Ch.5-6 Flashcards
What is an autotroph?
Bacteria that can use carbon dioxide or methane from the air as a source of carbon.
Name the 6 most abundant elements in microbes.
- Carbon - 50%
- Oxygen - 20%
- Nitrogen - 14%
- Hydrogen - 8%
- Phosphorous - 3%
- Sulfur - 1%
What is a heterotroph?
Bacteria that requires their carbon source already be in an organic form such as sugar or an amino acid.
What is an auxotroph?
A bacteria that can’t produce a certain vitamin and must get it from a host.
What is a bacteria that can produce their own energy from light?
Photoautotroph
What is a prokaryote that has adapted to survive in high salt conditions such as salt lake?
Halophiles
What is a bacteria that derives its energy from carbon dioxide and hydrogen to produce methane gas?
Methanogens
What are bacteria that derive their energy from minerals from the air and rocks?
Chemoautotrophs
What is a liquid media called?
A broth
What is a media called that consists of completely known chemicals?
“Defined” or “synthetic” media.
What type of media is the common “brain-heart infusion broth”?
Complex (non-synthetic) media
What type of media allows for certain bacteria to grow, but inhibits others?
Selective media
What type of medium will allow many bacteria to grow, but will make a specific bacteria change color due to ph or other factors?
Differential media
Molecules in a solution are always bouncing around and off one another. What is this called?
Brownian motion
- What is a bacteria that absolutely requires oxygen to grow?
- Bacteria that require the absence of oxygen to grow?
- Bacteria that can grow with or without oxygen?
- Bacteria that require low oxygen levels?
- Obligate aerobes
- Obligate anaerobes
- Facultative anaerobes
- Microaerophiles
What are bacteria that grow in acidic environments called?
Alkaline rich environments?
Acidophiles
Alkalinophiles
What are microorganisms that require a temperature below -12C in order to grow called?
Psychrophiles
What are microorganisms that grow optimally at 37C called?
Mesophiles
What are thermophiles?
Archaea (not bacteria) that grow best at high temps (above 55C)
What are cold-adapted Mesophiles called?
psychrotrophs
What do you call bacteria that cannot grow at high temps, but are not killed at high temps for a short time (such as pasteurization).
Thermoduric bacterium
What is the most abundant component of living bacteria?
Water
How are pure bacterial cultures obtained?
By streaking bacterial samples onto a Petri dish so that individual bacteria are isolated and can grow into colonies.
What prevents a bacterial cell from rupturing due to internal osmotic (hydrostatic) pressure?
The strength of the peptidoglycan layer.
There are 2 names given to the process of bacterial cell division or duplication. What are they?
Cell division
Binary fission
When bacteria are picked from a Petri dish and placed in a fresh broth, they don’t initially multiply. What is this phase called?
Lag phase
What are the 4 phases of bacterial growth?
- Lag - initially not multiplying when placed on the culture
- Log - dividing at a set rate (exponential growth)
- Stationary - dividing and dying at the same rate due to limited nutrients and buildup of waste products.
- Death -
What do you get when you combine glucose and fructose?
Disaccharide sucrose (common table sugar)
What is the process of breaking down glucose called?
What is the byproduct of this process?
Glycolysis Pyruvic acid (2) and ATP (2)
What is the transfer of electrons to oxygen coupled to the synthesis of ATP called?
Oxidative phosphorylation
How many ATP are yielded from glycolysis of 1 glucose?
2 ATP
How many ATP are yielded from 1 glucose in the KREBS cycle?
30 ATP
Is fermentation aerobic or anaerobic?
explain briefly what happens to sugar during fermentation.
Anaerobic
Pyruvic acid is produced from glycolysis, then rather than going through the KREBS cycle, the pyruvic acid is converted to ethyl alcohol.
True or False: Fungi are photosynthetic?
False
If 1 bacterium goes through 4 generations, how many bacteria will result?
16
How long will it take 10 bacteria to exceed 100 if the doubling time is 30 minutes?
2 hours
What information does a turbidimetric assay yield?
Number of bacterial cells (alive or dead) in a solution by use of a spectrophotometer.
The use of energy and building blocks to make new cellular materials:
Anabolism
The breakdown of complex materials:
Catabolism
All the chemical processes occurring in the cell:
Metabolism
Protein catalysts that cells use to convert some molecules into others:
Enzymes
What is activation energy?
Activation energy refers to the amount of heat necessary for a chemical reaction. Enzymes can greatly reduce the activation energy.
What are the 3 major pathways of catabolism in organisms.
- Glycolysis
- KREBS cycle
- Electron transport
Name 2 possible final electron acceptors in anaerobic respiration.
Nitrate
Sulfate
True or False: DNA has no functional activity.
True: DNA must be transcribed to RNA which is then translated into proteins which are then used for gene expression.
What is the enzyme responsible for DNA transcription into mRNA?
RNA polymerase
In bacteria, RNA polymerase (enzyme responsible for transcription), requires a “helper” before transcription begins and mRNA is made. What is this helper called?
Sigma or Cofactor
What is an RNA polymerase binding site on DNA called?
Promotor
What is a gene cluster that is transcribed from a single Promotor (RNA polymerase binding site on DNA)?
Operon. The genes of an opening typically encode
An operon is a gene cluster. What are individual genes in an operon called?
