Biological Molecules Overview

A small unit that forms a larger molecule.

A large molecule made from many monomers joined together.

A chemical reaction where a molecule is broken down into smaller parts by adding water.

A chemical reaction where two molecules join together and a water molecule is released.

A single sugar unit.

A carbohydrate formed by two monosaccharides.

A carbohydrate formed by many monosaccharides.

A chemical bond that joins monosaccharides together in a polysaccharide.

A chemical test used to detect the presence of reducing sugars, such as glucose and fructose. It involves heating the sample with Benedict's reagent, which changes color from blue to brick red (orange-brown) in the presence of a reducing sugar.

A sugar that can donate electrons in a chemical reaction, like glucose or fructose. They have a free aldehyde or ketone group that can react with Benedict's reagent.

A sugar that cannot donate electrons in a chemical reaction, such as sucrose or lactose. These have their aldehyde or ketone group locked in a glycosidic bond, preventing it from reacting with Benedict's reagent.

It indicates the presence of starch. The iodine reacts with the starch to give a blue/black coloration.

A type of lipid composed of one glycerol molecule and three fatty acids joined by ester bonds. They are the primary form of fat storage in the body.

A long chain of carbon atoms with a carboxyl group at one end. They are building blocks of triglycerides and can differ in length and saturation.

A type of fat where all the carbon-carbon bonds in the fatty acid chain are single bonds. Typically found in animal fats and solid at room temperature.

A type of lipid containing at least one carbon-carbon double bond, making it flexible and liquid at room temperature.

Triglycerides are excellent energy storage molecules due to their high ratio of carbon-hydrogen bonds to carbon atoms, meaning they store a lot of energy in a small volume.

Similar to triglycerides, but one fatty acid is replaced by a phosphate group. This makes the molecule polar, with a hydrophilic head and hydrophobic tails.

In an aqueous environment, phospholipids spontaneously form a bilayer with their hydrophilic heads facing outwards and hydrophobic tails facing inwards.

Glycolipids are formed when carbohydrates attach to the phospholipids on the cell surface membrane. They play a crucial role in cell recognition.

A test to detect the presence of lipids. A cloudy-white color indicates a positive result due to lipid droplets forming an emulsion.

Using water as a sample in the emulsion test serves as a control, ensuring that any cloudy appearance is due to lipids and not other factors.

Water molecules form hydrogen bonds, which require a lot of energy to break. This helps to stabilize temperature and prevent extreme fluctuations in living organisms.

Breaking hydrogen bonds in water to evaporate it requires substantial energy. Therefore, water has a high latent heat of vaporization, meaning it absorbs a lot of heat during evaporation, leading to a cooling effect.

Strong attraction between water molecules due to hydrogen bonding. This cohesion enables water to be transported effectively in plants (xylem) and supports columns of water.

Iron ions are essential components of hemoglobin, which is the oxygen-carrying molecule in red blood cells.

Sodium ions are involved in co-transport mechanisms, helping to move glucose and amino acids across cell membranes.

Enzymes speed up chemical reactions by lowering the activation energy needed for the reaction to occur.

Enzymes are globular proteins with a specific 3D shape determined by their amino acid sequence. This shape allows them to bind to specific substrates.

The active site is a small region on the enzyme where the substrate binds. It is made up of a few specific amino acids.

When a substrate binds to the active site, the enzyme's shape changes slightly to fit the substrate more snugly. This improves bonding and helps the reaction proceed.

Enzymes have an optimal temperature at which they work best. Below the optimum, the reaction rate is slow. Above the optimum, the enzyme denatures and loses its shape, causing the reaction rate to decrease.

Enzymes also have an optimal pH at which they function best. Changes in pH can disrupt the bonds in the enzyme's tertiary structure, altering its shape and causing it to lose activity.

Increasing enzyme concentration generally increases reaction rate, as more active sites are available to bind with substrates. However, beyond a certain point, the reaction rate will plateau, as substrate concentration becomes the limiting factor.

Increasing substrate concentration generally increases reaction rate, as more enzyme-substrate complexes form. However, beyond a certain point, the reaction rate plateaus, as enzyme concentration becomes the limiting factor.

An enzyme that unwinds the DNA double helix by breaking the hydrogen bonds between the complementary bases.

The process where specific nitrogenous bases (Adenine with Thymine, and Guanine with Cytosine) pair up to form hydrogen bonds in DNA replication.

An enzyme that joins activated nucleotides together to form a new DNA strand during replication.

The strong chemical bond that connects nucleotides together in a DNA strand.

The breakdown of ATP (adenosine triphosphate) into ADP (adenosine diphosphate) and a phosphate molecule, releasing energy.

An enzyme that produces ATP during photosynthesis and respiration by joining ADP and inorganic phosphate.

A molecule with an uneven distribution of charge, creating a slightly positive and slightly negative end.

A substance that dissolves other substances, like water dissolving sugar.