Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Pathology
First chapter.
| Question | Answer |
|---|---|
| Define pathology | Study of suffering |
| Disease originates at which level and who discovered this? | Cellular level, Virchow. |
| How many base pairs are there in a human genome? | 3.2 billion base pairs |
| How many protein encoding genes are present in human genome? | 20,000 |
| How much percent that the protein encoding genes constitute in the human genome. | 1.5% |
| How much percentage of the DNA is transcribed and how much percentage of it is involved in gene expression. | 85% of our DNA is transcribed and 80% is devoted for the regulation of genes. |
| What are the five major classes of functional non- protein coding sequences in the human genome. | 1) Promoter and Enhancer 2)Binding sites for the factors that help in organizing and maintaining higher order chromatin structure. 3) Non-coding regulatory RNA's 4)Mobile genetic elements. 5) Specialized structural regions of DNA. |
| How much percent of the human genome is transcribed into non-coding regulatory RNA. | 60% |
| Two best studied non-coding regulatory RNA's are? | micro RNA(miRNA) and Long non-coding RNA's(lnc's ) |
| How much of human genome makes up for mobile genetic elements. | More than a third. |
| What are the specialized structural regions of a DNA? | Telomers and centromeres. |
| What is the major component of centromere? | Satellite DNA |
| What is the importance of satellite DNA? | To maintain the dense and tightly packed organization of heterochromatin. |
| How identical are two human beings(on the basis of DNA) | 99.5% . That's why individual variation, including differential susceptibility to diseases and environmental stimuli is just 0.5% |
| What are the two common forms of DNA variation in the human genome? | SNP - Single nucleotide polymorphisms. CNV's - Copy number variations |
| SNP's are uniallelic. True or False? | False, they are always biallelic. |
| What are SNP's? | SNP's are positions on the genome where one individual has one nucleotide where others have a different nucleotide. |
| How much percent of SNP's occur in coding region? | 1% |
| What happens if SNP's are present in the non-coding region of a genome? | Alter gene expression and have direct susceptibility towards the disease. |
| Neutral SNP's | No effect on gene function or phenotype. |
| SNP's that occur in the non-coding region are harmless? True or False? | TRUE |
| SNP's that occur in the coding region are harmful? True or False? | TRUE |
| What are CNV's? | Chromosomal deletion and duplication that involves large stretches of DNA that includes 1000 base pairs. |
| What is the importance of studying CNV's? | To know the change in the chromosomal structure and predict pharmacogenomic effects such as effectiveness of particular drug. |
| What is a chromatin? | Multiple nucleosomes are linked by a DNA linker are known as chromatin. |
| What is a nucleosome made of? | Nucleosome comprises of DNA that has 147 base pairs wrapped around a histone. Nucleosome is an octamer of histone proteins. |
| How long is the DNA? | 1.8m but it is wrapped around the histone and the entire genome can fit in a nucleus and its size reduces to 7-8 micrometers in diameters. |
| Histones are static or Dynamic? | They are DYNAMIC. |
| Name the two histone modifying factors | Chromatin remodeling complex and chromatin writer complexes. |
| What is the function of chromatin remodeling complex? | It helps in exposing the regulatory parts of the DNA like promoters. |
| What is the function of chromatin writing complex? | Methylation, Acetylation and Phosphorylation. |
| The three functions of chromatin writing complexes together are known as | MARKS |
| All the processes done by chromatin writing complexes can be reversible by? | Chromatin erases |
| Acetylation and Methylation mostly occur in which amino acids? | Lysine and Arginine |
| What is the function of histone acetylation? | Unwraps the DNA from the histone. For transcription. |
| What is the enzyme required for histone acetylation? | Histone Acetyltransferases. (HAT) - forms EUCHROMATIN. |
| What happens in histone deacetylation? (HDACs) | The DNA condenses are wraps around the histone. |
| What happens in histone methylation? | Histone methylation activates as well as repress for transcription. depending on the location of the residue. (MOSTLY INACTIVATION - FORMING HETEROCHROMATIN) |