Cistrons
Once DNA is transcripted into mRNA, it still must be decoded or “translated” for protein synthesis. What is the name of the part of the cell that performs “protein synthesis” or “translation”
Ribosomes
Prokaryotic _______________ contain 2 subunit complexes called 30s and 50s. The combined size of these equals ____________.
The Eukaryotic subunits are larger, _________ & ___________ equaling a total size of ___________.
Ribosomes. 70s.
40s, 60s
80s when combined
___________ helps in the process of “translating” or “protein synthesis” by binding to its corresponding codon on the ribosome and transferring the appropriate amino acid to the end of the growing amino acid chain.
tRNA
In prokaryotes, sometimes protein synthesis or “translation” may begin before the mRNA has detached from the DNA. What is this simultaneous synthesis of RNA and proteins called?
Coupling
A typical bacterium has approx. 5 million base pairs of DNA. How many base pairs of DNA does a typical human cell have?
6 billion
What does it refer to when said that eukaryotes are diploid and prokaryotes are haploid?
Diploid = 2 copies of each chromosome Haploid = 1 copy of each chromosome
In the 1920’s, British microbiologist showed that genes can functionally affect the character of cells, and that genes can be transferred from 1 cell to another. He proved this through a study where mutated bacteria were able to regain the functionality of having a capsule from dead wild-type bacteria. What did he term this?
The transforming principle
What is the enzymatic process of making another copy or “duplicate” of DNA?
Replication
Bacteria are prokaryotic, meaning they do not have a nucleus. Prokaryotes DNA, rather than being located in the nucleus, is primarily located in a circular structure inside the cell called the __________.
Nucleoid
What is the enzyme that performs DNA replication?
DNA polymerase
What is the most widely used vector (delivery method) for gene therapy?
Viruses (viral vectors)
American Geneticist Oswald Avery (1940’s) proved that genes were made of DNA by a study that showed the bacterial substance responsible for transformation was sensitive to ___________.
DNase
Who were the 2 geneticists that proved, in 1952, that DNA is the genetic material and not protein?
Hershey & Chase
Where does DNA synthesis begin?
The origin of replication
What are the 2 major classes of gene expression control?
Inducible systems
Repressible systems
Which type of gene expression is the following describing:
Mammals have ecoli in the intestinal tract where lactose might be found. Most of the time, ecoli has no need to turn on the “lac” operon. When milk is ingested, it introduces lactose. Some lactose molecules will bind to the “repressor” protein of the gene rendering the repressor inactive. This turns on the “lac” expression of the gene allowing the bacteria to utilize the external lactose to drive rapid cell growth.
Inducible gene expression as the presence of lactose induced the gene to be activated.
What do you call enzymes that break down proteins?
Proteases or proteinases
When do bacteria normally regulate gene expression?
During transcription
Which type of gene expression (inducible or repressible) has more fine control over how much expression occurs?
Repressible
Sometimes there are errors in DNA replication leading to incorrect nucleotides or base pairs. What are these called?
Mutations
What do you call a cell that has a mutation in its DNA sequence?
What do you call the parental strain lacking these mutations?
Mutants
Wild type organism
Chemicals and other factors not normally found in nature that alter DNA sequence or structure are called ____________.
Mutagens
Name the two types of mutations and describe the difference.
Spontaneous mutations: occur by mistakes in DNA synthesis or from things such as sunlight.
Induced mutations: caused by man made mutagens
What type of mutation converts a coding triplet into a stop codon, resulting in an incomplete protein.
Nonsense mutation
What type of mutation causes the letters of the codon to be completely out of register, so that the correct triplets are lost from that point onward?
Frame-shift deletions
What type of mutation removes 3 (or multiples of 3) nucleotides, but the sequence after the deletion is still correct?
In-frame deletions
What is the difference between genotype and phenotype?
Genotype is the actual DNA sequence.
Phenotype is the physical expression of the gene.
Some mutations occur outside of the structural genes, but can still cause phenotypical changes or mutations. What is this called?
Regulatory mutation
Some mutations can cause “systems” to be always turned on and unable to be shut off. This is a type of regulatory mutation that is termed a _________ __________.
Constitutive system
What are chemicals capable of causing mutations that lead to cancer?
Carcinogens
Developed in the 1970’s, this doctor developed a test to identify which chemicals cause mutations. What is his name, and what is the name of the test?
Dr. Bruce Ames
The Ames Test
Bacteria can transfer DNA from 1 cell to another. Bacterial gene transfer can occur by 3 methods. Name them.
Conjugation
Transduction
Transformation
In reference to the “conjugation” method of gene transfer, donor bacteria contain a plasmid called the F-factor. What does the F stand for?
Fertility
What are cells called that carry the “F-factor”?
Cells that don’t?
F+ or “male cells
F- or “female cells
Only bacteria classified as “competent bacteria” are capable of the type of gene transfer where they can transport available DNA (from other lysed bacteria) and transport it through their plasma membrane. What is this kind of gene transfer called?
Transformation
In which type of gene transfer does a sex pilus form a bridge between 2 bacteria?
Conjugation
What type of gene transfer is mediated by a bacteriophage?
Transduction
If a bacteria does not produce enzymes for the synthesis of product “X” because product “X” is already in ample supply, what is this process called?
Feedback inhibition.
