Answer+key


 * __ Solutions to the activities From Anaya Publisher __**
 * Page 11, Question 1: **
 * Unicellular: ** An organism made up of a single cell, which performs all three characteristic vital functions.
 * Multicellular: ** An organism made up by many cells, all of which come from the same original cell and work together as a whole unit.
 * Colony: ** Group of many unicellular organisms which, if separated, can continue to live independently.


 * Page 13, question 1: **
 * Plasmatic membrane. ** A very thin, elastic barrier which surrounds all cells and separates them from their environment. It regulates substances going in and out of the cell.
 * Organelle. ** Structures of different types located in the cytoplasm, responsible for performing diverse functions.
 * Nucleoid: ** Area of the cytoplasm on prokaryotic cells in which the DNA is located.
 * Nucleolus **. Spherical structure in the nucleus where the ribosome subunits are formed.


 * <span style="font-family: 'Times New Roman','serif'; font-size: 18.6667px;">Page 17, question 1: **
 * <span style="font-family: 'Times New Roman','serif'; font-size: 18.6667px;">Diffusion. **<span style="font-family: 'Times New Roman','serif'; font-size: 18.6667px;">The process by which small molecules pass through the cell membrane, moving from the side where they are at a higher concentration, to the other side, where they are at a lower concentration.


 * <span style="font-family: 'Times New Roman','serif'; font-size: 18.6667px;">Endocytosis. **<span style="font-family: 'Times New Roman','serif'; font-size: 18.6667px;">Process by which large substances which cannot pass through the membrane are incorporated into the cell. The substances are housed in the cytoplasm inside vacuoles which are formed when the cell membrane folds in on itself.


 * <span style="font-family: 'Times New Roman','serif'; font-size: 18.6667px;">Exocytosis. **<span style="font-family: 'Times New Roman','serif'; font-size: 18.6667px;"> The process of expelling waste substances located inside vacuoles from the cell. It occurs when the vacuoles fuse with the cell membrane.


 * <span style="font-family: 'Times New Roman','serif'; font-size: 18.6667px;">Anabolism. **<span style="font-family: 'Times New Roman','serif'; font-size: 18.6667px;"> Metabolic reactions in which simple molecules are joined together to form more complex ones.These reactions require energy. E.g. Photosynthesis.
 * <span style="font-family: 'Times New Roman','serif'; font-size: 18.6667px;">Catabolism. **<span style="font-family: 'Times New Roman','serif'; font-size: 18.6667px;">Metabolic reactions in which complex molecules are broken down and transformed into simpler ones, releasing energy. This energy is used to perform a variety of cellular functions, such as movement, transport of particles, cell division. Cellular respiration is one of the main catabolic reactions.

**Page 18 question 4**
===**Cellular respiration**. A catabolic process which takes place in the mitochondria, in which organic molecules such as glucose, in the presence of oxygen, oxidise and are converted into Co2 and water, releasing a large amount of energy.===

===**Photosynthesis.** An anabolic process which takes place in the chloroplasts, in which energy from sunlight is used to convert inorganic molecules (CO2, water and mineral salts) into organic molecules such as glucose. Oxygen is also released during the process.===