Biology Chapter 16: Prokaryotic and Composite Organisms

<p>The DNA becomes lighter (A)</p> Signup and view all the answers

<p>It promotes their proliferation by making them undetectable. (C)</p> Signup and view all the answers

<p>Ribosomes are targeted by several antibiotics (D)</p> Signup and view all the answers

<p>It signals the start of protein translation (D)</p> Signup and view all the answers

<p>It adds a glucose molecule to Lipid A to alter its affinity. (D)</p> Signup and view all the answers

<p>They disrupt the prokaryotic cell membrane. (B)</p> Signup and view all the answers

<p>It forms the structural component of ribosomes (A)</p> Signup and view all the answers

<p>It involves transcription, translation, and regulation (B)</p> Signup and view all the answers

<p>LpxE (D)</p> Signup and view all the answers

<p>By modifying the cell membrane structure. (D)</p> Signup and view all the answers

<p>DNA replication is semi-conservative (D)</p> Signup and view all the answers

<p>The gene is expressed from the plasmid despite locus disruption. (B)</p> Signup and view all the answers

<p>It adds a glycine to Lipid A enhancing its immune evasion. (A)</p> Signup and view all the answers

<p>31 proteins, 55 rRNA, and 23S RNA (C)</p> Signup and view all the answers

<p>They signal Rhizobia to activate Nod factor production. (A)</p> Signup and view all the answers

<p>It contains 21 proteins and 165 rRNA of 1540 nucleotides. (A)</p> Signup and view all the answers

<p>16S rRNA has regions of stems and loops. (D)</p> Signup and view all the answers

<p>They have thick walls to keep oxygen out. (C)</p> Signup and view all the answers

<p>Primers, polymerase, nucleotides, and Mg-containing buffer (A)</p> Signup and view all the answers

<p>It helps in the fixation of nitrogen, which is energy-intensive. (D)</p> Signup and view all the answers

<p>Their cellular structure, showing prokaryotic characteristics. (C)</p> Signup and view all the answers

<p>The expected results are approximately 1 +/+; 2 +/-; 1 -/- pups. (B)</p> Signup and view all the answers

<p>It provides mechanical strength to withstand osmotic pressure. (C)</p> Signup and view all the answers

<p>To bind to receptors to initiate plant nodule formation. (A)</p> Signup and view all the answers

<p>It involves complementary bases linking in opposite directions. (D)</p> Signup and view all the answers

<p>The decolorization step in the staining process. (A)</p> Signup and view all the answers

<p>They possess unique organelles that separate oxygen and nitrogen-fixing processes. (A)</p> Signup and view all the answers

<p>Active transport moves substances against their concentration gradient; passive transport moves them down. (C)</p> Signup and view all the answers

<p>To allow for configuration and regulation of RNA's structure. (C)</p> Signup and view all the answers

<p>It is an essential metal cofactor required for the reaction. (C)</p> Signup and view all the answers

<p>The peptidoglycan layer is hindered, leading to the bursting of the cell. (C)</p> Signup and view all the answers

<p>The presence of flavonoids released by the plant. (D)</p> Signup and view all the answers

<p>Facilitated diffusion. (C)</p> Signup and view all the answers

<p>A unique evolutionary adaptation for nutrient acquisition. (C)</p> Signup and view all the answers

<p>They can regulate the synthesis and degradation of their peptidoglycan layer. (A)</p> Signup and view all the answers

<p>Engage in phagocytosis due to their membrane structures. (B)</p> Signup and view all the answers

<p>ATP. (B)</p> Signup and view all the answers

<p>Thick peptidoglycan layer. (A)</p> Signup and view all the answers

<p>It may experience internal osmotic pressure leading to cell lysis. (B)</p> Signup and view all the answers

<p>Actinobacteria (B)</p> Signup and view all the answers

<p>Colony forming unit (A)</p> Signup and view all the answers

<p>Culture independent sample (D)</p> Signup and view all the answers

<p>This indicates a lack of data on the samples. (D)</p> Signup and view all the answers

