Comprehensive Solution Bundle for USMLE Step 1 and Step 2 Exams with Complete Answers.
Exam Study Guide Prep Questions
And Revised Correct Answers
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USMLE Step 1 and Step 2 Sample Solution Pack
**Step 1 Topics**
---
1. Biochemistry**
**Question 1:** Describe the process of glycolysis and its regulation.
**Solution:**
- **Glycolysis Overview:** Glycolysis is the metabolic pathway that converts glucose into
pyruvate, generating ATP and NADH in the process. It occurs in the cytoplasm and does not
require oxygen.
- **Key Steps:**
1. **Glucose to Glucose-6-phosphate (Hexokinase/Glucokinase):** This step is regulated by
feedback inhibition through glucose-6-phosphate.
2. **Fructose-6-phosphate to Fructose-1,6-bisphosphate (Phosphofructokinase-1, PFK-1):**
This is the rate-limiting step and is regulated by ATP (inhibitor), AMP (activator), and
fructose-2,6-bisphosphate (activator).
3. **Phosphoenolpyruvate to Pyruvate (Pyruvate Kinase):** This step is regulated by ATP
(inhibitor) and fructose-1,6-bisphosphate (feed-forward activation).
- **Energy Yield:** 2 ATP and 2 NADH per molecule of glucose.
---
#### **2. Physiology**
**Question 2:** Explain the cardiac cycle phases and the pressure changes that occur within the
heart chambers.
**Solution:**
- **Phases of the Cardiac Cycle:**
1. **Atrial Systole:** Atria contract, topping off the ventricles with blood. This corresponds to
the P wave on an ECG.
Exam Study Guide Prep Questions
And Revised Correct Answers
Guarantee Pass!!
USMLE Step 1 and Step 2 Sample Solution Pack
**Step 1 Topics**
---
1. Biochemistry**
**Question 1:** Describe the process of glycolysis and its regulation.
**Solution:**
- **Glycolysis Overview:** Glycolysis is the metabolic pathway that converts glucose into
pyruvate, generating ATP and NADH in the process. It occurs in the cytoplasm and does not
require oxygen.
- **Key Steps:**
1. **Glucose to Glucose-6-phosphate (Hexokinase/Glucokinase):** This step is regulated by
feedback inhibition through glucose-6-phosphate.
2. **Fructose-6-phosphate to Fructose-1,6-bisphosphate (Phosphofructokinase-1, PFK-1):**
This is the rate-limiting step and is regulated by ATP (inhibitor), AMP (activator), and
fructose-2,6-bisphosphate (activator).
3. **Phosphoenolpyruvate to Pyruvate (Pyruvate Kinase):** This step is regulated by ATP
(inhibitor) and fructose-1,6-bisphosphate (feed-forward activation).
- **Energy Yield:** 2 ATP and 2 NADH per molecule of glucose.
---
#### **2. Physiology**
**Question 2:** Explain the cardiac cycle phases and the pressure changes that occur within the
heart chambers.
**Solution:**
- **Phases of the Cardiac Cycle:**
1. **Atrial Systole:** Atria contract, topping off the ventricles with blood. This corresponds to
the P wave on an ECG.
