Explain the relationship between monomers and polymers, using polysaccharides as an example.
Identify three major roles of proteins.
Describe the parts of a nucleotide.
Think Critically
Experiment Suggest one or two simple experiments to determine whether a solid white substance is a lipid or a carbohydrate. What evidence would you need to support each hypothesis?
Infer Explain what the name “carbohydrate” might indicate about the chemical composition of sugars.
2.4 Chemical Reactions and Enzymes
Understand Key Concepts
An enzyme speeds up a reaction by
lowering the activation energy.
raising the activation energy.
releasing energy.
absorbing energy.
In a chemical reaction, a reactant binds to an enzyme at a region known as the
catalyst.
product.
substrate.
active site.
Describe the two types of energy changes that can occur in a chemical reaction.
What relationship exists between an enzyme and a catalyst?
Describe some factors that may influence enzyme activity.
Think Critically
Infer Why is it important that energy-releasing reactions take place in living organisms?
Predict Changing the temperature or pH can change an enzyme's shape. Describe how changing the temperature or pH might affect the function of an enzyme.
Use Analogies Explain why a lock and key are used to describe the way an enzyme works. Describe any ways in which the analogy is not perfect.
solve the CHAPTER MYSTERY
THE GHOSTLY FISH
The oxygen-binding abilities of hemoglobin enable the blood of most fish to carry nearly 50 times the oxygen it would without the protein. The ghostly white appearance of the antarctic ice fish results from its clear blood—blood without hemoglobin. Ice fish, however, are able to survive without hemoglobin because of the properties of water at low temperatures.
Oxygen from the air dissolves in seawater, providing the oxygen that fish need to survive. Fish absorb dissolved oxygen directly through their gills, where it passes into their bloodstream. The solubility of oxygen is much greater at low temperatures. Therefore, the icy cold antarctic waters are particularly rich in oxygen.
The large, well-developed gills and scaleless skin of ice fishes allow them to absorb oxygen efficiently from the water. Compared to red-blooded fishes, ice fishes have a higher blood volume, thinner blood, and larger hearts. So, their blood can carry more dissolved oxygen and the large hearts can pump the thinner blood through the body faster. These and other physical features, combined with the chemistry of oxygen in water at low temperatures, enable ice fish to survive where many other organisms cannot.
Relate Cause and Effect Ice fish produce antifreeze proteins to keep their blood from freezing; their body temperature stays below 0°C. How does low body temperature affect the blood's ability to carry dissolved oxygen?
Infer People living at high altitudes generally have more hemoglobin in their blood than people living at sea level. Why do you think this is so?
Predict If the antarctic oceans were to warm up, how might this affect ice fish?
Connect to the
The chemical reactions in all living things slow down at low temperatures. Since some of the most important reactions in our body require oxygen, how would low temperatures affect the ice fish's need for oxygen?
Table of Contents
- Formulas and Equations
- Applying Formulas and Equations
- Mean, Median, and Mode
- Estimation
- Using Measurements in Calculations
- Effects of Measurement Errors
- Accuracy
- Precision
- Comparing Accuracy and Precision
- Significant Figures
- Calculating With Significant Figures
- Scientific Notation
- Calculating With Scientific Notation
- Dimensional Analysis
- Applying Dimensional Analysis