Human and Plant Physiology - Coursework Example

The mesophyll tissue, which is made up of spongy cells, and palisade cells contain a huge number of chloroplasts. Chloroplasts contain chlorophyll (a green pigment) which absorbs light energy during photosynthesis. The leaf’s palisade tissue contains the greatest concentration of chloroplasts and it is in this tissue where most photosynthesis takes place (Adds, Larkcom, and Miller 2004, p3). Explain the Exchange of Oxygen and Carbon Dioxide between the Plant and Its Environment Gaseous exchange indicates the exchange of oxygen and carbon dioxide between the plant and its environment or surrounding.

There are two processes of gaseous exchange, photosynthetic gas exchange and respiratory gas exchange. In photosynthetic gas exchange, carbon dioxide is taken up and oxygen given off by the plant. On the other hand, in respiratory gas exchange, the plant takes up oxygen and gives off carbon dioxide. The process that predominates at a certain time can be determined at the leaf surface of the assimilating plant. Respiratory carbon dioxide escapes when it is dark. Under optimal conditions for assimilation, photosynthesis is maintained by the utilization of carbon dioxide set free through respiration.

This state of compensation is only evident when the process of gas exchange is shut off. It is important to note that gas exchange between the plant cells and its surroundings or the environment takes place by mass flow and diffusion (Larcher 2003, p91). Explain the Uptake of Water and Minerals by the Plant After the diffusion of mineral-rich soil water into the roots, the water reaches the vascular cylinder of the root through two ways, (a) by diffusing through the cell wall, and (b) by moving through the cytoplasm.

Water enters the cytoplasm through the diffusion across the plasma membrane of the cell in the root’s cortex or epidermis. Dissolved mineral cannot diffuse because the membranes are impermeable to ions (Evers, Starr, and Starr 2010, p418). Mineral ions enter the cytoplasm through the active transport process in the plasma membranes. In the cytoplasm, ions and water diffuse from one cell to the cell through plasmodesmata until they enter the vascular cylinder. After water and ions enter the vascular cylinder, they are distributed to the other parts of the plant by the xylem.

The plant’s cell wall is rigid but permeable to ions and water. Soil water can enter vascular cylinder by direct diffusion through the cell walls. The parenchyma cells in the root cortex are tightly packed, and they create a continuous pathway that permits the diffusion of mineral ions and water into the vascular cylinder from the epidermis. It is important to note that soil water diffusing into through the cell wall enters the vascular cylinder through the endodermal cell cytoplasm (Evers, Starr, and Starr 2010, p419).

Analyse the Benefits of Exercise and the Problems Associated With Obesity There are numerous health benefits of exercise. Exercise can minimize major illnesses such as stroke, diabetes, cancer, and heart disease by up to 50 percent. Exercise can lower up to 30 percent the risk of early death in an individual. Research indicates that physical activity or exercise can boost mood, energy, sleep quality, and self-esteem. Physical activity has been shown to reduce the risk of depression, Alzheimer’s disease, dementia, and stress.

People who do exercise regularly