result of their function?
Increased amounts of DNA
Increased amounts of rough endoplasmic reticulum
Increased numbers of lysosomes
Large mitochondria
03- The nuclei of both plant and animal cells contains one or more dense bodies known as nucleoli. Which one of the following correctly describes the function of nucleoli?
The function of new DNA molecules
The organization of the spindle during nuclear division
The replication of mitochondria following nuclear division
The formation of ribosomes
04- Which of the following cell structures contains the highest concentration of RNA?
Centriole
Chromosomes
Lysosome
Nucleolus
05- Which of the following in all eukaryotic cells?
Cell wall
Diploid nucleus
Flagellum
Membrane-bound organelles
06- A peptide bond is formed between.
An aldehyde group and an amino group
An aldehyde group and a carboxyl group
An aldehyde group and an ester group
A carboxyle group and an amino group
07- A sequence of amino acids may end in either an amino group (-NH2) or a carboxyl group (-COOH). What is the theoretical number of chemically different dipeptides that may be assembled from 20 different amino acids?
40
80
160
400
08- The secondary order of protein structure is.
The sequence of amino acids in the polypeptide chain.
The formation of peptide bonds between amino acids.
The coiling of the polypeptide chain.
The folding of the coiled polypeptide chain.
09- How many fatty acid molecules are normally present in a fat or oil molecule?
1
2
3
4
10- Most polysaccharides are composed of chains of condensed.
Cellulose units.
Hexose units.
Pentose units
Sucrose units.
11- Polysaccharides are synthesised in plants by the process of
Condensation.
Glycolysis.
Hydrolysis
Oxidation.
12- Which one of the following reactions results in the conversion of amino acids to proteins?
Condensation
Deamination
Hydrolysis
Phosphorylation
13- Which molecule is a co-factor used by dehydrogenase enzymes?
Coenzyme A
Cytochrome
Lactate
NAD
14- specificity of enzymes is due to
Their high molecular weight.
Their hydrogen bonding.
Their pH sensitivity.
Their surface configuration.
15- Which one of the following enzymes shows the greatest substrate specificity?
Lipase
Nuclease
Pepsim
Sucrase
16- An enzyme increases the rate of a reaction by
Supplying the energy required to start the reaction.
Increasing the rate of random collisions of molecules.
Removing the product of the reaction so allowing it to continue.
Bringing the reacting molecules into precise orientation with each other.
17- Which one of the following bonds permanently to the active site of an enzyme?
Allosteric inhibitor
Coenzyme
Competitive inhibitor
Non-competitive inhibitor
18- The reaction rate salivary amylase with starch decreases as the concentration of chloride ions is reduced. Which of the following describes the role of the chloride ions?
Allosteric inhibitors
Coenzymes
Cofactors
Competitive inhibitors
19- The absence of centrioles from higher plant cells means that during somatic cell nuclear division there is
No spindle formed.
No equatorial arrangement of chromosomes.
No new cell wall laid down at telophase.
No apparent organiser of mitotic spindles.
20- If one ignores the effect of crossing over, then the possible number of different haploid cells which could arise by the meiotic division of a diploid cell containing 10 chromosomes (i. e. n=5) is
2
4
8
32
21- The formation of chiasmata is an important feature of meiotic division because it
Ensures that the same genetic characteristics appear in daughter cells as in the parents.
Ensures that the number of genes in the new chromosomes remains constant.
Provides opportunities for new genotypes to arise.
Prevents homologous from pairing.
22- 'Suddenly, the chromatids belonging to each chromosome part company and move towards the opposite poles of the spindle.' This is a description of mitotic
Anaphase.
Interphase.
Metaphase
Prophase.
23- During which phase of meiosis are chiasmata formed?
Prophase I
Metaphase I
Anaphase II
Metaphase II
24- The absence of centriols from higher plant cells means that during somatic cell nuclear division there is
No apparent organiser of mitotic spindles.
No equatorial arrangement of chromosomes at metaphase.
No new cell wall laid down at telophase.
No spindle formed.
25- A molecule of transfer RNA has the anticodon sequence UAC. What will be the corresponding nucleotide sequence in the DNA?
ATG
AUG
TAG
TUG
26- The two pyrimidine bases most commonly found in DNA are
Uracil and thymine.
Cytosine and uracil.
Cytosine and thiamin.
Cytosine and thymine.
