Essential Biology: Human Health & Physiology (HL)



Essential Biology: Human Health & Physiology (HL)

This document includes 222 questions on:

Core, AHL and Option H: Further Human Physiology

Paper 1 and 2 ask questions on Core and AHL topics:

6.1: Digestion 6.2: The Transport System 6.3: Defense Against Infectious Disease

6.4: Gas Exchange 6.5: Nerves, Hormones, Homeostasis 6.6: Reproduction

11.1: Defense Against Infectious Disease 11.2: Muscles and Movement

11.3: The Kidney 11.4: Reproduction

1. What do the following prefixes and suffices refer to?

Gastro- -cyte

Pleur- -ase

Cardi- -in

Neur- -one

Renal- -ogen

Hepa-

Ortho-

Myo-

2. Define enzyme.

3. Define substrate.

4. Define macromolecule.

5. Distinguish between catabolic and anabolic metabolic reactions.

6. Explain why digestion of large food molecules is essential.

7. Complete the table to show the substrate, product and enzyme of digestion of these food macromolecules:

| |Carbohydrates |Lipids (fats) |Proteins |

|Type of Enzyme |carbohydrase | | |

|Example of enzyme | | |trypsin |

|Product(s) | | | |

|Source of enzyme | |pancreas | |

|Optimum pH | | | |

8. Where might one find an enzyme with an optimum pH of 2?

9. Outline how the following factors affect the rate of an enzyme-catalysed reaction:

a. Substrate concentration

b. pH

10. Explain the need for enzymes in digestion, with a focus on temperature and energy.

A graph showing the difference between a catalysed and uncatalysed reaction is useful.

11. Digestion of large food molecules is through enzyme-assisted hydrolysis.

Complete the equation below to show hydrolysis of a dipeptide.

[pic]

12. Label the diagram of the human digestive system below.

Annotate each structure with its function and describe how it carries out this function.

13. The stomach is extremely acidic.

a. What is this acid? What the function of this acid?

b. What part of the stomach aids mechanical digestion? How?

c. Which enzyme is released by the stomach? Where from? How is it controlled?

14. Much digestion and absorption occurs in the small intestine.

a. How is the acidic chyme neutralized in the small intestine?

b. What feature of the ileum wall allows for greater absorption of food molecules?

c. By which mechanism is the bolus of food moved along the intestines?

15. In the space below, draw and label a single intestinal villus.

Include epithelial cells, lacteal and capillaries.

Explain the significance of the structures of the villus in absorption of digested food molecules.

16. Distinguish between ingestion, digestion, absorption, assimilation, egestion and excretion.

Ingestion

Digestion

Absorption

Assimilation

Egestion

Excretion

17. Distinguish between the small and large intestines in terms of structure and function.

18. What substances are egested as faeces?

19. How can a high-fibre diet promote intestinal health?

Digested food molecules are carried in the blood around the body.

20. Other than digested food molecules, what other substances are transported in the blood?

21. What are the functions of the following components of blood:

Plasma

Platelets

Erythrocytes

Leukocytes

22. Draw and label a simple diagram of the heart showing:

Right and left atria and ventricles, atrio-ventricular and semi-lunar valves, aorta, pulmonary artey, pulmonary vein, vena cava and cardiac muscle.

23. Where is the cardiac muscle thickest? Why?

24. Distinguish between oxygenated and deoxygenated blood.

25. Outline the journey of a single red blood cell taking one full circuit of the transport system, starting and finishing at the liver. You could use a flow chart/cycle for this.

26. Why is the flow of blood described as double circulation?

27. What is a myocyte?

28. Explain the myogenic origin of the heartbeat.

29. Name and label the parts of the heart responsible for initiation and propagation of the heart beat.

30. What is meant by the term indefatigable?

31. Complete a flow chart to show how heart rate changes with exercise.

Include the roles of the blood, medulla oblongata, nerves, SA node and the Vagus nerve.

32. What is the effect of the hormone adrenalin?

33. Compare the structure and functions of these blood vessels:

| |Artery |Capillary |Vein |

|Diagram | | | |

|(labeled, cross section) | | | |

|Function | | | |

|Travels… |From… |Through … |To … |

|How is structure related to | | | |

|function? | | | |

34. Distinguish between ventilation, gas exchange and respiration.

35. Capillaries deliver deoxygenated blood to and carry oxygenated blood from the alveoli of the lungs. Draw a simple diagram to show the flow of blood and gas exchange at the alveolus.

36. What structural adaptations of alveoli suit them to their function of gas exchange?

37. By which two methods is a concentration gradient of CO2/O2 maintained at the alveolus?

38. Draw and label a simple human ventilation system, including:

Mouth/nose, trachea, bronchi, bronchioles, alveoli, lungs, ribs, intercostal muscles and diaphragm.

