A Level Biology Revision Notes

Comprehensive A Level Biology revision notes providing information and assistance for all UK examination boards (AQA, OCR, Edexcel) as well as international curriculum (CIE).

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Derived Lipids- Steroids and Terpenes

Steroids

Derived lipids, also known as complex lipids, are a category of lipids that are derived from simple lipids through chemical modifications or enzymatic processes. They are more complex in structure compared to simple lipids like triglycerides, which consist of glycerol and fatty acids. Derived lipids can be classified into various subtypes based on their specific …

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Compound Lipids – Phospholipids and Glycolipids

Phospholipids

Compound lipids, also known as complex lipids, are a diverse group of lipids that contain fatty acids, glycerol, and other non-lipid components such as phosphate, sugars, or amino acids, and play a wide range of roles in cellular structure and function, including as membrane components, energy stores, and signaling molecules. Phospholipids Phosphoglycerides Read more about …

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Simple Lipids- Fats, Oils and Waxes

triglycerides

Simple Lipids are esters of fatty acid with farious alcohols. Simple Lipids – Fats and Oils (Triglycerides) Read more about Lipid Structures and Functions Waxes Frequently Asked Questions Where are fats and oils? Fats are lipids having saturated fatty acids while oils have unsaturated fatty acids in them. What are waxes? Waxes are a type …

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Lipids- Introduction and Classification

Classification of Lipids-2

The lipids are a large and heterogeneous group of substances of biological origin that are easily dissolved in organic solvents such as methanol, acetone, chloroform, and benzene. By contrast, they are either insoluble or only poorly soluble in water. Their low water solubility is due to a lack of polarizing atoms such as O, N, …

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Properties of Polysaccharides

Hyaluronic acid

Polysaccharides are high molecular weight carbohydrates which, on hydrolysis, yield mainly monosaccharides or products related to monosaccharides. They may also be regarded as polymeric anhydrides of simple sugars.

Functions of Carbohydrates

When it comes to the functions of Carbohydrates, let’s start with the basics. Carbohydrates, one of the essential macronutrients in our diet, are not merely a source of energy but multifaceted molecules with a wide array of functions in biology. Beyond their role as the body’s primary energy source, carbohydrates serve as integral components in …

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Properties of Disaccharides

Maltose

When it comes to the properties of disaccharides, let’s start with the basics. Disaccharides, a category of carbohydrates, are remarkable molecules with distinctive properties that contribute to their vital roles in biological processes and nutrition. These compounds are composed of two monosaccharide units joined together by a covalent bond known as a glycosidic linkage. While …

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Properties of Monosaccharides

Fructose

Monosaccharides, often referred to as the “building blocks of carbohydrates,” are simple sugars with a remarkable array of properties that underpin their fundamental roles in biology and nutrition. These small, water-soluble molecules are characterized by their sweet taste and their role as a primary source of energy for living organisms. Monosaccharides exhibit distinctive chemical properties, …

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Carbohydrates – Introduction and Classification

Disaccharides

Introduction Carbohydrates are one of the four major classes of biomolecules along with proteins, nucleic acids, and lipids. Carbohydrates are compounds that contain at least three carbon atoms, a number of hydroxyl groups, and usually an aldehyde or ketone group. They may contain phosphate, amino, or sulfate groups. First, carbohydrates serve as energy stores, fuels, and …

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Structure of RNA

Structure of the basic elements of RNA

RNA differs from DNA in three aspects. First, the backbone of RNA contains ribose rather than 2’-deoxyribose. That is, ribose has a hydroxyl group at the 2’-position. Second, RNA contains uracil in place of thymine. Uracil has the same single-ringed structure as thymine, except that it lacks the 5’-methyl group. Thymine is in effect 5’-methyl-uracil. …

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