What is growth in biological terms?
The irreversible increase in an organism's dry mass, size, and complexity.
What is required for effective growth?
Material buildup (anabolism) must exceed material breakdown (catabolism).
How does growth in plants differ from animals?
In plants, growth is continuous at the apex, while in animals, it is more uniform with defined stages.
What are the three main processes of growth?
Cell division, cell enlargement, and cell differentiation.
What is mitosis?
A type of cell division that produces cells identical to the parent cell, important for growth and repair.
What is meiosis?
A type of cell division that reduces chromosome numbers by half, essential for genetic variation.
What happens during the interphase of mitosis?
Chromosomes elongate and form chromatids, preparing for division.
What occurs in the prophase of mitosis?
Chromosomes become visible, and spindle fibers begin forming as the nuclear membrane disappears.
What is the key event in metaphase during mitosis?
Chromosomes align at the cell's equator and attach to spindle fibers at their centromeres.
What happens during anaphase of mitosis?
Sister chromatids are pulled to opposite poles of the cell by spindle fibers.
What is the final stage of mitosis, and what occurs?
Telophase, where the cell divides into two, and nuclear membranes reform in daughter cells.
Name three aspects of growth.
Mass, size, and cell number.
Where does rapid growth occur in plants?
At the root and stem tips.
What are the three regions of rapid growth in plants?
Region of cell division, region of elongation, and region of maturation.
What is a growth curve?
A graph that shows the growth rate of an organism over time, often with a sigmoid shape.
What are the three phases of a sigmoid growth curve?
Lag phase, log (exponential) phase, and stationary phase.
Name two external factors affecting growth.
Temperature and light.
How do hormones regulate growth?
Hormones like auxins and gibberellins in plants and thyroxine and somatropin in animals promote growth.
What role do auxins play in plant growth?
They promote or inhibit cell elongation in stems and roots.
What is the function of thyroxine in animals?
It influences growth and metabolism, produced by the thyroid gland.
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