plant nutrition (topic 6)

Question 1

photosynthesis

Answer 1

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

Question 2

word equation for photosynthesis

Answer 2

carbon dioxide + water → glucose + oxygen (in presence of light and chlorophyll)

Question 3

what is chlorophyll

Answer 3

green pigment that is found in chloroplasts, transfers energy from light into energy in chemicals, for the synthesis of carbohydrates

Question 4

chemical equation for photosynthesis

Answer 4

6CO2 + 6H2O → C6H12O6 + 6O2

Question 5

what are the 5 storing of carbs made in photosynthesis

Answer 5

starch, cellulose, glucose, sucrose, nectar

Question 6

outline uses of each type of carb storage

Answer 6

starch as an energy store
cellulose to build cell walls
glucose used in respiration to provide energy
sucrose for transport in the phloem
nectar to attract insects for pollination

Question 7

magnesium ions importance

Answer 7

important for making chloropyll, magnesium ion present in core of each chloropyll molecule, lack of magnesium means lack of chlorophyll which makes plant less green visibly

Question 8

nitrate ions importance

Answer 8

used for making amino acids, which are used to make protein needed for growth

Question 9

what is the importance of chlorophyll in photosynthesis

Answer 9

chlorophyll, present in green leafs, after being exposed to light and doing photosynthesis produce starch, meaning chlorophyll is essential for photosynthesis to occur, to investigate this use variegated leaves and let them go through photosynthesis, then test for presence of starch in each of the white and green areas, using iodine solution( blue black positive and brown orange negative), starch is product of photosynthesis, thus positive for starch means photosynthesis took place

Question 10

importance of carbon dioxide in photosynthesis

Answer 10

carbon dixoide, being a reactant needed in photosynthesis, is essential for the process to occur and produce starch. To investigate this put same plant in half with potassium hydroxide (substance that absorbs carbon doxide) and half with carbon dioxide, let them do photosynthesis and measure production of starch again

Question 11

importance of light in photosynthesis

Answer 11

light is necessary for photosyntehsis to occur. to investigate this, cover part of a leaf with aluminium foil, meaning light cant penetrate, and half without, then measure production of starch.

Question 12

what can control rate of photosynthesis

Answer 12

intensity of light, amount of carbon dioxide, temperature

Question 13

light intensity and photosynthesis

Answer 13

The rate of photosynthesis increases as the intensity of the light increases.

Note that this is seen up to a certain point. Increasing the intensity of light beyond that point would not cause any further increase in the rate of photosynthesis, as the temp or light intensity would be limiting factor

Question 14

carbon dioxide concentration and photosyntehsis

Answer 14

The rate of photosynthesis increases as the carbon dioxide concentration increases.

This is seen up to a certain point. Increasing the carbon dioxide concentration beyond this point will not cause any further increase in the rate of photosynthesis. Until other things were limiting instead

Question 15

temperature and photosynthesis

Answer 15

Enzymes work best at the optimum temperature. As the temperature increases, the rate of photosynthesis increases up to a point and then starts decreasing because of denaturation of the enzyme.

Question 16

what is a limiting factor

Answer 16

a factor that prevents a rate from increasing

Question 17

Hydrogen carbonate indicator

Answer 17

An indicator used to show carbon dioxide concentration in solutions. The indicator changes colour depending upon the concentration level.
low- magenta purple
mid- red
high- organge

Question 18

respiration vs photosynthesis

Answer 18

respiration- releases co2 to surroundings
photosynthesis- absorbs co2 from surroundings

Question 19

what are adaptations present in leafs for photosynthesis to occur efficiently

Answer 19

large surface areas, which exposes a larger area to sunlight and air, and helps in the easier absorption of these materials.

thin, which ensures that the carbon dioxide from the air diffuses quickly to the photosynthetic cells. The thinness of the leaves also helps the light to penetrate easily.

Question 20

what are the structures present in a leaf

Answer 20

cuticle, upper epidermis, palisade mesophyll (chloroplasts), spongy layer (vascular bundle(phloem and xylem)) (air spaces), lower epidermis (stomata and guard cells)

Question 21

cuticle function and adpatations

Answer 21

stops water from evaporating from the leaf, waxy layer

Question 22

chloroplats function and adpatations

Answer 22

the site of photosynthesis, contains chlorophyll to absorb light, and enzymes and structures needed for photosynthesis

Question 23

upper epidermis function and adpatations

Answer 23

protects the inner cells, thin layer without chloroplasts, which lets light pass through for photosynthesis

Question 24

palisade mesohpyll layer function and adpatations

Answer 24

tissue in which photosynthesis happens, box-shaped cells that pack closely together; each cell has lots of chloroplasts pushed to the edges of the cell by a large vacuole so they can absorb more light

Question 25

xylem function and adpatations

Answer 25

carries water and mineral ions from the roots to the leaf, made from dead cells, forming hollow, waterproof tubes, through which water passes

Question 26

phloem function and adpatations

Answer 26

carries sucrose away from the leaf, consists of sieve tubes (through which the sucrose is transported) and companion cells (that provide energy for the transport)

Question 27

vascular bundle function and adpatations

Answer 27

contain the xylem and phloem tissues

Question 28

lower epidermis function and adpatations

Answer 28

protects the inner cells, thin layer that (apart from guard cells) does not contain chloroplasts, which lets light pass through for photosynthesis

Question 29

guard cells function and adpatations

Answer 29

work in pairs to control the size of the opening of a stoma, entry and loss of water from the guard cells (due to osmosis) results in changes in their shape; this in turn leads to the opening and closing of the stoma

Question 30

stomata function and adpatations

Answer 30

controls the diffusion of water vapour and gases in and out of the leaf, the size of the opening changes in response to the internal and external environments of the plant

Question 31

air spaces function and adpatations

Answer 31

allow diffusion of gases throughout the leaf

Question 32

spongy mesophyll function and adpatations

Answer 32

site of gas exchange, cells are loosely spaced, creating air spaces to allow diffusion of gases throughout the leaf