| What happens in histone phosphorylation? | Helps in activating as well as condensing the DNA for transcription. |
| What is DNA methylation? | Silences the transcription |
| DNA methylation takes place in which amino acids? | Adenine and Cytosine |
| What enzyme helps in DNA methylation? | DNA methyltransferases. (Demethylating enzymes, methylated DNA - binding proteins) |
| What are chromatin organizing factors? | These are epigenetic factors. |
| Which histone acts as a DNA linker? | Histone H1 acts as a DNA linker. |
| What is Epigenetics | Mechanisms that cause change in the gene expression but not in the DNA sequence. These mechanisms include DNA methylation, Histone modification and activity of non-coding RNA. |
| What is the function of miRNA? | Regulation of proteins (NOT PROMOTION OF PROTEINS). From DNA to mRNA and then to proteins. miRNA's act on mRNA and prevent them from being translated. Each miRNA is specific for mRNA. |
| Explain how miRNA works in posttranscriptional silencing. | The miRNA gets transcribed into primary miRNA(pri-miRNA). This pri-miRNA are further transcribed into smaller fragments of miRNA by an enzyme called DICER(precursor miRNA). Then later this forms mature single stranded miRNAs of 21-30 nucleotide.(RISC) |
| What are RNA-induced silencing complex (RISC)? | The unwinded miRNA duplex is known as RISC. |
| How many miRNA's human genome encodes? | 6000miRNA's (30% of total protein coding genes). |
| Name the two ways in which miRNA silences mRNA to form proteins. | The pairing between the single stranded miRNA and its target mRNA. directs the miRNA to either cleave the mRNA or represses it. |
| Dysregulation of miRNA causes what diseases? | Cancer or Heart disease. |
| How many nucleotides to miRNA have? | 22 |
| How are siRNA are important for gene silencing? | The double stranded RNA segments are introduced into a cell which interacts with dicer and becomes a small piece of dsRNA. this is then broken down and forms a single stranded RISC. This will now act like miRNA. |
| Importance of siRNA's | To study gene function and also for therapeutic agents to silence pathogenic genes. |
| Function of long coding RNA | 1)Gene activation 2)Gene suppression 3) Chromatin modification(acetylation and methylation) 4)Stabilizes secondary and tertiary protein structures. |
| What is CRISPER Cas9 system? How is this helpful? | It is a genome editing system. CRISPER and Cas9 can cut the target DNA at specific locations. It helps in selectively edit mutations in DNA. |
| How does compartmentalization of internal organs help a cell? | It creates unique intra- cellular environments(High calcium or low pH) that allows for better functioning of the cell. |
| Function of RER | Synthesize protein for the plasma membrane. |
| Function of Golgi apparatus | Packaging and transport within the cell. |
| Function of SER | Synthesis of steroid hormone and lipids, modification of hydrophobic compounds into water- soluble molecules for export. |
| Which internal organelle is the disposal complexes of a cell that degrade cytosolic proteins? | PROTEOSOMES |
| Suicidal bag of the cell, performs autophagy, they contain degradative enzymes that digest macromolecules, proteins, lipids and nucleic acid. | LYSOSOME |
| This cell organelle contains catalase, peroxidase and other oxidative enzymes and break down long chain of fatty acids and generate H2O2 in this process. | PEROXISOMES. |
| This cell organelle is the site of senescent intracellular organelle breakdown.(Autophagy) | LYSOSOME |
| By what process and where is most of the cells energy made? | Mitochondria, mitochondrial oxidative phosphorylation. |
| What in the cell is responsible to generate intracellular second signals like diacylglycerol and inositol triphosphate? | Phosphatidyinositol. |
| Phosphatidyinositol is found where on the cell membrane? | In the inner leaflet. |
| This is a cell membrane component is responsible for apopstosis and a also a cofactor in blood clotting. It is present in the inner leaflet, but when it gets flipped then it becomes prone to apopstosis. | Phosphatidylserine. (negatively charged) |
| Glycolipids and sphingomylein are found in which part of the cell | Extracellular leaflet. (Sperm-egg fusion and inflammatory cell recruitment) |
| The proteins and the glycoproteins on the plasma membrane are responsible for what? | They are responsible for ion and metabolite transport, fluid-phase and receptor mediated uptake of macromolecules and cell-ligand, cell matrix and cell-cell interactions. |
