Lecture 29 – Metabolic pathways and Glycolysis

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What was the significant discovery regarding respiration in the late 1800s?

It occurs only in aerobic conditions.

It is essential for life and can occur without O2. (correct)

It only occurs in plants.

It is a spontaneous process.

Who observed that fermentation is an enzymatic process in the late 1890s?

Harden and Young

Manasseina (correct)

Bucher brothers

Emden and Meyerhof

What did the Bucher brothers demonstrate regarding fermentation?

It requires oxygen.

It can occur in cell-free extracts. (correct)

It produces only alcohol.

It is a non-enzymatic process.

Which pathway is known as the Embden-Meyerhof pathway?

Glycolysis (B) Signup and view all the answers

What is the role of zymase in fermentation?

It is a non-dialysable large molecule required for fermentation. (B) Signup and view all the answers

What are enzymic cofactors?

Non-protein substances required for enzyme activity (B) Signup and view all the answers

What did Harden and Young conclude about phosphate in glycolysis?

It is a limiting factor in the rate of glycolysis. (B) Signup and view all the answers

Which of the following is an advantage of the in vitro approach to studying metabolism?

Control over experimental conditions (B) Signup and view all the answers

What is a disadvantage of using an in vivo approach?

There are many variables to consider. (C) Signup and view all the answers

What are the three stages of energy metabolism?

Large to smaller molecules, Acetyl-CoA production, CO2 production (B) Signup and view all the answers

Why are metabolic pathways necessary?

They enable gradual energy extraction from glucose. (B) Signup and view all the answers

What is the primary function of cofactors in metabolic pathways?

They assist in electron transfer. (D) Signup and view all the answers

How many ATP molecules are produced during glycolysis?

2 (B) Signup and view all the answers

What is the net gain of ATP from one glucose molecule during glycolysis?

2 (C) Signup and view all the answers

Which of the following is a characteristic of glycolysis?

It is a linear pathway located in the cytosol. (C) Signup and view all the answers

What happens during the investment stage of glycolysis?

ATP is consumed. (B) Signup and view all the answers

In glycolysis, what is produced during the payout stage?

4 ATP and 2 NADH (B) Signup and view all the answers

How is glycolysis regulated?

By feedback inhibition and activation. (A) Signup and view all the answers

Which enzyme in glycolysis is regulated by feedback inhibition?

Hexokinase (HK) (A) Signup and view all the answers

What role does phosphofructokinase (PFK) play in glycolysis?

It is a key regulatory enzyme. (B) Signup and view all the answers

What is the primary product of glycolysis?

Pyruvate (C) Signup and view all the answers

Which molecule is a key electron carrier in glycolysis?

NAD+ (B) Signup and view all the answers

What does the term "catabolism" refer to?

Breakdown of molecules for energy (B) Signup and view all the answers

What does "anabolism" describe in metabolic processes?

Synthesis of complex molecules (B) Signup and view all the answers

What is the significance of irreversible steps in metabolic pathways?

They act as control points for regulation. (B) Signup and view all the answers

What metabolic pathway produces ATP from glucose without oxygen?

Glycolysis (C) Signup and view all the answers

Why is ATP considered an energy carrier?

It undergoes hydrolysis to release energy. (B) Signup and view all the answers

What byproduct is generated from fermentation in yeast?

Ethanol and CO2 (B) Signup and view all the answers

How does glycolysis contribute to biosynthetic pathways?

By generating carbon skeletons (B) Signup and view all the answers

What is a common feature of all metabolic pathways?

They involve multiple enzymes and intermediates. (B) Signup and view all the answers