Photosynthesis

Question 1

What is the process through which plants make their own food?

Answer 1

Photosynthesis

Photosynthesis involves using carbon dioxide from the air and water from the soil to produce carbohydrates.

Question 2

What are the reactants and products of photosynthesis?

Answer 2

Reactants: Carbon Dioxide + Water
Products: Glucose + Oxygen

The chemical equation is: 6CO2 + 6H2O → C6H12O6 + 6O2.

Question 3

What energy source do plants use during photosynthesis?

Answer 3

Light

Plants convert light energy into chemical energy during photosynthesis.

Question 4

What does a plant do with glucose produced during photosynthesis?

Answer 4

Converts it into starch for storage

Starch can be tested for using iodine.

Question 5

What is the test for the presence of starch in leaves?

Answer 5

Use iodine solution

If starch is present, the leaf turns black; if not, it stays orangey brown.

Question 6

What is the first step in testing a green leaf for starch?

Answer 6

Place a leaf in boiling water to soften it

This helps to prepare the leaf for further testing.

Question 7

What is the purpose of using ethanol in the starch test?

Answer 7

To decolorize the leaf

Ethanol is flammable, so ensure the flame is off before using it.

Question 8

What does it indicate if only parts of a variegated leaf turn black when tested for starch?

Answer 8

Chlorophyll is needed for photosynthesis

Only green areas show starch presence, confirming the role of chlorophyll.

Question 9

What experiment can be conducted to test if light is necessary for photosynthesis?

Answer 9

Cover part of a geranium leaf with black paper

After exposure to light, only the uncovered part will turn black when tested for starch.

Question 10

Fill in the blank: Photosynthesis converts light energy into _______.

Answer 10

Chemical energy

Question 11

True or False: Starch is produced in all parts of the leaf during photosynthesis.

Answer 11

False

Starch is only produced in areas where chlorophyll is present.

Question 12

What is the purpose of destarching a plant?

Answer 12

To ensure that no starch is present before testing for photosynthesis

Destarching is typically done by keeping the plant in a dark room for a period of time.

Question 13

What is the function of potassium hydroxide in the photosynthesis experiment?

Answer 13

To absorb CO₂, preventing the leaf from accessing it

This demonstrates that CO₂ is necessary for photosynthesis.

Question 14

What color change indicates the presence of starch in a leaf?

Answer 14

Bluey-black

This color change occurs when iodine is applied to the leaf.

Question 15

What experimental setup is used to collect oxygen produced by a water plant?

Answer 15

An inverted funnel and an inverted tube or gas syringe

This setup captures oxygen bubbles released by the plant.

Question 16

How can you confirm the gas collected from a water plant is oxygen?

Answer 16

By inserting a glowing splint into the gas; if it relights, it is oxygen

This is a classic test for the presence of oxygen.

Question 17

What is the first step in investigating how light intensity affects photosynthesis in Elodea?

Answer 17

Place Elodea in a beaker of water

This sets up the environment for the experiment.

Question 18

What are the three main limiting factors of photosynthesis?

Answer 18

• Light intensity
• Carbon dioxide concentration
• Temperature

Each of these factors can limit the rate of photosynthesis if they are in short supply.

Question 19

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

Answer 19

It increases up to a certain point where it plateaus

After reaching the plateau, either CO₂ or temperature becomes the limiting factor.

Question 20

What is the definition of a limiting factor in the context of photosynthesis?

Answer 20

The component of a reaction that is in the shortest supply and limits the rate of reaction

This concept is crucial for understanding how various factors affect photosynthesis.

Question 21

Fill in the blank: A limiting factor is the component of a reaction that is in the _______.

Answer 21

shortest supply

Question 22

What occurs to the rate of photosynthesis when carbon dioxide concentration increases?

Answer 22

It increases to a point

This increase continues until another factor becomes limiting.

Question 23

Why is light intensity, CO2 concentration and temperature the limiting factors?

Answer 23

Light intensity - chlorophyll uses light energy during photosynthesis.

Carbon dioxide concentration- one of the raw materials needed for photosynthesis.

Temperature - An enzyme driven ration needed to find the optimum pH.

Question 24

What must be increased to increase the rate of photosynthesis?

Answer 24

Either light intensity or temperature

Photosynthesis is affected by environmental factors such as light and temperature.