27- The potentiality for replication of deoxyribose nucleic acid depends on
Covalent bonds between bases.
Electrovalent bonds between base and phosphate groups.
High energy bonds between phosphate groups.
Hydrogen bonds between bases.
28- which statement describes the base pairing in nucleic acids?
Purine bases always pair with other purine bases.
Purine bases can only pair with pyrimidine base.
High energy binds between phosphate groups.
Hydrogen bonds between bases.
29- The nitrogenous bases present in RNA are the same as those present in DNA except that
Adenine replaces cytosine.
Adenine replace thymine.
Uracil replace adenine.
Uracil replaces thymine.
30- An anti-codon is the sequence of the nitrogenous bases on the
Complementary strand of DNA which codes for one amino acid.
Complementary strand of mRNA which codes for one amino acid.
TRNA molecule where the amino acid is attsched.
TRNA molecule which recognises the appropriate sequence of bases on the mRNA.
31- What is a codon?
A length of DNA which codes for a particular protein.
A part of the transfer RNA molecule to which a specific amino acid is attached
A part of the transfer RNA molecule which recognises the triplet code on the messenger RNA
A part of the messenger RNA molecule that has a sequence of bases coding for an amino avid
32- What is anticoden?
Three bases on a DNA molecule coding for an amino acid in transelation
Three bases on a mRNA molecule after transcription from DNA
Three bases on a tRNA molecule involved in transcription from DNA
Three bases on a tRNA molecule involved in translation into protein
33- Genetic recombination in bacteria leads to variation. Which process leading to genetic recombination in bacteria involve a virus?
Conjugation
Plasmid replication
Transduction
Transformation
34- Which feature occurs only in the life cycle of the influenza virus?
Host cell DNA is destroyed by lytic enzymes.
Host cell ribosomes are used to synthesis viral proteins.
Viral RNA acts as templates for viral DNA synthesis.
Virus enter the host cell by endocytosis.
35- A gene transfer occurred between two strains of bacteria. It was observed that cell-cell contact is NOT required, and a filter that removes viruses eliminates transfer. This would mean that the transfer occurred by
Conjugation.
Transformation.
Transposition.
Transduction.
36- Viruses have some of the properties of living organisms. Which of the following is a characteristic of all organisms, but not of viruses?
Ability to control metabolism.
Ability to reproduce.
Genetic information stored as nucleic acid.
Possess plasma membrane.
37- A region of eukaryotic DNA consists of over fifty repeats of the same sequence of twelve bases. Where is this repetitive region least likely to be found?
An exon
An intron
A polymerase binding site
Satellite DNA
38- What causes cancer in cells?
I-Damage to genes.
II-Chemical damage to cell membranes
III-UV damage to transport proteins
I only
III only
I and III only
All of above
39- Which of the following is NOT a mechanism whereby a proto-oncogene is converted to an oncogene?
Methylation of bases
Point mutation
Gene transposition
Chromosome translocation
40- Which of the following does NOT lead to cancer formation?
Both tumour suppressor alleles are knocked out by mutation.
Infection by viruses
Gene for telomerase is inactivated.
Production of Ras oncogene.
41- In domestic cats the genes for yellow fur and black fur are an allelic pair which are sex-linked and codominant. When black females are mated with yellow males, which one of the following is the expected proportion of heterozygotes in the offspring?
0%
25%
50%
75%
42- Which one of the following phenotypic features of Man can be affected only by the genotype?
Height
Intelligence
Skin colour
Number of different blood group antigens
43- Which one of the following genotypes cannot occur amongst the offspring from a mating between a person of blood group A and a person of blood group B?
AA
AB
AO
BO
44- In the construction of chromosome maps, the evidence is derived mainly from
Cross-over values
Electron microscopy.
Hereditary effects of chromosome fragmentation.
Genetic ratio.
45-Which one of the following is a correct outline of the main events in photosynthesis?
Oxygen reacts with a carbohydrate to produce water and carbon dioxide in the presence of light.
Light joins carbon dioxide to an acceptor compound which is then reduced by hydrogen obtained from water.
Light splits water and the resulting hydroxyl group combines with a compound which has incorporated carbon dioxide.
Carbon dioxide combines with an acceptor compound and this is reduced by hydrogen split from water by light.
46- Which metal atom is present in chlorophyll?
Copper
Iron
Magnesium
Phosphorus
47- Why is RuBP important in the process of photosynthesis?
It is a source of phosphate ions.