| What are the four mechanisms by which proteins are attached to the lipid bilayer of the plasma membrane? | 1)Integral or transmembrane proteins with hydrophobic alpha helix. 2)Synthesized by free ribosomes in cytosol may be modified post translationally by addition of prenyl group that insert into cytosolic side of PM. |
| What are the four mechanisms by which proteins are attached to the lipid bilayer of the plasma membrane? CONTINUED | 3)Attached to extracellular face by glycosylphosphatidylinositol tails that are added post translationally 4)Peripheral membrane proteins are attached by noncovalent bond to true membrane proteins. |
| Passive diffusion | Small, nonpolar molecules like O2, Co2 diffuse easily across the PM. Large hydrophobic molecules like steroid molecules like Vit D and estradiol can also pass the PM H2O1 passes through aquaporins. |
| Lipid bilayer is an effective barrier for large non-polar molecules? TRUE or FALSE? | TRUE |
| Lipid bilayer is permeant to ions. TRUE OR FALSE? | FALSE. Due to their charge and hydration they are impermeant. |
| Role of a carrier | 1)Energy dependent 2)Slow transport 3)Undergoes a conformational change in order to transport. |
| Role of a channel | 1)Channels create a hydrophilic pore which when open will allow the rapid movement of solutes. Channels are used when the concentration gradients can drive the solute movement.(Allows size and charge restricted molecules to enter) |
| Hypertonicity - What is the movement of the water? | Movement of water outside the cells. |
| Hypotonicity - What is the movement of the water? | Movement of water inside the cells. |
| What happens if the cell fails to generate energy? | Osmotic swelling and eventually cell rupture. |
| What is endocytosis and what are its types? | The uptake of fluid and macromolecules by the cells is known as endocytosis.Depending on the size of the vesicle it can be pinocytosis(cellular drinking) or phagocytosis(cellular eating). Phagocytosis is restricted to few cell types.(neutrophils, macroph |
| Exocytosis | Transport of macromolecules outside of the cell. The proteins from RER and Golgi are in the secretory vesicles which fuse with the PM and transport them out. |
| What is transcytosis? | Where endocytosis is occuring at one end of the membrane and exocytosis at the other end. |
| Receptor mediated endocytosis. | The macromolecules they attach to a particular receptors on the PM and forms a clathirin -coated pits. It then pinches of the PM and forms vesicle |
| What is potocytosis? | Cellular sipping. |
| Cytoskeleton | Adapt to a particular shape, maintain polarity, organize intracellular organelles and migrate depends on an intracellular scaffold of structural proteins that form the cytoskeleton. |
| Three major classes of cytoskeleton proteins. | Actin microfilaments Intermediate filaments Microtubules |
| Actin micro filaments | Most abundant 5-9nm in diameter. Formed from Globular protein actin. |
| Intermediate filaments | 10nm in diameter Provides tensile strength so that cell can bear mechanical stress |
| Vimentin is found where? | Mesenchymal cells. |
| Where is Desmin found? | Muscle cells, actin and myosin contract. |
| Function of neurofilaments | Critical for neuronal axon structure and confer both strength and rigidity. |
| Where are cytokeratins expressed? | In the epithelial cells (there are 30 types). |
| What are Lamins? | Forms the nuclear lamina, define nuclear shape, and can regulate transcription. |
| What are microtubules? | 25nm in diameter Composed of non-covalently organized alpha and beta tubulin dimers organized into hallow tubes. These fibrils are polarized and have a positive and negative charge. Kinesins - Anterograde (- to +) Dyneins - Retrograde (+ to -) |
| Which filament helps in sister chromatin segregation during mitosis? And forms the core of the primary cilia? | Microtubules |
| Tight junctions are also known as? | Occluding junctions. Seal the adjacent junctions so that there is no para- cellular movement of ions. They maintain cellular polarity (by separating apical and basal membranes). Structure could be modified for epithelial healing and inflammatory cell mi |
| Desmosomes/adhering junctions are also known as? | Anchoring junctions Closely associated with and adjacent to tight junctions. Found more on the basal side. |
| What are hemidesmosomes? | When a desmosome attaches the cell to the ECM |
