Human Bio - Unit 3 - Common Exam Q (WACE)

Explain the mode of action of lipid soluble hormones (4 marks) (WACE 2018)

- Hormone diffuses past plasma membrane of target cell
- hormone attaches to receptor complex in cytoplasm/hormone receptor complex formed in cytoplasm
- complex enters the nucleus
- complex binds to DNA and activates specific genes/transcription of mRNA/protein synthesis occurs

Describe the process that, under normal circumstances, stimulates the release of thyroid stimulating hormone (TSH) from the pituitary gland (5 marks) (WACE 2017)

- Stimulus: low levels of thyroxine/decreased body temperature/decreased rate of metabolism
- Receptor: stimulates receptors in hypothalamus
- Triggers release of TSHrf/releasing factors
- TSHrf travels in blood vessel network of infundibulum towards APG (anterior pituitary)
- stimulates release of TSH into the blood from APG

Explain the role of Medulla Oblangata in decreasing carbon dioxide concentrations in the blood (5 marks) (WATP 2024 SA)

- central chemoreceptors in medulla oblongata sensitive to CO2/pH change
- and pass nervous impulses/action potentials to respiratory centre in medulla oblongata
- which sends nerve impulses via the phrenic and intercostal nerves
- to cause the diaphragm and intercostal muscles
- to contract and relax faster
IF MENTION 'PERIPHERAL CHEMORECEPTORS' IT IS WRONG (as the question is specifically asking for medulla)

Define homeostasis (2 marks) (WATP 2024 SA)

- maintenance of a relatively constant internal environment
- for the body's optimal functioning/in constantly changing external environment

Reasons why parents might choose to vaccinate their child (4 marks) (WATP 2024)

ANY 4 OF:
easy access/peers are vaccinating/requirement for childcare/free/high level of maternal education/they themselves were vaccinated/believe it will protect their child against the disease

Explain how a bacterial pathogen stimulates the hypothalamus to reset the thermostat and therefore results in a fever (4 marks) (WACE 2017 SA)

MUST HAVE:
- Hypothalamus responds to pyrogens/hypothalamus responds to chemicals released from macrophage
ANY 3 OF:
- Macrophages respond to entry of pathogen/bacteria
- macrophage ingests pathogen/bacteria
- macrophage produces interleukin 1/chemical signals
- bacteria/pathogen releases endotoxins/toxins/pyrogens
- cytokines produce pyrogens
- pyrogens released into the blood
- pyrogens alter body's temperature sensors (making the body think it is cooler then it actually is)

Describe the process of inflammation (5 marks) (WACE 2019 ER)

- mast cells release histamine/histamine triggered
- vasodilation increases, increasing blood flow/increasing permeability of capillaries
- causing heat, redness and swelling
- histamine attracts phagocytes to the area
- phagocytes consume pathogens (and debris)

STIMULUS: In 2012, a team of Australian and Chinese scientists discovered the bones of a new human species in the Red Deer Cave located in a province of China. Archaeologists retrieved over 30 fossilised bones, including three partial skulls, two lower jaws, isolated teeth, rib and limb bones. The fossils of this human species, now known as the Red Deer Cave people, were tested and dated at about 11 500 years old.

QUESTION: Describe how bioinformatics and comparative genomics can be used to determine the interrelatedness between the Red Deer Cave people and other hominids (6 marks) (WACE 2019 ER)

DESCRIBES BIOINFORMATICS AND USE IN CONTEXT (3 MARKS):
- MUST MENTION: the greater the degree of similarities in specific genes (and nucleotides) the closer the evolutionary relationship between two species
ANY TWO OF:
- combines computer science, statistics, mathematics and engineering to analyse biological data
- techniques such as image and signal processing used to extract results from large amount of raw data
- raw data obtained from biochemical testings
- testing highlights the amount of similarity between the species

DESCRIBES COMPARATIVE GENOMICS AND USE IN CONTEXT (3 MARKS):
- MUST MENTION: the greater the degree of alignment (similarity) of the genome (genomic sequence), the closer the evolutionary relationship between the two species
ANY TWO OF:
- genomic features may include DNA sequence, genes, gene order, regulatory sequences and other genomic structural landmarks or biomarkers
- uses the principle that common features of two organisms will often be encoded within that DNA that is conserved evolutionarily between them
- approach start by checking for alignment of genome sequence and look for DNA sequences that share a common ancestry
- testing infers the evolutionary relationship between two species

Describe the cause of Parkinson's disease (2 marks) (WACE 2020 SA)

ANY 2 OF:
- damage/degeneration to nerve cells in the brain
- reduced dopamine levels
- dopamine is required for smooth control of muscles and movement

Describe the physiological mechanisms that cause fever (8 marks) (WACE 2020 ER)

- hypothalamus increases thermostat setting of body (person feels cold)
- pyrogens released
- produced by white blood cells or pathogens
- muscles begin to shiver
- blood vessels constrict
- both processes help to drive up body temperature
- macrophage engulfed pathogen
- macrophage stimulated to release interleukins/cytokines
- interleukins/cytokines enhance the pyrogens