Chapter 21, Problem 1STP

Summary Introduction

Introduction :

Fungi are classified by their structure and patterns of reproduction. Some fungi only can reproduce asexually through mitosis. Asexual reproduction in fungi also includes fragmentation, budding, and spore production. Many fungi can reproduce both asexually and sexually. Sexually reproducing fungi produce spores by the process of meiosis. Yeast is a unicellular fungus that requires nutrition for its life and development

Answer to Problem 1STP

Correct answer :

The correct answer is option (A) Carbon dioxide

Explanation of Solution

Explanation/justification for the correct answer :

Option (A) Carbon dioxide. If oxygen is low than yeast can still extract energy from sugar so its by-products are alcohol and carbon dioxide under these conditions. This carbon dioxide gas is what creates the bubbles in the bread, which allows the bread to grow. So, the correct answer is option (A).

Explanation for incorrect answer :

Option (B) Ethanol. Alcohol is a toxin and so, as the alcohol concentration is too high, the yeast cannot expand. So, this is an incorrect answer.

Option (C) Oxygen. Yeast can use oxygen in the process called "respiration" to release the energy from sugar The more sugar there is, the more active the yeast will be and the more quickly its development will be. So, this is an incorrect answer.

Option (D) Simple sugar. Yeasts feed on sugars, producing carbon dioxide and ethyl alcohol in the process. So, this is an incorrect answer.