116 Questions
What is the key process that plant cells use chloroplasts for?
Photosynthesis
Which structure is unique to plant cells and not present in animal cells?
Cell wall
What function do microtubules serve in animal cells?
Organize cell content
What is the primary source of glucose for animal cells?
Food intake
Which organelle is responsible for microtubule nucleation during cell division?
Centrosome
In neurons, what is the primary function of microtubules?
Transport organelles and materials
In DNA, which nitrogenous base pairs with Guanine?
Cytosine
What type of bonds link adjacent nucleotides in a DNA strand?
Phosphodiester bonds
Which sugar is found in DNA but not in RNA?
Deoxyribose
What process targets histones in Huntington's disease?
Deacetylation
Which groove in the DNA double helix is shallower and narrower?
Minor groove
What is the most common function of the phosphate group in nucleotides?
Allowing interaction with DNA histones
What is a key difference between prokaryotic and eukaryotic cells?
Prokaryotic cells contain a membrane-bound nucleus, while eukaryotic cells have DNA in a single circular loop.
What is a distinctive feature of prokaryotic cells that aids in their movement?
Pili / flagella structures
How does the DNA arrangement in prokaryotic cells differ from that in eukaryotic cells?
Prokaryotic cells contain multiple separate chromosomes, while eukaryotic cells have a single circular loop of DNA.
Which organelle is present in eukaryotic cells but absent in prokaryotic cells?
Mitochondria
What is the primary biological function of microfilaments?
Cell transport
Which type of intermediate filaments is most common in cells that undergo mechanical stress?
Type I keratins
In what biological process do actin filaments form a contractile ring around the 'waist' of the cell?
Cell division
Which cytoskeletal polymer is the most flexible and can cross-link with microtubules and microfilaments?
Intermediate filaments
What is the default state of a microfilament when actin monomers are added as quickly as they are removed?
Treadmilling
Which disease has been associated with reduced microtubule stability?
Alzheimer's disease
How do most pathogens manipulate the host cytoskeleton?
Manipulating actin-filament networks
'Treadmilling' is associated with the dynamics of which cytoskeletal component?
Microfilaments
What is the name of the chemical substance present in the nucleus that controls all the chemical changes in cells and determines cell type and organism produced?
Deoxyribonucleic acid(DNA)
What is the role of the ribosome in protein synthesis?
Building proteins
Which process involves the movement of the tRNA from the A site to the P site in protein synthesis?
Translation
What happens during translation in protein synthesis?
Conversion of RNA to protein
What is a key difference between prokaryotic and eukaryotic DNA?
Prokaryotic DNA is linear, while eukaryotic DNA is circular.
What feature distinguishes plant cells from animal cells?
Having cell walls
Which characteristic is unique to archaea among prokaryotes?
Cell wall composition
What is the function of release factors in protein synthesis termination?
Releasing completed polypeptide chains
Which organelle is responsible for energy production in eukaryotic cells?
Mitochondrion
What type of symbiosis describes one organism living inside another?
Endosymbiosis
What distinguishes unicellular prokaryotic cells from eukaryotic cells?
DNA structure
What is a major difference between translation and transcription in protein synthesis?
Transcription produces mRNA, while translation produces proteins.
Which type of metabolism involves using acetate as an electron donor and ferrihydrite as an electron acceptor without fermentation?
Anaerobic metabolism
What is a unique characteristic of the RNA complex in Archae body cells?
Contains 10 subunits
What is the key difference in the composition of DNA between prokaryotic and eukaryotic cells?
Prokaryotic DNA is circular without proteins, while eukaryotic DNA is linear with proteins.
Which type of cells has ribosomes with a size of 70S?
Prokaryotic cells
In the cell cycle, during which phase does DNA replication occur?
S phase
What is the primary function of the cytoskeleton in eukaryotic cells?
Support cell structure and movement using flexible cilia and flagellin
What is the main form of motility in prokaryotic cells?
Rotating flagellum made by flagella
'Okazaki fragments' are primarily involved in which process during DNA replication?
Lagging strand replication
What is the central dogma of molecular biology?
Genetic information flows from DNA to RNA to protein
How does the nucleus control the cell?
By regulating gene expression and controlling DNA replication
What is the function of histones in chromosomes?
Support the structure of chromosomes
What is the role of ribosomes in protein synthesis?
Decoding mRNA and assembling amino acids into proteins
What is the relationship between a gene and a sequence of triplets on DNA?
A gene is a sequence of triplets that code for a complete protein
What happens when a cell divides?
DNA replication results in identical DNA in each nucleus
How does the genetic code control protein production?
By controlling the order in which amino acids are joined up
What is the function of nerve growth factors in nerve cells?
To transcribe genes related to nerve cell growth and survival
Why are chromosomes considered to be made up of DNA and proteins?
Proteins provide structural support to DNA in chromosome formation
What distinguishes one gene from another?
The varying number of triplets within a gene
Why is mRNA transported from the nucleus to the cytosol?
To serve as a template for protein synthesis
What is the main role of cohesins in the cell during mitosis?
Facilitate separation of sister chromatids
During which phase of the cell cycle does a cell stop dividing and enter a resting phase?
Gap 0
What is the main function of the centrosome in a eukaryotic cell?
Initiate spindle formation
Which statement best describes prometaphase in mitosis?
'Late prophase' where chromosomes are condensed
What is the specific role of the 16S ribosomal RNA in translation initiation?
Binds to the Shine-Dalgarno sequence
In agarose gel electrophoresis, what primarily determines the movement of charged particles within the electric field?
