1. TRANSPORT IN PLANTS
AND ANIMALS.
Transport defined. Transport in unicellular organisms.
• This is the movement of substances from • The unicellular organisms (e.g. bacteria)
one part of the body of an organism to have a large surface area to volume
another. ratio hence transport of substances is
• It involves the movement of materials to through diffusion across their cell
the sites where they are required and the membranes and within the cells of the
removal of metabolic wastes from the site organism.
of production to the site of elimination. Transport in multicellular organisms.
Importance of a transport system. • They have a small surface area to
• It facilitates the distribution of nutrients volume ratio .This makes the tissues
and oxygen to all living cells of the body. and organs far removed from the site of
• It facilitates the removal of metabolic waste supply of the materials.
products (e.g. nitrogenous wastes and • This requires a transport system to
carbon (IV) oxide from the body cells. supply materials to the deep seated
organs and also remove metabolic wastes.
1-Feb-21 © Sam Obare 1
, TRANSPORT IN PLANTS
• Simple plants e.g. mosses and STRUCTURE OF A ROOT.
liverworts lack specialized transport
system hence the transport of • The root is the part of the plant
substances occur through diffusion, which is embedded in the soil.
osmosis and active transport. Functions of the root.
• Higher plants have specialized 1. Anchorage- holding the plant
transport system called vascular firmly in the soil.
system. 2. Absorption- of water and
• The vascular bundle consists of: mineral salts.
1. xylem- it transports water and
mineral salts from the soil to other
parts of the plant.
2. Phloem- it transports
manufactured food substances e.g.
glucose from the leaves to other
parts of the plant.
1-Feb-21 © Sam Obare 2
,INTERNAL STRUCTURE OF A ROOT
1-Feb-21 © Sam Obare 3
, 6. Endodermis- this is a single layer
1. Root cap- it consists of simple of cells which surround the vascular
parenchyma cells that protect the bundle. It controls the amount of
root tip/ apical meristem as the water and mineral salts entering the
root tip pushes past soil particles. vascular bundle. It is characterized
2. Piliferous layer- this is a special by;
epidermis of young roots whose a) Starch grain that stain blue-black
cells form/ which give rise to root with iodine.
hairs.
b) Casparian strip which has
3. Cortex- it consists of loosely impervious deposit on the radial and
packed parenchyma cells. It acts as cross walls.
storage tissue.
7. Root hairs- they arise from the
4. Pericycle-this is a single layer of epidermal cells.They provide a large
cells below the endodermis that surface area for absorption of water
gives rise to lateral roots. and mineral salts.
5. Vascular bundle- it consists of
xylem and phloem. In monocot
root, the xylem alternates with
phloem. In dicot root, xylem is star
shaped and the phloem is located
between the arms of the xylem.
1-Feb-21 © Sam Obare 4
AND ANIMALS.
Transport defined. Transport in unicellular organisms.
• This is the movement of substances from • The unicellular organisms (e.g. bacteria)
one part of the body of an organism to have a large surface area to volume
another. ratio hence transport of substances is
• It involves the movement of materials to through diffusion across their cell
the sites where they are required and the membranes and within the cells of the
removal of metabolic wastes from the site organism.
of production to the site of elimination. Transport in multicellular organisms.
Importance of a transport system. • They have a small surface area to
• It facilitates the distribution of nutrients volume ratio .This makes the tissues
and oxygen to all living cells of the body. and organs far removed from the site of
• It facilitates the removal of metabolic waste supply of the materials.
products (e.g. nitrogenous wastes and • This requires a transport system to
carbon (IV) oxide from the body cells. supply materials to the deep seated
organs and also remove metabolic wastes.
1-Feb-21 © Sam Obare 1
, TRANSPORT IN PLANTS
• Simple plants e.g. mosses and STRUCTURE OF A ROOT.
liverworts lack specialized transport
system hence the transport of • The root is the part of the plant
substances occur through diffusion, which is embedded in the soil.
osmosis and active transport. Functions of the root.
• Higher plants have specialized 1. Anchorage- holding the plant
transport system called vascular firmly in the soil.
system. 2. Absorption- of water and
• The vascular bundle consists of: mineral salts.
1. xylem- it transports water and
mineral salts from the soil to other
parts of the plant.
2. Phloem- it transports
manufactured food substances e.g.
glucose from the leaves to other
parts of the plant.
1-Feb-21 © Sam Obare 2
,INTERNAL STRUCTURE OF A ROOT
1-Feb-21 © Sam Obare 3
, 6. Endodermis- this is a single layer
1. Root cap- it consists of simple of cells which surround the vascular
parenchyma cells that protect the bundle. It controls the amount of
root tip/ apical meristem as the water and mineral salts entering the
root tip pushes past soil particles. vascular bundle. It is characterized
2. Piliferous layer- this is a special by;
epidermis of young roots whose a) Starch grain that stain blue-black
cells form/ which give rise to root with iodine.
hairs.
b) Casparian strip which has
3. Cortex- it consists of loosely impervious deposit on the radial and
packed parenchyma cells. It acts as cross walls.
storage tissue.
7. Root hairs- they arise from the
4. Pericycle-this is a single layer of epidermal cells.They provide a large
cells below the endodermis that surface area for absorption of water
gives rise to lateral roots. and mineral salts.
5. Vascular bundle- it consists of
xylem and phloem. In monocot
root, the xylem alternates with
phloem. In dicot root, xylem is star
shaped and the phloem is located
between the arms of the xylem.
1-Feb-21 © Sam Obare 4
