LET Practice Test in Biology

1. PRACTICE TEST IN LET BIOLOGY
1. Where do producers obtain their energy?
A. From other producers
B. From the consumers
C. From the decomposers
D. From the sun
2. Why do you experience not seeing things clearly for some seconds when
you enter suddenly a well-lighted room after coming from a dark room,
you?
A. The pupils are not adapted to the dark
B. The eyes are adapted to the light only
C. The pupils are not dilated yet
D. Light had caused temporary blindness
3. What term is used to describe the ability to maintain a constant internal
environment?
A. Metabolism
B. Growth and development

2. C. Homeostasis
D. Thermoregulation
4. What is the most common cause of cardiovascular disease?
A. Fatty deposits in the arteries
B. Inadequate supply of red blood cells
C. Lack of sodium in the diet
D. Increased heartbeat
5. Which is the smallest unit of life that can survive and reproduce on its own?
A. Cell
B. Organ
C. Tissues
D. Population
6. Which region of a vertebrate forebrain is considered with the neutral-
endocrine control of visceral activities?
A. Cerebellum
B. Thalamus
C. Hypothalamus
D. Pituitary
7. Which of the following is the building block carbohydrate?
A. Amino acid
B. Nucleotide
C. Fatty acid
D. Monosaccharide
8. Why it is necessary men have more red blood cells per cubic millimeter of
blood than women?
A. Man does strenuous activities and need more energy
B. They have bigger physique and need more blood
C. Man waste more blood cells and need extra

3. D. They are more prone to anemia disorders
9. Which of the following is the building block of protein?
A. Amino acid
B. Nucleotide
C. Fatty acid
D. Monosaccharide
10.Where does protein synthesis take place?
A. Ribosomes
B. Lysosomes
C. Endoplasmic reticulum
D. Golgi bodies
11.Why are our lips “redder” than our palm?
A. There is increased blood flow in the lips
B. Lips are heavily keratinized
C. Lip epidermis is thinner
D. Many blood vessels are located around the lips
12.Which of the following cannot be found in prokaryotes?
A. Cytoplasm
B. Plasma membrane
C. Membrane-bound nucleus
D. DNA
13.What do we call mutation that is brought about by the earth natural
radioactivity?
A. Continuous
B. Induced
C. Lysosomes
D. Chloroplast

4. 14.Which of the following organelles produces turbo pressure against cell wall
and mainly acts as water reservoir
A. Plastids
B. Vacuole
C. Lysosomes
D. Chloroplast
15.What is the branch crobial organisms is used in the creation of genetically
modified organisms?
A. Pseudomonas vulgaris
B. Bacillus thuringensis
C. Agro bacterium tumafaciens
D. Escherichia coli
16.What is the branch of zoology that is devoted to the study of fish?
A. Helmintology
B. Ichthyology
C. Chondrichthyes
D. Ornithology
17.The process involved in the production of mRNA using DNA as template is
termed _______?
A. Transcription
B. Replication
C. Gene manipulation
D. Reverse transcription
18.What is the most abundant inorganic compound in the protoplasm?
A. Fluid
B. Blood
C. Plasma
D. Water

5. 19.Which is the riches type of tropical rain forest in the Philippines?
A. Molave forest
B. Dipterocarp forest
C. Mangrove forest
D. Pine forest
20.What muscie is described as involuntary, not striated, and have a single
nucleus?
A. Smooth
B. Skeletal
C. Cardiac
D. Connective
21.We feel warmer just before it rains because __________.
A. Heat is released by the evaporation of water
B. The clouds prevent heat from escaping the earth
C. There is an increased relative humidity
D. Heat is released by the condensation of water vapor
22.Which of the following is not considered as a reproductive cell?
A. Gamete
B. Somatic cell
C. Egg cell
D. Sperm cell
23.The cell wall of plant is made of _______.
A. Lipids
B. Cellulose
C. Protein
D. Cell membrane
24.Which of the following is the correct sequence of the level of organization
from lowest to highest?

