What are hormones?
Chemical substances produced by glands and carried in the blood to target organs to alter activity.
Name two hormones that affect all body cells.
Thyroxine and growth hormones.
What is the role of hormones in homeostasis?
They regulate the composition of the internal environment.
Which gland is known as the "master gland"?
The pituitary gland.
Name a hormone secreted by the pituitary gland and its function.
Follicle-stimulating hormone (FSH) stimulates egg and sperm production.
What is the function of thyroxine?
It regulates growth and development by increasing the basal metabolic rate.
Which gland produces insulin and glucagon?
The pancreas.
How does insulin regulate blood glucose levels?
It lowers blood glucose by stimulating liver cells to store glucose as glycogen.
What is the function of glucagon?
It raises blood glucose levels by converting glycogen to glucose.
Which hormone prepares the body for action by increasing heart rate and glucose availability?
Adrenaline.
What is testosterone, and what does it stimulate?
A male hormone that stimulates the development of male reproductive organs and characteristics like muscle growth and deeper voice.
Name two functions of oestrogen.
Development of female secondary sexual characteristics and regulation of the menstrual cycle.
What role does progesterone play in pregnancy?
It inhibits ovulation and maintains the uterine lining for embryo development.
What are plant hormones?
Chemical substances that coordinate plant growth and response to environmental stimuli.
What are auxins, and where are they produced?
Plant hormones produced at shoot tips that influence cell division and elongation.
Name one function of gibberellins.
Stimulate seed germination and fruit enlargement.
What do cytokinins do in plants?
Stimulate cell division and delay aging.
What is the role of abscisic acid in plants?
It inhibits growth and induces dormancy during unfavorable conditions.
How is ethene used in plants?
It promotes fruit ripening and inhibits lateral bud growth.
Name two agricultural uses of plant hormones.
Synthetic auxins as herbicides and cytokinins to preserve stored vegetables.
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