Lower Science BK7 Bio

1. the layer of tall photosynthetic cells just below the upper epidermis of a leaf
4. one of hundreds of cells found on the outer surface of roots which increase the surface area for absorption
7. the layer of cells on the top surface of a leaf
10. differences between members of the same species
11. a particle made of either RNA or DNA, surrounded by a protein coat
13. polymers of amino acids; they are important nutrients for living organisms used in growth and repair
14. a coloured substance, such as haemoglobin
16. a sample, for example a piece of rock, or a single organism of a species
17. (of a cell) with a structure that increases its ability to carry out its function
19. the layer of photosynthetic cells just below the palisade layer with large air spaces
20. the most common type of cell in blood; circular with a depression in each side (biconcave)

2. a group of organisms that can reproduce together to produce fertile offspring
3. breaking down food to release energy that the organism can use
5. making more organisms of the same species
6. a coloured substance or dye that is used to colour cells
8. a cell found just beneath the upper surface of a leaf, specialised to carry out photosynthesis
9. detecting changes in the environment
12. a nucleic acid found in all living cells
15. a group of similar cells working together to perform a function
18. a structure that is often, but not always, present in plant cells; it contains a liquid called cell sap