6. A. Cells-system-organs-tissues
B. System-organs-tissues-cells
C. Cells-tissues-organs-system
D. Tissues-systems-cells-organs
25.At metaphase of the meiotic division, the chromosomes are attached to the
spindle fibers as ________.
A. Double chromatids
B. Non-homologous pairs
C. Single chromatid strands
D. A tetrad of four chromatids
26.Which of the following is an example of behavioral adaption?
A. Thick green stems of the cactus plant
B. Thick fur of the bear
C. Shedding leaves during summer
D. Presence of cuticle on the upper surface of the leaves
27.The bipolar nature of the cell membrane is due to _______.
A. Presence of carries
B. Presence of
C. Phospholipids bilayer
D. Integral proteins
28.Which of the following is made up of diploid number of cells?
A. Zygote
B. Sperm cell
C. Egg cell
D. Both B and C
29.Which plant has underground stem modified for reproduction?
A. Ginger
B. Camote

7. C. Tubers
D. Strawberry
30.Which of the following structures serve as a passageway of food and air?
A. Epiglottis
B. Trachea
C. Pharynx
D. Larynx
31.Which kind of relationship is exhibited by algae and fungi in lichen?
A. Commensalism
B. Parasitism
C. Symbiosis
D. Competition
32.What do you call the finger-like folds on the inner linings of the small
intestine?
A. Villi
B. Appendix
C. Rugae
D. Cecum
33.Aside from ADP, what else is the end production of the dark-reaction phase
of ohotosynthesis?
A. Carbon dioxide
B. Surag
C. Carbon
D. Starch
34.What is that flap-like structure that prevents the food from going the
wrong way during swallowing?
A. Epiglottis
B. Larynx

8. C. Esophagus
D. Pharynx
35.Which pigment is dominant in red algae?
A. Phycocyanin
B. Fucoxanthin
C. Chlorophyll
D. Pharynx
36.What is the membrane that surrounds the lungs?
A. Pleura
B. Meninges
C. Peritoneum
D. Pericardium
37.What is that 3-carbon sugar formed during the dark reaction phase of the
photosynthesis?
A. ADP
B. NADPH
C. ATP
D. PGAL
38.What is the product of carbohydrate digestion?
A. Fatty acid
B. Glucose
C. Amino acid
D. Nucleic acid
39.What process is responsible for the upward movement of the water in very
tall trees?
A. Osmosis
B. Capillary action
C. Turgor pressure

9. D. Transpiration
40.What is the enzyme in the mouth that breaks starch to maltose?
A. Peptidase
B. Ptyalin
C. Pepsin
D. Maltase
41.What do you call the types of symmetry where the body parts are paired on
either side of the body?
A. Dorsal
B. Bilateral
C. Radial
D. Ventral
42.Which is considered as the respiratory center of the brain?
A. Cerebellum
B. Medulla oblongata
C. Cerebrum
D. Thalamus
43.Which stage of incomplete metamorphism is undergone by grasshopper?
A. Nymph, pupa, adult
B. Egg, larva, pupa, adult
C. Egg, nymph, adult
D. Egg, pupa, adult
44.Which of the following is NOT part of the thoracic cage?
A. Clavicle
B. Ribs
C. Costal cartilages
D. Sternum

10. 45.Where does the toxin substance secreted by bees and ants through their
sting originate?
A. Silk glands
B. Intestines
C. Rectal glands
D. Salivary glands
46.What is the longest bone in the body?
A. Humerus
B. Ferum
C. Tibia-fibula
D. Clavicle
47.Which cause our bones to turn brittle and easily break?
A. Turning into muscle tissues
B. Increase in flexibility
C. Turbidity decrease
D. Removal of collagen
48.How many bones does an adult human body has?
A. 201
B. 200
C. 217
D. 206
49.What do you call automatic responses to an external stimulus?
A. Reflex
B. Instinct
C. Impulse
D. All of these
50.What structure provides flexible support and protection to the spinal cord?
A. Skull

11. B. Ribs
C. Vertebral column
D. Sternum
51.Which hormone is insufficient in cretinism?
A. Glucagon
B. Adrenalin
C. Insulin
D. Thyroxine
52.Which of the following is both endocrine and an exocrine gland?
A. Gastric glands
B. Thyroid glands
C. Pituitary glands
D. Pancreas
53.What organ is controlled by the automatic nervous system?
A. Skeletal
B. Muscles
C. Heart
D. Both A and B
54.What do you call food in a semi-liquid form, partially digested and mixed
with hydrochloric acid?
A. Gastric secretion
B. Gastric fluid
C. Mucosa
D. Chime
55.Which is considered the master gland due to its influence on the activity of
all the other glands?
A. Thyroid
B. Adrenal

