5.1

Question 1

define photosynthesis

Answer 1

the process by which plants manufacture carbohydrates from raw materials using energy from light

Question 2

word equation for photosynthesis?

Answer 2

carbon dioxide + water –> glucose + oxygen, in the presence of light and chlorophyll

Question 3

what is chlorophyll?

Answer 3

it is a green pigment in plants. it transfers light energy
into chemical energy in molecules, for the synthesis of carbohydrates.

Question 4

what happens during photosynthesis?

Answer 4

In photosynthesis, plants combine the raw materials carbon dioxide (from the air) and water (from the soil) to form glucose and oxygen

Question 5

why is chlorophyll nessacary for photosynthesis?

Answer 5

Because chlorophyll absorbs light (usually sunlight), which is nessacary for photosynthesis to occur.

Question 6

why is light nessacary for photosynthesis?

Answer 6

because the sunlight is the initial energy that starts photosynthesis. The light causes a chemical reaction that breaks down carbon dioxide and water and converts them into sugar (glucose) and oxygen

Question 7

why is carbon dioxide nessacary for photosynthesis?

Answer 7

Because it provides the carbon required for the plant to produce glucose

Question 8

Describe the importance of nitrate ions and magnesium ions

Answer 8

Nitrate ions:
To make amino acids which are used to make proteins

Magnesium ions:
Are absorbed by plants and used to make chlorophyll

Question 9

what are chloroplasts (not chlorophyll!)

Answer 9

a plastid that contains chlorophyll and in which photosynthesis takes place

Question 10

Identify chloroplasts, cuticle, guard cells and
stomata, upper and lower epidermis, palisade
mesophyll, spongy mesophyll, vascular bundles,
xylem and phloem in leaves of a dicotyledonous
plant

Answer 10

(see photo in quizlet)

Question 11

Describe the cuticle

Answer 11

Cuticle: made of wax, secreted by upper epidermis. Helps to prevent water loss.

Question 12

Describe the upper epidermis

Answer 12

Upper epidermis: a protective layer & barrier to disease. allows sunlight to penetrate.

Question 13

describe the palisade mesophyll

Answer 13

Palisade mesophyll:
No gaps between cells. Cells are long, packed with chloroplasts. Main region for absorption of light for photosynthesis. most chloroplasts found here.

Question 14

describe the spongy mesophyll

Answer 14

Spongy mesophyll: Spherical, loosely packed, contain chloroplasts but not as many as palisade. has air spaces between cells allow gas exchange.

Question 15

describe the vascular bundle

Answer 15

Vascular bundle: Thin vein made of xylem and phloem.
Xylem vessels bring water & minerals to the leaf, phloem vessels transport sugars & amino acids away from the leaf.

Question 16

describe the lower epidermis:

Answer 16

Lower epidermis:
Stomata present, acts as a protective layer

Question 17

describe the stomata

Answer 17

Stomata: pores in a stomata allows the movement of gases into and out of the leaf.

Question 18

describe the guard cells

Answer 18

Guard cells regulate whether the stomata is open or closed. they regulate the loss of water vapour during transpiration.

Question 19

State the balanced equation for photosynthesis

Answer 19

see on the syllabus :)

Question 20

Outline the subsequent use and storage of the
carbohydrates made in photosynthesis

Answer 20

• Chloroplasts (containing chlorophyll) are responsible for trapping light energy.
• This energy is converted to chemical energy for the formation of carbohydrates (glucose).
• Glucose is usually changed to sucrose for transport around the plant, or to starch for storage.
• Oxygen is released as a waste product or used by the plant for respiration.

Question 21

Investigate and describe the effect of varying
light intensity and temperature on the rate of
photosynthesis (e.g. in submerged aquatic plants)

Answer 21

The reaction of photosynthesis controlled by enzymes. because of this, the rate of photosynthesis is affected by temperature.

At low temperatures = very limited
At high temperatures = enzymes are denatured.

** As light intensity increases, so does the rate of photosynthesis. ****
**The rate of photosynthesis is directly proportional to the light intensity **

***However, the rate cannot be increased indefinitely, a point is reached where all the chloroplasts cannot trap anymore light. (remember the graph??) **

Question 22

Describe the significance of the xylem and phloem

Answer 22

Xylem: the tissue that delivers water from the roots to the leaf
Phloem: the tissue that transports glucose away from the leaf. These tissues form vascular bundles in the plant.

Question 23

describe the importance of gas exchange

Answer 23

Gas exchange:
It happens in the spongy mesophyll tissue of the leaf.
To get to the spongy mesophyll cells inside the leaf, gases diffuse through small pores called stomata. They also open or close to control the loss of water from leaf by the process of transpiration.

Question 24

describe the importance of light absorption

Answer 24

Absorbing light energy:
Light absorption happens in the palisade mesophyll tissue of the leaf. Palisade cells are column shaped and packed with many chloroplasts. They are arranged closely together so that a lot of light energy can be absorbed.

Question 25

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

Answer 25

Nitrogen:
-To make proteins
-without it = Slow growth, weak stem, yellow leaves.

Magnesium:
-To make chlorophyll
-without it = yellowing of leaves

Question 26

how do each of the factors affect the rate of photosynthesis?

light intensity, carbon dioxide concentration, temperature

Answer 26

as light increases, rate of photosynthesis increases

as carbon dioxide increases, rate of photosynthesis increases

as temperature increases, rate of photosynthesis increases up to a maximum after which it decreases rapidly

Question 27

name four tissues in a leaf

Answer 27

(any from) cuticle, epidermis, spongy mesophyll, palisade mesophyll, xylem

Question 28

why is a large surface area inside a leaf essential for photosynthesis?

Answer 28

because it maximizes the rate of diffusion.

Question 29

why is a transparent epidermis a adaptation for photosynthesis?

Answer 29

it allows as much light as possible to pass through the cells to reach the palisade cells below where there are chloroplasts