Biology and Plants for Nursing School Entrance Exam Study Guide

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Biology and Plants for Nursing School Entrance Exam Practice Problems

1. Distinction between Plants and Animals

Plants are multicellular eukaryotes, nearly all terrestrial in origin, though some have evolved so that they can live in water. They differ from animals in structure, life cycle, and modes of nutrition, and are the mainstay of most ecosystems on Earth. They draw their energy directly from light—mainly sunlight—and directly or indirectly feed the rest of the creatures on Earth, including animals; without them most ecosystems would simply die. They are autotrophic in nutrition, making their food by photosynthesis, or the conversion of light energy into chemical energy, a property they share with algae and certain prokaryotes.

2. Photosynthesis
   1. Definition

   Photosynthesis: the process by which light energy, captured by the chloroplasts of plants, is converted to chemical energy

   2. Process

   Plants are equipped with the light-absorbing molecules chlorophyll a and chlorophyll b and certain carotenoid pigments that are accessory in photosynthesis

3. Cellular Anatomy

The cell walls of plants consist mostly of cellulose, and they store food in the form of starch. See Section A of this chapter for more on the structure of plant cells.

4. Nutritional Requirements

In order to live, plants require both macronutrients, including carbon, oxygen, hydrogen, nitrogen, sulfur, phosphorus, calcium, potassium, and magnesium; and micronutrients, including iron, chlorine, copper, manganese, zinc, molybdenum, boron, and nickel.

5. Structure and Function

Plants are classified as either nonvascular or vascular.

1. Nonvascular Plants

Nonvascular plants have simpler tissues than vascular plants. They are covered by a waxy cuticle to prevent dehydration, require water to reproduce, and lack woody tissue and so do not grow tall but rather grow in mats low to the ground. The nonvascular plants include mosses, liverworts, and hornworts.

2. Vascular Plants

Vascular plants have much more elaborate tissues, including vascular tissue; cells are joined into tubes for transport of nutrients and water throughout. There are two types of vascular tissue: phloem, which transports sugars from leaves to other parts of the plant; and xylem, which transports water and dissolved mineral nutrients from roots to other parts of the plant. Vascular plants are of two types: seedless, including horsetails and ferns, and seed plants. Seed plants in turn fall into two categories:

• Gymnosperms: seeds are uncovered; plants achieve fertilization mainly through windborne pollen. This category includes conifers and cyads, pines, firs, and spruce.
• Angiosperms: flowering plants such as garden and wild flowers and hardwood trees; the dominant plant form today (about 235,000 species). Angiosperms have the most advanced structural form; seeds are enclosed in carpels; animals and insects are employed for transfer of pollen in order to achieve fertilization. Important structures of flowering plants include its flower, which is the reproductive structure (includes the stamen, with filament and anthers, petals, pistil with its stigma, style, ovary, and sepal); and the fruit, which is the structure formed from the ovary of a flower, usually after ovules have been fertilized, and which protects dormant seeds and aids dispersal.
6. Reproduction and Development

Some plants reproduce sexually; seeded plants hold an egg, which, after the plant matures, is fertilized by pollen from itself or another plant. Others reproduce asexually by cloning; bulbs, feelers, and rhizomes require only one plant; there is no change in the chromosome number; and the offspring is exactly the same genetically as the parent. Fixed nitrogen is important to all aspects of a plant's life cycle.