Biology: Exam Three

51. Which one of the following research activities has been conducted at Armauer Hansen Research Institute?

A. Improving crop production through genetic engineering
B. Conserving the genes of endemic plants and animals
C. Developing drugs for leshmaniasis and tuberculosis
D. Assessing the nutritional status of mothers and babies

52. Which one of the following alternatives contains only protein rich cereals?

A. Red kidney peas, maize and white pea
B. White kidney peas, red kidney peas and chickpea
C. Wheat, red kidney peas and sesame
D. Barley, chickpea and groundnut

53. Which one of the following statements is correct about the process of digestion in the stomach?

A. Pepsin hydrolyzes protein molecules into amino acids.
B. Lipase hydrolyzes fat molecules into fatty acids and glycerol.
C. Bile hydrolyzes bigger fat molecules into smaller droplets.
D. Amylase hydrolyzes starch molecules into maltose.

54. Which one of the following statements is correct about the role of trypsin in digestion? It acts on

A. lipids in the small intestine.
B. maltose in the mouth.
C. protein in the small intestine.
D. starch in the stomach.

55. Which one of the following descriptions about absorption of nutrients in the digestive system is correct?

A. Glycerol molecules are first absorbed into the hepatic portal vein and then to lacteal.
B. Amino acid molecules are directly absorbed from small intestine into the blood.
C. Fatty acids molecules are absorbed from small intestine directly into the blood.
D. Glucose molecules are first absorbed into the lacteal and then enter into the blood.

56. Which biological tool is correctly matched with its function?

A. Petri dishes - to culture microorganisms
B. Burette - to measure mass of a substance
C. Theodolite - to measure the rate of water flow
D. Centrifuges - to collect insects

57. Which one of the following properties permits insects to freely walk on water? Its high

A. specific heat capacity
B. adhesive force
C. surface tension
D. latent heat of vaporization

58. A student centrifuge a solution containing plant material in order to separate them based on their mass. After 10 minutes of centrifugation some of the components move to the bottom (A), others to the middle layer (B) and the remaining once to the top layer (C). Which alternative shows the mass of the components in decreasing order?

A. C > A > B
B. A > B > C
C. A = B = C
D. B > A > C

59. Which one of the following statements shows the future promise of biological sciences?

A. Finding alternative living place for human population
B. Using stem cells to repair damaged organs and grow new organ
C. Advising the government on how to conserve environment
D. Finding the adaptation mechanism of plant in new condition

60. Which one of the following alternatives contains only organic molecules?

A. Glucose, carbon dioxide, glycine and linoleic acid
B. Methane, calcium carbonate, linoleic acid and glucose
C. Linoleic acid, glucose, carbon carbonate and methane
D. Methane, glycine, linoleic acid and glucose

61. According to biological scenario, structure is related to function, which one of the following is correctly described?

A. Trachea - millions of air sacs for diffusion of O₂ and CO₂
B. Alveoli - supported by cartilage for swallowing food
C. Larynx - hair like strictures for mucus production
D. Nasal passage - large surface area with hairs for filtration of air

62. As compared to the exhaled air, the inhaled air contains

A. 70% oxygen, 0.03% carbon dioxide and 30% nitrogen.
B. 16% oxygen, 4% carbon dioxide and 80% nitrogen.
C. 21% oxygen, 0.04% carbon dioxide and 80% nitrogen.
D. 80% oxygen, 20% carbon dioxide and 0.04% nitrogen.

63. What is the scientific reason behind the preference of high altitude areas for training by the Ethiopian Athletes? Because

A. the RBCs produced are more efficient than those at low altitude.
B. it helps them to adapt to the high atmospheric pressure of mountains.
C. it helps them to increase their lung capacities.
D. the oxygen density is higher than the low altitude.

64. How does oxygen is transported in the human body? It is transported

A. by simple diffusion along concentration gradient from the lungs to the heart.
B. from the red blood cells to actively respiring tissues by facilitated diffusion.
C. by the blood plasma from lower concentration to higher concentration.
D. from the lungs to actively respiring tissue by hemoglobin of RBC.

65. Which one of the following statements is well justified. why the left ventricle is tough in nature? Because it

A. forces oxygenated blood out of the heart.
B. returns deoxygenated blood to the heart.
C. forces deoxygenated blood out of the heart.
D. returns oxygenated blood to the heart.

66. What mechanism was used by Gregor Mendel to protect the garden peas from self-pollination? He

A. opened the flower bud before pollen matured.
B. sterilized the male part of the flower using chemicals.
C. selected pure dominant traits for breeding.
D. covered the flower and protects it from pollinating agents.

67. Gregor Mendel crossed two pure-breeding traits of pea plants in his experiment and found only one of the traits expressed in the first generation. This shows that the

A. expressed trait must be determined by the recessive allele.
B. two traits in the F1 generation were equally expressed.
C. expressed trait must be determined by the dominant allele.
D. alleles masked in the F1 generation were lost due to mutation.

68. Which one of the following statements correctly describes chromosome structure?

A. The pair of chromosomes is heterozygous in nature.
B. Chromosomes are similar to a gene in structure.
C. Chromosomes are made up of histone bounded DNA.
D. The DNA is wrapped with ribose sugar to form a chromosome.

69. The breeding mechanism that improves the performance of animals or plants using particular traits is

A. self-breeding.
B. selective breeding.
C. combination of traits.
D. test cross.

70. Which one of the following birth control methods is correctly matched with its function?

A. Hormonal method - prevents follicle development and ovulation
B. Physical method - reduces the lining of the uterus
C. Natural method - prevent the ovum from reaching to the uterus
D. Surgical method - avoids early embryo implantation

71. Which one the following statements explains how the allosteric inhibitors affect enzymes activities? By binding to the

A. substrate and preventing it from binding to the active site
B. site other than the active site and altering the shape of the active site
C. active site and altering the shape of the active
D. active site of an enzyme and blocking the substrate

72. Why are enzymes considered special molecules in metabolism? Because

A. metabolic processes can produce special products in the presence of enzymes.
B. enzymes facilitate metabolic reactions under controlled physiological conditions.
C. reactions can't totally take place in the absence of enzymes.
D. enzymes are protein molecules that act as a source of energy.

73. Which of the following is the most advanced and recent event in the history of cell biology?

A. Discovery of the double-helix structure of DNA
B. Enovation of the first scanning electron microscope
C. Sequencing of the human genome
D. Description of the Golgi apparatus

74. A student focused a slide of an onion epidermal cell on pre-estimated width of 2 millimeter field of view under a microscope. What will be the width of each individual cell if you count 8 cells that fit to the field of view during your observation?

A. 16 millimeter
B. 0.40 millimeter
C. 4 millimeter
D. 0.25 millimeter

75. Which one of the following statements is correct about the differences between eukaryotic and prokaryotic cells? Prokaryotic cells have

A. membrane bound organelles whereas eukaryotic cells don't have it.
B. small ribosomes whereas eukaryotic cells have large ribosomes.
C. division of labor whereas eukaryotic cells don't have it.
D. cell wall whereas eukaryotic cells don't have cell wall.

Biology Exam: Questions 51 - 75

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