Epic BLG 1502 Exam Answers

a) Dermal tissue system: is the outer protective layer which covers the entire body of the plant. It protects the organ (leaf/stem/root) against physical damage, desiccation and pathogenic organisms. The dermal tissue of non-woody plants usually consists of a single layer of tightly packed cells called the epidermis. In woody plants, the epidermis is replaced by the periderm which mainly consists of nonliving cork cells b) Vascular tissue system: consists of two vascular tissues, i.e. xylem and phloem that are responsible for carrying out long distance transport of materials between roots and shoots. It is continuous throughout the plant but is arranged differently in each organ. The xylem conveys water and minerals upwards from root to shoot and the phloem transports organic nutrients from where they are made to where they are needed. The xylem is composed of tracheids and vessel elements, the latter occurring in most flowering plants and some gynosperms. Both tracheids and vessels elements are dead at maturity. The phloem of flowering plants. c) Ground tissue system: consists of tissues that are neither dermal nor vascular. It includes the parenchyma, collenchyma and sclerenchyma tissues that are specialised for function such as storage, photosynthesis and support. The pith is the ground tissue found internal to the vascular tissue while the cortex is external to the vascular tissue. 1.2 Growth occurs just behind the tip in three overlapping zones of cell at successive stages of primary growth namely: 1-Cell division: • This includes root apical meristem and its derivatives • This region produces new root cells, including cells of the root cap 2- Elongation: • Occurs just a few mm behind the tip of the root • Most of the growth occurs here as root cells elongate ( at times up to 10 X their original length) 3- Differentiation: • Also known as zone of maturation • In this zone cells complete their differentiation and become distinct cell types. 2.1 Format is binomial or two-part format (1) namely first the genus(1) and then the second specific epithet(1). First part capital letter(1), second part lowercase letter (1) and both underlined or in Italics (1) e.g. Homo sapiens 2.2 1- Alternation of generations. 2- Muticellualr, dependent embryos. 3- Walled spores produces in sporangia. 4- Multicellular gameangia. 5- Apical Meristems 3. Taproot • Occurs in eudictos and gymnosperms • Has one main vertical root, the tap root • This main root , the taproot, developes from an embryonic root • Tap root penertrate deeply • They are well adapted to deep soils where the groundwater is not close to the surface Fibrous root system • Occurs mostly in monocots • The embryonic root dies early and does not form a taproot • Instead, many roots emerge from the stem • These roots are known as adventitious roots • Each small root forms its own lateral roots • Fibrous root systems is a mat of generally thin roots spreading out below the soil surface • These roos systems do not penetrate deeply and are therefore adapted to shallow soils or regions where rainfall is light and does not moisten the soil much below the surface layer • Their main function is absorption and to prevent erosion • Some add support and anchorage while others store water and nutrients or absorb oxygen from the air. 4. Mammary glands, hair, endothermic, four chambered heart, diaphragm, large brain, parental care, differentiation of teeth.