ASVAB Science Biology Practice Test 3

Question – 1

1. In Drosophila, if the X/A ratio is 1 it is a

  • A. Male

  • B. Female

  • C. Intersex

  • D. Metamale

  • E. Metafemale

  • Answer:B

  • Answer Explanation:In Drosophila sex is determined by the ratio of number of X chromosomes present to the number of autosomes. If the X/A ratio is 1it is a female. If the ratio is 0.5 it is a male. If the ratio is greater than one it is a metafemale and if the ratio is lesser than 0.5 then it is a metamale. The intersex has ratio that is greater than 0.5 and lesser than 1.

Question – 2

2. The phospholipids present in bilayer of plasma membrane have

  • A. Hydrophilic head

  • B. Hydrophobic head

  • C. Hydrophilic tail

  • D. Both hydrophobic and hydrophilic head

  • E. Both B and C

  • Answer:A

  • Answer Explanation:The phospholipid bilayer of plasma membrane was explained by Singer and Nicolson. According to the phospholipid bilayer structure of plasma membrane, the protein molecules float in a fluid phospholipid bilayer. The phosphate heads of phospholipids are hydrophilic and face outside to the aqueous environment. The hydrocarbon tails of phospholipids are hydrophobic and face inwards. The plasma membrane does not possess a hydrophobic head and hydrophilic tail of phospholipids.

Question – 3

3. The process by which immature cells develop into matured cells of a specific lineage is

  • A. Organogenesis

  • B. Differentiation

  • C. Growth

  • D. Pattern formation

  • E. Morphogenesis

  • Answer:B

  • Answer Explanation:Differentiation is the process by which an immature cell develops into a mature cell type. Example: Formation of RBC from an erythroblast. A fully differentiated cell is generally not capable of undergoing division.

Question – 4

4. In humans, the embryos produced by in vitro fertilization (IVF) are placed in

  • A. The uterus of mother

  • B. Vagina of mother

  • C. Fallopian tube of mother

  • D. Ovary of mother

  • E. Both C and D

  • Answer:A

  • Answer Explanation:In vitro fertilization (IVF) is a process of fertilization of egg outside the body, in lab conditions. The resulting embryo from IVF is placed in the uterus of mother after 4-5 days for its further growth. Gamete intrafallopian transfer and zygote intrafallopian transfer are similar procedures to IVF where gametes and zygotes are transferred to the fallopian tube respectively.

Question – 5

5. The embryonic skeleton is made up of

  • A. Hyaline cartilage

  • B. Yellow elastic cartilage

  • C. White fibrous cartilage

  • D. Both yellow and white fibrous cartilage

  • E. Both hyaline and white fibrous cartilage

  • Answer:A

  • Answer Explanation:Embryonic skeleton is made up of hyaline cartilage. Hyaline cartilage is a semi-transparent, very elastic and strong cartilage. Yellow elastic cartilage contains a matrix made up of yellow elastic fibres and collagen and they have greater elasticity than hyaline cartilage. White fibrous cartilage is highly tough whose matrix is made up of densely packed white collagen fibres.

Question – 6

6. Cancer of connective tissue is called

  • A. Sarcoma

  • B. Lymphoma

  • C. Carcinoma

  • D. Myeloma

  • E. Glioma

  • Answer:A

  • Answer Explanation:Sarcoma refers to cancer of connective tissues like bones, cartilage etc. Lymphoma, carcinoma and glioma refer to cancer of lymphoid cells, epithelial cells and brain cells respectively.

Question – 7

7. The part of small intestine that opens into large intestine is called

  • A. Pyloric sphincter

  • B. Duodenum

  • C. Jejunum

  • D. Ileum

  • E. Caecum

  • Answer:D

  • Answer Explanation:The small intestine is divided into three regions namely duodenum, ileum and jejunum. The stomach opens into duodenum through a valve called pyloric sphincter. Next to duodenum is jejunum and ileum. Ileum, a more coiled structure which absorbs nutrients from digested food is connected to large intestine. Caecum is a region of large intestine.

