Photosynthesis and Digestion Quiz

Functions of Life (Nutrition and Respiration)

• Plants create food through photosynthesis
• Plants also respire and release carbon dioxide.
• Animals obtain energy by digesting food.

Photosynthesis

• Photosynthesis is how producers (plants) use light energy to turn carbon dioxide and water into glucose and oxygen.
• The process occurs in chloroplasts that contain chlorophyll.
• The balanced chemical reaction for photosynthesis is 6CO2 + 6H2O → C6H12O6 + 6O2
• Glucose is used by an organism, and oxygen is released for other organisms.
• Plants are producers that can be consumed by primary consumers and on up the food chain to apex predators.

Leaf Adaptations

• Leaves have a large surface area to absorb more light, while some have reduced leaves when sunlight is intense.
• Short leaf structures aid in the quick movement of carbon dioxide in and oxygen out.
• Chlorophyll in chloroplasts absorb light, especially the UV portion of the light spectrum.
• Veins transport water and sugars to and from different parts of the leaf.
• Stomata are openings in the leaves that allow for gas exchange (oxygen in, carbon dioxide out).
• The waxy cuticle of the leaf prevents water loss.
• The epidermis is a single outer layer to enable more light to pass through to the palisade cells.
• The palisade layer is found directly under the upper epidermis and contains many chloroplasts to enable maximum sunlight absorption.
• Spongy mesophyll aids in gas exchange and supports the leaf structure.

Factors Affecting Photosynthesis

• Abiotic factors, such as light intensity, carbon dioxide levels, and temperature affect photosynthesis rates.
• The compensation point is when the rate of photosynthesis equals the rate of respiration.
• Higher light intensity and carbon dioxide levels yield higher photosynthetic rates.
• Optimal temperature helps increase the kinetic energy of enzymes in photosynthesis. Temperatures too high or too low impact the enzymes and limit photosynthesis.

Oxygen Production Experiment

• Plants produce oxygen through photosynthesis and experiments can illustrate this.
• An experiment using an aquatic plant, test tube, water, sodium hydrogen carbonate, and a splint can show the presence of oxygen produced.
• The test allows light to show the oxygen produced, but does not quantify the amount.

Nutrition (Holozoic Nutrition)

• Holozoic nutrition involves ingesting solid organic matter, digesting it, and absorbing the nutrients.
• The alimentary canal is responsible for the digestion process, including the mouth, salivary glands, esophagus, stomach, pancreas, liver, small intestine, and large intestine (colon/rectum/anus).
• The mechanical and chemical processes of digestion further break down food to absorb the nutrients.
• Digestion, absorption, assimilation, and egestion are integral steps in nutrient handling.

Digestive Enzymes

• Digestive enzymes are proteins that help speed up the chemical reactions of digestion, such as breaking down starch and glycogen to maltose by amylase or breaking down proteins by pepsin and trypsin.
• Salivary amylase is responsible for digesting starch, and pepsin breaks down proteins in the stomach, while trypsin breaks down the proteins in the small intestine.
• Lipases break down lipids, and other enzymes function in specific pH ranges in the digestive track.

Enzymes

• Enzymes are proteins that speed up chemical reactions without being consumed in the process.
• Enzymes are specific for their reaction; they are crucial for anabolism and catabolism.
• Enzymes have optimal temperatures and pH levels at which they are most effective.
• Enzymes can be denatured by extreme temperatures.
• Poisons can inhibit enzymes by interrupting their activity.

Cellular Respiration

• Cellular respiration combines oxygen with food molecules to produce energy in the form of ATP.
• It is a catabolic reaction that breaks down glucose to smaller molecules to release energy and build ATP.
• Aerobic respiration (in the presence of oxygen) occurs in mitochondria.
• Anaerobic respiration (without oxygen) produces less ATP, with products such as lactic acid in animals.

Alcoholic and Lactic Acid Fermentation

• A process alternative to aerobic respiration that occurs in the absence of oxygen or low oxygen conditions.
• Alcoholic fermentation is used in the production of alcohol like beer, and lactic acid fermentation yields lactic acid.