BIOL121 WORKSHEET
Due: 3 am Tuesday 9th October (Week 10)
Submit: via Turnitin link on BIOL121 LEO page
Weighting: 20% final grade
Answers must be in an easy to read colour that is distinctly different to black.
QUESTION 1
Fill in the blank boxes to complete TWO rows of your choice in the following table, which summarises the name, location and function of a variety of cells throughout the body. The first line is completed as an example of the level of detail required. Only the first TWO rows completed will be marked (1 mark/row; 2 marks total)
Cell name Where would you usually expect to find this cell type? What is its job (or primary role)?
Melanocyte In the deep layer of the stratified squamous epithelium of the skin. Production of melanin to protect underlying tissue from harmful UV radiation.
Spontaneously depolarise to trigger contraction of cardiac muscle. Establishes the heart rate.
Schwann cell
Maintain the protein and mineral content of the surrounding bone matrix.
Non-specific immune surveillance of peripheral tissues (recognising and destroying abnormal cells).
Contains large quantities of haemoglobin, enabling it to bind and transport respiratory gases.
Parathyroid chief cells
QUESTION 2
Name the personal protective equipment that should be worn when handling someone else’s urine, and explain why those items are needed. (2 marks)
QUESTION 3
Complete the table to compare how the following cells carry out the third line of defence:
• B-lymphocytes
• Cytotoxic T-lymphocytes
Some sections are completed for you to help guide your answers. (0.5 marks/box; 4 marks total)
B-lymphocytes Cytotoxic T-lymphocytes
Overall role Produce antibodies
Target Antigen-bearing host cells recognised as ‘foreign’; e.g., cancer cells, virus-infected cells, or cells with intracellular bacteria
Facilitated by which helper cell?
Is this specific immunity?
(yes or no)
What cells provide long-term immunity?
QUESTION 4
The following paragraph refers to muscle contraction. Fill in each of the blanks to complete the paragraph using terms from the list provided. More terms than necessary are provided, and terms may be used more than once. (0.5 mark each; total 3 marks)
The action potential spreads along the , until it reaches a T-tubule. The action potential continues down the T-tubule, where it triggers the release of from the . This exposes binding sites on . heads bind to the exposed sites on to form cross-bridges.
• Na+ • sarcoplasm • mitochondria
• K+ • sarcolemma • Golgi apparatus
• Ca2+
• Mg2+ • sarcoplasmic reticulum
• sarcomere • myofibril
• myosin
• actin • nucleus • myofilament
QUESTION 5
Describe the role of osteoblasts and osteoclasts in the regulation of blood calcium ion concentration. You must include the role of the relevant hormones for full marks. (3 marks)
QUESTION 6
Describe how the hypothalamus controls the release of hormones from the:
A. anterior lobe of pituitary gland
B. posterior lobe of the pituitary gland
In your answer, give specific examples and clearly name any hormones involved. (2 marks/lobe)
QUESTION 7
Duchenne muscular dystrophy (DMD) is recessive sex-linked disorder, which causes muscle degeneration and premature death. A couple is pregnant with a boy and neither has DMD. The father’s family has no history of DMD, but the mother is unsure of her genetic family history as she was adopted. The mother decides to take advantage of some of the new genomic screening tests and learns information about a large number of her genes. She finds that she is a carrier of the DMD-affected allele. (3 marks total)
A. What is the mother’s genotype? Explain your reasoning. (1 mark)
B. What is the father’s genotype? Explain your reasoning. (1 mark)
C. What is the likelihood of the male foetus having DMD? Use a Punnett square to explain your answer. (1 mark)
QUESTION 8
Describe the changes in volume and pressure inside the chest cavity during a normal, quiet exhalation. Explain why these changes are occurring, and the effect upon airflow. (4 marks)
QUESTION 9
Regarding quiet ventilation, which process is active — inhalation or exhalation? Briefly explain your answer. (1 mark)
QUESTION 10
The graph below displays the oxygen dissociation curve and factors that affect the release of oxygen from haemoglobin (Hb). Explain how these factors will affect the release of oxygen into the blood supply of a hard-working skeletal muscle. (3 marks)

Image from http://www.gpnotebook.co.uk/simplepage.cfm?ID=20250669
QUESTION 11
Choose ONE of the blood types below and answer the following questions. Only the FIRST completed column will be marked
A. State the type of antigens found on the surface of those red blood cells, and the type of antibodies found in the plasma of a person with the blood type shown. Type your answer in the table below (1 mark total)
B. Could a person with your chosen blood type safely receive type AB blood via transfusion? Explain your answer below. (2 marks)
Blood Group A B AB O
Red blood cell type
Antigens on red blood cells
Antibodies in plasma
QUESTION 12
Why is injury to the medulla oblongata usually fatal? (2 marks)
QUESTION 13
Complete the following table summarising the effects of autonomic innervation on target tissues. You must include both the effect upon the target tissue and a consequence of this stimulation in your answer.
