Week 8 Flashcards
Polysaccharides syn from activated glucose. (3)
- Uridine diphosphoglucose (UDPG)
- Adenosine diphosphoglucose
- add active glucose to polymer fragments
Gluconeogenesis
Synthesis of glucose from phosphoenolpyruvate.
Pentose (C5 sugars) formation?
by removal of one carbon atom from a hexose
Purpose of C5?
for synthesis of nucleic acids
What happens in pentose phosphate pathway?
Glucose oxidized to CO2, NADPH, ribulose-5-phosphate
Pentose catabolized through this pathway
Produces several 4-7 carbon sugars
Gen NADPH for deoxyribonucletide and fatty acid biosynthesis
Amino acids, how to obtain?
If not from environment, synthesized from glucose or other carbon sources
How are amino acids grouped? Where do carbon skeletons come from?
Into structural families based on shared biosynthetic steps
Come from intermediates of glycolysis or CAC
Where is amino group from?
Typically from inorganic nitrogen source. Ex. NH3
Amino group from glutamate or glutamine can be transferred by transminase/aminotransferase shuttles
Nucleotides components and construction?
Purine and Pyrimidines
From multiple carbon and nitrogen sources
Purines
Inosinic acid skeleton is precursor to adenine and guanine
Pyrimidines
Uridylate skeleton is precursor to thymine, cytosine, and uracil
Archaea and fatty acids?
Do not contain fatty acids: have hydrophobic isoprenoids instead
Fatty acid biosynthesis:
How many carbons?
How?
Two carbons at a time
Acyl carrier protein holds growing fatty acid during synthesis and releases it
Each C2 acetyl originates from C3 malonate; CO2 released
Can be unsaturated branched or contain odd numbers of carbon atoms
Fatty acid biosynthesis
Fatty acid biosynthesis in diff species/temps? What’s most common in bacteria?
Low temp: shorter, more unsaturated
High temp: Longer, more saturated
Bacteria commonly have C12 -C20 lipids
Lipid Biosynthesis; first step for bacteria and eukaryotes?
Additional of fatty acids to glycerol
Simple triglycerides have glycerol esterified to 3 fatty acids
In complex lipids, one carbon modified with polar group
Growth
traditionally defined as increase in cell #
Binary fission
Cell division cell to twice its minimum size
Generation time
time required for microbial cells to double in number
Each daughter cell receives? (2)
Chromosome
Sufficient copies of all other cell constituents to exist independently
Bacterial cell cycle
Consists of a sequence of events from formation of new cell through to next cell division
Two pathways in bacterial cell cycle
- chromosome replication and partitioning (Dna)
- Septation and division (cell wall)
Most bacterial chromosomes are circular ________
dsDNA
Key features of replication? (4)
- Origin of replication
- Terminus site
- Replisome
16 proteins for DNA synthesis - DNA rep in both directions from origin
MreB
Actin homolog (euk microfil)
Determination of cell shape + chromosome segregation
Forms spiral bands inside cell
Par proteins
Analogous to mitotic apparatus in euk
Move to opposite cell poles while holding OriR
Helps desperate chromosomes and plasmids during CD
Septation and Division steps (3)
- selection of site for septum formation
- assembly of cell wall synthesizing machinery
- construction of cell and septum formation
Wall band
Junction between new and old peptidoglycan
What do autolysins do?
Carry out limited digestion of peptidoglycan
Activity allows new material to be added to wall and division to occur
Occurs during cellular growth and reproduction
Weakens cell wall and can lead to lysis
Inhibition of peptidoglycan synthesis