Size of the molecules
What is the purpose of loading buffer/dye when preparing DNA samples for gel electrophoresis?
To help DNA sink to the bottom of the well
What is a key consideration for maintaining sterility inside a biological safety cabinet?
Minimizing clutter inside the cabinet
Which end of the gel is attached to the Cathode (-) during electrophoresis?
Top loading end
What is a recommended practice when working inside a biological safety cabinet to avoid contamination?
Touching face and hair with gloves on
What is the purpose of warming cell culture media and additives to 37˚C in a water bath before using them?
To ensure optimal temperature for cellular growth and viability
Why must all materials be disinfected with 70% ethanol before starting cell culture procedures?
To ensure a sterile working environment and prevent contamination
What is the consequence of seeding cells at a high cell count/density in cell culture?
Overpopulation leading to cell death
During meiosis I, what happens in Anaphase I that distinguishes it from Anaphase in mitosis?
Homologue pairs are separated
What is the purpose of using trypan blue in mammalian cell culture and viability staining?
To stain cells that have already died
What occurs during Prophase I of meiosis that does not happen in mitosis?
Crossing over between homologous chromosomes
How does 100% ethanol treatment affect bacterial cells?
Ruptures the cell membrane, killing the bacteria
What happens to live cells with intact membranes when stained with trypan blue?
They are not colorized by trypan blue
What is the main difference between Mitosis and Meiosis II?
Separation of sister chromatids
In metaphase of meiosis where do the homologous chromosomes line up?
Metaphase plate
Which stage of cell division marks the transition from a haploid state to a diploid state?
Telophase I
What is the main outcome of crossing over during Prophase I of meiosis?
Exchange of genetic material between nonsister chromatids
Which organelle is responsible for forming a new cell wall in plant cells during cytokinesis?
Golgi apparatus
What is the key challenge in ensuring an equal split between new cells during cell division?
Attachment of kinetochores to the spindle
What happens during Anaphase II of meiosis?
Sister chromatids separate and move to opposite poles
What is the primary function of the synaptonemal complex during Prophase I of meiosis?
Holding together homologous chromosomes
What is a distinguishing feature of Meiosis II compared to Meiosis I?
Sister chromatids separate
How do the resulting cells differ after meiosis compared to mitosis?
Resulting cells are haploid after meiosis and diploid after mitosis
Which site in the ribosome does the first, empty tRNA drift out from after the peptide bond is formed?
E site
What type of codons signal the termination of translation in mRNA?
Stop codons
In prokaryotes, what is the main factor that influences the regulation of gene expression?
Nutrient availability
Which component of an operon binds to the operator and halts transcription?
Repressor protein
In the Lac Operon, what molecule can turn on gene expression by preventing the repressor protein from binding to the operator?
Inducer
What is the primary function of the trp operon in E.coli when tryptophan is available in the environment?
Synthesizing more tryptophan
What is the function of the repressor protein produced by the regulatory gene in the trp operon?
Inhibit gene expression
How are the genes in the trp operon transcribed?
As a continuous strand of mRNA
What does the Lac Operon turn on when a specific small molecule is present?
Inducer binding to repressor
What is the role of corepressors in regulating gene expression in repressible operons like Trp Operon?
Turn off gene expression
What happens when an inducer molecule binds to a repressor protein in inducible operons like Lac Operon?
Prevents repressor from binding to operator, allowing transcription
During transcription, what is the role of promoters on DNA?
Serving as recognition points for binding of RNA polymerase
What happens during transcription termination?
RNA polymerase transcribes a sequence known as a terminator
Which process involves the removal of introns and the splicing of exons in mRNA?
RNA splicing
What is the function of 5' capping during RNA processing?
Preventing mRNA degradation
What is a key characteristic of tRNA molecules?
Have an anticodon complementary to mRNA codon
Which component of the ribosome holds the tRNA molecule carrying the next amino acid to be added to the growing polypeptide chain?
A site
What is the function of aminoacyl-tRNA synthetases?
Attach specific amino acids to tRNA molecules
Which stage of protein synthesis involves the assembly of the initiation complex with mRNA and ribosomal subunits?
Initiation
What provides the energy for assembling the initiation complex during translation initiation?
GTP
What does translation elongation involve?
tRNA moving from P site to A site in ribosome
What is the role of splicing during RNA processing?
Join coding exons while removing introns from pre-mRNA
What is the function of 'm7G' addition during RNA processing?
Protect mRNA from degradation and aid in translation initiation at ribosome
What is the function of lacA in the lac operon?
Function unclear
In prokaryotic transcription initiation, which DNA sequence is essential for starting transcription?
Pribnow box
What occurs when Rho factor reaches the transcription bubble in Rho-dependent termination?
Rho pulls the RNA transcript and DNA strand apart
What causes RNA polymerase to stall in Rho-independent termination?
Complementary binding of C and G nucleotides
What is the role of the Shine-Dalgarno sequence in prokaryotic translation?
Complementary to 16S rRNA in the ribosome
What is the composition of prokaryotic ribosomes?
*30S and *50S subunits
Which type of termination strategy relies on a stable hairpin structure?
*Rho-independent termination
Translation elongation is characterized by:
*Formation of peptide bonds between amino acids
Transcription initiation in prokaryotes requires:
*Interaction with Pribnow box at -10 site
Translation termination involves:
*Release of polypeptide from ribosome
This quiz covers the process of protein synthesis by the ribosome, including initiation, elongation, translocation, and termination. Learn about the steps involved in creating a polypeptide chain.
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