BIOLOGY 2019 Unit 3 Key Topic Test 7 – Cellular signals QUESTION BOOK

Question 1 Signalling molecules interact with specific target cells due to the target cells having A. matching signalling molecules B. transcription factors connected to the DNA C. transport proteins in the cell memb ...

Question 1 Signalling molecules interact with specific target cells due to the target cells having A. matching signalling molecules B. transcription factors connected to the DNA C. transport proteins in the cell membrane D. receptors with complementary binding sites Question 2 Pheromones are a group of signalling molecules that may be released by mammals or insects which affect the behaviour of others of its species. The mode of transmission of pheromones is A. intracellular B. extracellular C. release into the environment D. passed from individual to individual during mating Question 3 Cytokines are a signalling molecule used when signalling in the immune system. Some forms of cytokines are involved in autocrine signalling meaning that signals A. bind to receptors on the same cell B. travel to receptors on surrounding cells C. move through the blood to the lymph nodes D. activate plasma cells Question 4 Signal transduction is a 3-step process that occurs in cells. Reception gives rise to a signal cascade in the transduction phase of the process. A signal cascade refers to A. multiple signalling molecules attaching to multiple receptors B. activation of secondary messengers C. G proteins binding to an internal receptor D. the altering of the cellular response through gene expression 2019 BIOLOGY KEY TOPIC TEST  TSSM 2019 Page 4 of 9 Question 5 Testosterone is a steroid hormone that is lipid soluble. As such it must be A. hydrophilic B. hydrophobic C. able to dissolve in blood plasma D. lipophobic Question 6 Receptors for signalling molecules must be on the surface of a membrane or inside the cell. A signalling molecule that is amino acid based such as glucagon A. attaches to an intracellular receptor B. enters the cell via facilitated diffusion C. attaches to DNA as a transcription factor D. attaches to an extracellular receptor Question 7 A G protein coupled receptor is activated when A. it binds to a ligand B. a signal cascade reaches the nucleus C. a messenger molecule enters a cell D. a hydrophobic molecule attaches to the external receptor site Question 8 An experiment was undertaken to determine whether a signal molecule was steroid based or amino acid based. To determine which type it is, a scientist should test A. if a cell produces a G protein in response B. if the molecule enters the cell C. if the signal molecules would bind to each other D. if DNA is released from the nucleus and connects to the signal molecule Question 9 A definition of apoptosis is A. programmed cell death B. caspase cleavage C. death ligand pathway D. mitochondrial pathway activation 2019 BIOLOGY KEY TOPIC TEST  TSSM 2019 Page 5 of 9 Question 10 Apoptosis would occur if an individual A. has just cut a finger B. had rapidly growing cancer cells C. was recovering from an infection D. had webbing between their toes as an adult Question 11 Mitochondria play a key role in apoptosis because mitochondria A. release ATP for energy for general cellular functions B. provide ATP for activating lysosome enzymes C. release caspases into the cytosol D. respond to stress by releasing death ligands Question 12 Common components of both the intrinsic and extrinsic model of apoptosis involves A. death ligands attaching to mitochondria B. DNA damage C. caspase activation D. necrosis Question 13 Which of the following steps is NOT a change that occurs in apoptosis. A. Dissolving Membranes B. Cell shrinkage C. Nuclear fragmentation D. Membrane blebbing Question 14 In amphibians, apoptosis occurs to remove cells from the gills, tails and fins of tadpoles. The blebs that are produced from the process of apoptosis in amphibians are A. Recycled by phagocytes to be reused in building new cells B. Excreted through digestion by restriction enzymes C. Converted to ATP via the mitochondria in the blebs D. Released from the body of the amphibian when it drops its tail. 2019 BIOLOGY KEY TOPIC TEST  TSSM 2019 Page 6 of 9 Question 15 Iodine can be used to promote apoptosis in mammals by weakening the mitochondrial membrane in cells. This form of induced apoptosis is A. Extrinsic as the iodine acts as a death ligand B. Intrinsic as iodine attaches to a death receptor on the cristae of the mitochondria C. Extrinsic as iodine causes the DNA in the mitochondria to leak out D. Intrinsic as the iodine activates a caspase pathway 2019 BIOLOGY KEY TOPIC TEST  TSSM 2019 Page 7 of 9 SECTION B - Short-answer questions Instructions for Section B Answer all questions in the space provided. Write using a blue or black pen. Question 1 Signal transduction is a 3-step process that involves messenger molecules creating changes in individual cells with specific target receptors. Chemical messengers including hormones, neurotransmitters, pheromones and cytokines act in mammalian systems to stimulate cells. In human immune systems, histamine, a monoamine, acts in response