Exam V Flashcards

Question

S CDK/Cyclin Association

Answer 1

CyclinE-Cdk2

Answer 2

CyclinA-Cdk2

Answer 3

CyclinB-Cdk1 (called Cdc2)

Answer 4

Regulates G1/S and G2/M checkpoints Blocks cell cycle if DNA is damaged Severe damage leads to apoptosis (programmed cell death) p53 levels are increased in damaged cells, allowing time for DNA repair by blocking the cell cycle p53 mutation is the most frequent mutation leading to cancer Mutated p53 found in >50% of cancers *employs Bcl-2 family to induce apoptosis at mitochondrial level (via Bax)

Answer 5

extreme case of p53 mutation; genetic defect in p53 leads to a high frequency of cancer in affected individuals

Answer 6

The protein can be found in two states: 1. hypophosphorylated where the protein is not phosphorylated much 2. hyperphosphorylated – a lot of phosphorylation Hypophosphorylation: pRb is bound to E2F and this will keep the E2F from acting as a TF; and cyclins will phosphorylate the Rb, becoming hyperphosphorylated and loses the E2F and can work as a TF; G2 will then occur because the necessary enzymes for it are now able to be synthesized; these kinases work in response to extracellular agents ex. Damage through carcinogenic substance, etc.

Answer 7

dephosphorylates CDK and allows progress from G2/  M

Answer 8

Triggers progression through the cell cycle i.e. moves the cell from G1  S  G2  M; includes CDKs and cyclins

Answer 9

referred to oncogenes, but originally are proto-oncogenes that control the cell cycle activate at G0 and G1, and they keep the cells that are in G0 within G0, but when mutated then they cannot keep them in G0 and the cells go into G1 and start the cycle Some of the cancer that are proven to have involvement of c-Jun and c-Myc are the Tcell lymphomas and leukemias

Answer 10

Chromatin condensation Chromosomes become visible in the light microscope Nucleolus disappears Centrioles move to opposite poles of the cell Centrioles originate from the centrosome