<p>They are harmed by oxygen and do not utilize it. (A)</p> Signup and view all the answers

<p>Respiratory electron acceptors (A)</p> Signup and view all the answers

<p>They fail to identify non-culturable microbes. (C)</p> Signup and view all the answers

<p>62% (B)</p> Signup and view all the answers

<p>They can utilize oxygen or nitrate depending on availability. (A)</p> Signup and view all the answers

<p>It enables the sequencing of all available genomes in a sample. (C)</p> Signup and view all the answers

<p>Fluorescence movement varies in growing populations (B)</p> Signup and view all the answers

<p>Non-growing bacteria maintain unchanged fluorescence signal across time. (A)</p> Signup and view all the answers

<p>Growing E. coli transformed with a plasmid. (D)</p> Signup and view all the answers

<p>They exhibit intramolecular base pairing. (B)</p> Signup and view all the answers

<p>Growing cells showed a dynamic fluorescence pattern. (D)</p> Signup and view all the answers

<p>It has varied physical properties based on metabolic state. (B)</p> Signup and view all the answers

<p>Cytoplasmic properties can differ significantly between different bacterial strains. (C)</p> Signup and view all the answers

<p>It enhances the fluidity and movement within the cytoplasm. (A)</p> Signup and view all the answers

<p>It phosphorylates a histamine in response to external signals. (C)</p> Signup and view all the answers

<p>Magnesium acts as a repressor, keeping the receptor kinase inactive. (A)</p> Signup and view all the answers

<p>It serves as a substrate for kinase and directly activates genes. (B)</p> Signup and view all the answers

<p>Misfolded proteins in the environment. (A)</p> Signup and view all the answers

<p>The pathway gets activated due to derepression. (C)</p> Signup and view all the answers

<p>It is reversible and can adapt to changing conditions. (A)</p> Signup and view all the answers

<p>An enzyme for lysine modification on LPS. (C)</p> Signup and view all the answers

<p>Directly regulating transcription of target genes. (D)</p> Signup and view all the answers

<p>31 proteins + 55 rRNA + 23S RNA (A)</p> Signup and view all the answers

<p>16S rRNA (A)</p> Signup and view all the answers

<p>Ethidium bromide (C)</p> Signup and view all the answers

<p>1:2:1 (B)</p> Signup and view all the answers

<p>Serves as a cofactor for polymerase (D)</p> Signup and view all the answers

<p>Base pairing occurs within the same molecule (B)</p> Signup and view all the answers

<p>Genotyping (A)</p> Signup and view all the answers

<p>Involves complementary strands binding in opposite directions (B)</p> Signup and view all the answers

<p>Heating to 95 degrees Celsius for 25 seconds (C)</p> Signup and view all the answers

<p>Primers hybridize to the DNA template (D)</p> Signup and view all the answers

<p>72 degrees Celsius (B)</p> Signup and view all the answers

<p>Smaller fragments migrate faster towards the positive end (C)</p> Signup and view all the answers

<p>To hybridize at specific DNA sequences (C)</p> Signup and view all the answers

<p>The genetic similarity between organisms (C)</p> Signup and view all the answers

<p>To separate the resulting digestion products (A)</p> Signup and view all the answers

<p>To flank the target sequence effectively (C)</p> Signup and view all the answers

<p>The splitting of water (A)</p> Signup and view all the answers

<p>Photosystem 2 (B)</p> Signup and view all the answers

<p>The extinction of many anaerobic organisms (C)</p> Signup and view all the answers

<p>Removing electrons from water molecules (B)</p> Signup and view all the answers

<p>They split water to release energy. (A)</p> Signup and view all the answers

<p>Formation of water (D)</p> Signup and view all the answers

<p>NADPH (C)</p> Signup and view all the answers

<p>Evolution of aerobic respiration (D)</p> Signup and view all the answers

<p>Only eukaryotes undergo meiosis, while prokaryotes do not. (A)</p> Signup and view all the answers

