Lecture 12: Biosynthesis

These flashcards cover key concepts from the lecture on biosynthesis, focusing on polysaccharides, amino acids, nucleotides, and fatty acids.

What is gluconeogenesis and why is it important for polysaccharide synthesis?

Gluconeogenesis synthesizes glucose from non-carbohydrate sources, which is crucial for polysaccharide production when glucose is not available.

What are the activated forms of glucose used in polysaccharide synthesis in prokaryotes?

Uridine diphosphoglucose (UDPG) and adenosine diphosphoglucose (ADPG).

What is the precursor for glycogen in prokaryotes?

Adenosine diphosphoglucose (ADPG) is the precursor for glycogen.

How are pentoses formed from hexoses?

Pentoses are formed by the removal of one carbon atom from a hexose.

What is the major pathway for pentose production?

The pentose phosphate pathway.

What are the products of the pentose phosphate pathway?

NADPH and ribulose 5-phosphate.

What role does NADPH play in biosynthesis?

NADPH is used as a reductant in biosynthetic reactions like the production of deoxyribonucleotides.

From where do amino acids derive their carbon skeletons?

From intermediates of glycolysis or the citric acid cycle.

How is the amino group typically derived for amino acid biosynthesis?

It is typically derived from inorganic nitrogen, such as ammonia (NH3).

What is the precursor to adenine and guanine in purine biosynthesis?

Inosinic acid.

What is the precursor to thymine, cytosine, and uracil in pyrimidine biosynthesis?

Orotic acid.

What are the structural components of lipids?

Fatty acids and glycerol.

What do Archaea use instead of fatty acids in their membrane lipids?

Isoprene.

How are fatty acids synthesized?

Fatty acids are synthesized 2 carbons at a time using acyl carrier proteins (ACPs).

What happens to the third carbon during the synthesis of fatty acids?

The third carbon is released as CO2 during the incorporation of C2 units.

How does fatty acid composition vary between species?

It varies with growth temperature; lower temps lead to shorter, more unsaturated fatty acids, while higher temps lead to longer, more saturated fatty acids.

What is the role of polar groups in lipid assembly?

Polar groups are necessary for forming the proper membrane architecture (hydrophobic interior, hydrophilic surfaces) in all domains.

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

Ester bonds.