PORTAGE BIOD 101 MODULE PROBLEM SET

PORTAGE BIOD 101 MODULE PROBLEM SET 1. Why are lipids unique among the biomacromolecules? - ANSWER Lipids are unique among the biomacromolecules because most of them are insoluble in water. Additionally, lipids are not monomers but are assembled from smaller molecules that are chemically linked together. 2. Why are lipids insoluble in water? - ANSWER Lipids are insoluble in water because they are made mostly of non-polar hydrocarbon chains. As water is polar, it will only dissolve other polar or ionically bonded substances. Lipids are non-polar, and this is why they are insoluble in water but can be dissolved with nonpolar solvents such as alcohol. 3. Describe the structure of a phospholipid. - ANSWER Phospholipids contain two main components: (1) a polar head group joined to (2) a non-polar tail group. The head group is composed of a charged phosphate group and (usually) a nitrogen-containing group. The head is attracted to polar substances, such as water, and is therefore hydrophilic (water loving). The tail group is a hydrocarbon (a molecule containing an H and C) composed of non-polar fatty acid chains. The tail repels water and is therefore hydrophobic (water fearing). 4. Name the functions of proteins as mentioned in the molecule. - ANSWER Proteins can (1) act as enzymes and regulate metabolic functions, (2) store amino acids, (3) act as hormones, (4) form antibodies for immunological defense, (5) act as carriers for transport and also form membrane channels, (6) form cell surface receptors to receive chemical messages, and (7) act as structural molecules for support and movement. 5. What 3 types of protein fibers make up the cytoskeleton? - ANSWER Microtubules, microfilaments, and intermediate filaments 6. Which type of cell junctions are mechanical structures that wrap around the cell to prevent extracellular fluid from leaking? -gap junctions -synaptic junctions -tight junctions -desmosomes - ANSWER Tight junctions 7. What is matter, and what states can it exist in? - ANSWER Matter is anything that takes up space, by having a volume, and has mass. Matter can exist in a solid, liquid, gaseous, or plasma state. All matter is made up of certain basic substances called elements. 8. Explain the difference between essential and trace elements. - ANSWER Essential elements are required for human life. Trace elements are required only in small quantities. 9. Ionic Bond - ANSWER Generated based on the attraction between oppositely charged particles. 10. Covalent Bond - ANSWER Occurs when electrons are shared by two atoms to complete the valence shells of both. 11. Hydrogen Bonds - ANSWER Forms a relatively weak bond that is easily broken. 12. Cations are _____ charged ions, and anions are _____ charged ions. - ANSWER positively; negatively 13. Describe how the shape of a protein is related to its function. - ANSWER Proteins can be assembled into a variety of shapes which allows them to serve a variety of functions. Some functions of proteins are to make many needed protective tissues such as skin, hair, and fingernails. Proteins also form enzymes (catalysts that speed up chemical reactions) and are used to make needed substances such as hemoglobin, which carries oxygen in red blood cells. 14. What are some of the main differences between prokaryotic and eukaryotic cells? - ANSWER Prokaryotes are simple cells with three defining characteristics: (1) small size, (2) non-enclosed genetic material, and (3) lack of organelles and other internal membrane-bound structures. Eukaryotes are more complex, 10-100x larger, have a nucleus, and contain membrane-bound organelles. 15. Which of the following are not one of the organic compounds that make up biomacromolecules? -lipids -proteins -ribosomes -carbohydrates - ANSWER Ribosomes 16. What are carbohydrates? - ANSWER Carbohydrates, commonly referred to as sugars, are the primary source of fuel for organisms and have the same three elements in their main structure: carbon, hydrogen, and oxygen. 17. What structure of the cells are complexes of tiny manufacturing plants that assemble proteins? -endoplasmic reticulum -lysosomes -nucleus -ribosomes - ANSWER Ribosomes