topic one
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卡片预览 (24 张)
rules of cell theory
Living organisms are composed of cells (one or more) – that is, cells are the building blocks of organisms. Cells are the smallest units of life – that is, a cell is the basic unit capable of carrying out all the functions of a living organism. Cells come from pre-existing cells (omni cellulae e cellula) – that is, cells do not show spontaneous generation.
Striated muscle tissue is composed of repeated units called
sarcomeres
what sort of pattern do muscle cells show
striated/stripy
how large is the avergae muscle fibre cell
30mm long (very large)
what idea do musle cells challenge
the idea that the cell has one nucleus, as the muscle cell is multinucleated.
how large is acetabularia
0.5 to 10cm
what are the three parts of acetbaularia
the rhizoid (small roots), the stalk and a top umbrella made of branches that may fuse into a cap
what notions does acetbabularia challenge
that they must be simple in structure and small in size.
what are aseptate fungal hyphae
long threads (hyphae) with many nuclei. They have no dividing cell walls, called septa (singular: septum). The result of this is shared cytoplasm and multiple nuclei (singular: nucleus).
what idea do aspetate fungal hyphae challenge
the idea that a cell is a single unit as the fungal hyphae have many nuclei, are very large and possess a continuous, shared cytoplasm.
typical size of an animal cell
10 to 20 micrometers in diameter
calculating magnification
magnification = size of drawing / actual size
1000nm in micrometers
1 micrometer
1000 micrometers in mm
1 mm
how to convert 1mm into micrometers
multiply by 1000
how to convert 1micrometer to nm
multiply by 1000
what are the functions of life
metabolism response growth reproduction excretion homeostasis nutrition
define metabolism
The regular set of life-supporting chemical reactions that takes place within the cells of living organisms.
define growth
an increase in size or shape that occurs over a period of time
define response
A reaction by the living organism to changes in the external environment.
define homeostasis
The maintenance of a constant internal environment by regulating internal cell conditions.
define nutrition
The intake of nutrients, which may take different forms in different organisms. Nutrition in plants involves making organic molecules (during photosynthesis), while nutrition in animals and fungi involves the absorption of organic matter.
define reproduction
The production of offspring, either sexually or asexually, to pass on genetic information to the next generation.
define excretion
The removal of waste products of metabolism and other unimportant materials from an organism.