12. C. Pituitary
D. Parathyroid
56.Which part of the brain is responsible for intelligence, memory and learned
behavior?
A. Cerebellum
B. Cerebrum
C. Medulla
D. Thalamus
57.Which of these materials is not a major component of the plasma
membrane?
A. Phospholipids
B. Glycoprotein
C. Proteins
D. DNA
58.Which form of RNA delivers information fromDNA to be used in making
protein?
A. Messenger RNA
B. Ribosomal RNA
C. Transfer RNA
D. All of the above
59.Which of the following is not a type of cell?
A. Bacterium
B. Amoeba
C. Sperm
D. Virus
60.Which property of water is probably MOST important for the functioning of
organisms at the molecular level?
A. Cohesion and high surface tension

13. B. High specific heat
C. High heat of vaporization
D. Versatility as a solvent
61.Which of the following statements is true of diffusion?
A. It requires an expenditure of energy by the cell
B. It is a passive process
C. It occurs when molecules move from a region of lower concentration
to one of higher concentration
D. It requires a membrane
62.Which of the following is FALSE in comparing prophaseI of meiosis and
prophase of mitosis?
A. The chromosomes condense in both
B. Tetrads form in both
C. The nuclear envelope disassembles in both
D. A spindle forms in both
63.Which are small, irregularly-shaped cells without nuclei but are rich in ATP?
A. Leukocytes
B. Thrombocytes
C. Lymphocytes
D. Erythrocytes
64.What branch of Biology is involved when one is studying the characteristic
structure and functions of all kinds of cells?
A. Cytology
B. Morphology
C. Physiology
D. Histology
65.Which part of seed appears as a scar which marks the entry of the pollen
tube during fertilization?

14. A. Seed leaf
B. Cotyledon
C. Testa
D. Hilum
66.Which type of tissue is responsible for the secondary growth in stems and
roots of vascular plants?
A. Meristematic cells
B. Cambium
C. Palisade layer
D. Epidermis
67.Which biome grows tropical grassland with scattered individual trees and
larger herbivores?
A. Tundra
B. Rain forest
C. Grassland
D. Savanna
68.What do you call that process in birds wherein they shed off features at
least once a year?
A. Skinning
B. Molting
C. Furrowing
D. Migrating
69.What chemical controls metamorphosis among insects?
A. Enzymes
B. Estradol
C. Pheromones
D. Ethylene
70.Which of the following makes up the plant cell wall?

15. A. Nucleic acid
B. Cellulose
C. Protein
D. Lipids
71.Which of the following is not true of fungi?
A. Some are pathogenic
B. Some are photosynthetic
C. Some are edible
D. Formsymbiotic relation with algae
72.Which of the following is not true of plants?
A. Some are pathogenic
B. Some are photosynthetic
C. Some are edible
D. Formsymbiotic relation with algae
73. Which of the following is considered multi-cellular?
A. Embryo
B. Fertilized egg
C. Egg cell
D. Sperm cell
74.What hormone promotes the growth of the uterine lining for the
implantation of the embryo?
A. Lactogenic hormone
B. Progesterone
C. Testosterone
D. Oxytocen
75.Which of the following pair of organisms are closely related?
A. Spider and mosquito
B. Frog and crocodile

16. C. Man and monkey
D. Ants and aphids
76.What does it mean if the blood pressure of human is 110/70?
A. The systolic pressure is 70
B. The diastolic pressure is 70
C. The pulse rate is 110 beats per minute
D. Both B and C
77.Which of the following happens when man exhale?
A. The residual volume of the lungs decreases
B. The diaphragm contracts
C. The volume of the thoracic cavity decreases
D. The lung contracts
78.Which of the following regulate breathing?
A. RBC concentration
B. Number of haemoglobin
C. Hormone level in blood
D. CO2 and O2 concentration and pH level sensors
79.Which of the following has the lowest velocity of blood flow
A. Veins
B. Arteries
C. Capillaries
D. Arterioles
80.How many carbon atoms can each pyruvic acid supply into the Kirb’s cycle?
A. 8
B. 6
C. 4
D. 2

