Macromolecules & Biological Membranes

Fluid Mosaic Model

It describes the membrane as a flexible lipid bilayer with proteins embedded; replaced the Davson-Danielli model.

Phospholipid

A phospholipid has hydrophilic heads and hydrophobic tails.

Membrane Proteins

They transport substances, act as receptors, enzymes, and provide structural support.

Membrane Carbohydrates

They are involved in cell recognition and signaling.

Selective Permeability

Only certain molecules can cross; small nonpolar molecules pass easily, while ions and polar molecules do not.

What is the polymer principle?

Polymers are built by linking together monomers through chemical bonds.

What are proteins and their role in living organisms?

Proteins are macromolecules that perform a variety of functions, including catalyzing biochemical reactions, providing structural support, and regulating processes.

What are the monomers of proteins?

The monomers of proteins are amino acids.

What are the four levels of protein structure?

Primary structure (sequence of amino acids), secondary structure (alpha helices and beta sheets), tertiary structure (3D shape), and quaternary structure (assembly of multiple polypeptides).

What does denaturation of a protein mean?

Denaturation refers to the process where a protein loses its native structure and function due to external stressors like heat or pH changes.

What are chaperonins?

Chaperonins are proteins that assist in the proper folding of other proteins.

What are carbohydrates and their roles in living organisms?

Carbohydrates are macromolecules that serve as energy sources and structural components; their monomers are monosaccharides.

Name some common carbohydrates.

Ribose, glucose, fructose, galactose, sucrose, and lactose.

How are sugars named?

Sugars are typically named based on the number of carbon atoms they contain and their functional groups.

What are lipids and their roles in living organisms?

Lipids are hydrophobic molecules that serve as energy storage, structural components of cell membranes, and signaling molecules.

What does a typical fat look like?

A typical fat consists of glycerol and three fatty acids, forming a triglyceride.

What are nucleic acids and their roles in living organisms?

Nucleic acids, such as DNA and RNA, store and transmit genetic information; their monomers are nucleotides.

What is the basic structure of DNA?

DNA is composed of two strands forming a double helix, with a backbone of sugar and phosphate and nitrogenous bases paired in the center.

What is Chargaff's rule?

Chargaff's rule states that in DNA, the amount of adenine equals thymine, and the amount of cytosine equals guanine.

What experiment did Griffith conduct and what did he discover?

Griffith conducted experiments with Streptococcus pneumoniae and discovered the phenomenon of transformation, where non-virulent bacteria became virulent.

Who are Hershey and Chase and what experiment did they conduct?

Hershey and Chase conducted the famous experiment using bacteriophages to demonstrate that DNA is the genetic material.

Who are Wilkins and Rosalind Franklin and what were they working on?

Wilkins and Rosalind Franklin were molecular biologists known for their work on X-ray diffraction images of DNA, which contributed to the discovery of its structure.

Who are Watson and Crick and what work did they do?

Watson and Crick are credited with the discovery of the double helix structure of DNA based on the data from Franklin and others.

At a very basic level, how is DNA replicated?

DNA replication involves unwinding the double helix and synthesizing new complementary strands using existing strands as templates.

What are prions and what diseases do they cause?

Prions are misfolded proteins that can induce other proteins to misfold, leading to neurodegenerative diseases such as Creutzfeldt-Jakob disease.

What bond links monosaccharides to form polysaccharides?

Glycosidic linkage (formed by dehydration synthesis)

What bond links amino acids to form proteins?

Peptide bond (between amino and carboxyl groups)

What bond links nucleotides to form nucleic acids (DNA/RNA)?

Phosphodiester bond (between phosphate group and sugar)

What bond links fatty acids to glycerol in lipids?

Ester bond (between hydroxyl of glycerol and carboxyl of fatty acid)

dehydration synthesis

A chemical reaction in which two molecules covalently bond to each other with the removal of a water molecule.