MCAT Biology Exam Questions and Answers 100% CorrectMCAT Biology Exam Questions and Answers 100% CorrectMCAT Biology Exam Questions and Answers 100% CorrectMCAT Biology Exam Questions and Answers 100% CorrectMCAT Biology Exam Questions and Answers 100% Co
4 views 0 purchase
Course
MCAT
Institution
MCAT
Central Dogma - ANSWER - DNA → RNA → Protein
Purines
- which bases?
- how many rings? - ANSWER -
Pyrimidines
- which bases?
- how many rings? - ANSWER - Remember: "Pyrimidine" has a "y" in it; so does "cytosine" and "thymine."
MCAT Biology Exam Questions and
Answers 100% Correct
Central Dogma - ANSWER - DNA → RNA → Protein
Purines
- which bases?
- how many rings? - ANSWER -
Pyrimidines
- which bases?
- how many rings? - ANSWER - Remember: "Pyrimidine" has a "y" in it; so does
"cytosine" and "thymine."
Phosphodiester Bond - ANSWER - Joins one nucleotide to the next; between the 3rd
C of one ribose and the 5th C of the other to create the sugar-phosphate backbone
Directionality of DNA (convention) - ANSWER - 5' → 3'
(but strands are antiparallel, so other strand is opposite)
3' of DNA attached to ... - ANSWER - OH
5' of DNA attached to ... - ANSWER - Phosphate group
DNA composition - ANSWER - 1. Phosphate group
2. 5-Carbon sugar
3. Nitrogenous base (A, T, G, C)
Which nitrogenous bases form 2 hydrogen bonds? - ANSWER - A, T
,Which nitrogenous bases form 3 hydrogen bonds? - ANSWER - G, C
Replisome - ANSWER - Proteins that govern the replication process
Promoter - ANSWER - Required for transcription. Sequence of DNA nucleotides that
signals beginning point for transcription.
Primer - ANSWER - Required for DNA replication
Consensus sequence - ANSWER - Most common promoter sequences; closer the
DNA nucleotides are to the consensus sequence, the more tightly the RNA
polymerase can bind, which leads to more frequent transcription (and vice versa)
Origin of replication - ANSWER - Where replication begins. Prokaryotes have 1;
eukaryotes have many on each chromosome
DNA synthesis: direction of synthesis - ANSWER - 5' → 3'
(the DNA is read 3' → 5')
Steps of replication (5) - ANSWER - 1. Helicase unzips double helix
2. RNA polymerase builds a primer
3. DNA polymerase adds leading/lagging strands
4. Primers removed
5. Okazaki fragments joined
RNA vs. DNA: differences - ANSWER - RNA:
- C2 is oxygenated (has OH)
- Single stranded
- Uses uracil instead of thymine
- Can move through nuclear pores out of nucleus
,DNA
- C2 is deoxygenaged (has H)
- Double stranded (double helix)
- Uses thymine
- Stuck in the nucleus
Transcription - ANSWER - Process of making RNA (rRNA, mRNA, tRNA)
RNA polymerase - ANSWER - Synthesizes RNA in transcription
Transcription: Steps - ANSWER - 1. Initiation - transcription factors, transcription
initiation complex (including RNA pol) finds promoter
2. Elongation - Template/antisense DNA strand is read and complementary RNA
synthesized in 5' → 3' direction (same as DNA synthesis); DNA is read in 3' → 5'
(also same as DNA synthesis)
3. Termination - temination sequence marks end, special proteins dissociate RNA pol
from DNA
Gene regulation - ANSWER - Most occurs at transcription via repressors and
activators, which bind near promoter and affect activity of RNA polymerase
Operon - ANSWER - Entire transcript in a prokaryote; includes multiple genes
(polycistrionic). I.e., lac operon - operator, repressor, genes, promoter, etc.
RNA post-transcriptional processing - ANSWER - pre-mRNA altered in 3 ways:
1. addition of nucleotides
2. deletion of nucleotides
3. modification of nitrogenous bases
5' cap - ANSWER - Added to mRNA as an attachment site in protein synthesis and
protection against degradation by exonucleases. Done with GTP.
, 3' poly A tail - ANSWER - Added to mRNA to protect from exonucleases.
snRNPs - ANSWER - Recognize introns and snip them out
Intron - ANSWER - Non-coding region of mRNA. Is removed by snRNPs (and
spliceosome complexes) and then degraded in nucleus.
Exon - ANSWER - Coding region of mRNA. Remains after activity of snRNPs and
spliceosome. Then exits the nucleus for translation.
DNA denaturation: conditions, effects - ANSWER - Conditions:
1. Salt solution
2. High pH (basic) solution
3. High temperature
Effects:
- Double helix separates because hydrogen bonds are disrupted
- DNA with more G-C pairs (G-C forms 3 H bonds, while A-T has only 2) has a greater
Tm, so takes more energy to melt
Restriction Enzymes - ANSWER - - method bacteria use to protect themselves from
viruses is to cut viral DNA w/these (bacterial DNA is methylated, so differentiated)
- can form recombinant DNA (artificially) using these
Cloning DNA - ANSWER - Recombinant DNA can be placed in bacteria using a vector
(plasmid or virus), then grown. Screened by including an antibiotic resistance gene
and a lacZ gene to find which colonies actually took up the vector.
cDNA - ANSWER - Complementary DNA. Used often in cloning because has no
introns (and therefore is active). Produced in RT PCR from mRNA.
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller NursingTutor1. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $18.49. You're not tied to anything after your purchase.
