B1 Biological Molecules

Flashcards covering key concepts from lecture notes on biological molecules and processes, including carbohydrates, lipids, proteins, nucleic acids, DNA replication, transcription, and translation.

What type of bond is formed between glycerol and fatty acids in triglycerides?

Ester bond

Name the four main classes of macromolecules.

Carbohydrates, Lipids, Proteins, Nucleic Acids

What is the primary function of polysaccharides like starch and glycogen?

Energy storage

What is the role of cellulose in plants?

Structural support in cell walls

What property of lipids makes them insoluble in water?

Hydrophobic nature

What are the monomers of proteins?

Amino acids

What type of reaction links monomers to form polymers?

Condensation reaction

What process breaks down polymers into monomers using water?

Hydrolysis

Name three common monosaccharides.

Glucose, Fructose, Galactose

What determines the properties and uses of glucose?

Its isomers (alpha and beta), solubility, stability, and ability to be oxidized

Where is glycogen stored in animals?

Liver and muscle cells

What are glycoproteins and what is their primary role?

Proteins with carbohydrates attached, playing a role in cell-cell recognition

What is the key difference between saturated and unsaturated fatty acids?

Saturated fatty acids have no double bonds, while unsaturated fatty acids have one or more double bonds.

What is the structure and function of a phospholipid bilayer?

A double layer of phospholipids with hydrophilic heads and hydrophobic tails, forming a cell membrane.

How do steroids pass through the phospholipid bilayer?

Due to their hydrophobic nature

What are the components of a nucleotide?

Pentose sugar, nitrogenous base, and phosphate group

Name the nitrogenous bases in DNA and RNA.

DNA: Adenine, Thymine, Guanine, Cytosine; RNA: Adenine, Uracil, Guanine, Cytosine

Describe the structure of DNA.

Double helix with sugar-phosphate backbone and complementary base pairing (A-T, C-G)

What is the role of complementary base pairing in DNA?

Stabilizes the double helix, maintains base sequence during replication, and ensures correct protein production during gene expression

What is the significance of the universality of the genetic code?

All living organisms use the same code, suggesting a common ancestor.

What is the purpose of DNA replication?

To create an exact copy of the DNA for new cells during cell division

Describe the semi-conservative nature of DNA replication.

Each new DNA double strand contains one original strand and one newly synthesized strand.

What are the roles of helicase and DNA polymerase in DNA replication?

Helicase unwinds the DNA double helix, and DNA polymerase builds the new DNA strand.

What is PCR and what is it used for?

Polymerase Chain Reaction, used to amplify small fragments of DNA

How does gel electrophoresis separate DNA molecules?

By size and amount of charge

What applications exist for PCR and gel electrophoresis?

DNA profiling, paternity testing, and forensic investigation

What is the generalized structure of an amino acid?

A central carbon bonded to an amino group, carboxyl group, hydrogen atom, and R-group

How are peptide bonds formed?

Through a condensation reaction between the carboxyl group of one amino acid and the amino group of another

What are essential amino acids?

Amino acids that the body cannot produce and must obtain from food

What is the role of the genetic code in protein synthesis?

It provides the instructions for the synthesis of proteins through transcription and translation.

What is denaturation and what causes it?

The process where the structure of a protein is altered, leading to a loss of function, caused by changes in pH or temperature

Describe transcription.

The production of messenger RNA (mRNA) using DNA as a template

What is the role of RNA polymerase in transcription?

It binds to DNA, separates the strands, and builds the mRNA molecule.

Describe translation.

The process where the code from mRNA is read and used to synthesize polypeptides

What components interact to carry out translation?

mRNA, ribosomes, and tRNA

What is the role of tRNA in translation?

It recognizes and binds to the corresponding code on mRNA, transferring the appropriate amino acid to the end of the polypeptide

What is an anticodon?

A 3-base code on tRNA that is complementary to a matching codon on mRNA

What does the degeneracy of the genetic code refer to?

The redundancy in the genetic code, where multiple codons code for the same amino acid