NAME:
STUDENT NO:
BOT2603 ASSIGNMENT 02
UNIQUE NO: 682029
Question:1
1.1) Fick’s Law of Diffusion, states that molecules will diffuse from a region of
high concentration to a region of low concentration, or down a concentration
gradient. Fick's law states that the rate of diffusion of a substance across unit
area (such as a surface or membrane) is proportional to the concentration
gradient.
The formula is: J=D (C1-C2)/ (X1-X2)
J=diffusion flux; D= diffusion coefficient; C= difference in concentration;
X=distance between point 1 & 2.
, 1.2) The source-sink principle shows/states that the photosynthetically active
parts of a plant are referred to as the source. The areas of active growth and
areas of storage are referred to as sink in plants. However, a source is not
always a source, and a sink is not always a sink. For example, leaves that act as
sources when the plant is fully grown are known to act as sinks when the plant
is growing. The source in a plant is responsible for synthesizing the sugars
required for plant growth, whereas the sink in the plants uses the sugars for
immediate use and store the rest for future needs.
Example: The leaves act as a source in fully grown plants, and the seeds, fruit,
flowers and storage organs act as sinks in fully grown plants.
1.3) Humus is dark, organic material that forms in soil when plant and animal
matter decays. Humus contains many nutrient minerals that improves the
health and fertility of the soil. Humus ranges in color from brown to black,
consisting of about 60% Carbon, 6% Nitrogen, and smaller amounts of
Phosphorus and Sulphur. As humus decomposes, its components are changed
into forms usable by plants. Humus is organic matter in soil that has broken
down as far as it can and is now stable. It is black and jelly-like, and coats soil
particles, ‘glueing’ them together to form crumbs, or aggregates. Soil with
humus maintains soil pH, prevents erosion by holding particles together, traps
oxygen which is needed for root development, and holds nutrients to prevent
from leaching.
Question:2
2.1) Incipient plasmolysis is defined as the osmotic condition where 50% of the
cells are plasmolysed. At this point, the osmotic potential inside the cell
matches the osmotic potential of the medium on average. Incipient
plasmolysis is the initial stage of plasmolysis as in this stage water starts to
move outside the cell of the plant. In this phase the volume of the cell
decreases and the cell wall becomes detectable. If a plant cell is placed in a
hypertonic solution, the plant cell loses water and hence turgor pressure by
plasmolysis: pressure decreases to the point where the protoplasm of the cell
STUDENT NO:
BOT2603 ASSIGNMENT 02
UNIQUE NO: 682029
Question:1
1.1) Fick’s Law of Diffusion, states that molecules will diffuse from a region of
high concentration to a region of low concentration, or down a concentration
gradient. Fick's law states that the rate of diffusion of a substance across unit
area (such as a surface or membrane) is proportional to the concentration
gradient.
The formula is: J=D (C1-C2)/ (X1-X2)
J=diffusion flux; D= diffusion coefficient; C= difference in concentration;
X=distance between point 1 & 2.
, 1.2) The source-sink principle shows/states that the photosynthetically active
parts of a plant are referred to as the source. The areas of active growth and
areas of storage are referred to as sink in plants. However, a source is not
always a source, and a sink is not always a sink. For example, leaves that act as
sources when the plant is fully grown are known to act as sinks when the plant
is growing. The source in a plant is responsible for synthesizing the sugars
required for plant growth, whereas the sink in the plants uses the sugars for
immediate use and store the rest for future needs.
Example: The leaves act as a source in fully grown plants, and the seeds, fruit,
flowers and storage organs act as sinks in fully grown plants.
1.3) Humus is dark, organic material that forms in soil when plant and animal
matter decays. Humus contains many nutrient minerals that improves the
health and fertility of the soil. Humus ranges in color from brown to black,
consisting of about 60% Carbon, 6% Nitrogen, and smaller amounts of
Phosphorus and Sulphur. As humus decomposes, its components are changed
into forms usable by plants. Humus is organic matter in soil that has broken
down as far as it can and is now stable. It is black and jelly-like, and coats soil
particles, ‘glueing’ them together to form crumbs, or aggregates. Soil with
humus maintains soil pH, prevents erosion by holding particles together, traps
oxygen which is needed for root development, and holds nutrients to prevent
from leaching.
Question:2
2.1) Incipient plasmolysis is defined as the osmotic condition where 50% of the
cells are plasmolysed. At this point, the osmotic potential inside the cell
matches the osmotic potential of the medium on average. Incipient
plasmolysis is the initial stage of plasmolysis as in this stage water starts to
move outside the cell of the plant. In this phase the volume of the cell
decreases and the cell wall becomes detectable. If a plant cell is placed in a
hypertonic solution, the plant cell loses water and hence turgor pressure by
plasmolysis: pressure decreases to the point where the protoplasm of the cell
