EXAM 2 Flashcards
Inorganic ions that stabilize enzyme conformation and function.
Cofactors
Organic molecules required for proper enzyme function.
Coenzymes
Regulate enzymes by binding to an enzyme’s active site (where the substrate binds) preventing substrate binding.
Competitive inhibitors
Noncompetitive (allosteric) inhibitors bind to
Allosteric sites
______ is the first step in the breakdown of glucose, resulting in the net formation of 2 ATP 2 NADH and 2 pyruvate molecules
Glycolysis
Organisms performing ______ _____ use alternative electron transport system carriers for the ultimate transfer of electrons to the final non-oxygen electron acceptors
anaerobic respiration
The energy of this proton motive force can be harnessed by allowing hydrogen ions to diffuse back through the membrane by _______ using ____ _____
Chemiosmosis
ATP synthase
Noncompetitve (allosteric) inhibitors bind to allosteric sites by inducing a
conformational change in the enzyme that prevents it from functioning
As hydrogen ions diffuse through down their electrochemical gradient,
components of ATP synthase spin, making ATP from ADP and P by ______ _____
oxidative phosphorylation
______ uses an organic molecule as a final electron acceptor to regenerate NAD from NADH so that glycolysis can continue
Fermentation
____ ____ ____ composed of a series of membrane associated protein complexes and associated mobile accessory electron carriers
Electron Transport System (ETS)
Energy carriers (electron carriers/ also vitamins)
FAD/FADH2
NAD+/NADH
_____ includes chemical reactions that break down complex molecules (catabolism) and those that build complex molecules (anabolism)
Metabolism
Reactions that remove electrons from donor molecules, leaving them oxidized are
Oxidation reactions
Reactions that add electrons to acceptor molecules leaving them reduced are
reduction reactions
Classifications of chemotrophs
Chemoautotrophs
Chemoheterotrophs
Classifications of phototrophs
Photoautotrophs
Photoheterotrophs
Chemotrophs use ____ as their energy source
Chemicals
Phototrophs use ____ as their energy source
Light
Carbon source of Chemoautotrophs
CO2
Carbon source of Chemoheterotrophs
Organic compounds
Carbon source of Photoautotrophs
CO2
Carbon source Photoheterotrophs
Organic compounds
Examples of Chemoheterotrophs
All animals
most fungi
protozoa
bacteria
Examples of Photoautotrophs
All plants
algae
Most bacterial cells divide by
binary fission
Cells in a closed system follow a pattern of growth with four phases:
Lag
Logarithmic
Stationary
Death (decline phase)
____ is no increase in number of living cells
Lag
Exponential increase in number of living cells
Logarithmic
Plateau in number of living bacterial cells; rate of cell division and death roughly equal
stationary
exponential decrease in number of living bacterial cells
death (decline phase)
Transcription and Translation are
Gene Expression
The DNA replication process is ______________ which results in two DNA molecules each having one parental strand of DNA and one newly synthesized strand
Semiconservative
During ______ the ________ strand of DNA is synthesized continuously from a single primer
Elongation
Leading
The _____ strand is synthesized discontinuously in short _____ fragments
lagging
Okazaki
The linear strand of eukaryotic chromosomes necessitates__________ to protect genes near the end of the the chromosomes
Telomeres
_____ extends telomeres preventing their degradation in some cell types
Telomerase
RNA polymerase binds to DNA at a sequence called a _______ during the initiation of __________
Promoter
transcription
Eukaryotic genes that encode polypeptides are composed of coding sequences called ______
exons
It is essential that all the intron-encoded RNA sequences are completely and precisely removed from a _______ before _____ _____
pre-mRNA
protein synthesis
A heritable change in DNA
Mutation
Affects a single base pair
Point mutation
if the mRNA codon codes for the same amino acid
Silent mutation
if the mRNA codon codes for a different amino acid
Missense mutation
if the mRNA codon becomes a stop codon
Nonsense mutation
______ ____ ___ is an important way for asexually reproducing organisms like prokaryotes to acquire new traits
horizontal gene transfer
The mechanisms of horizontal gene transfer is typically used by
bacteria
The three different mechanisms of of horizontal gene transfer are
Transformation
Transduction
Conjugation
