Asteroids, comets and meteors
These three short online lessons discuss asteroids, comets and meteors.
These three short online lessons discuss asteroids, comets and meteors.
Plant cells have a cell wall in addition to a cell membrane, whereas animal cells have only a cell membrane. Plants use cell walls to provide structure to the plant. Plant cells contain organelles called chloroplasts, while animal cells do not. Chloroplasts allow plants to make the food they need to live using photosynthesis.
Introduction to passive and active transport
Osmosis is the movement of water across a semi-permeable membrane from an area of low solute concentration to an area of high solute concentration. Osmosis helps regulate the flow of water in and out of cells, which is crucial to their function.
Other objects in the solar system are discussed in this online textbook viz. asteroids, meteorites, comets and dwarf planets.
Overview of animal and plant cells. Topics include cell walls, vacuoles, chloroplasts, peroxisomes, lysosomes, mitochondria, etc.