CHAPTER -5PLANT CELL AND ANIMAL

CELL

A project made by –NANDEESH LAXETTY

IX C

PLANT CELL………..

PLANT CELL The tremendous variety of

plant species is, in part, a reflection of the many distinct cell types that make up individual plants. Fundamental similarities exist among all the cell types, however, and the similarities indicate the common origin and the interrelationships of the different plant species. Each individual plant cell is at least partly self-sufficient, being isolated from its neighbors by a cell membrane, or plasma membrane, and a cell wall.

FUNCTIONS……..

The most important feature distinguishing the cells of plants from those of animals is the cell wall. In plants this wall protects the cellular contents and limits cell size. It also has important structural and physiological roles in the life of the plant, being involved in transport, absorption, and secretion.

Within the cell wall are the living contents of the cell, called the protoplast. These contents are bounded by a cell membrane composed of a phospholipids bi-layer. The protoplast contains the cytoplasm, which in turn contains various membrane-bound organelles and vacuoles and the nucleus, which is the hereditary unit of the cell.

Vacuoles are membrane-bound cavities filled with cell sap, which is made up mostly of water containing various dissolved sugars, salts, and other chemicals.

CONT. FUNCTIONS…………

Plastids are types of organelles, structures that carry out specialized functions in the cell. Three kinds of plastids are important here. Chloroplasts contain chlorophylls and carotenoid pigments; they are the site of photosynthesis, the process in which light energy from the sun is fixed as chemical energy in the bonds of various carbon compounds. Leucoplasts, which contain no pigments, are involved in the synthesis of starch, oils, and proteins. Chromoplasts manufacture carotenoids.

Whereas plastids are involved in various ways in storing energy, another class of organelles, the mitochondria, are the sites of cellular respiration. This process involves the transfer of chemical energy from carbon-containing compounds to adenosine triphosphate, or ATP, the chief energy source for cells.

CONT. FUNCTIONS…………

Two other important cellular contents are the ribosomes, the sites at which amino acids are linked together to form proteins, and the Golgi apparatus, which plays a role in the secretion of materials from cells. In addition, a complex membrane system called the endoplasmic reticulum runs through much of the cytoplasm and appears to function as a communication system.

The nucleus controls the ongoing functions of the cell by specifying which proteins are produced. It also stores and passes on genetic information to future generations of cells during cell division.

ANIMAL CELL……….

Most animals start life as a single fertilized cell, which divides many times to produce the thousands or millions of cells needed to form a functioning body. During this process, groups of cells develop different characteristics and arrange themselves in tissues that carry out specialized functions. Epithelial tissue covers the body’s inner and outer surfaces, while connective tissue binds it together and provides support. Nervous tissue conducts the signals that coordinate the body , and muscle tissue–which makes up over two-thirds of the body mass of some animals–contracts to make the body move.

PARTS AND FUNCTIONS………

Cell membrane - the thin layer of protein and fat that surrounds the cell. The cell membrane is semipermeable, allowing some substances to pass into the cell and blocking others.

Cytoplasm - the jellylike material outside the cell nucleus in which the organelles are located.

Golgi body - (also called the Golgi apparatus or golgi complex) a flattened, layered, sac-like organelle that looks like a stack of pancakes and is located near the nucleus. It produces the membranes that surround the lysosomes. The Golgi body packages proteins and carbohydrates into membrane-bound vesicles for "export" from the cell.

Lysosomes - (also called cell vesicles) round organelles surrounded by a membrane and containing digestive enzymes. This is where the digestion of cell nutrients takes place.

CONTD. PARTS AND THEIR FUNCTION

Mitochondrion - spherical to rod-shaped organelles with a double membrane. The inner membrane is infolded many times, forming a series of projections (called cristae). The mitochondrion converts the energy stored in glucose into ATP (adenosine triphosphate) for the cell.

Nuclear membrane - the membrane that surrounds the nucleus. Nucleolus - an organelle within the nucleus - it is where

ribosomal RNA is produced. Some cells have more than one nucleolus.

Nucleus - spherical body containing many organelles, including the nucleolus. The nucleus controls many of the functions of the cell (by controlling protein synthesis) and contains DNA (in chromosomes). The nucleus is surrounded by the nuclear membrane.

Ribosome - small organelles composed of RNA-rich cytoplasmic granules that are sites of protein synthesis.

CONTD. PARTS AND THEIR FUNCTION

Rough endoplasmic reticulum - a vast system of interconnected, membranous, infolded and convoluted sacks that are located in the cell's cytoplasm. Rough ER is covered with ribosomes that give it a rough appearance. Rough ER transports materials through the cell and produces proteins in sacks called cisternae

Smooth endoplasmic reticulum - a vast system of interconnected, membranous, infolded and convoluted tubes that are located in the cell's cytoplasm. The space within the ER is called the ER lumen. Smooth ER transports materials through the cell. It contains enzymes and produces and digests lipids and membrane proteins; smooth ER buds off from rough ER, moving the newly-made proteins and lipids to the Golgi body, lysosomes, and membranes.

Vacuole - fluid-filled, membrane-surrounded cavities inside a cell. The vacuole fills with food being digested and waste material that is on its way out of the cell.

DIVISION AND REPRODUCTION….

Organisms could not grow or function properly if the genetic information encoded in DNA was not passed from cell to cell. DNA is packaged into structures called chromosomes within a cell. Every chromosome in a cell contains many genes, and each gene is located at a particular site, or locus, on the chromosome. Chromosomes vary in size and shape and usually occur in matched pairs called homologues. The number of homologous chromosomes in a cell depends upon the organism - for example, most cells in the human body contain 23 pairs of chromosomes, while most cells of the fruit fly Drosophila contain 4 pairs.

DIFFERENCE BITWEEN PLANT CELL AND ANIMAL CELL…………

ANIMAL CELL PLANT CELL

SHAPE Round Rectangular

CHLOROPLAST Does not contain

chloroplasts

Contains chloroplasts for making of

food

CELL WALL None Yes

LYSOSOMES Lysosomes occur in

cytoplasm.

Lysosomes usually not

evident.

PLASTIDS No Yes

VACUOLE More than one smaller

vacuoles

One big central vacuole

SIMILARITIES BITWEEN PLANT CELL AND ANIMAL CELL…………

PLANT CELL ANIMAL CELL

Golgi Apparatus Present Present Nucleus Present Present

Mitochondria Present Present Cytoplasm Present Present Ribosome Present Present