Cucumber seedlings

Question 1

What is the role of the glyoxylate cycle during the germination of fatty seeds?

Answer 1

Converts lipids to sugars critical for cell wall synthesis and energy generation

The glyoxylate cycle is unique to plants and operates during early growth when photosynthesis is not possible.

Question 2

What key enzyme catalyzes the cleavage of isocitrate in the glyoxylate cycle?

Answer 2

Isocitrate lyase (ICL)

ICL converts isocitrate to glyoxylate and succinate.

Question 3

What are the two types of germination observed in seedlings?

Answer 3

Epigeal germination and hypogeal germination

Epigeal germination has cotyledons above ground, while hypogeal keeps them underground.

Question 4

What parts of the seedling should be identified during the observation?

Answer 4

Cotyledons, apical buds, and roots

These parts are crucial for understanding seedling development.

Question 5

How is glyoxylate production measured in seedlings?

Answer 5

Using a reaction with 2,4-dinitrophenylhydrazine to produce a detectable yellow derivative

This method allows quantification of glyoxylate levels.

Question 6

What is the expected outcome regarding enzyme activity during seedling growth?

Answer 6

Identification of developmental stages and their association with enzyme activity

This helps in understanding the metabolic demands of seedlings.

Question 7

What is the purpose of preparing cotyledon extracts from cucumber seedlings?

Answer 7

To conduct enzyme assays and quantify enzyme activity

Maintaining extracts on ice prevents degradation.

Question 8

What components are included in the reaction buffer for enzyme assays?

Answer 8

Magnesium chloride, mercaptoethanol, and potassium phosphate

These components create an optimal environment for enzyme activity.

Question 9

At what temperature should the enzyme assays be incubated?

Answer 9

30°C

This temperature is suitable for enzyme reactions.

Question 10

What is used to establish a standard curve for glyoxylate concentration?

Answer 10

Sodium glyoxylate

Calibration is necessary for accurate measurements of glyoxylate production.

Question 11

What is the expected trend in enzyme activity during germination?

Answer 11

Peaks during early germination stages when lipid reserves are converted to sugars

This correlates with the developmental progress of seedlings.

Question 12

How does the glyoxylate cycle support seedling growth in the absence of photosynthesis?

Answer 12

By converting stored lipids into usable sugars for energy

This process is crucial during the initial growth phase of seedlings.

Question 13

What learning outcome involves calculating enzyme activity?

Answer 13

Ability to calculate enzyme activity and interpret its significance

This skill is essential for understanding metabolic processes in plants.

Question 14

Fill in the blank: The glyoxylate cycle is critical for converting _______ to sugars during germination.

Answer 14

lipids

This conversion is essential for energy and growth during early seedling development.

Question 15

True or False: The glyoxylate cycle is present in both plants and animals.

Answer 15

False

The glyoxylate cycle is unique to plants.