Chapter 5: Plant nutrition

Question 1

Formula for photosynthesis

Answer 1

6CO2 + 2H2O —–> C6H1206 + 6O2

Question 2

What is Photosynthesis

Answer 2

The fundamental process by which plants manufacture carbohydrates (sugars) from raw materials using energy from sunlight.

Question 3

Key requirements for photosynthesis

Answer 3

Carbon dioxide (CO2) is absorbed from the atmosphere through stomata (tiny pores) in leaves.
Water (H2O) is absorbed from the soil through the roots.
Light energy is captured by chlorophyll, a pigment present in chloroplasts within plant cells.

Question 4

Products after Photosynthesis

Answer 4

Glucose (a simple sugar) and oxygen (O2) are released as a gas.

Question 5

Importance of Photosynthesis

Answer 5

Provides the primary source of energy for plants (glucose used for cellular respiration).
Supports the production of other organic molecules needed for growth and development.
Oxygen released during photosynthesis is essential for respiration in plants and animals.

Question 6

Factors Affecting Photosynthesis

Answer 6

Light intensity, Carbon dioxide concentration, Temperature and Water availability

Question 7

Light intensity

Answer 7

Increased light intensity generally increases the rate of photosynthesis up to a point, beyond which it may damage the photosynthetic apparatus.

Question 8

Carbon dioxide concentration

Answer 8

Higher CO2 concentration can enhance photosynthesis up to an optimal level.

Question 9

Temperature

Answer 9

The optimal temperature range for photosynthesis varies depending on the plant species. Extreme temperatures can disrupt the process.

Question 10

Water availability

Answer 10

Water is essential for various aspects of plant function, including photosynthesis. Drought stress can significantly reduce photosynthetic activity.

Question 11

Mineral Nutrients for photosynthesis

Answer 11

Plants also require mineral nutrients from the soil for proper growth and development. These are absorbed by the roots in the form of dissolved ions.
Essential elements and Deficiency symptoms

Question 12

Essential elements for photosynthesis

Answer 12

Some key elements needed by plants include nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg), and calcium (Ca).

Question 13

Deficiency symptoms

Answer 13

Lack of specific mineral nutrients can lead to visible deficiencies in plants, affecting growth, leaf colour, and overall health.

Question 14

Importance of Plant Nutrition

Answer 14

Understanding plant nutrition is crucial for various fields, including agriculture, horticulture, and environmental science.
Proper management of soil nutrients and environmental factors can optimize plant growth and crop yield.

Question 15

Describe the significance of the features of a leaf in terms of functions, including:
– palisade mesophyll and distribution of chloroplasts
– photosynthesis
– stomata, spongy mesophyll cells and guard cells

Answer 15

Palisade Mesophyll & Chloroplasts: These densely packed cells in the upper layer contain abundant chloroplasts, maximizing sunlight capture for photosynthesis.

Stomata, Spongy Mesophyll & Guard Cells: Tiny pores (stomata) controlled by guard cells allow CO2 intake for photosynthesis. Spongy mesophyll cells with air spaces facilitate gas diffusion (CO2 in, O2 out).

Question 16

Describe the significance of the features of a leaf in terms of functions, including:
– xylem for transport and support
– phloem for transport

Answer 16

Xylem: This vascular tissue transports water and minerals from the roots to the leaves, providing essential materials for photosynthesis and support.

Phloem: This vascular tissue transports sugars produced by photosynthesis from the leaves to other parts of the plant for energy and growth.

Question 17

Describe the importance of:
– nitrate ions
– magnesium ions

Answer 17

Nitrate Ions (NO3-) for Making Amino Acids.
Magnesium Ions (Mg²⁺) for Making Chlorophyll

Question 18

Explain the effects of nitrate ion and magnesium ion deficiency on plant growth

Answer 18

The lack of nitrate and magnesium ions can lead to a domino effect, ultimately hindering plant growth, development, and overall health.

Question 19

Nitrate Ion (NO3-) Deficiency; Impact

Answer 19

Stunted growth, yellowing leaves and the overall weakness is Limited protein synthesis weaken the plant’s overall structure and function. It may be more susceptible to pests and diseases.

Question 20

Magnesium Ion (Mg²⁺) Deficiency; Impact

Answer 20

Disrupted photosynthesis, Reduced energy production and Interveinal chlorosis.