Prokaryotic structural genes of related function are often organized into
Operons
One that is default on and is turned off
Repressible operon
A _____ binds to a _______ a DNA sequence within the regulatory region
Physically blocks transcription of these operons
repressor
operator
The trp operon is a classic example of a _____ _____
Repressible operon
When tryptophan accumulates tryptophan binds to a repressor which then binds to the operator preventing ____ ______
further transcription
one that is default off and is turned on
Inducible operon
Cells can be counted by
Direct cell count
Direct microscopic cell count
Coulter counter
Pour plate
Serial dilutiions
____ ____ ___ counts dead and live cells
direct cell count
_____ _____ ____ _____ counts dead and live cells on a calibrated slide
direct microscopic cell count
___ _____ uses electrical resistance in saline solution to count cells, counts dead and alive cells
coulter carrier
____ ____ (bacteria mixed with the agar then poured into a plate)
pour plate
_____ _____ (bacteria spread over the agar)
methods; count only live cells
spread plate
_____ ______ repeated 1 ml in 9ml solutions to achieve 30-300 colony forming units
Serial dilutions
_____ ____ can be used to estimate culture density by measuring
indirect methods
_______ of a culture or live cell density by measuring metabolic activity
turbidity
Microorganisms vary in their requirements for
Molecular oxygen
____ ____ depend on aerobic respiration and use oxygen asa terminal electron acceptor. They cannot grow without oxygen
Obligate aerobes
______ ______ cannot grow in the presence of oxygen. they depend on fermentation and anaerobic respiration using a final electron acceptor other than oxygen
obligate anaerobes
______ ______ show better growth in the presence of oxygen but will also grow without
Facultative anaerobes
______ ____ do not perform aerobic respiration they can grow in the presence of oxygen.
Most of these anaerobes test negative for the enzyme _____
Aerotolerant anaerobes
Catalase
______ need oxygen to grow albeit at a lower concentration than 21% oxygen in air
Microaerophiles
What are the three different enzymes found found in detoxification of reactive oxygen species
peroxidase
superoxide dismutase
catalase
X- (2H+) + H2O2 -> oxidized - x +2H2O
Peroxidase
Destroys super oxide anion (2O2-) usually present in a cell that can tolerate O2
Superoxide Dismutase
2H2O2 —> 2 H2O + O2
Catalase
Most bacteria in this group and they grow best at neutral pH close to 7.0
Neutrophil
Grow optimally at pH near 3.0
Acidophiles
are organisms that grow optimally between pH of 8 and 10.5
Alkaliphiles
Grow best in the temp range of 0-15 degrees C
Psychrophiles
Thrive between 4 and 25 degrees C
Affect refrigerated food
psychotrophs
grow best at moderate temp
Pathogens usually _________
Mesophiles
______ and _______ are adapted to life at temperatures above 50 degrees C
Thermophiles
Hyperthemophiles
Require high salt concentration in the medium
Halophiles
Organisms can grow and multiply in the presence of high salt but do not require it for growth and are an important source of foodborne illnesses because they contaminate foods preserved in salt
Halotolerant
Require high atmospheric pressure for growth
Barophiles
In 1928 _______ _______ showed that dead encapsulated bacteria could pass genetic information to live nonencapsulated bacteria and transform them into harmful strains
Frederick Griffith
_____ ______ are composed of _______ each of which contains a pentose sugar a phosphate group and a ________ base
Nucleic acids
Nucleotides
nitrogenous
A _______ comprises of the five carbon sugar and nitrogenous base
Nucleoside
DNA and that the amount of ______ is approximately equal to _______
these relationships were later determined to be due to complementary base pairing
Guanine
Cytosine
DNA is composed of two complementary strands oriented ______ to each other with the _______ _________ on the exterior of the molecule
antiparallel
phosphodiester back bones
DNA is used for information storage, this info is transmitted from parent to offspring through
vertical gene transfer
The entire genetic conent of a cell is its
Genome
A ________ is the observable characteristics of a cell or organism at a given point in time and results from the complement of genes currently being used
Phenotype
________ DNA in eukaryotes includes the chromosomes found within organelles of prokaryotic origin that evolved by endosymbiosis
Extrachromosomal