Biology: Exam Two

26. Gene flow is the movement of genetic material

A. without altering the allele frequencies.
B. that drives a population towards perfection.
C. where organisms either join or leave a population.
D. without affecting the balance of gene pool of a population.

27. Which one of the following options is a constituent of peripheral nervous system?

A. Afferent nerves, brain and automatic motor nerves
B. Somatic sensory nerves, spinal cord and efferent nerves
C. Spinal cord, afferent nerves and somatic sensory nerves
D. Afferent nerves, efferent nerves and somatic motor nerves

28. Which one of the following structures of neurons is correctly paired with its function?

A. Axon - receives signal from muscle
B. Cell body - maintains structure and supply energy
C. Myelin sheath - reduces nerve impulse transmission
D. Dendrites - protects the neuron and insulate it

29. Which one of the following statements explain how nerve impulse is occurred? It occurs as a result of

A. charge difference across the membrane of axon.
B. the movement of neurotransmitter molecules into myelin sheath.
C. the movement of neurotransmitter molecules out of cell body.
D. balanced charge across the membrane of dendrites.

30. Which one of the following statements is an acceptable justification of the importance of synapse? Synapse is

A. the mechanism of protecting the axon from external damage.
B. a connection between the appendages of consecutive neurons.
C. the facilitator of the reverse flow of neurotransmitter chemical in neurons.
D. a conductor of action potential towards the end of the dendrite.

31. Which one of the following arrangement of molecules in the fluid mosaic model of the cell membrane is correct?

A. Phospholipids fill the protein like a sandwich to retain its rigidity.
B. Phospholipid molecules are peripherally attached to proteins.
C. Protein molecules are studded between the phospholipid bilayers.
D. Phospholipids are inserted into the bilayer of protein molecules.

32. What is the role of cholesterol in the cell membrane? It

A. anchors integral proteins to the cytoskeleton.
B. reduce the fluidity of the cell membrane.
C. transports hydrophilic molecules into the cell.
D. acts as receptor site for hormones and other signaling molecules.

33. This item is based on the following table about the function of cellular organelles.

No.	Features	Mitochondria	Golgi body	Lysosomes	Ribosomes
1	The site of protein synthesis	NO	YES	NO	YES
2	Modifies and distributes molecules	NO	YES	NO	NO
3	Site of aerobic respiration	YES	NO	NO	NO
4	Digest foreign cells	NO	NO	YES	YES

Which numbers in the above table show the correct function of the given organelles?

A. 2 and 4
B. 2 and 3
C. 1 and 3
D. 1 and 4

34. Which one of the following is the main function of Bowman's capsule of the human kidneys?

A. Mineral reabsorption
B. Prevent back flow of urine
C. Water preservation
D. Ultrafiltration of blood

35. Potato slices of equal weighed were immersed in four different concentrations of salt solutions. The solutions were 1.5, 1.0, 0.5, and 0.1 molars. After a day, the potato slices were reweighted. Which potato slice weighs the least? The one from

A. 0.1 molars
B. 1.5 molars
C. 1.0 molars
D. 0.5 molars

36. Suppose you took a container and divided it into two halves by a membrane which is permeable to water and labeled the two halves as "A" and "B" . Finally,you added hypertonic solution to "A" and hypotonic solution to "B". What will be the expected result of this experiment? The water level of

A. "A" remains constant.
B. "B" decrease.
C. "B" rise up.
D. both "A" and "B" rise up.

37. What is the justification for feeling warm while sweating a lot in a very humid condition?

A. The lower rate of evaporation of water from the skin surfaces
B. Closure of the glands in the epidermal layer of the skin
C. Unequal distribution of ions on membrane of cells
D. An increase in metabolic rate as temperature increases

38. Among the following statements, one briefly describes the concept of climate change. It is the

A. sudden change in an average rain fall of a limited area.
B. radical change of local weather condition that sustain for less than a year.
C. global change in the temperature, precipitation and wind conditions.
D. gradual change of atmospheric temperature over a short period of time.