39. Complete the table below to show the events of ventilation (breathing):

| |Inhalation |Exhalation |

|Diaphragm | | |

|Abdominal muscles |relax | |

|External intercostals muscles | | |

|Internal intercostals muscles | | |

|Lung Volume | | |

|Air pressure in lung | |increases |

|Movement of Air | | |

40. Control of ventilation rate, like the heart rate, is via the autonomic nervous system.

Under exercise, there is more CO2 in the blood.

a. At which part of the brain is this increased CO2 detected?

b. What is the effect of this on breathing rate?

41. Extend the organizational chart below to show some components of the central and peripheral nervous systems.

[pic]

42. Draw a simple diagram of a motor neuron (nerve cell), including:

Cell body, nucleus, dendrites, axon, terminal branches, motor end plates, myelin sheaths, Nodes of Ranvier and the direction of the nerve impulse.

43. Describe the journey of a nerve impulse in the reflex arc, from the stimulus to the effector.

44. Define resting potential.

45. Define action potential.

46. Complete the diagram below to show why the resting potential of a neuron is negative.

47. Define depolarization.

48. Define repolarisation.

49. Annotate the graph below to explain what is happening in each stage of an action potential (AP).

Include the movement of ions into and out of the cell and how this occurs.

50. What is the importance of the refractory period in propagation of an action potential?

51. What is the importance of these membrane proteins in nerve impulses?

Sodium-potassium pump

Sodium channel

Potassium channel

52. Define synapse.

When an AP reaches the terminal end of a neuron, it is converted from an electrical signal to a chemical message for synaptic transmission.

53. What form does this ‘chemical message’ take?

54. Complete the summary of synaptic transmission below:

55. Neurotrasmitters are specific to their receptors.

What does this mean?

56. Some drugs act as competitive inhibitors to neurotransmitters.

What would be the effect of this?

When a nerve impulse reaches the terminal end of a motor neuron, it intitiates muscle contraction, causing movement in the body.

57. What are the roles of the following components in movement in the body?

Nerves

Muscles

Bones

Joints

Tendons

Ligaments

58. In the space below, draw and label a simple diagram of a human elbow joint.

Include the radius, ulna, humerus, biceps and triceps. Label and state the functions of the joint capsule, synovial fluid and cartilage.

59. Outline how the biceps and triceps work antagonistically in ‘bend’ and ‘extend’ of the arm.

60. Compare these types of joints:

| |Elbow |Knee |Shoulder/ Hip |

|Type of joint |hinge | | |

|Range of movement | |Hinge movement with some pivoting| |

| | |possible | |

61. Label this section of a striated muscle cell with the names and functions of each structure.

62. Which part of the muscle cell is depolarized when an action potential reaches the neuromuscular junction?

63. Why are there so many mitochondria in a muscle cell?

64. The electron micrograph below shows a section of a myofibril.

a. Label the dark and light bands and z-lines.

[pic]

b. How many full sarcomeres are shown in this image?

c. Draw a simple diagram of the corresponding sarcomeres, showing the actin and myosin fibres (with myosin heads)

65. Annotate the diagrams below to show how muscle contraction occurs in a sarcomere.

Include the roles of sarcolemma, sarcoplasmic reticulum, Ca2+, actin binding sites, cross bridges, myosin heads, ATP.

66. Compare these two electron micrographs of a skeletal muscle sarcomere.

|Contracted or relaxed? | | |

|Sarcomere length | |Shorter |

|Z-bands | |Closer |

|H-bands |No change |

|Light bands | | |

|Dark bands |No change |

67. What can be deduced from this in terms of relative roles of actin and myosin fibres?

68. Distinguish between nerves and hormones.

| |Nerves |Hormones |

|Route |Direct from coordinator to effector |Through: |

| | |From: |

| | |To: |

|Signal type | |Chemical |

|Time to take action | |longer |

|Duration of effects | | |

69. The endocrine system is responsible for hormone-mediated communication within the body.

Which endocrine glands are mostly responsible for:

Control of blood sugar

Control of body temperature

Control of water levels in blood

Initiation of puberty

Production of sex cells

70. Draw a simple flow chart to show how the endocrine system functions based on stimulus, hormone secretion and negative feedback control.

71. Define homeostasis.

72. List five factors that are maintained through homeostasis.

73. Complete the flow chart below to show how the hypothalamus controls body temperature through hormones. What are the body’s responses?

The Kidney is responsible for filtering toxins out of the blood and maintaining osmoregulation.

