What is the normal range of blood pH in a healthy human?
6.5 - 7.2
7.5 - 8.0
7.35 - 7.45
6.8 - 7.0
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WhyHealthy human blood is tightly buffered to a pH of about 7.35–7.45, slightly alkaline.
2Multiple choice
How are biological systems regulated?
Exclusively by the rates of ATP production and consumption, which dictate all cellular activities without specific control mechanisms
Through complex networks of feedback loops (primarily negative feedback), hormonal and nervous system control, and cellular/molecular mechanisms that maintain homeostasis and respond to internal and external changes
Primarily through continuous positive feedback loops that amplify deviations from a set point, leading to rapid change
By glucose concentration only
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WhyBiological systems are regulated by feedback loops, hormonal and nervous control that maintain homeostasis.
3Multiple choice
What is the maintenance of a stable internal environment called?
Diffusion
Metabolism
Osmosis
Homeostasis
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WhyHomeostasis is the maintenance of a stable internal environment within narrow limits.
4Multiple choice
Which type of feedback loop is primarily used in homeostasis?
Feedforward feedback
Positive feedback
Negative feedback
Random feedback
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WhyNegative feedback counteracts deviations from the set point, keeping conditions stable.
5Multiple choice
What organ plays a key role in regulating blood glucose levels?
Brain
Liver
Kidney
Pancreas
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WhyThe pancreas secretes insulin and glucagon to regulate blood glucose concentration.
6Multiple choice
Which hormone lowers blood glucose levels?
Adrenaline
Insulin
Glucagon
Thyroxin
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WhyInsulin lowers blood glucose by promoting cellular uptake and glycogen storage.
7Multiple choice
What hormone raises blood glucose levels?
Insulin
Glucagon
Melatonin
Cortisol
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WhyGlucagon raises blood glucose by stimulating glycogen breakdown in the liver.
8Multiple choice
Which type of diabetes is characterized by the destruction of pancreatic beta cells?
Gestational diabetes
Type 1 diabetes
Type 2 diabetes
Diabetes insipidus
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WhyType 1 diabetes results from autoimmune destruction of insulin-producing pancreatic beta cells.
9Multiple choice
Which type of diabetes is often associated with insulin resistance?
Type 1 diabetes
Diabetes insipidus
Gestational diabetes
Type 2 diabetes
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WhyType 2 diabetes is characterised by target cells becoming resistant to insulin.
10Multiple choice
What part of the brain is the primary thermoregulatory control center?
Hypothalamus
Thalamus
Cerebellum
Medulla oblongata
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WhyThe hypothalamus acts as the body's thermostat, coordinating thermoregulatory responses.
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Homeostasis: The maintenance of a stable internal environment within narrow limits despite changes in external conditions.
Negative feedback: A control mechanism in which a change in a variable triggers a response that reverses that change, returning it towards the set point.
Set point: The target value around which a controlled variable is kept by homeostatic mechanisms.
Effector: A structure (such as a muscle or gland) that carries out the corrective response directed by the control centre.
Antagonistic hormones: A pair of hormones with opposite effects, such as insulin and glucagon, allowing precise two-way control.
Insulin: A hormone from pancreatic β cells that lowers blood glucose by promoting glucose uptake and storage as glycogen.
Glucagon: A hormone from pancreatic α cells that raises blood glucose by stimulating breakdown of glycogen in the liver.
Osmoregulation: The homeostatic control of the water and solute balance of body fluids, carried out chiefly by the kidney.