<p>Cytoplasmic genetic material can result in a phenotype not following a simple ratio. (C)</p> Signup and view all the answers

<p>Chloroplasts originated from bacterial ancestors. (B)</p> Signup and view all the answers

<p>Chloroplasts have two membranes, supporting endosymbiotic theory. (D)</p> Signup and view all the answers

<p>Microscopy observations. (D)</p> Signup and view all the answers

<p>The phenotypes may show variability not explained by nuclear inheritance. (A)</p> Signup and view all the answers

<p>Early 20th century. (A)</p> Signup and view all the answers

<p>They are involved in photosynthesis. (D)</p> Signup and view all the answers

The cell envelope's primary function is as a permeability barrier, preventing unwanted substances from entering or leaving the cell.

The movement of molecules across a membrane from a high to low concentration, without energy input.

The movement of molecules across a membrane from a low to high concentration, requiring energy input.

The Gram stain differentiates bacteria based on their cell wall structure, specifically the peptidoglycan layer.

Peptidoglycan is a structural component that provides strength to the bacterial cell wall, counteracting internal osmotic pressure.

Gram-positive bacteria possess a thick peptidoglycan layer, which retains the crystal violet stain during the Gram staining procedure.

Gram-negative bacteria have a thinner peptidoglycan layer, which does not retain the crystal violet stain.

The pressure difference between the internal and external environment of a cell, which can lead to cell lysis (bursting) if uncontrolled.

The process where a cell engulfs other cells or materials.

Prokaryotic cells, like bacteria, have rigid cell walls that prevent phagocytosis.

Lipopolysaccharide (LPS) can adapt to changing environments by modifying its structure.

An enzyme that adds glucose to Lipid A, reducing its affinity to toll-like receptors.

Immune system components that recognize LPS, triggering an immune response.

The core component of LPS, providing a foundation for modification.

An enzyme that dephosphorylates Lipid A, making pathogens less detectable.

Cationic antimicrobial peptides that disrupt prokaryotic cell membranes.

The transfer of genetic material between organisms, potentially restoring a disrupted cellular function.

Enzyme adding glycine to lipid A, potentially impacting resistance to CAMP.

A classic experiment demonstrating that DNA replication is semi-conservative. It used heavy nitrogen (N15) to label DNA, then tracked the distribution of labeled DNA during replication in normal nitrogen (N14).

DNA replication where each new DNA molecule consists of one original strand and one newly synthesized strand. This preserves the information of the original DNA molecule.

A technique that separates molecules based on their density by spinning them at high speeds. Heavier molecules settle at the bottom of the centrifuge tube.

A three-nucleotide sequence in mRNA that codes for an amino acid. It directly specifies which amino acid should be incorporated into a protein.

A special sense codon (AUG) that initiates protein synthesis. It signals the ribosome where to start reading the mRNA sequence.

A cellular machine that converts the genetic code in mRNA into a protein sequence. It's composed of rRNA and protein.

A type of RNA that forms part of the ribosome structure. It plays a crucial role in protein synthesis by interacting with both mRNA and tRNA.

Some antibiotics work by targeting the ribosome, interfering with protein synthesis in bacteria. This disables bacterial growth.

Prokaryotic ribosomes are composed of two subunits: a large subunit (31 proteins + 55 rRNA + 23S RNA) and a small subunit (21 proteins + 165 rRNA).

A relationship where both the plant and bacteria benefit. The plant provides nutrients for bacteria, and bacteria fix nitrogen for the plant.

The process of bacteria colonizing plant roots, creating specialized structures called nodules where nitrogen fixation takes place.

Intramolecular base pairing occurs within a single RNA molecule, where complementary bases pair with each other, forming loops and stems.

