Cytoplasm A jelly-like material that contains dissolved nutrients and salts and structures called organelles. It is where many of the chemical reactions happen.
Nucleus Contains genetic material, including DNA, which controls the cell’s activities.
Cell membrane Its structure is permeable to some substances but not to others. It therefore controls the movement of substances in and out of the cell.
Mitochondria Organelles that contain the enzymes for respiration, and where most energy is released in respiration.
Ribosomes A tiny organelle where protein synthesis occurs.
There is no mixing of oxygen-rich and oxygen-poor blood.
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The right atrium and right ventricle of the human heart pump oxygen-poor blood to the lungs and the left atrium receives oxygen-rich blood. They never mix.