to pathogens by acting on smooth muscle cells increasing the permeability of capillaries to white blood cells. a. What are the 3 steps of signal transduction histamine would be involved in to increase permeability? _____________________________________________________________________ _____________________________________________________________________ b. What type of receptor would histamine attach to in smooth muscle cells? Explain. _____________________________________________________________________ _____________________________________________________________________ c. What effect would this type of signal have on the smooth muscle cells of capillaries? _____________________________________________________________________ _____________________________________________________________________ 3 + 3 + 1 = 7 marks Cortisol is a steroid hormone that is released to suppress the immune system which can cause a reduction in histamine’s effects and therefore inflammation. d. What type of receptor would cortisol attach to in smooth muscle cells to reduce the effects of histamine? Explain. _____________________________________________________________________ _____________________________________________________________________ e. What cellular response would cortisol have on smooth muscle cells? _____________________________________________________________________ _____________________________________________________________________ 2 + 2 = 4 marks 2019 BIOLOGY KEY TOPIC TEST  TSSM 2019 Page 8 of 9 Question 2 Apoptosis is a natural regulatory process of programmed cell death after a cell receives a signal resulting in the removal of cells that are no longer needed or may be a threat to an organism. Part of the intrinsic pathway process that causes apoptosis in cells is the targeting of mitochondria by apoptotic proteins causing mitochondrial swelling and the activation of caspases. a. Name 2 causes that can initiate the mitochondrial pathway? _____________________________________________________________________ _____________________________________________________________________ b. Why does damage to mitochondria initiate the death of the cell? _____________________________________________________________________ _____________________________________________________________________ c. Caspases are enzymes that are activated in response to mitochondrial stress. What effect do caspases have? _____________________________________________________________________ _____________________________________________________________________ 2 + 2 + 2 = 6 marks Question 3 The death receptor pathway is another way of receiving an apoptosis signal. TNF alpha is a cytokine produced by activated macrophages that is released to cause apoptosis in tumour cells. a. TNF alpha is a death ligand. What is a ligand? _____________________________________________________________________ _____________________________________________________________________ b. Is TNF alpha hydrophobic or hydrophilic? Explain. _____________________________________________________________________ _____________________________________________________________________ c. TNF alpha causes a signal cascade. What is a signal cascade? _____________________________________________________________________ _____________________________________________________________________ 2019 BIOLOGY KEY TOPIC TEST  TSSM 2019 Page 9 of 9 d. What is activated by TNF alpha in the targeted cells? _____________________________________________________________________ _____________________________________________________________________ 1 + 2 + 1 + 2 = 6 marks Question 4 Apoptosis is a controlled process to reduce the effects on other cells and to minimise issues that would occur if cells went through necrosis a. State 2 steps of the apoptosis pathway that occur before the formation of apoptotic bodies? ____________________________________________________________________ b. Macrophages engulf the apoptotic bodies that are formed by apoptosis. What is the advantage of phagocytosis after apoptosis? _____________________________________________________________________ _____________________________________________________________________ 2 + 1 = 3 marks Question 5 Pheromones are released by some mammals and insects as a signalling molecule. There is alarm, food trail and sex hormones which affect behaviour or physiology. In wasps some species such as Vespula germanica known in Australia as the European wasp, release a volatile substance that makes the wasps aggressive when protecting the nest. a. What is the difference between a hormone and a pheromone? _____________________________________________________________________ _____________________________________________________________________ b. Why do European wasp pheromones act only on other European wasps? _____________________________________________________________________ _____________________________________________________________________ c. The European wasp marks animals that disturb their nest with an alarm pheromone attracting other wasps to the sting site. If stung what should humans do to the sting site?