Biomolecules/Chem
What reaction is used to join polymers? To break them apart?
Condensation/dehydration synthesis to join, hydrolysis to break
Draw out the amino acid subunit. Then connect it to another amino acid subunit (using what reaction?). Identify the peptide bond.
(Apparently I can't add images without the premium verison lol please see slide 10 in the class 3 slides gracias)
Name the three differences between RNA and DNA
U instead of T, single stranded, ribose sugar with OH instead of deoxyribose sugar with H
Name the modifcations that happen to RNA to make it suitable to leave the nuclues as mRNA.
5' cap, 3' poly A tail, intron splicing
True or false: DNA --> RNA --> ribosome
False! Central dogma: DNA (replication) --> RNA (transcription) --> Protein (translation) think of the final product in each process
List some of the differences and similarities between prokaryotes and eukaryotes
Similar: use DNA, ribosomes, have cell membranes; Differences: size (prokaryotes much smaller), nucleus, organelles
What are the 3 "special" amino acids and why are they special?
Glycine: R group is just an H so very little chem interactions; Cysteine: makes disulfide bonds with other cysteines; proline: R group binds with backbone, so can't form alpha helix
What are the 3 structural parts that make up DNA? Which parts make up the backbone?
Phosphate groups and deoxyribose sugar --> backbone; nitrogenous bases (A, C, G, T)
How does the cell determine where/when RNA transcription happens?
Transcription factors will bind to the promoter region.
What are the functions of the tRNA molecule?
Name the 4 main macromolecules and their monomers.
Carbs: sugars/monosaccahrides; Lipids: many subunits; Proteins: amino acids; Nucleic Acids: nucleotides
What would happen if you changed an amino acid in a binding site of an enzyme?
Because binding sites need many strong non-covalent interactions with their substrate, it is likely that the substrate won't bind as well.
Which base pairing is stronger? G/C or A/T? Why?
G/C is stronger because there are more hydrogen bonds (3) than A/T
Why do eukaryotic cells have introns?
It is thought that proteins can be "customized" because different exons can be spliced out with the introns -- called alternative splicing.
Why is one of the phospholipid tails bent? Does this help/hurt membrane fluidity?
Why is an ionic bond (or electrostatic interaction) the strongest noncovalent interaction?
Ionic is a fully negative/positively charged atom (think Na+ or Cl-). Hydrogen bonds are partial charges and not as strong. Van der Waals and hydrophobic don't involve charges and are weaker.
Name the bonds used for the 4 levels of protein structure.
1: Covalent peptide bonds between backbone; 2. H bonds between backbone (no R groups!) 3. Covalent disulfide bonds between two cysteines, non covalent interactions between backbone/R groups; 4. same as 3 but multiple proteins
DNA replication is often described as "bidirectional, semi-conservative, and asymmetrical". Explain what these terms mean using what you know about DNA replication.
Bidirectional: synthesis happens in both directions of the replication bubble. Semi-conservative: new molecules have one parent strand and one daughter strand. Asymmetrical: Always a leading strand and lagging strand
How could a cell regulate the amount of proteins it is making via mRNA?
You can make multiple proteins from one mRNA, you can also have proteins clean up mRNA to stop overproduction of a protein.
How does the length of the phospholipid tails affect membrane fluidity?
Longer tails = more LDFs = more interactions = harder to break apart = less fluid!
How do you identify a polar covalent bond vs a non-polar covalent bond?
In biology, usually bonds with O or N will be polar as O and N are highly electronegative. C-H bonds will always be nonpolar.
How would you identify which amino acids are nonpolar/hydrophobic vs. polar/hydrophilic?
Side chains with an O or an N are usually polar. Side chains with carbon rings or C and H only are usually nonpolar (also remember FAMILY VW). Charged aa have a + or - somewhere in the R group.
Describe all of the proteins involved in DNA replication and the process of DNA replication. Best if you can draw it out!
First ORC, then helicase unwinds, then primases adds RNA primers, then DNA polymerase makes new strands, then repair polymerase fixes primers + lagging strand, ligases glues all strands back together
What are some differences between replication and transcription? Try to name 5!
How it starts: ORC/promoter region; DNA/RNA, use two strands or one strand, different proteins used, RNA has processing but DNA doesn't
How do you know where to start translation?
You need to start at the 'AUG' start codon.