The first row has been completed as an example. (1 mark/box; 4 marks total)
Target tissue Effect of sympathetic stimulation Effect of parasympathetic stimulation
Contractile force of the heart Contractile force increases; more blood pumped from heart No parasympathetic innervation of ventricular myocardium; therefore, no result
Airways in the lungs
Pupil
QUESTION 14
The paragraph below relates to this graph, which describes changes in membrane potential over time.
A. Fill in each of the blanks to complete the paragraph using terms from the list provided. More words than necessary are provided, and terms may be used more than once. (0.5 marks each; 3.5 marks total)
During , the ¬ of the cell is 70 mV more negative than the of the cell. When a stimulus is applied, the membrane potential must reach in order for an Action Potential to be fired. At the start of an Action Potential, Na+ channels open and Na+ ions the cell. This phase is called .
The is the period of time in which the nerve membrane can start another action potential only if a much greater stimulus than usual is applied.
• Na+ • negatively • peak action potential
• K+ • positively • absolute refractory period
• Ca+ • repolarisation • relative refractory period
• inside • depolarisation • +35 mV
• outside
• enter
• exit • hyperpolarisation
• resting membrane potential • -70 mV
• -55 mV
B. Referring to the graph above, at which numbered point do potassium gates begin to open? (0.5 marks)
QUESTION 15
Antidiuretic hormone and aldosterone influence water and electrolyte balance of the body. The following table summarises the main characteristics of these hormones; your task is to fill in the empty cells in the table. (0.5 marks/box; 4 marks total)
Antidiuretic hormone Aldosterone
Where is this hormone synthesized?
Which gland secretes this hormone?
Primary effect?
Mechanism of action
(How does it work?)
QUESTION 16
The following table describes the three elementary steps of urine formation. Complete the missing parts of the table. (0.5 marks/cell; 3 marks total)
Step in urine formation Where does this step take place? What happens?
Filtration
Water and/or solutes are transported from the tubular lumen to peritubular capillaries (blood)
Along the length of the tubular network; the exact location depends on the substance being transported
QUESTION 17
List two (2) differences between the external and internal urethral sphincters. The differences must relate to structure, function or innervation of these sphincters. (0.5 marks/difference; 1 mark total)
QUESTION 18
Explain how baroreceptors contribute to control blood pressure during a short period of widespread vasodilation. (3 marks)
QUESTION 19
Name four (4) major vessels attached to the heart, and explain where they receive blood from, and where they carry blood to (4 marks)
Major vessel Receives blood from Carries blood to

QUESTION 20
Explain the term ‘normal sinus rhythm’. (1 mark)
QUESTION 21
Complete the table on the heart valves below by briefly explaining the function of each and stating when each set of valves is closed. (0.5 per box; 2 marks total)
Type of heart valve What is their function? When are the valves closed?
Semilunar valves
Atrioventricular (AV) valves