It is an intermediate in sucrose formation.
It is an acceptor molecule for hydrogen.
It is an acceptor molecule for carbon dioxide.
48- Which statement only applies to carbon fixation in photosynthesis?
GP (PGA) is reduced to carbohydrate.
The reactions are not dependent on temperature.
At low light intensity these reactions limit the rate of photosynthesis.
A 2-carbon compound is the acceptor for carbon dioxide.
49- The amount of energy released from a given quantity of glucose is greater in aerobic respiration than in anaerobic respiration. By approximately how much is the energy yield increased in animals?
3 times
9 times
12 times
18 times
50- Which one of the following is the main biochemical process which takes place inside the mitochondrial matrix?
Photophosphorylation
The formation of latice acid
The translation of messenger RNA
The tricarboxylic acid cycle.
51- What is the approximate ratio of ATP synthesised during anaerobic respiration compared with aerobic respiration?
1:2
1:10
1:20
1:30
52- Which molecule is common to both glycolysis and the Calvin cycle?
Hexose phosphate
NADP
Pentose phosphate
Triose phosphate
53- The approximate width of a cell membrane is
0.01 nm
0.10 nm
1.0 nm
10.0 nm
54- Which cell component forms pinocytic vesicles?
Cell surface membrane
Endoplasmic reticulum
Lysosome
Nucleolus
55- Which technique provided the primary evidence for the fluid mosaic model of the cell membrane?
Cell fractionation
Chemical analysis of membrane proteins
Chemical analysis, microscopic staining
Freeze-fracture
56- By which process does glucose move into red blood cells from the plasma?
Active transport
Endocytosis
Facilitated diffusion
Osmosis
57- In a healthy mammal, which one of the following will lead indirectly to increased production of glycogen in liver cells?
A reduction in insulin output
A high glucose content in the diet
An increase in thyroxine production
A reduction in the amino acid concentration in the blood
58- As a result of the activity of insulin there is
Increased uptake of glucose by muscles.
Decreased uptake of glucose by cells
The presence of glucose in the urine
Deposition of fat in blood vessels.
59- Under which of the following circumstances will insulin be secreted?
The blood sugar level in the liver is low.
The blood sugar level in the hepatic portal vein is low.
The blood sugar level in the islets of Langerhans is high
The glycogen level in the skeletal muscle is high.
60- What does increase in the secretion of insulin produce?
A decrease in glucose metabolism
An increase in blood sugar level
An increase in glucose permeability of cells
An increase in the conversion of glycogen to glucose
61- Which one of the following identifies the role of acetylcholine in nerve physiology?
It increase the resting potential of the cell.
It increases the selective permeability of the cell membrane.
It activates the sodium pump mechanism of the cell.
It increases the potassium concentration inside the cell.
62- Which of the following is common to all neurones?
A cell body which contains a nucleus
A thick myelin sheath
Presence of nodes of Ranvier
Presence of Schwarnn cells
63- What will occur if the receptor sites on the postsynaptic membrane are blocked by a drug at the neuromuscular junction?
Inhibition of acetylcholine release
Inhibition of cholinesterase
Muscle contraction
Muscle paralysis
64- Impulses travel very rapidly along nerves to the leg muscle of a mammal?
A nerve impulse is an all-or-nothing phenomenon.
The nerves contain myelinated fibres.
There is a high concentration of Na+ ions inside the axons.
There is a potential difference across the axon membranes.
65- The frequency of a mutant gene in a population would be likely to increase if
The gene were selectively advantageous.
The gene were dominant.
The gene were sex-linked.
The population increased.
66- Which of the following increases variation within a gene pool?
Chromosome inversion
Crossing over
Gene mutation
Random fusion of gametes
67- Which of the following increases the number of different alleles in a population?
Crossing over
Gene mutation
Random fusion of gametes
Reassortment of chromosomes in meiosis
68- Which one of the following pairs represents analogous features?
Elephant tusks and human incisors
Insect wing and bat wing
Teleost erythrocyte and mammalian erythrocyte
Mole fore-limb and bird wing
69- For what purpose is the polymerase chain reaction used?
To cut DNA
To join DNA sequences
To produce DNA
To clone cells
70- Plants are more readily manipulated by genetic engineering than are animal cells because
Plant genes do not contain introns.
More vectors are available for transferring recombinant DNA into plant cells.
A somatic plant cell can often give rise to a complete plant
Plant cells have larger nuclei.