39. The type of gene mutation that results in the change of a triplet (GAG) in a normal hemoglobin to another triplet (GTG) in sickle-cell hemoglobin is

A. deletion mutation.
B. insertion mutation.
C. non-disjunction.
D. substitution.

40. As a result of human activities, huge amount of carbon dioxide has been accumulated in the atmosphere. What is the consequence of this phenomenon?

A. Drop in temperature of the earth and death of aquatic organisms
B. Increased rate of uptake of carbon dioxide by green plants
C. Reduction in the sea level and death of aquatic animals
D. Preventing certain amount of heat escaping back to the space

41. What was the main objective of the United Nations Framework Convention on Climate Change (UNFCCC)?

A. Reduction of the monopole utilization of border crossing rivers to prevent climate change
B. Prevention of dangerous man - made interference with the climate system
C. Prohibition of developing countries from setting up big industries that could affect the climate
D. Donation of high carbon projects related to climate change by the developed countries

42. Which of the following is true concerning the evidences of evolution?

A. Organisms which have little genetic relationship show similar behavior.
B. Organisms which live in the same area have similar evolutionary history.
C. Species that live in the same geographic area have the same genetic makeup.
D. Species that are closely related share the most similar DNA sequences.

43. In a fox population, foxes with thicker fur survived better in cold climate compared to those with thinner fur, however, foxes with thinner fur survived better when the climate was very hot. What type of natural selection is described in this scenario?

A. Diversifying selection
B. Stabilizing selection
C. Directional selection
D. Disruptive selection

44. In human evolution brain size increased over the courses of evolution. Which alternative contains hominids arranged in an increasing order of brain size?

A. Homo neandertalensis → Homo erectus → Homo habilis → Homo sapiens
B. Homo erectus → Homo habilis → Homo neandertalensis → Homo sapiens
C. Homo habilis → Homo erectus → Homo neandertalensis → Homo sapiens
D. Homo erectus → Homo neandertalensis → Homo habilis → Homo sapiens

45. Which one of the following statements correctly explains the genetic drift? It is a change in allele frequency due to

A. independent assortment of chromosomes.
B. non-random mating of individuals in a population.
C. relocation of species into other areas.
D. chance based sampling error.

46. Which one among the following processes occurs during the light independent phase of photosynthesis?

A. Cyclic photophosphorylation of ADP in the thylakoid
B. Excitation of electrons from chlorophyll molecules
C. Reduction of triose molecules by hydrogen from NADPH
D. Splitting of water molecules into its components

47. As compared to non- cyclic photophosphorylation, the cyclic photophosphorylation uses the

A. photosystem I as the last electron acceptor.
B. photosystem I to produce ATP and reduced NADP in the stroma.
C. photosystem II as the first electron donor to NADP.
D. hydrolysis of water to replace electrons lost from photosystem II.

48. Which one of the following chemical reactions summarizes the process of photosynthesis?

A. C₅H₁₀O₅ + 6O₂ → 6CO₂ + 12O₂ + 12H₂O
B. 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ + ATP
C. 6CO₂ + 12H₂O → C₆H₁₂O₆ + 6O₂ + 6H₂O
D. C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + ATP

49. Which one of the following statements properly describes the structure of ATP? It is made up of

A. one adenine base attached to a pentose sugar and three phosphate groups.
B. two adenine bases attached to a hexose sugar and three phosphate groups.
C. one adenine base attached to a ribose sugar and two phosphate groups.
D. two adenine bases attached to a deoxyribose sugar and two phosphate groups.

50. Which one of the following descriptions about glycolysis is correct? It is a process

A. of producing acetyl CoA from pyruvate by releasing CO₂.
B. that produces a net of 4 ATP through substrate level phosphorylation.
C. that takes place in the cytosol with high demand of oxygen.
D. of breaking down of a glucose molecule to two pyruvates.

Biology Exam: Questions 26 - 50

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