Environmental Science Exam Revision: Key Concepts and Acts
Environmental Science Exam Revision
This document consolidates critical definitions, concepts, years, and frequently asked questions for Units 3, 4, 5, and 7 to optimize your exam preparation.
Unit 3: Ecosystems and Ecosystem Services
Key Terms and Pioneers
- Ecosystem: Term coined by A.G. Tansley (1935). It is the smallest structural and functional unit of ecology.
- Ecology: Term coined by E. Haeckel.
- Ecotone: The transition zone where two different ecosystems meet (e.g., estuary). Species abundant here
Principles of Fermentation and Soil Microbiology
Understanding Fermentation
Fermentation is a metabolic process converting carbohydrates into acids, gases, or alcohol using yeasts, bacteria, fungi, or molds, typically under anaerobic conditions. It is one of the oldest applied microbiology techniques, enhancing nutritional quality, preservation, flavor, and food safety. It is widely used in food production, pharmaceuticals, biofuels, and biopolymers.
Biochemical Basis
- Begins with glycolysis producing pyruvate.
- In the absence of oxygen, pyruvate is
Essential Microbiology and Immunology Concepts
1. Conjugation
Definition: Conjugation is a method of horizontal gene transfer in bacteria where genetic material is transferred from a donor cell to a recipient cell through direct physical contact.
Role of Plasmid: It requires a plasmid (F-plasmid) that codes for the formation of a sex pilus.
Mechanism:
- Donor Cell (F+): Contains the F-plasmid and produces a sex pilus.
- Contact: The pilus attaches to the recipient cell (F-) and pulls it closer.
- Transfer: One strand of the plasmid DNA is transferred through
Reproduction and Inheritance: Essential Biology Concepts
Sexual Reproduction in Flowering Plants
1. What is Double Fertilization?
Answer: Double fertilization is a characteristic feature of angiosperms. In this process, two male gametes are involved in fertilization. One male gamete fuses with the egg cell to form a diploid zygote (syngamy). The other male gamete fuses with two polar nuclei to form a triploid primary endosperm nucleus (triple fusion). Thus, two fusions occur in the same embryo sac, so it is called double fertilization.
2. What is Triple
Read MoreHuman Physiology: Urine Formation, Endocrine & Nervous Systems
Physiology of Urine Formation
Physiology of urine formation: Kidneys form urine by filtration and secretion of waste materials from the blood. In addition, selective reabsorption by tubular cells contributes to the maintenance of homeostasis and the regulatory activities of the kidneys.
Formation of Urine
The urinary system: The nephrons of the kidney perform this function. Primarily, three processes are involved in the formation of urine: glomerular filtration, tubular reabsorption, and tubular secretion.
Read MoreReproductive Health and Contraception Essentials
Reproductive Health: Questions and Answers
Fundamental Concepts of Reproductive Health
1. Why does Cu-T act as an effective contraceptive?
Answer: Cu-T releases copper ions which reduce sperm motility and prevent fertilization. It also prevents implantation in the uterus.
2. What do you understand by reproductive health?
Answer: Reproductive health means a healthy reproductive system and the ability to reproduce safely without disease or complications.
3. What substances are present in semen?
Answer: Semen
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