Question

1. when yeast cells are deprived of oxygen, they switch from aerobic respiration to alcohol fermentation, producing

a. lactic acid and nad+
b. ethanol and co2
c. atp and pyruvate
d. water and o2

1. the process of catabolism relates to anabolism because

a. catabolism builds complex molecules, while anabolism breaks them down
b. anabolism provides the energy (atp) and building blocks that catabolism requires
c. catabolism provides the energy (atp) and building blocks that anabolism requires
d. both processes have a net consumption of atp

1. which organelle contains both the necessary enzymes for the krebs cycle and the components for the electron transport chain?

a. chloroplast
b. nucleus
c. mitochondrion
d. vacuole
section ii: true/false (10 questions, 2 points each = 20 points)
instructions: read each statement. if the statement is correct, write t on the answer sheet. if the statement is incorrect, write f on the answer sheet.

1. t/f: both archaea and bacteria lack a membrane - bound nucleus, classifying them as prokaryotes.
2. t/f: the rough endoplasmic reticulum () is primarily involved in lipid synthesis, while the smooth endoplasmic reticulum () synthesizes proteins.
3. t/f: a reaction that releases energy and proceeds spontaneously is called an exergonic reaction.

Explanation:

1. Yeast cells undergo alcohol fermentation without oxygen. In this process, pyruvate is converted to ethanol and \(CO_2\). Lactic acid is produced in lactic acid fermentation (not yeast's alcohol fermentation). ATP is produced in glycolysis (a part of both aerobic and anaerobic pathways but not the main products asked here in terms of fermentation end - products). Water and \(O_2\) are not products of alcohol fermentation.
2. Catabolism breaks down complex molecules (e.g., glucose in glycolysis) to release energy (as ATP) and produce smaller molecules (building blocks). Anabolism uses these ATP and building blocks (e.g., amino acids from protein catabolism to build new proteins). So catabolism provides what anabolism needs.
3. The mitochondrion is the site of the Krebs cycle (in the mitochondrial matrix) and the electron - transport chain (in the inner mitochondrial membrane). Chloroplasts are for photosynthesis. The nucleolus is involved in ribosome synthesis. Vacuoles are for storage, etc.
4. Archaea and Bacteria are prokaryotes as they lack a membrane - bound nucleus.
5. The rough endoplasmic reticulum is involved in protein synthesis (due to ribosomes attached), and the smooth endoplasmic reticulum is involved in lipid synthesis.
6. An exergonic reaction releases energy (\(\Delta G<0\)) and can occur spontaneously (although enzymes may speed it up).

Answer:

1. B. Ethanol and \(CO_2\)
2. C. Catabolism provides the energy (ATP) and building blocks that anabolism requires
3. C. Mitochondrion
4. T
5. F
6. T