Answer 11

``` Nuclear membrane dissolves Creation of kinetochores Proteins attachment to the chromosomal centromeres Microtubules attach at the kinetochores Chromosomes movement begin ```

Answer 12

Spindle fibers align the chromosomes along the middle of the cell nucleus- Metaphase plate Ensure correct separation of chromosomes and equal distribution between the daughter nuclei Each new nucleus will receive one copy of each chromosome

Answer 13

Separation of paired chromosomes at the kinetochore Move to opposite poles of the cell Motion results from a combination of Kinetochore movement along the spindle microtubules Physical interaction of polar microtubules MT push at the poles of the cell causing pulling of chromosomes and elongation of the cell itself

Answer 14

Chromosomes arrive at opposite poles of cell Formation of new membranes around daughter nuclei Chromosomes disperse into chromatin Not visible under the light microscope anymore Spindle fibers and associated MT degraded Cytokinesis may begin - Partitioning of the cell

Answer 15

During mitosis, the 23 pairs of human chromosomes condense and are visible with a light microscope. A karyotype analysis usually involves blocking cells in mitosis and staining the condensed chromosomes with Giemsa dye. Giemsa dye stains regions of chromosomes that are rich in the base pairs Adenine (A) and Thymine (T) producing a dark band.

Answer 16

46 chromosomes with XY = normal male; 46 XX is a normal female 47 XX with +21 = trisomy 21 female/abnormal 47 XY with +21/ 46 XY = the male has a mix of normal and abnormal cells = mosaic; therefore they have less symptoms than regular trisomy 21 because the normal cells can compensate for abnormal ones 47, XY, +24 = there is no 24th chromosome! 46 XY, del (4) of p14= male has normal chromosome number, but has a deletion in chromosome 4 on short arm (p) band number 14 46 XX dup(5p) = normal number of chromosomes with a duplication of short arm on chromosome 5

Answer 17

Chromosomes 13 has one half missing and the other one has something added to it Chromosome 14 – part of this chromosome came to the chromosome 13 Written: 46, XX -13,-14 Normal phenotype This is abnormal organization; sometimes leads to normal phenotype or sometimes has some defects; it depends on how mitosis reacts to it risks: spontaneous abortion or abnormal child

Answer 18

Fluorescence in situ Hybridization Used to determine additions or deletions If no hybridization = know something is missing Labelled probe hybridized to chromosomes from metaphase, prophase, or interphase Sometimes have chromosome that has an addition and you see large chromosome This can be done at any stage of mitosis

Answer 19

Reproduction by mitosis only; there is no change genes Trees keep the type of fruits the same because the same genes, so if we had sexual reproduction, then the fruits would change Offspring called clones meaning that each is an exact copy of the original organism This method of reproduction is rapid and effective allowing the spread of an organism Since the offspring are identical, there is no mechanism for introducing diversity

Answer 20

is a process to convert a diploid cell to a haploid gamete, and cause a change in the genetic information to increase diversity in the offspring

Answer 21

has 2 chromosomes (dyads) and 4 chromatids: | one chromosome coming from each parent

Answer 22

Trisomy 21- Autosomal aneuploidy Most common surviving trisomy Extra chromosome- Maternal contribution (95%) Significant problems: Mental retardation, Respiratory infections, Leukemia, Congenital heart defects, GI tract obstruction Increased risk for trisomy 21 is maternal age of 35 or greater

Answer 23

Condition in which an individual has two or more genetically distinct cell lines derived from a single zygote, but differing because of mutation or nondisjunction

Answer 24

45, X rarely born alive; one of the survivable monosomies 1. Characteristically broad “webbed” neck. 2. Reduced stature 3. Poorly developed sexual secondary characteristics 4. Usually infertile because of gonadal dysgenesis 5. Rarely undergo menarche 6. Estrogen treatment 7. Around 30-40% mosaic, mostly 45,X/46,XX

Answer 25

due to mechanical, chemical, or viral infection damages premature death causes inflammation - can be chronic Cellular swelling Membranes are broken ATP is depleted Cell lyses, eliciting an inflammatory reaction DNA fragmentation is random, or smeared In vivo, whole areas of the tissue are affected

Answer 26

due to signals internally or externally to prevent threats of disease/cancer as well as aids in the developmental process (tadpole tails, fingers/toes, and nerve cells) Cellular condensation Membranes remain intact (blebbing and shrinkage) Requires ATP Cell is phagocytosed, no tissue reaction Ladder-like DNA fragmentation In vivo, individual cells appear affected apoptotic body formation = engulfed no inflammation mitochondrial leakage *no nucleus is required for apoptosis because the proteins are always expressed, but not active all the time due to inhibitory mechanisms *decision to enter PCD is final - all or nothing

Answer 27

central executioners of apoptosis they are substrates for each other; one caspase will break down another caspases to amplify the proteolytic cascade Asp is the target and where it is cleaved, whereas Cys is the active site that helps the one caspases cleave the other caspases

Answer 28

8, 9, 10, & 12

Answer 29

1. Proteolytic Cleavage- pro-caspase is cleaved and the ends attach to each other to activate the caspase (ex. caspase 3) 2. Induced Proximity- two molecules come close together causing the removal of the unnecessary parts leaving the rest to combine and form the active caspase (ex. caspase 8) 3 Oligomerization- Apaf-1, cytochrome c, and pro-caspase 9 come together to form a complex and this activates caspase 9

Answer 30

death ligands (Apo2L/TRAIL) bind to death receptors (DR4 or DR5) in order to recruit FADD to activate initiator caspase 8 or 10, which forms a complex, DISC, to activate effector caspase 3, 6, or 7 to cause apoptosis via CAD, Lamin, actin, adhesion molecules, etc. *the extrinsic and intrinsic pathways both lead to the activation of effector caspases *independent of p53 *mostly occurs through induced proximity mechanism Inhibits of this pathway: AKT and FLIP

Answer 31

DNA damage is detected by p53, which then signals the mitochondria/cytochrome c to leak out (also caused by ROS), which then activates initiator caspase 9, which then activates effector caspase 3, 6, or 7 to cause apoptosis *forms an apoptosome, which is a oligomerization mechanism complex

Answer 32

regulate apoptosis at the mitochondrial level by influencing the permeability of the mitochondrial membrane can be anti or pro-apoptosis Anti: Bcl-2 and Bcl xl Pro: bak, bad, etc. Only affect the intrinsic pathway because employed by p53

Answer 33

1.AIDS 2. Neurodegenerative disorders Alzheimer disease Parkinson disease Retinitis pigmentosa Cerebellar degeneration 3. Ischemic injury Myocardial infarction Stroke Reperfusion injury: blood returns to the tissue after ischemia (O2 deficiency) --> Tissue injury 4. Toxin-induced liver disease – more liver cells dying than produced ex. Alcohol

Answer 34

