Plants and Food

Question 1

What is the main storage carbohydrate in plants

Answer 1

Starch

Question 2

What are the useful products that glucose can be converted to and their uses?

Answer 2

1. Starch to use as a storage carbohydrate
2. Lipids used as an energy source for seeds.
3. Amino Acids to make proteins for growth

Question 3

What is the equation for Photosynthesis

Answer 3

Carbon Dioxide + Water –> Oxygen + Glucose

Question 4

What is the purpose of destarching a leaf?

Answer 4

To get rid of the starch that is left on the leaf at the beginning of the experiment.

Question 5

What is the substance that absorbs carbon dioxide from the environment

Answer 5

Soda Lime

Question 6

What is starch made out of

Answer 6

Glucose sub-units

Question 7

How do you show that oxygen is a waste product that is created during photosynthesis.

Answer 7

By submerging an aquatic plant in water and providing a sufficient amount of sunlight.

This will cause bubbles of oxygen gas to be produced underwater.

Question 8

What are isotopes

Answer 8

These are atoms of the same element with the same number of protons but different number of neutrons, therefore, causing different mass numbers.

Question 9

What is Photosynthesis

Answer 9

This is the use of simple inorganic molecules like carbon dioxide and water in the presence of chlorophyll and light to produce oxygen and glucose

Question 10

What is the role of the green pigment Chlorophyll

Answer 10

It is used to absorb light energy that is used for photosynthesis.

Question 11

What is the energy conversion that happens in photosynthesis

Answer 11

Light Energy —> Chemical Energy

Question 12

What are the functions of different parts of the leaf structure

Answer 12

Upper Epidermis:
This is the top most layer of the leaf and is transparent to allow light to pass in. It also contains a waxy cuticle to reduce water loss by evaporation.

Lower Epidermis:
These are the cells located at the bottom of the leaf and is where gas exchange takes place. This section of the leaf have pores called, “stomata” that are located between two very specialized cells called, “Guard cells” that increase or decrease the size of the stomata to let gas int and out.

Palisade Layer:
This layer is right below the upper epidermis and contains a large number of thin and long cells called, “palisade cells”. These cells contain hundreds of chloroplasts that are responsible for performing photosynthesis. This is the main site of photosynthesis.

Spongy Mesophyl:
These are the spongy mesophyl cells that are responsible for gas exchange. They also photosynthesis, but not as much as palisade cells.

Xylem:
These carry water and mineral ions throughout the plant that were absorbed by the roots at the bottom. They also supply the spongy mesophyl cells.

Phloem:
These carry the nutrients the plant produces by photosynthesis through the plant to parts of the plant that cannot make their own food.

Question 13

How is a leaf adapted for photosynthesis

Answer 13

• The leaf has a high surface area to absorb most of the sunlight, which increases the rate of photosynthesis.
• The leaf contains chlorophyll that it uses to absorb sunlight for photosynthesis.
• Contains a large number of palisade cells with a large number of chloroplasts in each cell to perform photosynthesis. This increases the rate of photosynthesis.
• The leaf has stomata to perform gas exchange between oxygen and carbon dioxide.

Question 14

What is the relationship between photosynthesis and respiration with the light intensity

Answer 14

As the light intensity increases, the photosynthesis rate is higher than the respiration so the plant produces less carbon dioxide.

As the light intensity decreases, the photosynthesis rate is lower than the respiration so the plant produces more Carbon Dioxide

Question 15

What is the indicator that is used to check for the presence of carbon dioxide

Answer 15

Hydrogen Carbonate

Question 16

What is the color of Hydrogen Carbonate in different carbon dioxide concentrations

Answer 16

High: Yellow
Normal: Orange
Low: Purple

Question 17

What are the factors that affect the rate of photosynthesis

Answer 17

• Temperature
• Carbon Dioxide concentration
• Light Intensity

Question 18

Why does the rate of photosynthesis level off even though the light intensity keeps on increasing

Answer 18

Because there are other factor that also affect photosynthesis. Therefore, even though the light intensity keeps on increasing, those other factors are still lacking. Ex: Carbon Dioxide concentration in the air.

These other factors are called, “limiting factors”

Question 19

What happens to the rate of photosynthesis as the light intensity increases

Answer 19

As the light intensity increases, the rate of photosynthesis increases but only up to a certain level. Then the rate of photosynthesis levels off because there are other factors that limit the rate of photosynthesis. Ex: Carbon Dioxide concentration, temperature

Question 20

What happens to the rate of photosynthesis as the carbon dioxide concentration increases

Answer 20

The rate of photosynthesis increases as the carbon dioxide concentration increases. However, only up to a certain level, which then levels off because of other limiting factors.

Question 21

What happens to the rate of photosynthesis as the temperature increases

Answer 21

The rate of photosynthesis increases as the temperature increases, but only up to a certain level. Because after the temperature goes beyond the optimum temperature, the enzymes start to denature, and the rate decreases.

Question 22

What are the substances that can be formed by glucose in plants

Answer 22

• Sucrose for transport
• Starch for storage
• Chlorophyll
• Lipid oils in seeds
• Proteins and DNA
• Cellulose for cell walls

Question 23

What are the uses of different mineral ions in plants?

Answer 23

Nitrates:
- Used to make proteins
- Used to make DNA
- Used to make Chlorophyll
etc

Potassium:
- Used to make enzymes needed for respiration and Photosynthesis.

Phosphates:

• Part of the cell membrane
• Used to make DNA and many other compounds.

Magnesium:
- Used to make Chlorophyll

Question 24

What are the deficiency symptoms for each ion in plants

Answer 24

Nitrates:

• Poor plant growth
• Older leaves turn yellow

Phosphates:

• Poor root growth
• Younger leaves turn purple.

Potassium:
- Leaves turn Yellow and have dead spots

Magnesium:
-Leaves turn yellow.