CELL PROCESSES SEPTEMBER 2015 CELL PROCESSES A CELL

CELL PROCESSES SEPTEMBER 2015

CELL PROCESSES • A CELL must undergo certain processes in order to ensure the survival of the organism as a whole. • Each cell in your body is constantly taking in nutrients, getting rid of wastes, producing substances needed by other cells, releasing energy and reproducing.

NUTRITION- taking materials into the cell that provide energy and are needed for growth

DIGESTION • DIGESTION- nutrients are broken down (by enzymes) to be used by the cells • The primary sites of intracellular digestion are organelles known as the lysosomes, which are membrane-bounded compartments containing a variety of enzymes.

RESPIRATION • All organisms, including plants and animals, break down simple sugars into carbon dioxide and water and release energy. • The cell uses the energy to build, repair, and reproduce cells. • Respiration occurs in the mitochondria of cells.

RESPIRATION • RESPIRATION- using oxygen to release energy from food • Cellular respiration allows organisms to use (release) energy stored in the chemical bonds of glucose (C 6 H 12 O 6). The energy in glucose is used to produce ATP. Cells use ATP to supply their energy needs. Cellular respiration is therefore a process in which the energy in glucose is transferred to ATP. • Cellular respiration takes place in all cells. mitochondria

PHOTOSYNTHESIS • Plants use light energy (for example sunlight) to combine carbon dioxide and water to make simple sugars. • Plant cells also release oxygen gas. • Once the sugars are formed, they are either used by the plant or stored in the vacuoles. • Photosynthesis occurs in the chloroplasts.

PHOTOSYNTHESIS • Photosynthesis is the process of converting light energy to chemical energy and storing it in the bonds of sugar. This process occurs in plants and some algae. Plants need only light energy, CO 2, and H 2 O to make sugar. The process of photosynthesis takes place in the chloroplasts, specifically using chlorophyll, the green pigment involved in photosynthesis.

RESPIRATION Table 1. Comparison of photosynthesis and respiration Photosynthesis Respiration Produces sugars from light energy Stores energy Occurs only in cells with chloroplasts Releases oxygen Uses water Uses carbon dioxide Requires light Burns sugars for energy Releases energy Occurs in most cells Uses oxygen Produces water Produces carbon dioxide Occurs in dark and light

EXCRETION • EXCRETION- removing wastes from the cell (involves getting rid of unwanted or toxic substances)

SECRETION • SECRETION- making and giving off useful chemical compounds (involves producing substances that are necessary for the cell to function such as enzymes and hormones)

MITOSIS • Cell reproduction is called mitosis and occurs in the nucleus of the cell. • Mitosis enables a cell to make an exact copy of it. • Mitosis is a process of cell division, which results in the production of two daughter cells from a single parent cell. • The daughter cells are identical to one another and to the original parent cell. • Mitosis is needed for growth, replacement, and Asexual reproduction.

REPRODUCTION • REPRODUCTION- when the cell divides to produce more of its own kind Plant cells showing different stages of mitosis Binary fission in bacteria