Nucleic Acids
What bond connects sugars and phosphates together in DNA?
phosphodiester bond
What bond is between amino acids in a polypeptide?
Peptide bond
Which enzyme unravels the DNA double helix to reduce torsional strain
Where does translation take place?
In ribosomes (either free floating or on the RER)
How can DNA be the same in every cell yet every cell look and function differently (have different transcriptomes/proteomes?)
Epigenetics - genes can be turned on/off and/or the central dogma processes are regulated (gene expression)
What nitrogenous base is found in RNA instead of thymine? What type of nitrogenous base is it?
Uracil, pyrimidine
When more than one polypeptide is bonded together
What is the function of primase?
Primase lays down RNA primers to tell DNA pol III where to begin replication
What are the names of the strand mRNA is copied from vs the other strand?
mRNA copies from the template/antisense strand
The other strand is the sense/coding strand
What are the two types of transcription factors and what do they do?
Activators bind to enhancer sites and increase transcription. Repressors bind to silencer sites and decrease transcription.
No, the two strands are antiparallel so one will run 5' to 3' and the other will run 3' to 5'. The 3' end is where the sugar hangs off, the 5' end is where the phosphate group hangs off.
How can proteins be modified after being made?
Disulfide bonds, conjugation, chemical modifications, proteolytic cleavage
Name two functions of DNA polymerase III
What is the function of a signal sequence on mRNA? What type of protein will be made?
A signal sequence transfers the mRNA + ribosome to attach to the rough ER so that after being made the protein will be sent extracellularly
Proteins can be degraded by proteasomes via the process of ubiquitination
Name two similarities and two differences between DNA and RNA
Similarities: nucleic acids, nucleotides, have sugars and phosphate groups and nitrogenous bases, involved in transcription, etc.
Differences: T in DNA U in RNA, RNA can leave the nucleus, DNA is double stranded, RNA has ribose sugar, etc.
Name at least 4 bonds/interactions that are present in the tertiary structure of a protein
What is the difference between DNA pol I and ligase?
DNA pol I removes primers and fills them in with nucleotides. Ligase phosphodiester bonds the new nucleotides together
What are the 3 modifications that must be made to mRNA before it leaves the nucleus?
5' methyl cap, 3' poly A tail (adenylation), introns removed (may be alternatively spliced)
How can histones be modified to both increase and decrease transcription?
If histones are methylated, transcription is decreased
If histones are acetylated, transcription is increased
What is Chargaff's rule
The amount of As will equal Ts and Cs will equal Gs (or amount of pyrimidines and purines will be equal)
Why are globular proteins soluble in water but fibrous proteins are not?
Globular proteins have polar amino acids on the outside, fibrous proteins have nonpolar amino acids on the outside
Why do Okazaki fragments occur?
Since DNA pol III can only build nucleotides 5' to 3', on one strand, it will build away from the movement of helicase, so it will constantly have to restart replication
Describe the elongation + translocation steps of translation
What is the role of inducers on the lac operon?
Lactose is an inducer that binds to the repressor of the lac operon, removing the repressor and allowing for the transcription of the lactose metabolism associated genes by RNA polymerase