Unit 3: Cellular Engeretics

5. Describe the role of energy in living organisms.

All living organisms need energy to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is the set of life-sustaining chemical processes that enables organisms transform the chemical energy stored in molecules into energy that can be used for cellular processes.

11) How is ATP made?

Although cells continuously break down ATP to obtain energy, ATP also is constantly being synthesized from ADP and phosphate through the processes of cellular respiration. Most of the ATP in cells is produced by the enzyme ATP synthase, which converts ADP and phosphate to ATP.

18) Compare an ectotherm to an endotherm. Give examples of each type of organism.

An ectotherm (reptile/amphibian) relies primarily on its external environment to regulate the temperature of its body. Endotherms (birds) are able to regulate their body temperatures by producing heat within the body. ... ectotherms is the way that animal habitats are set up

6) Compare catabolic to anabolic reactions.

Anabolism refers to the process which builds molecules the body needs; it usually requires energy for completion. Catabolism refers to the process that breaks down complex molecules into smaller molecules; it usually releases energy for the organism to use.

19) Describe the floating leaf disk assay test. What environmental factors affected the rising of the leaf discs?

As photosynthesis proceeds oxygen is released into the interior of the leaf, which changes the buoyancy--causing the disks to rise. Since cellular respiration is taking place at the same time, consuming oxygen, the rate that the disks rise is an indirect measurement of the net rate of photosynthesis.

3. Explain how changes to the structure of an enzyme may affect its function.

Because so much of an enzyme's activity is based on its shape, temperature changes can mess up the process and the enzyme won't work. High enough temperatures will cause the enzyme to denature and have its structure start to break up. ... An increased acidity near an enzyme can cause its shape to change.

1. Describe the properties of enzymes.

Catalytic properties: Enzymes are biological catalyst. The small quantity of enzymes catalyses the larger quantities of substances. ... Specificity of enzyme: Enzymes are highly specific in nature, i.e., a particular enzyme can catalyse a particular reaction.

7. Explain how cells capture energy from light and transfer it to biological molecules for storage and use.

Cellular respiration splits and oxidizes glucose to form ATP molecules. During photosynthesis, plants capture light energy and use it to power chemical reactions in the plant cells. ... The carbon dioxide and water are expelled from the organism and the energy is stored in a molecule called adenosine triphosphate or ATP.

3) How can a scientist make an enzyme reaction increase in production rates?

Enzyme concentration: Increasing enzyme concentration will speed up the reaction, as long as there is substrate available to bind to. ... Substrate concentration: Increasing substrate concentration also increases the rate of reaction to a certain point.

2. Explain how enzymes affect the rate of biological reactions.

Enzymes are biological catalysts. Catalysts lower the activation energy for reactions. The lower the activation energy for a reaction, the faster the rate. Thus enzymes speed up reactions by lowering activation energy.

9. Explain how cells obtain energy from biological macromolecules in order to power cellular functions.

Fermentation and cellular respiration use energy from biological macromolecules to produce ATP. Respiration and fermentation are characteristic of all forms of life. Cellular respiration in eukaryotes involves a series of coordinated enzyme-catalyzed reactions that capture energy from biological macromolecules.

5) What is denaturation? What causes this process to occur?

If a protein loses its shape, it ceases to perform that function. The process that causes a protein to lose its shape is known as denaturation. Denaturation is usually caused by external stress on the protein, such as solvents, inorganic salts, exposure to acids or bases, and by heat.

17) What occurs when oxygen is not present? Describe the difference between alcohol and lactic acid fermentation.

In lactic acid fermentation, pyruvate from glycolysis changes to lactic acid. This type of fermentation is carried out by the bacteria in yogurt, and by your own muscle cells. In alcoholic fermentation, pyruvate changes to alcohol and carbon dioxide. This type of fermentation is carried out by yeasts and some bacteria.

6. Describe the photosynthetic processes that allow organisms to capture and store energy.

In photosynthesis, solar energy is harvested as chemical energy in a process that converts water and carbon dioxide to glucose. Oxygen is released as a byproduct. In cellular respiration, oxygen is used to break down glucose, releasing chemical energy and heat in the process.

8) Compare an endergonic to an exergonic reaction. Give examples of each.

In the exergonic reaction, the reactants are at a higher free energy level than the products (reaction goes energetically downhill). In the endergonic reaction reaction, the reactants are at a lower free energy level than the products (reaction goes energetically uphill).

8. Describe the processes that allow organisms to use energy stored in biological macromolecules.

Metabolism is the set of life-sustaining chemical processes that enables organisms transform the chemical energy stored in molecules into energy that can be used for cellular processes.

14) How did photosynthesis evolve?

Oxygenic photosynthesis originated in an ancestor of Cyanobacteria when an anoxygenic photosystem gave rise to a water-splitting photosystem

13) What organisms can perform photosynthesis?

Plants, algae, and a group of bacteria called cyanobacteria are the only organisms capable of performing photosynthesis

4. Explain how the cellular environment affects enzyme activity.

Temperature. As temperature increases, the reaction rate increases, but if the temperature passes the optimal range, the enzyme will stop functioning. pH. Each enzyme has a specific pH. Enzyme Concentration. Substrate Concentration. Presence of Inhibitors. Presence of Activators.

4) What could slow down the creation of products from an enzymatic reaction?

Temperature: Raising temperature generally speeds up a reaction, and lowering temperature slows down a reaction.

2) Describe how enzymes work. Make sure to include the terms products, reactants, and activation energy.

The activation energy is the energy required to start a reaction. Enzymes are proteins that bind to a molecule, or substrate, to modify it and lower the energy required to make it react. Reactants (or 'substrates') are the starting materials for a reaction. ... Because they speed up reactions, they are called catalysts.

5) Compare the first law to the second law of thermodynamics. Give examples of each.

The first law, also known as Law of Conservation of Energy, states that energy cannot be created or destroyed in an isolated system. The second law of thermodynamics states that the entropy of any isolated system always increases.

20) How does germination affect respiration rates?

The start of germination places substantial energy demands on the seed as plant growth processes take shape. As a result, cellular respiration rates increase to accommodate the cell-building activities required to break open the seed and produce the initial root and stem structures.

15) How are Photosystems II and I different? What colors of light do they like to absorb?

Two major photosynthetic pigments are chlorophyll a and chlorophyll b. 2. Both chlorophylls absorb violet, blue, and red wavelengths best.

16) The steps of cellular respiration are outlined to the right. For each step, identify what starts the reaction, what is created, and where the process takes place. a) Glycolysis: b) Kreb's Cycle/Citric Acid Cycle: c) Oxidative Phosphorylation (Electron Transport Chain)

a) Glycolysis is the metabolic pathway that converts glucose C₆H₁₂O₆, into pyruvate, CH₃COCOO⁻, and a hydrogen ion, H⁺. The free energy released in this process is used to form the high-energy molecules ATP and NADH. b) The tricarboxylic acid (TCA) cycle, also known as the Krebs or citric acid cycle, is the main source of energy for cells and an important part of aerobic respiration. The cycle harnesses the available chemical energy of acetyl coenzyme A (acetyl CoA) into the reducing power of nicotinamide adenine dinucleotide (NADH). c) Oxidative phosphorylation is the metabolic pathway in which cells use enzymes to oxidize nutrients, thereby releasing the chemical energy stored within in order to produce adenosine triphosphate. In most eukaryotes, this takes place inside mitochondria. Almost all aerobic organisms carry out oxidative phosphorylation.