Advanced Food Microbiology Quiz

Lactobacillus is the correct answer because it is a type of bacteria that is commonly used in the production of curd. It is a lactic acid bacteria that ferments lactose present in milk, converting it into lactic acid. This acidification process causes the milk to curdle and form curd. Lactobacillus is known for its ability to produce enzymes that break down lactose, making it an essential component in the curd-making process. Staphylococcus and Clostridium are not typically involved in curd formation.

Heat and high pressure are examples of physical stressors, while acid and salt are examples of chemical stressors. Physical stressors refer to external forces that can cause changes in the physical properties of an organism, such as temperature or pressure. Chemical stressors, on the other hand, refer to substances or compounds that can disrupt the chemical balance within an organism, such as acids or salts.

Glycolysis is the metabolic pathway that converts glucose into pyruvate. During this process, glucose is broken down into two molecules of pyruvate, along with the production of ATP and NADH. Pyruvate is then further metabolized in the presence of oxygen to produce more ATP through the Krebs cycle and oxidative phosphorylation. Therefore, the end product of glycolysis is pyruvate.

Microbial metabolism refers to the biochemical processes that occur within microorganisms to obtain energy and nutrients necessary for their survival and reproduction. This includes both anabolism, which involves the synthesis of complex molecules from simpler ones, and catabolism, which involves the breakdown of complex molecules into simpler ones to release energy. Therefore, microbial metabolism encompasses the overall metabolic activities of microbes, allowing them to fulfill their energy and nutrient requirements.

Formic acid is found in ants. Ants produce formic acid as a defense mechanism against predators. When threatened, ants release formic acid from their bodies, which acts as a deterrent or irritant to potential threats. This acid is responsible for the characteristic odor that is often associated with ants. Therefore, it can be concluded that formic acid is found in ants.

Oxidative phosphorylation is the correct answer because it is the final stage of respiration where ATP is formed through a series of electron transfer. During this process, electrons from NADH and FADH2 are passed through the electron transport chain, creating a proton gradient across the inner mitochondrial membrane. This proton gradient is then used by ATP synthase to produce ATP from ADP and inorganic phosphate. Therefore, oxidative phosphorylation is the stage where the majority of ATP is generated in cellular respiration.

Microbial attachment to food surfaces is necessary to offer protection from environmental stress. Environmental stress refers to any adverse conditions in the environment that can negatively impact microbial survival and growth. By attaching to food surfaces, microorganisms can form biofilms, which provide a protective barrier against environmental stressors such as temperature fluctuations, pH changes, and exposure to antimicrobial agents. This attachment allows microorganisms to better withstand and adapt to the challenging conditions, increasing their chances of survival and persistence on the food surface.

Maleic acid is found in grapes. Grapes contain a high amount of tartaric acid, which can be converted into maleic acid through a process called malolactic fermentation. This fermentation occurs naturally in grapes and is responsible for the smooth and balanced taste in wines. Therefore, grapes are a natural source of maleic acid.

Tartaric acid is found in apple. This acid is a naturally occurring compound that gives a sour taste to certain fruits, including apples. It is commonly used in the food industry as a flavoring agent and as a preservative. Tartaric acid can also be found in grapes, but it is more abundant in apples. Bananas and cauliflower do not contain tartaric acid.

Autotrophic organisms obtain carbon from CO2 and synthesize cell mass through photosynthesis, where they convert sunlight into energy. Heterotrophic organisms obtain carbon from organic compounds and synthesize cell mass through respiration, where they break down organic molecules to release energy.