Loops in RNA are regions where the RNA sequence does not have complementary base pairing, creating a bulge or loop in the molecule.

Plant-released chemicals that act as signals to attract specific bacteria, initiating the nodule formation process.

Anti-polarity in DNA refers to the opposite orientation of the two DNA strands, where one strand runs 5' to 3' and the other runs 3' to 5'.

A signaling molecule produced by bacteria that triggers plant root cell development and nodule formation.

A complex enzyme found in some bacteria that converts atmospheric nitrogen gas into ammonia, a usable form for plants.

PCR (Polymerase Chain Reaction) is a technique used to amplify DNA, creating millions of copies of a specific DNA region.

These bacteria have the ability to fix nitrogen, but they must create specialized environments to keep oxygen levels low.

Essential ingredients for PCR include template DNA, primers, polymerase, nucleotides, and a magnesium-containing buffer.

Specialized cells formed by cyanobacteria to isolate nitrogen fixation from oxygen, ensuring efficient conversion.

A knockout mouse is a genetically modified mouse where a specific gene has been removed or 'knocked out.'

These bacteria were initially mistaken for algae but are classified as bacteria. They play a crucial role in nitrogen fixation and have evolved to compartmentalize this process within their cells.

Genotype is determined by analyzing DNA isolated from a tail snip using PCR and specific primers.

A method of studying microbial communities without growing them in a lab. It involves extracting DNA directly from the environment and sequencing it to identify the organisms present.

A specific gene found in most bacteria, used to identify and classify different species. It has highly conserved regions, useful for comparing distant relatives, and variable regions, helping distinguish closely related species.

A group of organisms that share a common ancestor, based on their 16S rRNA gene sequence, even if their species identity is unknown.

Bacteria that cannot survive in the presence of oxygen and are harmed by it. They use other molecules for energy instead.

Bacteria that can survive both with and without oxygen. They use oxygen if available, but can switch to other energy sources in its absence.

Molecules used by bacteria to accept electrons during respiration, allowing them to produce energy. Some common examples include oxygen (O2) and nitrate (NO3-).

The human gut harbors a vast and diverse community of microbes, with numerous species and variations even between individuals.

A significant portion of the bacteria found in the human gut are still unknown, emphasizing the vast knowledge gap in this field.

Each person has a unique gut microbiome, reflecting a personalized ecosystem shaped by genetics, diet, and lifestyle.

Characterized by a low oxygen environment and a balanced community of microbes, including beneficial symbiotes.

Cytoplasm in prokaryotes is not just a simple, aqueous solution. It has distinct regions with varying properties, even without membranes like in eukaryotes.

The bacterial cytoplasm acts like a viscous, glass-like substance that can be fluidized by metabolic activity. This means the cytoplasm can change its consistency based on the cell's activity.

Fluorescent proteins can be used to track the movement of molecules within bacteria. In growing bacteria, the fluorescence moves around, while in non-growing or metabolically impaired bacteria, it remains stationary.

Like the bacterial cytoplasm, the eukaryotic nucleus also has different regions with distinct physical properties, influencing how molecules move and interact.

Long RNA molecules, through intramolecular base pairing, can create polymers that make the cytoplasm more viscous.

Scientists use fluorescent proteins to visualize and study the internal dynamics of cells, tracking the movement of molecules and gaining insights into cellular processes.

Ongoing research aims to understand how different regions in the cytoplasm and nucleus develop their unique physical properties and how these properties affect the cell's overall function.

A process where a signal is detected outside the cell and transmitted through the membrane to activate a response inside the cell. In prokaryotes, it's simpler compared to eukaryotes and often involves a sensor kinase and a response regulator.

A protein that senses an external signal and then activates a response regulator by adding a phosphate group (phosphorylation).

A protein activated by phosphorylation by a sensor kinase. It acts as a transcription factor, directly binding to DNA to activate or repress gene expression.

