Structure and function of microbial cells Flashcards
if we look at different kind of cells, can we identify properties that are shared by all cells?
Yes
Properties of all cells: 3
metabolism: cells take up nutrients, transform them, and expel waste
growth: nutrients in the environment are converted into new cell material to form new cells
evolution: cells evolve to display new properties.
Name the two types of metabolism
genetic: replication, transcription, translation
catalytic: energy biosynthesis
How would you capture evolutionary relationships?
Phylogenetic
Name properties that some cells have in common:
differentiation: some cells can form new cell structures such as pores
communication: cells interact with each other by chemical messenger
genetic exchange: cells can exchange genes by several mechanisms (donor->recipient)
motility: self-propulsion (flagellum)
whats is the genetic function of cells?
multiply and encode DNA=> DNA replication to make new proteins and DNA transcription of RNA than translation to make new proteins
what is the catalytic functions of cells?
energy conservation: ADP+Pi=>ATP
metabolism: generation of precursors of macromolecules
enzymes: metabolic catalyst
How does the surface affect molecule exchange with the outside?
bigger the volume, the relatively less surface you have.
Surface/volume=…..
Procaryote vs Eucaryote Internal structure of cells
cell wall, cytoplasmic membrane, ribosome, nucleoid, cytoplasm, plasmid
vs.
cell wall, cytoplasmic membrane, ribosome, cytoplasm, mitochondrion, nuclear membrane, nucleus, endoplasmic reticulum, Golgi complex
name and explain 3 characteristics of the membrane
permeability: prevents leakage and functions as a gateway for for transport nutrient into, and waste out of, the cell
protein anchor: site of many proteins that participate in transport bioenergetics, and chemotaxis
energy conservation: site of generation and use of the proton motive force
name 4 protein anchors
Sensors
• Adhesins
• Transporters
• Enzymes
whats the Ratio proteins/lipids
50% or less
what is the membrane mad of?
phospholipid bilayer=> PHOSPHATIDYLETHANOLAMINE=> 2 FA+glycerol+phosphate+ethanolamine
what type of bond do you find in bacteria eukaria and archaea
double ester bond and single ester bond respectively
what is the archaeal lipid chain made of?
Isoprene
what are the 5 variation of the Membrane of Archaea?
glycerol diether: glycerol+phytanyl (CH3 groups and isoprene units)
diglycerol tetraethers: 2 glycerol + biphytanyl
crenarchaeol:
lipid bilayer: glycerolphosphate+phytanyl+membrane protein
lipid monolayer: biphytanyl+membrane protein
In eukaryotes, the lipid bilayer is stabilized by…
a sterol, which consists of a polar head, a rigid planar steroid ring structure and a nonpolar hydrocarbon tail.
name 3 types of sterols found in eukaryotes
– Cholesterol – Animal cells
– Ergosterol – Fungi
– Stigmasterol – Plant cells and some protozoans
In bacteria the membrane is stabilized by …
hopanoids.
Are there any sterols in the membrane of a bacteria
almost always absent.
Storage of DNA in Bacteria and Archaea:
– Circular molecule, double
stranded.
– Generally haploid (one copy)
– Packaged with proteins (H‐NS and other Histone‐like protein), aggregates to form the nucleoid), = the chromosome
– DNA in the cytoplasm, ribosomal RNA encoded on the chromosome
– May also contain plasmids
Storage of DNA in Eukaryotes:
– Linear molecules, double‐
stranded.
– Generally diploid (two copies)
– Packaged with proteins (Histones) to form chromatin fibers, = the chromosome.
– DNA in the nucleus
– Nucleolus: (dense DNA that codes for ribosomal RNA, ribosomal proteins, immature ribosome)
How do all living things produce protein from DNA ?
Replication by DNA polymerase
Transcription of bottom strand by RNA polymerase to make RNA
Translation by Ribosome to make protein
what is the ribosome composed of?
Composed of ribosomal RNA and proteins
What is the role of the ribosome?
location in Eukaryotes
location in Procaryotes
Role is to translate mRNA into amino acid chains in order to form proteins.
– Prokaryotes: ribosomes are free in the cytoplasm or attached to cytoplasmic membrane.
– Eukaryotes: ribosomes are free in the cytoplasm or bound to the endoplasmic reticulum.