In young dicot stems and stems (usually the upright, vertical portion of a plant transports substances to and the leaves) that do not increase in thickness, xylem and phloem are arranged in vascular bundles in the cortex. In older stems and all woody stems, the vascular tissues form a cylinder between the cortex and the pith. The vascular bundles in a monocot are scattered throughout the stem. In vascular plants, the dominant sporophyte has two kind of well-defined conducting tissues. Xylem is specialized to conduct water and dissolved minerals, and phloem is specialized to conduct organic nutrients and hormones.
The cell wall protects the cell's plasma membrane. Outside the cell wall there is just a thin layer of pectin, wax and cutin to provide some padding, called the middle lamella. In some plants a secondary cell wall forms in the plants adult stages as an extra protection - this wall again is mostly made up of cellulose. Starch can be found in two forms. One is amylose an unbranched polysaccharide with 1-4 glycosidic bonds.
The shape of a cell is related to its function because of the adaptations made throughout time to make the cell as efficient as it can be. There are two types of cells, eukaryotic cells, which are generally plant and animal cells and prokaryotic cells which relate to bacteria and fungi, which undergo asexual production. Plants are anchored into the ground by roots. The function of roots is the transportation of water and mineral ions from the soil into the xylem to transport around the plant. The roots have an outer layer of cells called root hair cells that have a specific shape that makes the uptake of water and mineral ions more efficient.
Fungi Unlike bacteria and viruses, fungi are simple plant-like organisms which reproduce using spores. There are three types of fungal infections; ones which occur on the surface of the skin and hair; those which occur in the epidermis (such as ringworm and athlete's foot) and those which affect the deeper layers of skin – the dermis, subcutaneous tissue, muscle and fascia. Fungi may reach these layers as a result of penetrating wounds, or may be inhaled. Parasites Parasites differ from bacteria in that they need a living host to survive and reproduce, although not all parasites affect the host. Parasites can be acquired through contact with a contaminated surface, via infected water or food and through contact with contaminated bodily fluids such as blood, faecal matter and sexual contact.
Examples of fungi are Penicillium, yeast and mushrooms. Plants are multicellular and carry out photosynthesis. The cells are eukaryotic, have cell walls made of cellulose and vacuoles containing cell sap. Also, they have chloroplasts containing photosynthetic pigments. The main plant phyla include mosses, liverworts, ferns and conifers.
Skin and the Integumentary System A. Skin is composed of 2 main layers 1. Epidermis is made of keratinized stratified squamous epithelial tissue, is superficial to the dermis, and is avascular. 2. Dermis is mainly connective tissue, is deep to the epidermis, and is vascular * The skin contains collagen (for strength) and elastic (for stretch) fibers.
P2 There are two different types of epithelial tissue these are simple and compound. Simple Epithelium- this type of epithelium tissue is from an animal consisting of one of more layers of closely packed cells. The cells can vary in structure depending on their function which may be protective, secretory or absorptive. This epithelium tissue covers external and internal surfaces of the body. Compound Epithelium – this type of epithelial tissue is made to withstand wear and tear.
5) What is the system where no roots stand out as the main one? A fibrous root system. 6) Why are grassroots particularly useful? They hold the top soil in place, preventing erosion. 7) What is an organ system consisting of nodes (the points at which leaves are attached), and internodes (the stem segments
Onion, Cheek, and Elodea cells are all eukaryotic. Onion and Elodea cells are plant cells. Cheek cells are animal cells. They all have nuclei and cell membranes. 2.
Discuss the role of the microflora on skin in different parts of the body. Give examples. • The type of microflora found on the skin varies in other parts of the body. One species of microflora, Corynebacterium acnes, live in the hair follicles, usually without harm to a person. However, when the dead skin from the epidermis occasionally blocks a sebaceous gland of a hair follicle, the bacteria may infect surrounding tissue resulting in inflammation and causing a pimple.