Magnesium acts as a repressor of the signal transduction pathway. When magnesium levels are high, the sensor kinase is inactive. When magnesium levels drop, the pathway activates.

A gene that is directly controlled by the response regulator. Its expression is either increased or decreased in response to the signal.

Gram-negative bacteria have a signaling pathway sensitive to misfolded proteins. The sensor kinase detects these proteins and activates a target gene that codes for a protease. This protease degrades the misfolded proteins.

An enzyme that breaks down proteins. In the context of misfolded proteins, it acts as a quality control mechanism, removing damaged proteins and preventing them from disrupting cellular function.

Gram-negative bacteria have a unique signaling pathway to detect misfolded proteins. This pathway is vital for maintaining cellular health and dealing with stress.

An organism, like plants and certain bacteria, that uses light energy to split water and produce oxygen as a byproduct.

A visual representation of the electron flow during photosynthesis, depicting the energy levels of electrons in chloroplasts.

A complex of proteins and pigments in chloroplasts where water splitting occurs, releasing oxygen and electrons.

A protein complex in chloroplasts where energized electrons are further boosted to create a high-energy electron carrier.

The ability of a molecule, like NADH, to transfer electrons, driving metabolic reactions in cells.

A series of protein complexes in mitochondria that transfer electrons to oxygen, generating energy in the form of ATP.

The process of removing electrons from water molecules, generating oxygen and releasing energy.

The sudden increase in atmospheric oxygen levels billions of years ago, extremely harmful to most life forms at the time.

Prokaryotes do not undergo meiosis. This is a fundamental difference between prokaryotes and eukaryotes.

Cytoplasmic inheritance refers to the transmission of genetic material outside the nucleus, often within organelles like mitochondria and chloroplasts. This does not follow Mendelian patterns because it's not based on chromosomes.

Merezhkowsky proposed that chloroplasts originated from bacteria. This idea was based on microscopy observations and the chloroplast's role in photosynthesis.

Wallin expanded on Merezhkowsky's idea, noting the double membrane structure of chloroplasts. He coined the term 'endosymbiosis' for this theory.

Cytoplasmic inheritance is non-Mendelian because genetic material in organelles doesn't follow the usual inheritance patterns seen in chromosomes.

A key difference is the presence of meiosis in eukaryotes. Prokaryotes lack this process for cell division and reproduction.

The theory explaining how certain organelles, like mitochondria and chloroplasts, originated from free-living bacteria that were engulfed by eukaryotic cells.

The presence of a double membrane in chloroplasts, similar to bacterial cells, and their capability to carry out photosynthesis provide strong evidence for their bacterial origin.

PCR involves three main steps: denaturation, annealing, and elongation. Denaturation separates DNA strands at high temperature. Annealing allows primers to bind to the target sequence. Elongation extends the primers using polymerase, creating copies of the target DNA.

Agarose gel electrophoresis is a technique used to separate DNA fragments based on their size. DNA fragments are loaded into wells in a gel that is submerged in a buffer solution. An electric current is applied, causing DNA fragments to migrate towards the positive electrode. Smaller fragments move faster through the gel.

Woese's technique for comparing 16S rRNA sequences involves isolating ribosomes, digesting the 16S rRNA, separating the fragments by two-dimensional electrophoresis, and creating a distinctive fingerprint of the sequence.

The 16S rRNA gene is a genetic sequence present in most bacteria. It has conserved regions useful for comparing distant relatives and variable regions for distinguishing closely related species.

Phylotypes are groups of bacteria categorized based on their similar 16S rRNA sequences, even if their exact species identity is unknown.

Signal transduction in prokaryotes is a process where a signal outside the cell triggers a response inside the cell. It involves a sensor kinase that detects the signal and a response regulator that activates gene expression.

The Oxygen Catastrophe describes the sudden increase in atmospheric oxygen levels billions of years ago, which was toxic to many early life forms and led to major evolutionary changes.