74. Define osmoregulation.

75. In the space below, draw a simple diagram of the kidney. Label and state the roles of:

Renal vein, renal artery, cortex, medulla, pelvis, ureter.

76. The nephron is the functional unit of the kidney.

Label the diagram below with these structures and their functions:

Afferent arteriole, glomerulus, efferent arteriole, renal capsule, proximal convoluted tubule, Loop of Henle with descending and ascending loops, distal convoluted tubule, colecting duct.

77. Explain ultrafiltration in the renal capsule.

Include the roles of arterioles, fenestrations, capillary wall and basement membrane.

78. Which components of the blood are not filtered out by ultrafiltration? Why?

79. Outline selective reabsorption in the proximal convoluted tubule.

By which methods are water, salts and glucose reabsorbed?

80. What structural features of the proximal convoluted tubule assist it in this function?

81. Explain the functions of the loop of Henle.

How are salts removed in the descending and ascending loops?

What is the effect on the concentration of the medulla and the urine?

82. The water balance of the blood is finally adjusted in the collecting duct.

Explain how this works.

83. When a person is dehydrated, ADH (anti-diuretic hormone) is released into the blood.

What is the the effect of ADH on:

a. The walls of the collecting duct?

b. Water uptake into the blood?

c. Concentration of the urine?

84. Consider this data table:

a. Calculate the concentration of urea in the urine.

b. Why is such a large proportion of urea removed from the blood?

c. Explain why no proteins and macromolecules are present in the filtate or urine.

d. 100% of glucose is reclaimed. Explain how this occurs.

85. Blood glucose levels are maintained by hormones produced in the pancreas.

Complete the table to show glucoregulation.

| |High Blood Sugar |Low Blood Sugar |

|The pancreas contains… |___________________ cells… |___________________ cells… |

|…which secrete… | | |

|… carried in blood to…. |& | |

|… causing conversion of.. | | |

|… to … | | |

|Overall effect: |Glucose removed from blood |Glucose released into blood |

86. Diabetes mellitus is a disease in which regulation of blood glucose is difficult.

There are two types of diabetes (Type I and Type II)

Distinguish between them in terms of action, age of onset and risk factors.

Type I: Type II:

87. How can we tell from this table that the patient has diabetes?

88. Explain the presence of glucose in the urine of a patient with diabetes.

89. Suggest reasons why incidence of diabetes is increasing globally.

90. Diabetes has a strong hereditary link.

Name two other disorders which can be inherited, and state the cause.

1:

2:

91. Cancers (tumours) are not inherited, nor are they pathogenic.

What is a tumour?

92. Define pathogen.

93. Give named examples of the four types of pathogen.

94. List five methods by which pathogens can be transmitted.

95. Explain why antibiotics are not effective against viruses.

96. Distinguish between bacteriocidal and bacteriostatic antibiotics.

97. Outline the emergence of Multiple-Resistant bacteria as a result of overuse of antibiotics and subsequent evolution by natural selection.

98. How do the skin and mucous membrane act as the body’s primary defense against infection?

99. Blood clotting can prevent further entry of pathogens into the blood and stops bleeding.

Draw a simple flowchart to outline blood clotting as a metabolic pathway.

Include the roles of platelets, clotting factors, thrombin, fibrinogen, erythrocytes.

100. Draw a diagram to show how a phagocyte engulfs a pathogen by phagocytosis.

What is the role of lysozymes in this process?

101. What is the role of the following types of cells in defense against infectious diseases?

Phagocytes (macrophages)

B-cells

T-cells

Plasma cells

Memory cells

102. Distinguish between antigens (epitopes) and antibodies.

103. When a pathogen invades an organism, this is called a ‘challenge’

Outline the body’s ‘response’ to this challenge, leading to antibody production.

104. What is polyclonal selection?

105. How do antibodies allow the body to defeat a pathogen?

106. How does clonal selection when fighting a pathogen lead to immunity

against that same pathogen?

107. Distinguish between passive, active, artificial and natural immunity with examples of

each.

108. Annotate the graph to show how vaccination (immunisation) works.

109. Name one disease that has been eradicated through vaccination programmes.

110. Discuss the benefits and dangers of vaccination programmes.

Benefits Dangers

111. DefineHIV

112. Define AIDS

113. Distinguish between HIV and AIDS.

114. Explain the effects of HIV on the immune system.

115. Discuss the cause, tranmission, social and economic impacts of HIV.

116. How might HIV/AIDS affect developed nations differently to developing nations such as

regions of Africa?

117. Suggest reasons why a vaccine for HIV is difficult to produce.

118. The ELISA test can be used as a diagnostic test for HIV.

a. What does ELISA stand for?

