Exam #2 Medical Micro (ch.6,7,8,9)
The differences between DNA and RNA to test your understanding of these nucleic acids
-DNA is double-stranded, RNA is single-stranded. -DNA nucleotides contain deoxyribose whereas RNA nucleotides contain ribose. -There are multiple types of DNA with different functions whereas there is only one type of RNA.
_____________ refers only to energy-requiring metabolic processes that result in the biosynthesis of macromolecules and cellular structures.
Anabolism
What play a role in microbial sensing of the environment?
Antigenic Variation & Two-Component Regulatory Systems
The two strands of the DNA molecule are:
Antiparallel
Some enzymes require a cofactor or a coeznyme in order to be active. What is the difference between cofactors and coenzymes?
Cofactors are non-protein components that assist enzymes and are typically trace elements; coenzymes are organic cofactors that loosely carry molecules or electrons.
Where does the TCA cycle take place in bacteria?
Cytoplasm
Where is the ETC chain located in prokaryotic cells?
Cytoplasmic membrane
DNA replication
DNA replication begins when proteins separate the two DNA strands at the origin of replication, creating two replication forks. Once the strands are separated, primase enzymes operate at both replication forks and build short RNA primers. Helicase enzymes sit at the replication forks and continuously unzip the DNA. DNA polymerase then extends these primers by adding nucleotides complementary to the template strands. One of the strands is synthesized continuously in the 5' to 3' direction, growing toward the replication fork, while the other is synthesized in short spurts, again in the 5' to 3' direction, growing away from the replication fork. These short spurts result in fragments referred to as Okazaki fragments. The RNA primers are removed and replaced with DNA by DNA polymerase I. The Okazaki fragments are joined by DNA ligase, and this completes DNA replication.
Where do NADH and FADH2 go after being produced in the TCA cycle?
ETC
In prokaryotes and eukaryotes, the TCA cycle takes place in the mitochondria.
FALSE
How do chemolithotrophs acquire energy?
From inorganic compounds
Glycolysis is the central metabolic pathway that involves the breakdown of
Glucose
The Tricarboxylic Acid Cycle (TCA cycle) occurs after _________.
Glycolysis
When polysaccharides are broken down, their breakdown products can be oxidized for energy by entering which of the following metabolic pathways?
Glycolysis
Hydrogens are transported from other rxns to the ETC by
NADH & FADH2
The final electron acceptor at the end of the tandem photosystems of cyanobacteria when non-cyclic photophosphorylation is used
NADP
Glycolysis makes products that feed into
TCA cycle electron transport chain fermentation
One bacterial chromosome replicates to become two chromosomes with:
each made of one strand of DNA from the original chromosome and one newly synthesized strand
One advantage of having genetic control mechanisms is:
enzymes are only produced when they are needed
RNA interference (RNAi) is a mechanism by which
eukaryotic cells destroy RNA transcripts in a selective and specific manner to control gene expression.
Streptococcus pneumoniae lacks an electron transport chain. Therefore, S. pneumoniae generates ATP via _________.
fermentation
In prokaryotic cells undergoing respiration, protons are pumped
from inside the cell to outside the cell membrane.
When a repressor binds to the operator site on DNA:
it blocks RNA polymerase and mRNA synthesis
If a protein-encoding gene contains introns and exons, it is likely that
it is a eukaryotic gene
The three basic parts of a nucleotide are:
phosphate, deoxyribose sugar, nitrogenous base
T/F: Genes controlled by an activator have ineffective promoters.
True
T/F: The Calvin Cycle fixes carbon dioxide into organic molecules.
True
A mechanism that blocks transcription:
will block the production of mRNA
Aerobic respiration, the last carrier protein in the ETC transfers ___________ electrons to Oxygen
2 Electrons
During the ETC, ATP will be made from
ADP + Pi
The Calvin Cycle uses _________ and _________, produced in the light reactions of photosynthesis, to drive the fixation of carbon dioxide.
ATP & NADH
For each glucose molecule broken down by glycolysis, how many net ATP molecules are produced?
2
Hydrogen consists of
1 proton & 1 electron
1. DNA polymerase 2. Helicase 3. DNA ligase 4. DNA gyrase 5. Primase
1. DNA synthesis 2. Unwinding the DNA helix 3. Joining fragments of DNA 4. Temporary breaking of DNA strands 5. RNA primer synthesis
1. tRNA 2. rRNA 3. mRNA
1. Type of RNA molecule that carries amino acids to the growing peptide chain during translation. 2. Type of RNA molecule present in ribosomes. 3. Type of RNA molecule that contains the genetic information decoded during translation.
RNA polymerases
1. Use DNA as a template to synthesize RNA 2. Synthesize chains of ribonucleotides 3. Synthesize molecules shorter than a chromosome
The two strands of DNA are joined to each other or held together by:
Hydrogen Bonding
What's true of inducible operons?
Inducible operons are usually in the "on" state and are 'turned off' when not needed. The inducer is often the product of the enzyme that is encoded.
Where is the ETC chain located in eukaryotic cells?
Inner membrane of mitochondria
Consider common human pathogens. Most of their enzymes likely function best under which environmental conditions?
Low salt, Temp. around 37 Degrees C, Moderate pH around 7
A single nucleotide consists of ______,_______,______
Nucleobase, Phosphate Group, 5-Carbon Sugar
On one of the strands of bacterial DNA, the new complementary strand is synthesized discontinuously into small pieces of DNA called:
Okazaki fragments
Coordinated sets of genes that are regulated as a single unit are referred to as ______.
Operons
The terminal electron acceptor in aerobic respiration is
Oxygen
In Bacteria the electron chain is located in the
Plasma Membrane
The main purpose of cellular respiration is to
Produce energy
The two 3-carbon molecules that glucose is split into during glycolysis are converted through a series of steps ending in what 3-carbon molecule?
Pyruvate
The ETC is part of
Respiration
To which part of a DNA molecule are nucleotides added?
The hydroxyl group on the 3' end of the molecule.
Why would an organism use fermentation to generate ATP?
The organism is only capable of generating ATP via oxidative phosphorylation.
An alternative sigma factor would directly affect which process?
Transcription
Transcription
Transcription begins when RNA polymerase binds to the promoter region just upstream of a gene. The RNA polymerase separates the two strands of DNA and begins to transcribe the template strand. RNA polymerase moves along the template strand of DNA adding complementary RNA nucleotides. This continues until a terminator site in the DNA is reached. At this point, the mRNA transcript is released.
Why would it be beneficial for cells to wait until a critical population density is reached before expressing certain genes?
Without a certain density, it would be highly unlikely that the molecules produced by a cell in the group could find and bind to other cells of the population effectively.
Cytochromes contain
a metal ion which can accept and donate electrons
The energy released during the reactions of glycolysis is used to form
adenosine triphosphate
DNA polymerase:
can only add nucleotides in a certain direction
A culture of bacteria is breaking down sugars to yield energy. This is best described as ________.
catabolism
In some degradative pathways, in the absence of an inducer (e.g.: arabinose):
the activator protein can't bind to DNA, and RNA polymerase can't bind to the promoter site
In eukaryotic cells undergoing respiration, protons are pumped from
the mitochondrial matrix to the region between the inner and outer mitochondrial membranes (intermembrane space)
Cells prefer to use carbohydrates as energy sources because
they are such good donors of hydrogen and electrons