MCAT Biology Lec 2

group of proteins that govern DNA replication

prokaryotes

Yes, RNA

Initiation
- initiation factors find a promoter on DNA and assemble a transcription initiation complex, which includes RNA polymerase

RNA polymerase

2) elongation
3) termination

transcription level

several genes in a single transcript

operator + promoter + genes that contribute to a single prokaryotic mRNA

- codes for enzymes that metabolize lactose
- low glucose --> high cAMP
- cAMP activates CAP protein which beinds upstream to the promoter on lac operon.
- promoter is now activated

- if lactose is present, the lac repressor protein is inactivated.
- it then does not bind to the operator which is located downstream of the operon.

1) addition of nucleotides
2) deletion of nucleotides
3) modification of nitrogenous bases

small nucleor ribonucleoproteins that recognize nucleotide sequences at the ends of introns. They associate with proteins and loop the introns to bring the exons together.

a technique that allows scientists to identify nucleotide sequences by binding a known sequence with an unknown sequence.
- denature first and then allow separated strands to spontaneously associate with any other complementary nucleotide sequence.

artificially recombined DNA

restriction
palindromic

- recombinant DNA is placed in bacteria using a vector. The vector contains a gene for resistance to a certain antibiotic.
- The bacteria are then reproduced and an antibiotic is added to remove clones without the vector.
- also, the DNA is usually placed with an endonuclease that cuts the lacZ gene. When the lacZ gene is cleaved, the gene does not turn blue. If the lacZ gene is active it turns blue, meaning the DNA is not in that vector.

mRNA is reverse transcribed to form DNA

cDNA does not contain the introns that DNA contains.

- DNA is placed with primers (forward and reverse), heat resistant DNA polymerase, and nucleotides.
- Mixture is heated to denature DNA.
- Mixture is cooled to allow primers to anneal to complementary DNA strands.
- Mixture is heated to activate polymerase.
- Repeated many times to produce an exponential increase in DNA

same techniques. southern blot identifies specific sequences of DNA, northern blot identifies specific sequences of RNA.

- used to identify target fragments of known DNA sequence in a large population of DNA
1) DNA is chopped up into restriction fragments
2) fragments are separated through gel electrophoresis.
3) DNA is denatured into single strands.
4) Membrane blots the gel causing the DNA fragments to be transferred to membrane.
5) A probe is added, which marks the target fragment.
6) the membrane is exposed to radiographic film which reveals the location of the target fragment.

It detects a protein using antibodies.

identifies individuals instead of specific genes. They are the DNA fingerprints used to identify criminals in court cases.

more than one series of three nucleotides may code for any amino acid

any series of three nucleotides will only code for one single amino acid

20^200

- The large subunit + mRNA + small subunit
- Initiation is when methionine attaches at the P-site and signals the large subunit to join and form the initiation complex

sugars, lipids, or phosphate groups may be added to amino acids

this protein-RNA structure recognizes the signal peptide on the growing amino acid sequence and directs the ribosome complex to a receptor protein on the ER.

insertion or deletion in multiples other than 3

transposons are DNA segments that can excise themselves from a chromosome and reinsert themselves at another location

mutation that changes the organism even more, mutation that tends to revert the organism back to its original state

eight histones wrapped in DNA

diploid, haploid

cell begins to grow in size and produce new organelles and proteins.
passes G1 check point. If conditions are favorable for division, cells moves into S phase.

non growing state

replication of DNA

cell prepares to divide. organelles continue to duplicate. G2 checkpoint checks for MPFF (mitosis promoting factor). When it is high enough, mitosis is triggered.

chromosomes form, centrioles move to opposite ends, nucleolus and nucleus disappear, spindle apparatus begins to form

consists of aster (microtubules radiating from centrioles), microtubules growing from centromeres, and spindle microtubules connecting the two centrioles

structure of protein and DNA located at centromere of chromosomes

chromosomes align along equator

sister chromatids split, cytokinesis may start

nuclear membrane reforms, nucleolus reforms, chromosomes decondense, cytokinesis continues

spermatogonium or oogonium cell dafter replication occurs at the S phase of interphase

Meiosis II

Prophase I - homologous chromosomes pair up, crossing over may occur
metaphase I - line up as tetrads
anaphase I - separation of homolgues
telophase I - nuc membrane may or may not reform, cytokinesis may or may not occur

when the centromere of any chromosome does not split during anaphase I or II