Plant Tissues, Organs and Organ Systems Flashcards
List the 5 types of plant tissue.
Epidermal tissue, palisade
mesophyll, spongy mesophyll,
xylem & phloem, meristem
List the 3 plant organs.
Root, Shoot, Leaf
Describe the epidermal tissue
and its function.
A single layer of cells that
forms the outer layer of a
plant.
It is transparent so that light
can pass through it to the
palisade mesophyll.
It protects against water loss,
regulates that gas exchange or
water & mineral uptake.
Describe the palisade
mesophyll tissue and its
function.
A layer of cells immediately
below the epidermal tissue.
Tightly packed, regularly
shaped cells.
Contain many chloroplasts for
photosynthesis.
Describe the spongy
mesophyll and its function.
Found below the palisade
mesophyll tissue. Cells are
more round, there are many
gaps between the cells. They
have a large SA in contact with
the air spaces to maximise gas
exchange.
Describe the xylem and
phloem
tissue and
their function.
Xylem tissue carries water.
Phloem tissue carries sucrose.
Both tissues are found
together in vascular bundles.
What is the meristem?
A region of tissue where plant stem cells are produced and where much of the plant’s growth occurs (shoots and roots).
Describe plant roots and their
function.
White (no chloroplasts), absorb water via osmosis and minerals via active transport.
They anchor the plant into the
soil.
In some plants roots can store
starch.
On the outside of roots are root hair cells (specialised epidermal cells) and on the inside are phloem and xylem.
What is a shoot?
The stem, its leaves and its
buds. (everything above the
soil)
Describe how the stomata
open.
- Light causes ions such as
potassium to move into the
guard cell. - Concentration of ions
higher in guard cells than
outside of guard cells so
water moves into guard
cells via osmosis. - Inner wall of guard cell
thicker and less flexible so
the cell swells unevenly.
Define transpiration.
The gradual release of water
vapour from leaves to continue
the pull of water up to the leaves
from the soil.
Describe the path of water
through the plant.
Water enters root cells via
osmosis.
Water travels up the roots and
stem in xylem cells.
The xylem stem branches into
veins.
The veins carry the water to the
leaves.
The water evaporates and enters
the air spaces in the spongy layer.
Water vapour escapes through
the stomata.
What is the purpose of
transpiration?
Provide water for leaves and other
cells to keep them turgid.
Provide water for cells to carry out
photosynthesis.
Transport minerals to leaves.
Which factors affect the
rate of transpiration?
Temperature: at higher
temperatures the rate of
transpiration is faster.
Humidity: on a humid day,
transpiration rate is lower.
Wind: on windy days the water
vapour surrounding the plants is
blown away. Water evaporates
from the plant to replace the water
vapour.
Time of day: higher rate during the
day as more photosynthesis takes
place.
Define translocation.
The movement of sugar made
during photosynthesis from the
leaves of plants.