``` 1. Cancer Follicular lymphomas Leukemia Breast cancer Prostate cancer Ovarian cancer 2. Autoimmune disorders Systemic lupus erythematosus 3. Viral infections Herpesviruses, Poxviruses, Adenoviruses ```

Answer 35

includes events around the cell cycle checkpoints and the spindle assembly, which will control mitosis in cases of cell damage Mitosis and cell cycle are controlled by different checkpoints and proteins that will allow it to proceed in accordance to need, but if the cycle cannot stop before mitosis, their can be issues like aneuploidy ex. Spindle fibers are not released at appropriate time so they don’t pull the chromosomes appropriately causing a big problem in mitosis need it to abort the processes because you don’t want these cells to accumulate (with less or more chromosomes than needed creating chromosome instability or cancer) If occurs during metaphase/anaphase transition: caspase 2 is activated in response to DNA damage, mitochondrial membrane permeabilization, and release of cell death effectors

Answer 36

``` Cell-cycle-specific kinases *cyclin B1-dependent kinase Cdk1 – M- cyclin polo-like kinases Aurora kinases Cell-cycle checkpoint proteins, Survivin *P53 caspases Bcl-2 family members ```

Answer 37

2 prodomains from amino-termini are cleaved- discarded 2 small subunits from COOH termini cleaved and unite with 2 large subunits to active caspase Tightly regulated by Bcl2 family

Answer 38

Bax binds to outer mitochondrial membrane Facilitates the release of cytochrome c into cytosol Cyt. C binds adaptor protein- activation Adaptor-Cyt-c complex (7:7) A-Cc recruits procaspase 9 to the complex  Apoptosome Procaspase-9 activation leading to cascade of activating caspases which then induce apoptosis

Answer 39

itself acts antiapoptotic by inhibiting apoptosis by inactivating other members of “his” family: Bak, Bax & Bad Bad sequesters cell death inhibitory proteins such as Bcl2, but Serine/threonine protein kinase (Akt) inactivates Bad by phosphorylation leading to release of active Bcl2 Result: Apoptosis inhibited

Answer 40

Survival factors can bind to receptors on the cell surface An activation cascade includes activation of regulators of transcription to ctivate Bcl2 gene (nucleus) so the mRNA travels to cytoplasm where translation of Bcl-2 occurs, which inhibits apoptosis Nerve Cell Apoptosis: target cells secrete survival factor, and the nerve cells that do not have the factor undergo apoptosis to get rid of the extra nerve cells to make the processes more efficient

Answer 41

Myocardium Endothelium Extracellular matrix- cardiac jell in between First step in valve development- specification of cells that delaminate and move into cardiac jelly Endothelial-to-mesenchymal transformation Swelling of cardiac jelly and mesenchymal cells forming cushion Tapering, thinning to make the valve

Answer 42

NOTCH1-NOTCH4 Signaling pathway increases TGF-β, which increases the transcription factor “snail or Slug” activity, in turn causing down-regulation of VE-cadherin to decrease cell-cell adhesion causing the delamination of endothelial cells so cells can loosen from each other and growth via getting rid of contact inhibition Example of endocardial autocrine signaling

Answer 43

Restriction Endonucleases: cut at specific and they leave either sticky ends or blunt ends; the recognize these sites via a palindrome DNA ligase: anneals DNA together DNA polymerase: produces reverse complement DNA from a template; use Taq polymerase from hot springs so heat doesn’t denature it Reverse Transcription- cDNA made from RNA

Answer 44

Single-stranded DNA or RNA: cDNA, genomic fragments, synthetic oligonucleotides, RNA Identifies complementary sequence on larger single-stranded DNA or RNA Base-pairs with complementary sequence Annealing or hybridization

Answer 45

DNA fragments move toward anode (+) Separate based on size of DNA and percentage of gel Size determined relative to molecular markers Visualized with stain or by autoradiography DNA, RNA, or protein transferred to nitrocellulose sheets for blotting technique testing (S, N, or W)

Answer 46

Collections of DNA fragments Bacterial host or phage Genomic library is fragments of an entire genome Phage (20 kb inserts), BACs (150 kb) and YACs (1,000 kb) cDNA library contains just the expressed portion of the genome of a specific cell type under specific conditions Made from RNA using RT Plasmids (~2 kb inserts)

Answer 47

Southern: DNA bound by DNA probe Northern: RNA bound by DNA probe Western: proteins bound by Ab probe No alkali treatment for RNA or protein Western blot probed with antibody, not nucleic acid probe

Answer 48