Question – 8

8. Which of the following represents the proteins that control the material flow in and out of a cell membrane?

  • A. Motor proteins

  • B. Signaling proteins

  • C. Regulatory proteins

  • D. Transport proteins

  • E. Structural proteins

  • Answer:D

  • Answer Explanation:Proteins that transport substances in and out of cell membrane are known as transport proteins. Motor proteins are the proteins that move along a substrate. Proteins that take part in signal transduction are called signaling proteins. Proteins that control a gene or protein activity are called regulatory proteins. Proteins which give structural stability to cells are called structural proteins.

Question – 9

9. On which of the following sequences does methylation take place during mismatch repair?

  • A. GATC

  • B. GGTA

  • C. AGCT

  • D. GTTA

  • E. ATCG

  • Answer:A

  • Answer Explanation:In order to distinguish the parent strand from the daughter strand, methylation of adenine residues present in GATC sequence of the parent strand takes place. Methylation is catalyzed by Dam methylase.

Question – 10

10. Gametophyte stage is dominant in

  • A. Bryophytes

  • B. Pteridophytes

  • C. Conifers

  • D. Angiosperms

  • E. Both C and D

  • Answer:A

  • Answer Explanation:Plants have alternation of generations including gametophyte and saprophyte stages. The gametophyte stage is the sexual gamete producing stage. The gametes produced are haploid. Sporophyte stage is the asexual stage bearing diploid cells. Bryophytes have dominant gametophyte stage whereas the rest have sporophyte as the dominant stage.

Question – 11

11. The protists that contain DNA in their mitochondria are

  • A. Parabasalids

  • B. Kinetoplastids

  • C. Diplomonads

  • D. Both a and b

  • E. Both b and c

  • Answer:B

  • Answer Explanation:Kinetoplastids are protozoans with flagella. They have a special type of DNA called kinetoplast DNA or kDNA in their mitochondria. Some kinetoplastids cause serious diseases in human. Eg. Trypanosomabruceiis the causative agent of sleeping sickness. Parabasalids and diplomonads are the protists that do not have DNA in mitochondria.

Question – 12

12. Which of the following is produced sexually and endogenously?

  • A. Basidiospores

  • B. Ascospores

  • C. Teleutospores

  • D. Conidiospores

  • E. Both A and B

  • Answer:B

  • Answer Explanation:A spore produced endogenously in an ascus is called ascospore. Basiodospores are produced externally from basidium. Conidiospores are produced asexually in conidiophores. Teleutospores are binucleated structures or spores. The two nuclei then undergo fusion and then meiosis. This gives rise to a promycelium which subsequently develops into a basidiospore.

Question – 13

13. The type of interaction that occurs when an animal population produces a substance harmful to a competing population is

  • A. Cladogenesis

  • B. Interference

  • C. Antibiosis

  • D. Symbiosis

  • E. None of these

  • Answer:C

  • Answer Explanation:Antibiosis is a biological interaction between two organisms or species where one is affected by the secondary metabolite produced by the other. Interference is the biological interaction where organisms fight each other for a scarce resource. Symbiosis is the interaction between two species where both are benefitted. Cladogenesis is the evolutionary diversification (due to branching) from the ancestral lineage.

Question – 14

14. Organisms belonging to the same _________ can interbreed among themselves.

  • A. Ecosystem

  • B. Habitat

  • C. Population

  • D. Community

  • E. Biosphere

  • Answer:C

  • Answer Explanation:Population refers to a group of organisms of same species occupying the same habitat. As it contains organisms of the same species, interbreeding among organisms is seen. Ecosystem, habitat, community and biosphere are made up of more than one species and interbreeding cannot occur between any random organisms.

Question – 15

15. Which of the following is a peripheral protein?

  • A. Spectrin

  • B. Ankyrin

  • C. Aquaporins

  • D. Calcium pump

  • E. Both A and B

  • Answer:E

  • Answer Explanation:Peripheral proteins are bonded to the inner or outer layer of the plasma membrane. They don’t possess transmembrane domains. Spectrins and ankyrins are located at the cytosolic layer of the plasma membrane and they interact with the cytoskeletal proteins.

Score: 0/10

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