Plants

Question 1

define magnification

Answer 1

enlarging something in appearance not physical size

how big

Question 2

define resolution

Answer 2

ability of an imaging system to resolve detail in the object being imaged
(how clear/ability to tell 2 objects apart)

Question 3

examples of eukaryotes

Answer 3

animal
plant
fungi
protocti

Question 4

examples of prokaryotes

Answer 4

bacteria

archaea

Question 5

role of centrosome

or microtubule organising center (MTOC)

Answer 5

produce microtubules
e.g. spindle fibres
plant cell centrosome is simpler + has no centrioles

Question 6

role of lysosome

Answer 6

contain hydrolytic enzymes for intracellular digestion
more common in animal cells
found near vacuole in plant cells

Question 7

role of peroxisome

Answer 7

membrane bound packets of oxidative enzymes
contains reducing enzyme catalase
plant cells -> turn fatty acids to sugars
animal cells -> protect cell from its ken production of toxic hydrogen peroxide

Question 8

role of vacuole

Answer 8

membrane bound sac of cell sap
regulates turgor or pressure in plant cell
involved intracellular digestion + release of cellular waste products
animal cell -> small
plant cell -> store nutrients + waste, help cell increase in size during growth

Question 9

role of cell wall

Answer 9

rigid + made of polysaccharides (cellulose)
provides + maintains shape and gives protective barrier
fluid in vacuole pushes out against cell wall
PLANT CELLS ONLY

Question 10

role of chloroplasts

Answer 10

site of photosynthesis
contain chlorophyll -> gives green colour and ability to absorb energy from sunlight
have double outer membrane
PLANT CELLS ONLY

Question 11

structure of cellulose

Answer 11

beta glucose 1,4 glycosidic bonds
protein embedded in fibres makes it strong
H-bonds between parallel chains makes it strong
“mesh/net” like -> each layer perpendicular to rest
calcium + pectin -> adds strength to cell wall

Question 12

describe xylem

Answer 12

transports water + ions from roots to leaves
ONLY UP
dead cells

Question 13

describe phloem

Answer 13

transports water + glucose from leaf to rest of plant
DOWN UP + DOWN
living cells

Question 14

describe parenchyma

Answer 14

spherical packaging tissue that makes up most of cortex tissue
living cells
carries out metabolic functions 
thin cell walls  + usually turgid -> gives mechanical support for stems/roots
no lignin 
can re-differentiate into meristem
found though out cell
most abundant 
edible part of plants

Question 15

describe collenchyma

Answer 15

found below epidermis in stems/petioles
cellulose/pectin complex
provides strong cylinder for flexible strong tissue
living cells tightly packed in tubes -> can stretch
extra cellulose -> gives mechanical strength
no lignin
unevenly thick cell walls grow as cell grows
not found in roots

Question 16

describe sclerenchyma

Answer 16

thick, lignified, rigid cell walls that can’t stretch
cells usually die at maturity
more rigid than collenchyma
secondary cell wall present + impregnated with lignin
2 types:
fibres -> for support
sclereids -> very thick lignification
strong cell wall stays after cell death for support

Question 17

what do vascular bundles contain?

Answer 17

sclerenchyma (sometimes)
phloem
cambium -> dividing tissue
xylem

Question 18

define xylem

Answer 18

water-conducting tissue of vascular plants

Question 19

define tracheids

Answer 19

chief water-conducting cells/elements
elongated cells closed at both ends
walls opened by numerous pits

Question 20

define translocation

Answer 20

movement of sugars/food substances and ions through phloem tissue

Question 21

what are the main phloem components?

Answer 21

sieve elements

companion cells

Question 22

which cells are phloem made of

Answer 22

columns of parenchyma cells
each cell adapted to form sieve element
columns join to form sieve tubes

Question 23

how are sieve plates formed?

Answer 23

when cross walls between sieve elements become perforated
cell walls are thin
nucleus disintergrates
lumen filled with cell sap

Question 24

what happens as sieve elements mature?

Answer 24

organelles like nucleus, ribosomes, golgi body degenerate and are lost
this allows minerals to pass through them easier

Question 25

what organelles are in sieve elements?

Answer 25

cell walls
cell membranes
mitochondria
small amount of cytoplasm that lines inside of cellulose cell wal

Question 26

what are companion cells?

Answer 26

found next to a sieve element
very metabolically active
enable sieve elements to stay alive

Question 27

describe structure of companion cells

Answer 27

have norma plant cell structure with extra ribosomes + mitochondria
linked to sieve elements by many plasmodesma

Question 28

what are plant fibres made up of?

Answer 28

long tubes of plant cells

strong which makes them good for rope

Question 29

why are plant fibres renewable?

Answer 29

able to be planted and re-grown
maintains supply
biodegradable

Question 30

examples of plant fibres

Answer 30

cotton
sisal
curaua
linen
jute
manila hemp/abacá

Question 31

why are collenchyma not found in roots?

Answer 31

roots aren’t exposed to wind so no need for flexible support

Question 32

what is chlorenchyma?

Answer 32

parenchyma specialised for photosynthesis

e.g. palisade mesophyll cells with many chloroplasts

Question 33

what is aerenchyma?

Answer 33

parenchyma specialised for gas exchange

e.g. spongy mesophyll, in aquatic plants to give buoyancy

Question 34

describe fibres (SCLERENCHYMA)

Answer 34

dead long narrow cells 
thick lignified walls with small lumens
walls have simple pits
gives mechanical strength 
protects non-growing areas

Question 35

describe sclereids (SCLERENCHYMA)

Answer 35

dead short fat cells
heavy lignified walls -> mechanical strength
can occur in cortex, pith, xylem, phloem or testa of seeds