119. Tests such as the ELISA test and the HCG test for pregnancy use a large number of

antibodies. A marker is attached that changes colour when these antibodies are

activated by the presence of a specific antigen (such as HIV or HCG hormone).

a. Outline the process of monoclonal antibody production.

Include the roles of B-cells, tumour cells and hybridomas.

b. Name one therapeutic use of monoclonal antibodies.

120. List three diseases (other than HIV) that can be sexually transmitted and their effects.

121. Human Pappiloma Virus (HPV) is a pathogen that has been linked to cervical cancer.

a. How might a virus lead to cancer?

b. How could the following protect the reproductive health of women?

The HPV vaccine

Regular cervical smear tests

122. Draw and label the female reproductive system, including:

Vagina, cervix, uterus, endometrium, fallopian tubes, ovaries. Include also the bladder and urethra.

Annotate the diagram with the function of each part.

123. Zoom into the ovary. What is the function of each of these labelled parts?

124. Outline the process of

oogenesis.

Include the roles of mitosis, cell growth, meiosis, unequal division of cytoplasm and polar bodies.

125. A typical menstrual cycle lasts around 28 days and is controlled by hormones.

Name the origin and state the main functions of these hormones:

Follicle stimulating hormone (FSH)

Luteinising hormone (LH)

Oestrogen

Progesterone

126. The chart shows hormonal changes during the menstrual cycle.

Describe the events occurring at:

1-4 days

5-14 days

14-28 days

127. During which days of the cycle is a woman:

a. Most likely to conceive?

b. Least likely to conceive?

128. Draw and label diagrams of a mature sperm and a mature egg.

Include a scale bar with an estimate of size.

129. Draw and label the male reproductive system, including:

Testis, epididymis, sperm duct, seminal vesicle, prostate gland, urethra, penis and bladder.

Annotate the diagram with the function of each part.

130. What are three functions of testosterone in males?

131. Zoom into the testis. Draw a tissue plan diagram of the testis based on this light

micrograph. Include the functions of the labelled parts.

132. What are the roles of FSH and LH in spermatogenesis?

133. Draw a flow chart (like the oogenesis one above) to show the process of

spermatogenesis. Include mitosis, cell growth, meiosis and differentiation.

134. Oultine the roles of the epididymis, seminal vesicle and prostate gland in the production

of semen.

135. Compare spermatogenesis and oogenesis.

| |Spermatogenesis |Oogenesis |

|Number of gametes produced per | | |

|primary cell | | |

|Formation of gametes |Constant after puberty | |

|Number of meiotic divisions | | |

|Method of release of gametes | |Ovulation, controlled by LH |

|Number of gametes released |Millions | |

|Hormones used | | |

|Location | | |

136. Distinguish between fertilisation and pregnancy.

137. Fertilisation of an egg occurs in three basic stages. Describe them.

Acrosome reaction

Penetration of egg

Cortical reaction

138. How does this process prevent multiple fertilisations of the same egg?

139. Which type of cell division follows fertilisation and allows development of the

blastocyst?

140. During what time periods do we see these stages of development?

Zygote morula blastocyst embryo fetus birth

141. If a fertilised egg implants onto the endometrium, a hormone called HCG is released.

This causes progesterone levels to remain high, inhibiting FSH and LH.

a. Where is HCG produced? (choose one)

Pituitary placenta ovary embryo

b. What are two benefits of maintaining high progesterone levels during pregnancy?

c. What immune system molecule is used to detect HCG in pregnancy test kits?

Consider the diagram below.

142. What is the role of the amniotic sac and amniotic fluid?

143. Which hormones are released by the placenta?

144. Which materials are exchanged between the maternal and fetal blood?

145. How does the structure of the placenta aid in its function of supporting the developing

fetus?

Umbilical cord

Villi

Inter-villus spaces

Blood supply

Membrane

146. Another hormone, oxytocin, is essential in childbirth.

a. What is its role?

b. In what way is the action of oxytocin different to other forms of hormonal control?

c. What happens to progesterone levels in childbirth?

147. Outline the process of childbirth, beginning with engagement of the fetal head in the

cervix and ending with the ‘afterbirth’ of the placenta.

148. IVF (in-vitro fertilisation) is a reproductive technology that allows those with reproductive problems to conceive and have a normal pregnancy.

Annotate the diagram below with steps of IVF.

149. Discuss the ethical implications of IVF.

Consider human rights, morality and religion, safety, cost, psychological effects, effects on others, economic cost, research and other points of view you feel are appropriate.

Arguments for IVF: Arguments against IVF:

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