Biomolecules/Chem
Explain the difference between a saturated and unsaturated lipid. What different properties do they have?
Saturated means there are no double bonds in the tails, unsaturated means there is lt least one double bond in the tails. Unsaturatured lipids are more bulky so it can't condense as much as saturated lipids.
pH or high temp can denature a protein. Yes, this process can be reversed if the pH/temp return to normal but only sometimes (if disulfide bonds or broken or protein needs a chaperone protein to fold again, it might not fold again)
Define the terms: nucleosomes, chromosomes, chromatin, histones
Histones are proteins that wrap DNA, many histones together is a nucleosome, many nucleosomes makes chromatin, condensed chromatin is a chromosome. There is only one strand of DNA per chromosome.
True or false: DNA --> RNA --> ribosome
False! Central dogma: DNA (replication) --> RNA (transcription) --> Protein (translation) think of the final product in each process
Explain the difference between peripheral membrane proteins and transmembrane proteins
Peripheral membrane proteins do not go *through* the membrane (they are above or below it). Transmembrane proteins go through the membrane.
Explain pH and what lower or higher pH indicates.
pH is a measurement of if a compound is an acid or a base. pH ranges from 1 to 14, with 1 being the most acidic and 14 being the most basic
List 5 different possible protein functions.
Chaperone protein, membrane protein, ATP-synthase, oxidizer/reducer, synthase, protease, etc.
Explain why DNA polymerase always synthesizes ___ to ___.
5' to 3' (this should be tattooed in your brain!) Because the chemistry of doing it this way allows it to fix a mistake (or mutation) if it makes one
3'-GCU-5'
What are the three rules of Cell Theory?
1. All organisms are comprised of one or more cells. 2. Cells are the smallest living thing. 3. New cells arise from cell division
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.
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.
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
What determines the reading frame in translation? Why is the reading frame important?
The start codon, 5' AUG 3'. If you have the wrong reading frame, the entire sequence will be read differently (note if you shift over by 3 nucleotides, the reading frame will still be the same!)
List some of the differences and similarities between prokaryotes and eukaryotes
Similar: use DNA, ribosomes, have cell membranes, make ATP; Differences: size (prokaryotes much smaller), nucleus, organelles
List the four properties of water that make it essential for life.
Water is polar, high heat storage capacity, high vaporization temp, cohesion vs adhesion
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 6 in the Proteins Slides gracias)
Draw/explain what role telomerase plays in DNA replication. Does it follow the Central Dogma?
Telomerase helps extend the end of the DNA using RNA templates (opposite of central dogma -- using RNA to make DNA) because the lagging strand will always have a gap.
Explain the 3 post-modificaitons after transcription.
5' cap, 3' poly A tail, splice out introns (keep the exons!)
Explain how the surface area to volume ratio limits cell size.
The bigger a cell gets (volume increases) the more materials it needs to live. However if the surface area is much smaller, the cell doesn't have enough surfaces to take in all the materials it needs to survive. The bigger the ratio, the better!
Name the 4 main macromolecules and their monomers. How are the monomers joined together to form polymers?
Carbs: sugars/monosaccahrides; Lipids: many subunits; Proteins: amino acids; Nucleic Acids: nucleotides; Joined by condensation reaction, broken apart by hydrolysis
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
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
Go from DNA --> RNA --> Protein with this DNA sequence (ignore the need for a start and stop codon) 5'-AACGCTGTCCGTAGCTGC-3'
RNA: '3- UUGCGACAGGCAUCGACG- 5'
Protein: N-Leu-Arg-Gln-Ala-Ser-Thr-C
What makes up the cell membrane? Explain how the cell membrane is like a fluid mosaic.
The cell membrane is made up of phospholipids (with a hydrophilic phosphate head and hydrophobic lipid tails) and proteins. The proteins and phospholipids can move around freely and are spread apart.