properties of plants Flashcards
(26 cards)
explain the relationship between the structure and functions of a granum in photosynthesis
formed from many layers of thylakoid membranes to increase surface area for light absorption
thylakoid membranes contain chlorophyll to absorb light
electron carrier molecules in thylakoid membrane involved in ATP production
describe how nitrate ions are transported from the root to the leaves
through the xylem vessels
in water/ solution
name the monomer that makes up cellulose
beta glucose
unbranched chain
compare and contrast the structure of cellulose and amylopectin
both are polysaccharids/ polymers of glucose
both contain 1,4 GS bonds
cellulose contains beta glucose whereas amylopectin contains alpha glucose
cellulose is not branched/ does not contain 1,6 GS bonds- amylose is and does
devise a valid investigation to determine the effect of storage temperature on the tensile strength of manila rope and nylon rope
get pieces of rope of same length and diameter
store at range of temperatures (above and below suggested temp)
control humidity and period of time stored for
masses applied until rope breaks
calculate change in tensile strength
describe how the tensile strength of fibres could have been tested
tensile strength tested by adding masses to fibre until it breaks
calculate tensile strength by dividing force by cross-sectional area
control temperature/ length/ age of fibre
state one difference between the hexose sugar in cellulose and amylopectin
amylose contains alpha glucose and cellulose contains beta glucose
name the bond between adjacent cellulose molecules in a cellulose microfibril
hydrogen bond
explain why a seedling needs a supply of magnesium ions
magnesium needed to make chlorophyll
because chlorophyll is required for photosynthesis
shoots need chlorophyll to carry out photosynthesis to grow
devise an investigation about the effect of magnesium ion concentration on the growth of seedlings
range of magnesium ion concentrations
measure germination rate
use seedlings which were germinated in solutions containing all mineral ions
measurement of seedling growth
control temperature/ humidity
name a plant tissue that has lignin in its cell walls
xylem/ schlerenchyma
explain the role of the middle lamella when a plant cell completes mitosis
produced between adjacent new cells in cell plate
the middle lamella holds cell walls together
explain the function of the plasmodesma
cytoplasmic connection between cells
which allows transport and communication between cells
explain the effects of shortage of magnesium ions in a plant
[shortage] limits production of chlorophyll
lack of glucose produced due to less photosynthesis
therefore plant leaves may be yellow
plants may be smaller/ stunted growth
give two reasons why a sieve tube element does not require RER and ribosomes (ST does not contain nucleus)
there will be no transcription/ mRNA therefore ribosomes not required for translation
no proteins will be synthesised to be processed in RER
describe the structure of starch
polysaccharide of alpha glucose
monomers joined by 1,4 GS links
starch contains unbranched chains of amylose and branched chains of amylopectin
branches joined to chains by 1,6 GS links
explain why starch must be broken down before it can be used by plant cells
broken down to produce glucose
which is soluble and can be used in respiration
explain the difference in no of mitochondria between a sieve tube element and companion cell
companion cell has many mitochondria whereas sieve tube has few/ none
ST provides a channel so cellular contents are minimal
ST has limited/ no ability to carry out aerobic respiration
ATP/ energy is supplied to ST by companion cell
state what is meant by the term tensile strength
the pulling force the fibre can withstand before breaking
explain how structure and properties of starch are related to its function as a storage molecule
contains glucose needed for respiration/ energy
insoluble so has no osmotic effect (remains in cell)
amylose is coiled making starch compact so more can be stored
amylopectin is branched, contains 1,6 GS bonds so is rapidly hydrolysed
describe the positions in the stem of those tissues that contain lignin
sclerenchyma on outer side of vascular bundle/ phloem
xylem vessels on inner side of vascular bundle
describe the importance of magnesium ions in the production of plant fibres
essential for production of chlorophyll
chlorophyll necessary for photosynthesis for production of glucose
glucose needed to produce cellulose for cell walls
describe the arrangement of glucose monomers in a cellulose molecule
monomers connected by 1,4 GS links
alternate monomers are inverted
explain the relationship between the composition of starch and the rate of hydrolysis by enzymes
as amylose increases, the percentage of starch hyrolysed decreases
less amylose present, the greater the proportion of amylopectin
amylose is unbranched/ amylopectin is branched
amylopectin contains 1,4 and 1,6 GS bonds
branches/ greater number of terminal ends increases the rate of hydrolysis