``` Reaction contains - DNA template - dNTPS - One ddNTP DNA polymerase primer 5’ to 3’ Run on gel to separate by size Read bottom to top If you have the ddNTP, it terminates where it base pairs ex. ddATP will bind where A is supposed to be and the sequence will be terminated ```

Answer 49

Same principle as Sanger sequencing Different fluorolabel attached to each ddNTP (4 different colors) All 4 reactions performed in one tube electrophoresis performed in 1 lane of the gel (or column) Sequence read as bands pass the detector

Answer 50

Sanger: 4 tubes, 4 lanes on gel, radioactive, visualized by autoradiography Automated: 1 tube, 1 lane on gel (or column), nonrad!, visualized by fluorescent reader

Answer 51

``` Any change in the DNA sequence mutations variations between individuals SNP = single nucleotide polymorphism (point mutation) Deletions or insertions Expanded repeat sequences Can occur in genes or in noncoding regions of genome Majority are in non-coding regions ```

Answer 52

Denaturing, annealing, and extending Need: Primers (short oligonucleotides), dNTPs, Taq polymerase rapid amplification of DNA

Answer 53

mutation in CFTR gene that codes for the Cl- channel | 70% of cases = 3 base pair deletion coding for Phe

Answer 54

Repetitive sequences in tandem of variable length Highly variable regions of genome Variable number tandem repeats (VNTRs) aka, microsatellite DNA Unique to individual (or identical twins) Used for DNA fingerprinting and diagnosis Digest DNA at flanking sites Gel electrophoresis and specific probe Unique pattern and length of repeats DNA Fingerprinting: can show familial relationship; most done with PCR instead of restriction enzymes Diagnostic: Screen by digesting DNA with MstII and Southern blotting with a probe for the b-globin gene. example: sickle cell anemia normal vs. abnormal or both

Answer 55

Need to know EXACT mutation to test Depends on the sequence difference Prepare 2 oligonucleotides, one with normal and one with mutant sequence Easier with insertion/deletion than base-pair Label oligos, hybridize to spots of DNA on substrate under stringent conditions Should bind only if match exactly Normal sequence on top and abnormal on the bottom

Answer 56

Sequences the entire genome quickly Individual clones from a genomic library in YACs are broken up into smaller fragments by subcloning, which are then sequenced The results are fed into a computer that, by sequence comparison, aligns the fragments to reconstruct the entire genomic sequence

Answer 57

states that in cells with multiple X chromosomes, all but one are inactivated during mammalian embryogenesis. This happens early in embryonic development at random in mammals.

Answer 58

p or q arm, regions, bands, sub-bands

Answer 59

Chromosomal DNA is denatured and fixed, but the chromosomes retain their structure and remain visible under the microscope. A fluorescent DNA probe of the gene to be tested is then annealed to the fixed chromosomes. FISH analysis is used to test for deletions, the copy number of a gene, and of course its chromosomal location. Can only see large changes, not SNPs. FISH can be used with probes that hybridize with specific genes, or chromosome regions, or even repetitive sequences like Alu (forms own banding pattern) FISH can only test up to 12 chromosome pairs whereas CGH can test the full 23 pairs

Answer 60

allows scientists to visualize all of the human chromosomes at one time by "painting" each pair of chromosomes in a different fluorescent color. Combine probes that are specific to each chromosome to make it easier to sort them If you see red on a yellow chromosome, you can see a translocation Visualize large changes only

Answer 61

Structural: breakage or unequal crossing over during meiosis Numerical: nondisjunction

Answer 62

developed to survey DNA copy-number variations across a whole genome. With CGH, differentially labeled test (i.e. tumor) and reference (i.e. normal individual) genomic DNAs are co-hybridized to normal metaphase chromosomes, and fluorescence ratios along the length of chromosomes provide a cytogenetic representation of the relative DNA copy-number variation. Chromosomal CGH resolution is limited to 10-20 Mb -therefore, anything smaller than that will not be detected. A main disadvantage of conventional CGH is its inability to detect structural chromosomal aberrations, without copy number changes, such as mosaicism, balanced chromosomal translocations, and inversions.

Answer 63

arrays of genomic BAC, P1, cosmid or cDNA clones are used for hybridization instead of metaphase chromosomes in conventional CGH technique. Fluorescence ratios at arrayed DNA elements provide a locus-by-locus measure of DNA copy-number variation, represents a means of achieving increased mapping resolution. Basic assumption: ratio of binding of test and control DNA is proportional to the ratio of the concentrations of sequences in the two samples.

Answer 64

Newborn Screening Allows early detection and treatment PKU, galactosemia, hypothyroidism Hemoglobin disorders (HbS), muscular dystrophy Can be used to inform future reproductive decisions Heterozygote screening Find carriers in populations at risk Aid in reproductive decisions, prenatal diagnosis Pre-symptomatic diagnosis- for those at risk for certain disorders

Answer 65

