Exam 1 Flashcards
(35 cards)
Who is Hans Christian Gram?
developed the Gram Stain technique
Describe Gram Positive
Thick Cell wall composed of petidoglycan
Techoic acid (wall anchored) and lipoteichoic (acid membrane anchored)
Purple under microscope
Draw a Gram Positive stain
refer to study guide
Describe Gram Negative stain
outer cell membrane
Thin peptioglycan layer and cell membrane
Lipopolysaccharides (LPS) layer
Dram a Gram Negative Stain
refer to study guide
What is Binary fission?
The asexual reproduction of the
bacterial body where the cell grows 2x its original size and eventually splitting into 2
Describe the Binary fission
Ist- replicate DNA
2nd_ growth of the cell
3rd_ Cell elongates with a septum forming in the middle separating the 2 chromosomes
L4th- the cell splits down the middle forming 2 daughter cells containing a copy of the original parent cell
What are the stages of bacterial growth phases?
Lag phase - 1st stage of a bacteria’s lifevery little growth occurs here despite cells being metabolically active
Exponential phase - period with the most growth, continues as long as enough nutrients are available
stationary Phase- period where growth begins to slow down stop altogether. Typically begins occurring when supply of nutrients begin diminishing . Number of cells remain the same
Death Phase - period where cells begin to die at a high rate. This is due to a build-up of toxins.
What are the different cell shapes?
Cocci
Bacilli
streptococci
staphylococci
Spirochetes
What are the arrangements for Cocci?
shape- circles
Arrangement, singles, tetrads , irregular clusters (staphylococci)
What are the arrangements for Bacilli
shape-rods
Arrangements: single, diplobacilli, streptobacilli
What are the arrangements of streptococci?
chains of circles
What are the arrangements of spirochetes?
shape - flexible spiral (like a spring), periplasmic flagella
How is the lactose OPERON used in bacteria? Include environmental conditions.
refer to study guide for drawing
The protein (repressor) made from mRNA transcription clamps onto the promotor depending on the different environmental conditions.
High Glucose, no Lactose - Repressor stays on gives not expressed
Low Glucose, no Lactose - cAMP binds to CAP site, no gene expression
High Glucose, some Lactose- very slow/low levels of gene expression, no cAMP or repressor
Low Glucose, some Lactose- very strong (Turbo) expression, cAMP binds to CAP site, no repressor
What are the 3 segments of Lactose OPERON?
Regulator -gene that codes for repressor
Control Locus- composed of promoter and operator
structural Locus i made of 3 genes each coding for an enzyme needed to catabolize lactose
- B-galactosidasei hydrolyzes lactose
-Permease: brings lactose across the cell membrane
- B-galactosidase transacetylase: uncertain function
Describe Lactose operon: Inducible operon
is turned on by a substrate
- Normally off (without lactose, repressor binds with operator locus and blocks transcription of downstream structural genes)
- Lactose turns operon on
- Binding of lactose to repressor protein changes its shape and causes it to fall off the operator
- RNA polymerase can bind promoter —– cAMP induces heavy translation of lactose
Draw how DNA is replicated prior to binary fission in the bacteria or cellular mitosis in eukargotic pathogens. Make sure to include steps inorder and enzymes involved
30 different enzymes involved
*Topoisomerase - (gyrase-bacteria) binds upstream from origin of replication (A little clamp on the DNA strand)
- Helicase -unwinds and unzips DNA double helix and SSB’s (single stranded binding proteins) prevent H-bonding from reforming
- RNA primer- is synthesized (by RNA polymerase) at the origin of replication
*DNA polymerase 1 and 3:
3: adds bases that are complementary
1. replaces RNA primer with DNA nucleotides
- DNA ligase -ties DNA after synthesis
Draw DNA replication in Binary Fission
refer to study guide
How does nature allow variation (4 ways) to be introduced into an asexual reproducing bacterial population, please explain each methods
Transposition- process whereby DNA independently excises from one location in DNA molecule and integrate elsewhere
- Conjugation- transfer DNA through direct contact using conjugation pilus
- Transformation- mechanism of horizontal gene transfer in which naked environmental DNA is taken up by bacterial cell
*Transduction - mechanism of horizontal gene transfer in bacteria, genes are transferred through viral infection
what are the 3 ways to synthesize ATP?
glycolysis, krebs cycle, oxidative phosphorylation
Discuss the process in which glucose undergoes complete oxidation to yield 38 ATPs (Be sure to discuss where ATPs are produced in the process and involvement of electron carriers)
- Glycolysis - Glucose -> 2 Pyruvate (makes 2NADH and ZATP)
- Preparatory Step - makes Acetyl COA (2NADH and 2CO2 )
- Kreb’s Cycle- (6NADH, 2 FADH2, 4CO2, 2ATP)
- ETC (30 ATP)
What are the 6 types of microorganisms?
Bacteria
Archaea
Algae
Protozoa
Helminthes
Fungi
Viruses
Who is Sir Francis Bacon?,
developed scientific method
Who is Robert Hooke
made the earliest record of microbes
