Cell Biology & Biochemistry Series: Molecules of Life

Flashcards about molecules of life.

What are the characteristics of life?

Organisms consist of cells, grow and develop, regulate metabolic processes, react to stimuli, reproduce, and adapt to their environment.

What is the most basic level of structure in living things?

The molecular level.

What is a molecular formula?

Expresses the number of atoms in a molecule but does not convey its structure.

What are organic compounds?

Biological molecules that contain carbon.

What is the biggest component of most living organisms?

Water.

What does it mean for water to have a dipole nature?

Having two charges, a small positive charge on each of the two hydrogens and a small negative charge on the oxygen.

Define hydrophilic.

Substances that dissolve in water (e.g., salt).

Define hydrophobic.

Substances that do not dissolve in water (e.g., fats and oils).

What are the functions of water in living organisms?

Solvent medium for chemical reactions, part of plasma in animals, reagent during hydrolysis, supports plant cells, forms hydrostatic skeleton in animals, and regulates body temperature.

What are macronutrients, in terms of minerals?

Minerals needed in large quantities (e.g., C, H, N, P, S, Ca, Mg, Na).

What are micronutrients, in terms of minerals?

Minerals needed in small quantities (e.g., Fe, I).

What are the deficiency diseases associated with Nitrogen?

Kwashiorkor, Chlorosis.

What are the deficiency diseases associated with phosphorus?

Abnormal function of muscles.

What are the deficiency diseases associated with calcium?

Tooth decay & weak bones, Rickets (in children), Osteoporosis (in adults).

What are the deficiency diseases associated with magnesium?

Chlorosis, Muscle Spasms, Constipation, High Blood Pressure, Insomnia

What are the deficiency diseases associated with iron?

Anemia, Chlorosis

What are the deficiency diseases associated with iodine?

Goitre.

What are the two groups of vitamins?

Water-soluble vitamins (B and C) and fat-soluble vitamins (A, D, E, and K).

What is a deficiency disease of B1 Vitamin?

Beriberi (weak cardiac muscles, poor digestion, lack of energy, amnesia).

What is a deficiency disease of B2 Vitamin?

Sores in the corners of the mouth and dermatitis.

What is a deficiency disease of B3 Vitamin?

Pellagra (inflammation of tongue and mouth, diarrhea, dementia and pigmentation).

What is a deficiency disease of B6 Vitamin?

Sores in the mouth, dry eyeballs, loss of appetite, apathy, drowsiness

What is a deficiency disease of B12 Vitamin?

Anemia, poor memory, fatigue

Name the four types of Organic Compounds

Proteins, Lipids, Carbohydrates, and Nucleic Acids

What is the general formula for carbohydrates?

(CH2O)x

What is a pentose?

A five sided sugar, e.g. ribose and deoxyribose

List 3 monosaccharides

glucose, fructose, and galactose

What is a glycosidic bond?

A bond joining double-sugar molecules, the molecules are called disaccharides.

What monosaccharides compose sucrose?

glucose + fructose

What monosaccharides compose maltose?

glucose + glucose

What monosaccharides compose lactose?

glucose + galactose

What is cellulose?

A glucose polymer that is an important structural material found in plants consisting of unbranched chains of glucose molecules.

What is starch?

A polymer of glucose, made up of long chains of glucose molecules, and is an energy storage molecule in plants.

What is glycogen?

The energy storage compound in animal tissues and in many fungi and is chemically similar to amylopectin but more extensively branched.

What is chitin?

A polysaccharide structurally similar to cellulose with an acetyl group consisting of modified glucose units, found in the exoskeleton of arthropods and cell walls of fungi.

What happens during a condensation reaction?

Monosaccharides are joined together to form disaccharides and polysaccharides, releasing water in the process.

What happens during a hydrolysis reaction?

Compound sugars are broken down into their constituent monosaccharides, using a water molecule to provide the hydrogen and hydroxyl groups required.

What elements are lipids composed of?

Carbon, hydrogen, and oxygen (but with much more hydrogen compared to oxygen).

Give examples of lipids

Fats, oils, waxes, phospholipids, and steroids.

Give roles of Lipids

Biological fuels / energy, Hormones, Structural components of membranes, Protection against heat loss (insulation), Protection against physical shock

What is the primary structural component of all cellular membranes?

Phospholipids.

What are the differences between fats and oils?

Fats are solid at 20°C, and oils are liquid at 20°C. The physical state depends on the type of fatty acid attached to the glycerol molecule.

Describe saturated fats:

Mainly found in animal foods and have the maximum number of hydrogen atoms.

Describe unsaturated fats:

Plant based and have double bonds and fewer hydrogen atoms.

What happens during Lipid Condensation?

Triglycerides form when glycerol bonds with three fatty acids. When glycerol bonds with the fatty acid, an ester bond is formed and water is released

What does a phospholipid consist of?

A glycerol molecule, two fatty acid chains, and a phosphate (PO43-) group.

What is the basic structure of a steroid?

Three six carbon atom rings, and one five carbon atom ring.

What elements mainly consist proteins?

C, H, O, and N.

What is the bond between amino acids?

Peptide bond.

Give 4 importance of proteins

Involve in cellular reactions, structural role in cell membrane, permeability of cell membrane, building material in body

What happens during Condensation of proteins?

Amino acids are joined together to form peptide or polypeptide chains and a water molecule is released.

What happens during Hydrolysis of proteins?

Polypeptide chains are broken down into smaller peptide chains or simple amino acids. A water molecule provides a hydrogen and hydroxyl group.

What are the four levels of protein structure?

Primary, secondary, tertiary, and quaternary.

What happens during protein denaturation?

The loss of a protein’s three-dimensional structure, often resulting in loss of function and is often irreversible.

What are enzymes?

Catalysts that speed up biological reactions by lowering the energy needed for a reaction to take place.

What is the substrate?

The compound on which an enzyme acts.

What is the active site on an enzyme?

A specific region where the substrate binds and where catalysis occurs.

Briefly describe the lock and key model of enzyme action.

The substrate is drawn into a closely matching cleft on the enzyme molecule.

What happens during a catabolic reaction?

A larger molecule is broken down into smaller components, with the release of energy.

What happens during an anabolic reaction?

Smaller molecules are joined to form larger ones, requiring the input of energy.

How does temperature affect enzyme activity?

Enzyme activity increases with temperature, until the temperature is too high, leading to denaturation.

How does pH affect enzyme activity?

Extremes of pH away from the enzyme optimum can result in enzyme denaturation.

What are cofactors?

A nonprotein component (organic molecules or inorganic ions) that some enzymes require to be active.

What elements are nucleic acids made of?

C, H, O, N, P

What two types of nucleic acids are there?

DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).

What are the three components of a nucleotide?

Phosphate group, pentose sugar (5-carbon), and a nitrogenous base.

Name four nitrogenous bases

adenine (A), thymine (T), cytosine (C), and guanine (G).