Biological Molecules

Biological Molecules

<aside> 💡 Monomer: A building block, usually referring to the same type of ‘block’ that makes up something larger

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Carbohydrates:

• Provide energy and structural support(Cell wall)

• All carbohydrates include carbon, hydrogen and oxygen.

• Fiber is a carbohydrate that prevents constipation

• Foods: Breads, cereals, vegetables, fruits and seeds

• Extra glucose is converted into glycogen in the liver

Three types of Carbohydrates

The monomer of a carbohydrate is the monosaccharide - 1 sugar

Plants have cell walls of carbohydrates, specifically a large one known as cellulose

Fungi also have cell walls of carbohydrates, it is known as chitin

Examples:

• Glucose: Bread, rice and pasta(Glucose is also used to make ATP)

  • Because of that, it makes carbohydrates a fast source of energy for cells.

• Fructose: Fruits

• Galactose: Vegetables and dairy

Disaccharide - 2 sugar (Two monosaccharides combined together by a glycosidic bond):

• Monosaccharide + Monosaccharide = Disaccharide

• Maltose: Glucose and glucose

• Sucrose: Glucose and fructose

Polysaccharides - More than 10 sugars (more than two monosaccharides combined together by a glycosidic bond)

• Starch: Glucose, amylose and amylopectin

<aside> 💡 Dehydration Synthesis - Two monomers joining together by removing a water molecule Hydrolysis - Two monomers disconnecting by adding a water molecule

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If you continue joining together monosaccharides with glycosidic bonds you can make very long chains of sugars

They are perfect for storing sugar in a cell because they are insoluble so do not affect water potential in the cell

Lipids(Fats, Oils)

<aside> 💡 Saturated fats - single bonds connecting elements, extremely packed

Unsaturated fats - mixture of single and double bonds connecting elements, less packed

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• Lipids are a diverse group of compounds that are insoluble in water but soluble in organic solvents such as ethanol

• One thing lipids generally share is that they contain a hydrophobic component. Essentially, they dislike water. Which means they wont dissolve in water

• Lipids have a major function of being a source of long term energy storage

• When carbs are used up, lipids are also very important as a long term energy source that an organism can use.

• Cell membrane structure is made from lipids

• The monomer for lipids are glycerol and fatty acids

• The most common types of lipids are triglycerides (sometimes known as true fats or neutral fats), but other important lipids include waxes, steroids and cholesterol.

• Like carbohydrates, lipids contain carbon, hydrogen and oxygen, but they have a higher proportion of hydrogen and a lower proportion of oxygen.

• Connected by fatty acids

Proteins

Proteins are a diverse group of large and complex polymer molecules, made up of long chains of amino acids (20 types)

They have a wide range of biological roles, including:

Structural: Proteins are the main component of body tissues, such as muscle, skin, ligaments and hair

Catalytic: All enzymes are proteins, catalyzing many biochemiical reactions

Signalling: Many hormones and receptors are proteins

Immunological: All antibodies are proteins

All amino acids have the same general structure: the only difference between each one is the nature of the R group. The R group therefore defines an amino acid

The R group therefore defines an amino acid (determines the type of amino acid) .

The R group represents a side chain from the central ‘alpha’ carbon atom, and can be anything from a simple hydrogen atom to a more complex ring structures.

Essential Amino Acids:

histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine

Non Essential Amino Acids:

alanine, arginine, asparagine, aspartic acid (aspartate), cysteine, glutamic acid, glutamine, glycine, proline, serine, and tyrosine

Amino Acid + Amino Acid = Dipeptide + Dipeptide = Peptides

Dipeptides = Two amino acids

Peptides = Two dipeptides

Polypeptide = long unbroken chain of peptides (broken is peptide chain)

(Complex) Proteins = One of more polypeptide chains folded into a highly specific 3D shape

All of the bond between amino acids are called peptide bonds

When more amino acids are added to dipeptide, a polypeptide chain is formed

A protein consist of one or more polypeptide chains folded into a highly specific 3D shape.

There are up to four levels of structure in a protein: primary, secondary, tertiary and quaternary. Each of these play an important role in the overall structure and function of the protein

Types of protein structures

Fibrous Proteins

Fibrous proteins are formed from parallel polypeptide chains held together by cross-links. These form long, rope-like fibres, with high tensile strength and are generally insoluble in water.

Collagen-the main component of connective tissue such as ligaments, tendons and cartilage

Keratin-the main component of hard structures such as hair, nails, claws and hooves

Silk-forms spiders webs and silkworms cocoons

Globular protiens

Globular proteins usually have a spherical shape caused by tightly folded polypeptide chains.

The chains are usually folded so that hydrophobic groups are on the inside, while the hydrophilic groups are on the outside. This makes many globular proteins soluble in water.

Transport proteins-such as hemoglobin, myoglobin and those embedded in membranes

Enzymes-such as lipase and DNA polymerase

Hormones-such as oestrogen and insulin

Denaturing proteins

If the bonds that maintain a protein’s shape are broken, the protein will stop working properly and is denatured.

Changes in temperature, pH or salt concentration can all denature a protein, although the specific conditions will vary from protein to protein

Fibrous protein lose their structural strength when denatured, whereas globular proteins become insoluble and inactive.

DNA (Deoxyribonucleic Acid)

Was discovered by Watson and Crick

A-Adenine

G-Guanine

T-Thymine (U - Uracil, for RNA only)

C-Cytosine

DNA (Deoxyribonucleic acid) directs & controls all activities of all cells in an organism - RNA (Ribonucleic acid) helps

DNA → RNA → Protein

DNA: A, G, T, C

RNA: A, G, U, C

DNA Structure:

Made up of nucleotides

Sugar, phosphate, nitrogenous base

Polymers (chain of units): DNA (deoxyribonucleic acid, double helix, found in humans) or RNA (single helix, normally found in bacteria)

Base paring rule (complementary):

Adenine always binds with Thymine (A - T) (Purines, 2-H bonds)

Guanine always binds with Cytosine(G - C) (Pyrimidines, 3-H bonds)

Connected to each other through phosphodiester bonds

Nucleic Acids

Atoms: Carbon, Hydrogen, Oxygen, Phosphorus and Sulphur

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Digestion Products

Alkaline substance mixed with oil lets it mix with water