17. 81.How many oxygen is required each time to a molecule of glucose is
completely oxidized through aerobic respiration?
A. 3
B. 6
C. 12
D. 24
82.Which of the following will not be accepted by glycolysis for catabolism?
A. Starch
B. Glycerol
C. Fatty acid
D. Sucrose
83.Which of the following characteristic is common between echinoderms and
cnidarians?
A. They are both radically symmetrical
B. They have segmented bodies
C. Both have stinging cells
D. They have three embryonic tissue layers
84.Which of the following is true of Phylum Chordata?
I. Presence of notochord that provides skeletal support
II. Pharyngeal slits that have become modified for gas exchange
III. Dorsal hallow nerve cord that develops into the central nervous
system
A. II and III
B. I and II
C. I and III
D. I, II and III
85.Which of the following cannot be associated with fungi?
A. Absorptive nutrition
B. Decomposers

18. C. Autotrophs
D. Spore production
86.Which of the following does not involve mitosis?
A. Development of embryo
B. Growth
C. Production of gametes
D. Repairing of damaged tissues
87.Which of the followings is true of mammals?
I. They have four chambered heart
II. They produce milk for the young
III. They are warm blooded
A. I and II
B. II and III
C. I and III
D. I, II and III
88.What term describes an egg develop into a new organismwithout itself
being fertilized be a sperm?
A. Regeneration
B. Conjugation
C. Parthenogenesis
D. Fusion
89.Which of the following is responsible for formation of blood cell?
A. Cartilage
B. Bone narrow
C. Joints
D. Tendons
90.What is most likely happen when a species cannot adapt to the changes in
the environment?
A. It will be transform to another form

19. B. It will become extinct
C. It will be isolated
D. It will grow old
91.What term is used to describe the released of matured egg cell from the
ovary?
A. Fertilization
B. Copulation
C. Ovulation
D. Germination
92.Which of the following blood cells is responsible for blood clotting?
A. Erythrocytes
B. Leukocytes
C. Thrombocytes
D. Neutrophils
93.Where does ectopic pregnancy occur?
A. Uterus
B. Ovary
C. Cervix
D. Fallopian tube
94.Why is cell membrane semi permeability important?
A. It is important in determining the size of the cell
B. It controls the kind of substances that enters and leaves the cell
C. It controls the pressure and energy gradient
D. It allows the molecules to diffuse freely in and out of the cell
95.What theory of evolution accounts for snake’s disappearance of legs and
development of giraffe’s long neck?
A. Theory of use and disuse
B. Theory of natural selection

20. C. Theory of chromosomal change
D. Theory of action and interaction
96.Which of the following is an exocrine gland?
A. Plastids and pigments
B. Asters and centrioles
C. Chloroplasts and vacuoles
D. Cell wall and cell membrane
97.Which of the following is an exocrine gland?
A. Thyroid gland
B. Salivary gland
C. Pituitary gland
D. Adrenal gland
98.Which of the following is not an accessory organ of digestion?
A. Liver
B. Pancreas
C. Salivary gland
D. Adrenal gland
99.What hormonestimulates the development of male secondary sex
characteristics?
A. Estrogen
B. Prolactin
C. Testosterone
D. Progesteron
100. Which of the following parts performs both as reproductive and
urinary functions in males?
A. Ureter
B. Testes
C. Urethra
D. Scrotum

21. ANSWER KEY
1. D
2. C
3. C
4. A
5. A
6. C
7. D
8. A
9. A
10. A
11. C
12. C
13. C
14. B
15. D
16. B
17. A
18. D
19. B
20. A
21. D
22. B
23. B
24. C
25. A
26. C
27. C
28. A
29. C
30. C
31. C
32. A
33. B
34. A
35. D

22. 36. D
37. D
38. B
39. B
40. B
41. B
42. B
43. C
44. A
45. C
46. B
47. D
48. D
49. A
50. C
51. D
52. D
53. C
54. D
55. C
56. B
57. D
58. A
59. D
60. D
61. B
62. B
63. D
64. A
65. D
66. B
67. D
68. B
69. A
70. B
71. B
72. D
73. A

23. 74. B
75. C
76. B
77. C
78. D
79. A
80. D
81. B
82. C
83. A
84. D
85. C
86. C
87. D
88. C
89. B
90. B
91. C
92. C
93. D
94. B
95. A
96. B
97. B
98. D
99. C
100.C
BACKGROUND OF MR. CRISENCIO M. PANER:
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M.S. in Microbiology, UST
B.S. Biochemistry, UST
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