``` Works when gene is not known, but has been localized Indirect method, follows linked markers Need to test multiple family members Must determine linkage phase Not all matings are informative Recombination events can interfere Highly polymorphic short tandem repeats (STRs) are improving utility Pedigree example/diagram ```

Answer 66

Need to know molecular basis for mutation Trio sequencing Much data now available about many genes Many genes have many mutated forms May be simple or difficult to analyze Various techniques can be applied if a restriction site mutated, can use RFLP Direct genetic diagnosis requires typing the disease-causing mutation itself (specific mutation must be known). It is potentially more accurate than indirect diagnosis and does not require family information.

Answer 67

``` Samples amniotic fluid Usually done at 15 to 17 weeks Visualize fetus with ultrasound Sample taken with syringe and needle Cells grown for karyotyping and other tests Cytogenetic tests take 10 to 12 days Pregnancy loss ~0.5% above background ``` Drawbacks: Cannot be done early in pregnancy Long wait for cytogenetic results delays decision-making Cytogenetic changes may occur during culture

Answer 68

Can be done earlier, at 10 – 11 weeks Transcervical approach possible Samples placental tissues

Answer 69

Cordocentesis or percutaneous umbilical blood sampling (PUBS) Obtain blood from umbilical cord Can test hematologic disorders directly Hemoglobinopathies, etc.

Answer 70

``` Fetal cells can cross placenta Isolated in first trimester FISH/PCR NIPS – noninvasive prenatal screening Cell-free fetal DNA ```

Answer 71

Somatic cell therapy: treat certain tissues, get gene expression, not passed on in germline, even partial expression can alleviate symptoms Gene replacement therapy: insert functional copy of defective gene, may need to be tissue specific, may require proliferating tissue, usually uses viral vectors

Answer 72

Adenovirus: well-studied, no need for proliferating cells, does not integrate into chromosomes, limited expression time, immune response, can target liver, get good systemic response Retroviruses: insert into DNA of dividing cells, can maintain long-term expression, can interrupt genes, need targeting Adeno-Associated Virus (AAV): Little immune response seen, small insert capability so far, expression level limited Lentivirus (HIV family), SV40, other viruses under investigation Human artificial chromosomes Naked DNA Liposomes

Answer 73

Antisense therapy Ribozymes RNA interference (RNAi) Much effort is directed at cancer and AIDS

Exam V Flashcards

(98 cards)