71- To date, genetically modified food crops have been modified to
Produce needed human nutrients.
Resist insect pest.
Deliver vaccines.
All of the above
72- Which of the following characteristics is undesirable in cloning vectors used in genetic engineering?
Control their own replication
High copy number
Small in size
Vulnerable at several sites to a restriction enzyme
73- Stem cells are widely used in medical research. Which property of stem cells makes them particularly useful in this research?
They can be fused together to form a zygote.
They can divide and eventually give rise to a whole organism.
They can divide and be made to differentiate into various types of cell.
They will continue to divide indefinitely.
74- Which genetic modification could increase the yield of a crop measured as mass of crop produced per unit area per year?
Herbicide resistant plants
Delayed ripening in the fruits
More essential amino acids in the seeds
More vitamin A in the grain
75- Stem cells can be divided into four main types. Which of the four types of stem cell can differentiate into a limited range of tissues?
Adult stem cells
Embryonic stem cells
Fetal stem cells
Zygotic stem cells
76- Which property of embryonic stem cells makes them particularly useful in medical research?
They can be used together to form a zygote.
They can divide and are pluripotent.
They can divide and are totipotent.
They will continue to divide indefinitely
77- Which type of gene therapy is least effective in transferring DNA to the nucleus?
Adenoviruses
DNA attached to a ligand
Liposomes
Retroviruses
78- Which genetic modifications would not decrease the quantity of chemicals sprayed onto crop plants by farmers?
Fungus resistance
Herbicide resistance
Insect resistance
Virus resistance
79- Which of the following statements is false about hematopoietic stem cells?
Hematopoietic stem cells are able to reproduce continually.
Hematopoietic stem cells are present in minute quantities.
Hematopoietic stem cells can be found in the bone marrow.
Hematopoietic stem cells can differentiate into all specialised cells.
80- Large quantities of useful products can be produced through genetic engineering involving
Bacteria containing recombinant plasmids.
Mammals.
Transgenic plants.
All of the above
81- The oldest religion of the world is
Judaism
Christianity
Buddhism
Hinduism
82- Where is the Head quarter of the Amnesty International located?
Geneva
London
Paris
New York
83- Asian Development Bank was established in:
1964
1966
1968
None
84- Who were the three statesmen who formulated Non-Aligned Movement
Gandhi, Nasser, Tito
Nehru, Nasser, Tito
Chou-en-Lai, Bhutto, Nehru
Soe Kamo, Nasser, Tito
85- The permanent Secretariat of SAARC is established at:
Dehli
Islamabad
Kathmandu
Dhaka
86- Who was the founder of HAMAS in 1987:
Sheikh Ahmad Yassin
Yasser Arafat
Abu Nidal
None
87- How many official working languages are recognized by UNO?
8
6
4
None
88- In which month does the UN General Assembly usually meet every year?
August
September
October
November
89- The term of office of a judge of the International Court of Justice is?
5 years
7 years
9 years
None of these
90- Which is the largest country in Africa?
Sudan
Nigeria
Libya
None of these
91- In the composition of Earth, Oxygen is approximately:
20%
38%
46%
58%
92- The recipient of "Nishan-i-Haider" captain Kamal Sher Khan belonged to:
Punjab Regiment
Frontier Force Regiment
Sindh Regiment
Northern Light Infantry
93- In term of area, which is the largest Administrative district of Punjab
Bahawalpur
D.G Khan
Faisalabad
Lahore
94- Who was the first Muslim ruler of Indian Sub-Continent
Muhammad Bin Qasim
Mahmood Ghaznavi
Muhammad Ghuri
Qutab-ud-Din Aibak
95- Light travels from Sun to Earth is
2 minutes
4 minutes
6 1/2 minutes
8 1/2 minutes
96- The archaeological site of "Kot Diji" is located near the city of
Larkana
Thatta
Khairpur
Swat
97- Which of the following district of occupied Jammu and Kashmir has Buddhist majority population
Rajourial
Doda
Leh
None
98- Identify the musician who composed the National Anthem of Pakistan
Nisar Bazmi
Khalil Ahmed
Suhail Rana
Abdul Karim Chagla
99- Lake Manchar is the largest lake in Pakistan is situated at
Kaghan
Swal
Dadu
Lasbela
100- Velocity of Sound in Air per second is
250 meters
331 meters
434 meters
561 meters
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