| What happens in cases where there is loss of adherens junction protein E cadherin. | Gastric cancer and lobular carcinoma of breast. |
| Gap junctions are also known as? | Nexons or communicating junctions. |
| Site of all the transmembrane synthetic proteins and lipids for plasma membrane and cellular organelles. And, initial site of synthesis for secreted proteins. | Endoplasmic reticulum.(Even for itself). |
| What molecules help in folding and retaining proteins in the ER | Chaperone molecules. |
| What is ER stress response/ Unfolded protein response? | Excess number of misfolded proteins that the ER is unable to edit and degrade leads to ER stress. Failure to correct the overload will lead to cell death(apopstosis) |
| The two networks of golgi | Cis and trans |
| Which network of golgi is responsible for proteins, lipids are sorted and dipatched to other organelle, PM or secretory vesicles. | TRANS |
| SER | 1)Very sparse 2)Exists as a transition between RER to generate transport vesicles that carry newly synthesized proteins to Golgi. |
| Specialized SER in muscle cell is known as? | Sarcoplasmic reticulum. |
| Free ribosomes | For cytosolic proteins. |
| Lysosomes | Contains 40 different acid hydrolases(best at pH less than or equal to 5). these include proteases, nucleases, lipases, glucosidases, phosphatases, and sulphatases. |
| Lysosomal enzymes | They are formed in the lumen of ER and then tagged with mannose -6 - phosphate within the golgi apparatus. |
| What is the half life of mitochondria? | 1-10 days depending on the tissue, nutritional status metabolic demands and intercurrent injury |
| Two ways in which Mitochondria dies? | Necrosis and apopstosis |
| How does mitochondria die through necrosis? | Extracellular cell injury can damage mitochondria, inducing the formation of mitochondrial permiability pores |
| Where in the mitochondria can you find the cristae? | The mitochondria has two membranes and on the inner membrane there are enzymes of the respiratory chainfolded into cristae. Between the inner and outer membrane we have the intermembrane space where phosphorylation takes place. |
| Which layer of the mitochondria is embedded with porin proteins | Outer layer. These form the voltage dependent anion channels that are permeable to small molecules. |
| What is thermogenin? And, what is another name of thermogenin. | Inner membrane protein enriched in brown fat is called thermogenin. It is an hydrogen ion transporter that can dessipate proton gradient uncoupling it from oxidative phosphorylation. |
| How is thermogenin useful? | There is a rapid substrate oxidation without ATP synthesis that allows tissue with high level of UPC-1 to generate heat. |
| How many ATP does oxidative Phosphorylation produce? | 36-38 ATP molecule per glucose molecule. |
| Describe Warburg effect | Rapidly dividing cells(cancer cells both benign and malignant) increase their uptake of glucose and glutamine and switch to aerobic glycolysis. This phenomenon is known as Warburg effect. |
| How is intracellular signaling important? | It assures that all tissues act in appropriate concert. |
| What happens if there is loss of intracellular communication | Unregulated growth(cancer), detrimental response to external stress (shock) |
| Paracrine signaling | Affects the cells in the immediate vicinity |
| Autocrine signaling | Molecules secreted by the cell affect the same cell This is for synchronous differentiation, to activate and dampen a particular response. |
| Synaptic signaling | IN synapse. Neurotransmitters. |
| Endocrine signaling | Molecules secreted are transported a long distance in blood. |
| How is the signal transmitted? | Through receptors. |
| Why is cell signaling important? | For cell differentiation, cell proliferation, to perform a specialized function. |
| Four ways of cell- signaling | 1) Damaged cell 2)Adhering cells(gap junctions) 3) ECM(integrins) 4) Secreted molecules(growth factors and cytokines). |
| Two types of receptors based on location | 1)Intracellular 2) Cell - surface receptors. |
| Name the type of receptors based on the signaling mechanism and the intracellular biochemical pathways that they activate. | 1)Receptor associated kinase activity 2) Receptor tyrosine kinase 3) Receptors wit h no intrinsic catalytic activity 4)G-protein coupled receptors 5) Nuclear receptors 6)Other receptors. |
Created by:
Ashritha.R
Popular Pathology sets