LECTURE 2: cell chemistry II- organic molecules

Why is carbon the core of organic molecules?

Carbon has 4 outer electrons and can form many different covalent bonds with other atoms, allowing it to create molecules of many shapes and sizes. 

How many bonds can carbon form?

Carbon can form 2, 3, or 4 covalent bonds with other atoms. 

What types of bonds can carbon form?

Carbon can form single, double, and triple covalent bonds.

Why can carbon-based molecules have many different shapes?

The pattern of carbon bonds determines the shape of the molecule, allowing for great structural diversity. 

What are the four major classes of organic molecules?

Lipids, carbohydrates, proteins, and nucleic acids. 

What is a macromolecule?

A large molecule (polymer) made from smaller building blocks called monomers.

What are lipids?

Lipids are mostly hydrophobic organic molecules used for energy storage, insulation, protection, membranes, and signaling. 

Why are lipids hydrophobic?

They are mostly made of nonpolar carbon and hydrogen chains that do not interact well with water. 

What are fatty acids?

Long chains of mostly carbon and hydrogen that serve as building blocks for many lipids. 

What is the difference between saturated and unsaturated fatty acids?

Saturated fatty acids contain only single bonds. Unsaturated fatty acids contain at least one double bond. 

What is a triglyceride?

A lipid made of three fatty acids attached to one glycerol molecule. 

What are the functions of triglycerides?

Energy storage, insulation, and protection. 

What is a phospholipid?

A lipid that forms the primary structure of cell membranes.

What does amphipathic mean?

Having one polar (water-attracting) region and one nonpolar (water-repelling) region. 

Why are phospholipids important?

They form the plasma membrane that surrounds all cells. 

What are steroids?

Lipids that include cholesterol and many hormones.

Why is cholesterol important?

Cholesterol is used to make sex hormones, metabolism-regulating hormones, and substances involved in fat digestion. 

What are eicosanoids?

Lipid signaling molecules used for cell communication. 

What are carbohydrates?

Sugars and starches that serve as an important source of energy for the body. 

What is the main function of carbohydrates?

To provide energy that can be used to generate ATP. 

What are monosaccharides?

Single sugar molecules that serve as the building blocks of carbohydrates. 

What are disaccharides?

Carbohydrates made of two monosaccharides joined together. 

What are polysaccharides?

Large carbohydrates made of many monosaccharides linked together. 

Why are carbohydrates hydrophilic?

They contain polar covalent bonds that interact easily with water. 

What is glycogen?

A polysaccharide used to store glucose in the body. 

What are proteins made of?

Proteins are made of amino acids.

How many amino acids are found in the body?

Twenty different amino acids.

What are the four parts of every amino acid?

A central carbon, amino group, carboxyl group, and R group.

What is a peptide bond?

The bond that joins amino acids together.

What process forms peptide bonds?

Dehydration synthesis. 

What process breaks peptide bonds?

Hydrolysis

What is primary protein structure?

The linear sequence of amino acids. 

What is secondary protein structure?

A helix or sheet formed by hydrogen bonds between nearby amino acids.

What is tertiary protein structure?

The final three-dimensional shape of a single protein.

What is quaternary protein structure?

A protein made from multiple protein subunits joined together. 

Why is protein shape important?

Structure determines function. If a protein changes shape, it may stop working.

What causes protein denaturation?

Extreme changes in temperature or pH can cause proteins to unfold and lose function.

What are nucleic acids?

Molecules that store and transfer genetic information.

What are the two nucleic acids?

DNA and RNA.

What are nucleic acids made of?

Nucleotides

What are the three parts of a nucleotide?

A phosphate group, a sugar, and a nitrogenous base.

What sugar is found in RNA?

Ribose

What sugar is found in DNA?

Deoxyribose

What nitrogen bases are found in RNA?

 A, G, C, and U (uracil).

What nitrogen bases are found in DNA?

A, G, C, and T (thymine). 

What are the DNA base-pairing rules?

A pairs with T, and G pairs with C. 

What holds the two DNA strands together?

Hydrogen bonds between complementary bases. 

What is ATP?

ATP is the cell's main energy-carrying molecule.

What does ATP stand for?

Adenosine triphosphate. (Triphosphate means it contains three phosphate groups.)

How is ATP made?

ATP is formed when a phosphate group is added to ADP through phosphorylation.

How does ATP release energy?

The terminal phosphate group is removed, converting ATP to ADP and releasing energy.

What is ATP hydrolysis?

The breakdown of ATP into ADP and phosphate, releasing energy for cellular work. 

Why can ATP power chemical reactions?

ATP stores energy in its phosphate bonds. When the last phosphate is removed, energy is released and can be used to power cellular processes.

What is the plasma membrane?

The plasma membrane is the boundary that surrounds every cell. It is primarily made of phospholipids. 

Which lipid is the main component of the plasma membrane?

Phospholipids

Why are phospholipids ideal for cell membranes?

They are amphipathic, meaning they have a hydrophilic region and a hydrophobic region, allowing them to form a barrier around cells.