The Question is from neet-botany anatomy-of-flowering-plants , and it was created by the author NISHANTH

Question

A few drops of sap were collected by cutting across a plant stem by a suitable method. The sap was tested chemically. Which one of the following test results indicates that it is phloem sap?

NISHANTH · Accepted Answer

## CORE INFORMATION
✓ **Answer**: C
## CONCEPT FRAMEWORK
**Primary Concept**: Phloem sap characteristics
**Related Topics**: Plant transport, pH of biological solutions
**Prerequisites**: Basic knowledge of plant anatomy and physiology, understanding of pH
## SOLUTION PATHWAY
**Given Information**:
* Sap collected from a plant stem.
* Chemical test of the sap.
**Method & Steps**:
1. **Recall the composition of phloem sap**: Phloem sap is rich in sugars (sucrose) and other organic compounds. It also has a slightly alkaline pH.
Reasoning: Phloem is responsible for transporting products of photosynthesis, which include sugars. The pH is maintained to facilitate enzymatic activity.
2. **Analyze the options**: 
A. Absence of sugar: Incorrect. Phloem is known for transporting sugar.
B. Acidic: Incorrect. Phloem sap is not acidic.
C. Alkaline: Correct. Phloem sap is slightly alkaline due to the presence of various solutes.
D. Low refractive index: Incorrect. The high concentration of sugars and other solutes give it a relatively high refractive index compared to pure water.
Result: Alkaline is the correct option
Verification: Knowledge of phloem sap composition confirms the alkaline nature of phloem sap.
## OPTION ANALYSIS
[A] :x: Phloem sap is rich in sugars, not devoid of them.
[B] :x: Phloem sap is slightly alkaline, not acidic.
[C] ✓: Phloem sap generally has an alkaline pH.
[D] :x: The high concentration of solutes in phloem sap makes it have a relatively high refractive index.
## LEARNING AIDS
**Common Mistakes**:
1. Confusing phloem and xylem sap: Xylem sap is mostly water and minerals and has a different pH.
How to avoid: Remember that phloem transports sugars and other organic compounds, while xylem transports water and minerals.
2. Not knowing the general pH of biological solutions: Biological fluids are often slightly alkaline or neutral.
How to avoid: Review basic concepts of pH and biological systems.
**Quick Tips**:
1. Remember that phloem carries sugars and hence will have a higher concentration of solutes compared to xylem, which carries water.
2.  Associate alkaline with processes where organic compounds are being transported.

NISHANTH · Answer

Absence of sugar

NISHANTH · Answer

Acidic

NISHANTH · Answer

The correct Option is "Alkaline"

NISHANTH · Answer

Low refractive index

NEET Botany Anatomy of Flowering Plants MCQs

Select Topic

Question Tags

NEET Subjects

Our Bots

Company