Question 25

How does temperature affect the rate of photosynthesis?

Answer 25

Increases the rate until enzymes denature above 45 degrees ## Footnote Enzymes are crucial for photosynthesis and their denaturation leads to decreased rates.

Question 26

What happens to enzymes at temperatures above 45 degrees?

Answer 26

They denature ## Footnote Denaturation changes the shape of the enzyme, affecting its function.

Question 27

What is often the limiting factor in photosynthesis?

Answer 27

Temperature ## Footnote Temperature can restrict the rate of photosynthesis if it becomes too high.

Question 28

What is one adaptation of a leaf that maximizes light exposure?

Answer 28

Large surface area ## Footnote A larger surface area allows leaves to capture more sunlight for photosynthesis.

Question 29

Where are chloroplasts mainly found in a leaf?

Answer 29

In the palisade cells ## Footnote Palisade cells are located just below the upper epidermis and are optimal for photosynthesis.

Question 30

What types of transport systems do leaves have?

Answer 30

Xylem and phloem ## Footnote Xylem transports water, while phloem transports nutrients and organic products.

Question 31

Why do leaves not have chloroplasts in the epidermis?

Answer 31

To allow sunlight to penetrate to the mesophyll layer ## Footnote This adaptation facilitates efficient photosynthesis in the inner leaf layers.

Question 32

What is the function of air spaces in spongy mesophyll?

Answer 32

To allow gas exchange ## Footnote Air spaces facilitate the diffusion of carbon dioxide and oxygen.

Question 33

What is the role of stomata in leaves?

Answer 33

To allow carbon dioxide and oxygen to diffuse in and out ## Footnote Stomata are essential for efficient gas exchange during photosynthesis.

Question 34

How do leaves support themselves?

Answer 34

Supported by the stem ## Footnote The stem provides structural support to maximize light exposure.

Question 35

What are Palisade cells arranged like?

Answer 35

End on / vertical

Question 36

What feature of leaves helps to reduce water loss by evaporation?

Answer 36

Waxy cuticle

Question 37

What is the main purpose of having thin leaves in plants?

Answer 37

To keep as few cells and cell walls as possible between sunlight and chloroplasts

Question 38

What is the most common pigment used in photosynthesis?

Answer 38

Chlorophyll

Question 39

What color of light does chlorophyll reflect?

Answer 39

Green

Question 40

What are stomata?

Answer 40

Holes in leaves which allow gaseous exchange

Question 41

What surrounds the stomata?

Answer 41

A pair of guard cells

Question 42

What happens to the guard cells when the plant is short of water?

Answer 42

They close the stoma

Question 43

What role do magnesium ions play in plants?

Answer 43

For making chlorophyll

Question 44

What happens to leaves of a plant with magnesium deficiency?

Answer 44

Leaves turn yellow

Question 45

What do nitrates help to make in plants?

Answer 45

Amino acids and proteins

Question 46

What is the consequence of insufficient nitrates in plants?

Answer 46

Limited growth and older leaves turn yellow

Question 47

What do phosphates contain that is essential for plants?

Answer 47

Phosphorus

Question 48

What are the effects of a phosphate deficiency in plants?

Answer 48

Poor root growth and older leaves turn purple

Question 49

What is the role of potassium in plants?

Answer 49

Helps the enzymes needed for photosynthesis and respiration

Question 50

What are the consequences of potassium deficiency?

Answer 50

Poor flower and fruit growth and leaves turning yellow/discoloring

Question 51

List the uses of glucose in plants

Answer 51

* Respiration * Sucrose for transport * Starch for storage * Cellulose for cell walls * Conversion into lipids + amino acids * Chlorophyll * Proteins and DNA

Question 52

What is starch?

Answer 52

A molecule made from glucose that is used for storage.

Question 53

Why is starch considered more useful than glucose for storage?

Answer 53

Because it takes up less space and is more compact.

Question 54

What is one property of starch that prevents it from affecting osmotic concentration in a cell?

Answer 54

Starch is insoluble.

Question 55

Why is starch considered unreactive?

Answer 55

It does not readily participate in chemical reactions.

Question 56

True or False: Starch can diffuse out of a cell.

Answer 56

False.

Question 57

Fill in the blank: Starch is too _______ to diffuse out of the cell.

Answer 57

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