ASVAB Science Biology Practice Test 1

Question – 1

1. Name the carbon dioxide acceptor in photosynthesis which is made up of 5 carbon atoms?

  • A. Ribulose bisphosphate

  • B. Deoxyribose

  • C. Dihydroxyacetone

  • D. Galactose phosphate

  • E. Fructose

  • Answer:A

  • Answer Explanation:Ribulose bisphosphate is a 5 carbon molecule which binds with carbon dioxide and splits to form two 3-phosphoglycerate molecules in the presence of enzyme rubisco. Binding of carbon dioxide to ribose bisphosphate takes place in the dark reaction of photosynthesis.

Question – 2

2. Nodes of Ranvier refers to the

  • A. The projections of the cell body of neuron

  • B. Bulb- like structures at the axon terminal

  • C. Granular bodies in the neuron’s cytoplasm

  • D. Gap between two adjacent myelin sheaths of axon

  • E. Gap between two adjacent neurons

  • Answer:D

  • Answer Explanation:Each neuron consists of a cell body, dendrites and an axon. Dendrites are the branched projections from the cell body. The granular bodies present in the cytoplasm of cell body along with other organelles are called Nissl’s granules. The myelinated axons have nodes of Ranvier which refer to the gap between adjacent myelin sheaths. Bulb – like structures present in the axon terminal are called synaptic knobs which open in the synaptic cleft, the gap in the junction of two neurons.

Question – 3

3. Addition of _________ to a nucleoside makes it a nucleotide.

  • A. Nitrogenous base

  • B. Ribose

  • C. Deoxyribose

  • D. Phosphate

  • E. Water

  • Answer:D

  • Answer Explanation:Nucleoside is made up of a sugar (ribose and deoxyribose) and nitrogenous base by a gylcosidic bond. The nucleotide is made up of sugar, nitrogenous base and phosphate group. The phosphate group is attached to the sugar by a phosphodiester bond. Hence, addition of a phosphate group makes nucleoside a nucleotide.

Question – 4

4. Which of the following is not a function of salivary secretion?

  • A. Digestion of carbohydrates

  • B. Taste sensation

  • C. Lubrication

  • D. Digestion of proteins

  • E. None of these

  • Answer:D

  • Answer Explanation:Salivary secretion contains amylase enzyme which helps in carbohydrate degradation. It also helps in taste sensation and lubrication. Protein digestion is carried out by pancreatic and gastric enzymes.

Question – 5

5. Which of the following is a function of microvilli?

  • A. Secretion

  • B. Absorption

  • C. Protection

  • D. Both A and B

  • E. Both B and C

  • Answer:D

  • Answer Explanation:Microvilli are small finger-like projections of plasma membrane present mainly in the epithelial cell linings. They increase the surface area of intestine and by doing so they aid the intestine in absorption of nutrients. The microvilli present in the apical surface of hepatocytes help in secretion other than helping in absorption.

Question – 6

6. Name the component of water conducting tissue that is elongated and lignified.

  • A. Sieve tubes

  • B. Companion cells

  • C. Tracheids

  • D. Sclereids

  • E. Pericycle

  • Answer:C

  • Answer Explanation:Tracheids are the component of xylem that are single and have tapering ends. Their cell wall is lignified. They are associated with transfer of water and minerals and provide mechanical strength to plants. Sieve tubes, companion cells and sclereids are present in phloem. Pericycle is the tissue present in roots between endodermis and phloem.

Question – 7

7. Nuchal organs are present in

  • A. Scorpions

  • B. Earthworms

  • C. Parameciums

  • D. Pigeons

  • E. Salamanders

  • Answer:B

  • Answer Explanation:Nuchal organ is a ciliated pit located at the posterior end of prostomium of annelids like earthworms. Nuchal organs are involved in chemoreception (for detection of food).

Question – 8

8. A DNA molecule has 20% adenine and 30% thymine. The molecule is

  • A. Single stranded

  • B. Linear double stranded

  • C. Circular double stranded

  • D. Highly supercoiled

  • E. None of these

  • Answer:A

  • Answer Explanation:Adenine pairs with thymine. A normal double stranded DNA having 20% adenine should have 20% thymine. A single stranded DNA can have any amount of thymine irrespective of the adenine concentration.

Question – 9

9. Rain occurs due to

  • A. Precipitation of condensed water vapor

  • B. Sublimation

  • C. Evaporation

  • D. Percolation

  • E. Snowmelt

  • Answer:A

  • Answer Explanation:Rain is a form of precipitation which occurs due to the condensation of water vapors. When a portion of atmosphere is saturated with water vapor, it condenses and precipitates as rain, drizzle snow etc.

Question – 10

10. Warm-blooded animals use_________, a form of kinetic energy to maintain their body temperature.

  • A. Chemical energy

  • B. Mechanical energy

  • C. Radiant energy

  • D. Thermal energy

  • E. Electrical energy

  • Answer:D

  • Answer Explanation:The two primary forms of energies called kinetic energy and potential energy are important in biological systems. Heat or thermal energy is one kind of kinetic energy that helps the warm- blooded animals to regulate their body temperature.

Question – 11

11. Imago refers to

  • A. Eggs of insects

  • B. Pupa of insects

  • C. The larva of insects

  • D. The adult of insects

  • E. Embryo of insects

  • Answer:D

  • Answer Explanation:A sexually matured adult in winged state of an insect after metamorphosis is called imago. It follows the final ecdysis of the immature instar.

Question – 12

12. Which of the following collects metabolic wastes from an embryo in a reptile’s egg?

  • A. Yolk

  • B. Amnion

  • C. Allantois

  • D. Chorion

  • E. Yolk sac

  • Answer:C

  • Answer Explanation:Allantois is a membranous sac that develops from the posterior part of the embryo. In reptiles, the allantois collects the metabolic waste from embryo. In mammals, the allantois is necessary for the formation of umbilical cord and placenta. Yolk feeds the developing embryo. Amnion is a membrane that surrounds the fetus and contains the amniotic fluid. Chorion is a membrane that surrounds the amnion. Yolk sac is the outermost sac that nourishes the developing embryo.

Question – 13

13. The process of programmed cell death during homeostasis is called

  • A. Necrosis

  • B. Apoptosis

  • C. Autophagy

  • D. Necroptosis

  • E. Phagocytosis

  • Answer:B

  • Answer Explanation:Apoptosis is the death of cells in a controlled fashion as a response to signals. It is an important process in the development and homeostasis. Unprogrammed, premature cell or tissue death is called necrosis. The necrosis that takes place by defined pathway or by mechanism is called necroptosis.Phagocytosis is a process of engulfing. Autophagy is the process in which a cell self- digests its components.

Question – 14

14. Which of the following is less susceptible to alkali hydrolysis?

  • A. rRNA

  • B. mRNA

  • C. tRNA

  • D. DNA

  • E. miRNA

  • Answer:D

  • Answer Explanation:DNA possesses deoxyribose as its sugar component. The presence of deoxyribose is the reason for DNA’s stability under alkaline conditions. The RNAs have ribose sugar which makes it more susceptible.

Question – 15

15. Which of the following can lead to loss of pluripotency of stem cells?

  • A. Increased expression of oct-4 gene

  • B. Oct-4 siRNA transfection

  • C. Use of LIF

  • D. High expression of ??- catenin

  • E. None of these

  • Answer:B

  • Answer Explanation:Oct-4 is considered as a very important protein for maintaining the pluripotency of stem cells. siRNA against oct-4 will decrease its amount in the cell and thus it will negatively affect the pluripotency of the cell.

Score: 0/10

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