Biology Class 3 Flashcards

Question

Transposase

Answer 1

enzyme that cuts out transposon to relocate it somewhere else

Answer 2

1. IS Element: composed of regular transposon structure 2. Complex transposon: composed of transposae with some other genes flanked with inverted repeats 3. Composite transposon: composed of 2 transposae with central region in middle

Answer 3

1. Transposase gene codes for the "cut & paste" transposae enzyme 2. Transposae cuts transposon out & pastes it somewhere else

Answer 4

If one transposon is inserted in: Intergenic region, then likely no problems Coding region, then could disrupt the gene & cause less proteins to be formed If two transposons are inserted in: Same direction - DNA loops around and causes both to pair up & delete some coding area (therefore loss of genetic info) Opposite direction - DNA loops around and pair with each other BUT coding area is flipped (therefore less problematic, gene inversion, chromosome rearrangement)

Answer 5

Piece of DNA is flipped

Answer 6

Region of gene is duplication therefore the amount of mRNA increases = increases proteins therefore disrupts homeostasis

Answer 7

Due to faulty DNA repair (non-homologous end joining) or abnormal recombination between non-homologous chromosomes. Can cause gene fusion

Answer 8

Direct Reversal: Use white light to reverse damage Mismatch Repair Pathway: DNA polymerase & endonucleases do this; repairs DNA polymerases mistakes that happen DURING DNA replication; uses methylated strand as template to fix mismatch Base/Nucleotide Excision Repair: removes & replaces bad nucleotide DURING DNA replication Homology - directed Repair: intact DNA helps fix DS break that happen AFTER replication; use sister chromatid as template to repair broken strand & does it through homologous crossing over Non-homologous end-joining: patch the ends & ligase the DNA bc intact is better than broken; used for DS breaks too; no sister chromatids because happens BEFORE replication or in cells where replication doesn't happen; can be mutagenic

Answer 9

1. Semiconservative (one strand is old, one strand is new) 2. 5' - 3' 3. Requires a primer 4. Requires a template

Answer 10

Unwinds DNA

Answer 11

Cuts DNA, relaxes supercoiling

Answer 12

Synthesizes the RNA primer

Answer 13

Replicates DNA, proofreads, removes primer

Answer 14

Links okazaki fragments

Answer 15

1. At origin of replication, Helicase binds and so does Topoisomerase 2. RNA primer makes DNA in 5'-3' direction while reading in 3'-5' 3. DNA polymerase binds to primer & what makes DNA and elongates 4. Removes RNA primer and replaces with DNA 5. Ligase hooks okazaki fragments together

Answer 16

- Only 1 origin of replication - 5 DNA polymerases - goes through Theta replication - Multiple origins - Replication bubbles - several DNA polymerases composed of complex multisubunit enzymes

Answer 17

DNA Polymerase I: - low processivity - slow 5'-3' polymerase AND 3'-5' exonuclease - also a 5'-3' exonuclease to remove primer - adds nucleotides at RNA primer - DNA excision repair DNA Polymerase II: - 5'-3' polymyerase AND 3'-5' exonuclease - back up for DNA polymerase III - DNA repair DNA Polymerase III: - high processivity - fast 5'-3' polymerase AND 3'-5' exonuclease - adds nucleotides at ~400 bp downstream of ORI - main replicating enzyme - no known fx in DNA repair DNA Polymerase IV: - error prone 5'-3' polymerase activity - DNA repair DNA Polymerase V: - error prone 5'-3' polymerase activity - DNA repair

Answer 18

Elongates telomeres on parent strand of DNA 1. Includes its own RNA template 2. Reverse transcriptase activity (DNA from RNA)

Answer 19

DNA - double stranded - double helix - thymine - one type of DNA - Deoxyribose RNA - single stranded - Lots of different 3D shapes - uracil - multiple types of RNA - ribose

Answer 20

ribosomal RNA messenger RNA transfer RNA Others: heterogenous nuclear RNA (hnRNA) micro RNA (miRNA) small interfering RNA (siRNA)

Answer 21

- RNA polymerase binds at promoter and downstream at start site is where mRNA is made - RNA polymerase continues until it reaches stop site - RNA polymerase falls off at this point & mRNA leaves - DNA binding proteins bind to operator region (repressor - prevents more mRNA, enhancer - more mRNA)

Answer 22

1. Promoter Strong - lots of RNA Weak - less amount of RNA 2. DNA binding proteins Repressors Enhancers

Answer 23

Prokaryotes 1. Transcription and translation happens at same time 2. Polycistronic 3. No mRNA processing 4. 1 RNA polymerase Eukaryotes 1. Transcription happens in nucleus & translation happens in cytoplasm 2. Monocystronic 3. mRNA processing: 5' g cap, 3' a tail, splicing 4. 3 RNA polymerases (rRNA, mRNA, tRNA)

Answer 24

``` x = type of a.a. that's attached y = type of tRNA ```

Answer 25

aminoacyl tRNA synthetase

Answer 26

First two anticodon pairs bind normally (Watson-Crick pairing), third anticodon is more flexible ``` 5' Base in anticodon (tRNA) --> 3' Base in mRNA G --> C or U C --> G U --> A or G A --> U I -->A,U or C ``` * Sometimes adenine can be converted to inosine for more flexibility

Answer 27

Protein synthesis

Answer 28

Prokaryotic Large subunit - 50 s Small subunit - 30 s Total - 70 s Eukaryotic Large subunit - 60 s Small subunit - 40 s Total - 80 s

Answer 29

Svedberg tells you how fast it sediments (bigger the # = faster it sediments * Not addidtive because other factors affect sedimentation rates

Answer 30

1. mRNA (first codon) is present in the P site while the first tRNA is present in the A site 2. tRNA will translocate to A site and initiate translation 3. tRNA #2 will bind to codon at empty A site with a.a. attached 4. tRNA #2 and #1 a.a will bond and tRNA #1 now exits and tRNA will have 2 amino acids 5. Continue the process until termination codon is detected in A site

Answer 31

of amino acids x 4 = # of ATP needed 1 ATP for initiation 1 ATP for termination 2 ATP per tRNA loading 1 ATP for A site binding (1 less than original a.a) 1 ATP for translocation (1 less than original a.a)

Answer 32

1. Protein folding - aided by chaperonins 2. Covalent modification - phosphorylation, glycosylation, disulfide bridges, etc 3. Processing (most enzymes are made in non-active stage) - cleavage to activate protein (eg. zymogens) Pepsinogen (zymogen) ---> pepsin (active protein)

Biology Class 3 Flashcards

(57 cards)