Cells and Macromolecules
No structured nucleus (nucleoid)
• DNA is circular
• Lack complex membranous organelles
– No mitochondria
– No chloroplasts
– No endoplasmic reticulum
• Cell walls contain peptidoglycans
– (meshlike polymer of sugars+amino acids
that contribute to the cell wall)
What are the main 6 protein functions?
Regulation
Signaling
Enzyme
Structure
Movement
Transport
How does the single-stranded shape of RNA aid it?
The single strand allows RNA to take functional shapes, while the double-stranded nature of DNA makes it too stable to change form.
What are the 3 modifications of Transcription Elongation
RNA Capping, RNA Splicing, RNA poly-adenylation
What is the anticodon of tRNA
The region of tRNA that contains 3 nucleotides that are complementary to 3 nucleotides on the mRNA, which is called the codon.
Eukaryotes are similar to Archaea and Bacteria in what way?
Eukaryotes are most similar to Archaea in their machinery for replication, transcription, and translation, but are often more similar to Bacteria in their apparatus for metabolism.
What is the Amino Acid and its sidechain (polar, nonpolar) whose three-letter code is Ile, Asp, and Tyr
Isoleucine is nonpolar
Aspartic acid is negative
Tyrosine is polar
What are the 3 steps of Transcription
Initiation
Elongation
Termination
What is the difference between Mature and Premature RNA
Premature RNA still has introns, and Mature RNA does not.
Amino acids get attached to tRNAs by aminoacyl-tRNA- synthetases
How did mitochondria and chloroplasts evolve?
Likely originated from aerobic bacterium
that was engulfed by an archaeal anaerobic
cell. They formed a symbiotic relationship
What are the differences between alpha helices and beta sheets?
Alpha Helices
Side chains are sticking out, and its in a helical shape
Beta Sheets
Neighboring segments of the polypeptide backbone are aligned in a similar orientation, whether in parallel or antiparallel direction.
What are the General Transcription Factors of Initiation
TFIID, TBP, TFIIH
What are the 3 recognition points of splicing
GU -- A -- AG
What would happen to Translation if peptidyl transferase was not present?
A peptide bond is not formed, so the protein is malformed.
If the cell was low on Calcium what could help fix this?
Smooth ER
What are the 4 structures of protein? Describe them.
Primary, Secondary, Tertiary, Quaternary
Primary is the amino acids
Secondary is the alpha helices or beta sheets
Tertiary is the hydrophobic or hydrophilic shape,
Quaternary is the structure of multiple proteins
What are 3 ways that TFIIH aids in transcription
Contains a Helicase Subunit
Phosphorylates the C-terminal domain (CTD),
also called the C-terminal tail.
Phosphorylation of the RNAPII CTD helps RNAPII detach from the transcription initiation complex for the next step: elongation
What would happen if SR proteins were missing?
nothing would bind to exon sequences and help define exons, so splicing would be inaccurate.
If a protein misfolds, what would the cell use to correct it?
Molecular Chaperones
What are the 4 major macromolecules and what are their roles?
Protein - Enzymes
Carbohydrates - Energy
Lipids - Form Cell Membrane
Nucleic Acids - Form DNA and RNA
What are the bonds in the tertiary structure of proteins
1. ionic bonds
2. H+ bonds in AA side chains
3. Hydrophobic Clustering
4. Disulfide Bonds
5. Metal Ion Coordination Complexes
What do the 3 RNA polymerases encode
RNAP I and III transcribe genes encoding tRNA, rRNA, and other small RNAs. RNAP II transcribes most genes, including all that encode proteins
How would an RNA polymerase missing PAP affect mRNA
The missing PAP would mean the Mature mRNA would be too short and the poly-A-binding proteins would not bind.
A cell has no Ubiquitin. What could be some of the effects of this? Be in Detail
Proteasomes do not bind to misfolded proteins. Misfolded proteins are not destroyed, leading to errors and failed processes.