UCF Molecular Cell Biology Exam 1Actual Questions With Correct Detailed Answers.

Cell surface area to volume ratio - correct answer As a cell's size increases, its volume increases much more rapidly than its surface area. Smaller cells having a large ratio of surface area to volume means that they can have more communication. This is why cells are so small. Defining feature of eukaryotes - correct answer Nuclear envelope Structure of an amino acid - correct answer Alpha carbon is the center, amino group on the left, R group on the bottom, and carboxylic acid on the right. primary structure of protein - correct answer sequence of amino acids in poly peptide chain Non polar amino acids - correct answer hydrophobic, cluster at the core of the protein because the side chains are neutral Polar and charged amino acids - correct answer Tend to be on the outside of the protein, syrine, threonine, tyrosine can be phosphorylated Secondary structure of a protein - correct answer protein structure is formed by folding and twisting of amino acid chain. Helical structure, alpha helix or beta sheet. All held together by weak interactions between amino acids in a polypeptide. Only portions Chaperones - correct answer Proteins that recognize proteins being assembled in ribosomes and help them fold correctly into the tertiary structure tertiary structure - correct answer The third level of protein structure; the overall, three-dimensional shape of a polypeptide due to interactions of the R groups of the amino acids making up the chain. Quartenary Structure - correct answer When multiple polypeptides are forming a structure ex. Elastin disulfide bonds Disulfide bonds - correct answer Strong chemical side bonds that can only be broken by chemical solutions. Oxidation reaction. ME is a reducing agent Fibrillar collagens - correct answer the major structural proteins of connective tissues, are built of triple helices of procollagen polypeptides TSE - correct answer transmissible spongiform encephalopathies. Caused by prions. Damage human brain tissue regulation of gene expression - correct answer Determines the amount of protein produced Control of protein function - correct answer the protein is synthesized but its activity is restricted according to the needs of the cell ex. Phosphorylation catalyze by protein kinase. Might require phosphorylation for activation or deactivation ex. Binding of specific ligands. May create a binding site when they fold. Like cAMP binding to proteins due to weak interactions in pocket allosteric regulation - correct answer Importin - correct answer transport receptor that binds to the NLS of the cargo and interacts with the nuclear pore NLS (nuclear localization signal) - correct answer A short amino acid sequence that marks a protein for delivery to the nucleus. Ubiquitin - correct answer A protein that attaches itself to faulty or misfolded proteins and thus targets them for destruction by proteasomes Proteasomes - correct answer A giant protein complex that recognizes and destroys proteins tagged for elimination by the small protein ubiquitin. What form is genetic material in interphase? - correct answer Chromatin Heterochromatin (10%) - correct answer Eukaryotic chromatin that remains highly compacted during interphase and is generally not transcribed. Epigenetic. By centromere and telomere. Euchromatin (90%) - correct answer The less condensed form of eukaryotic chromatin that is available for transcription. Nucleolus - correct answer Lots of transcription activity due to ribosomes. Contains many copies of genes that have code for ribosomal dna constitutive heterochromatin - correct answer Regions that are always heterochromatic Permanently inactive with regard to transcription Usually contain highly repetitive sequences facutlative heterochromatin - correct answer Contain genes but become heterochromatic depending on cell type. Responsible for cell differentiation. Inherited axia - correct answer A piece of chromosome 4 becomes attached to chromosome 12. Characterized by progressive deterioration of motor skills Transposition - correct answer movement of DNA segments within and between DNA molecules Reading frames - correct answer How a single locus can produce more than one product Two types of repetitive DNA - correct answer Interspersed- not clustered but scattered Satellite/simple- Smaller, simpler, clustered Reassociation Assay - correct answer Using a restriction enzyme, putting the dna in boiling water, denaturing the dna, result is single strands dna allow dna to cool and reassociate as dna cools, the single strands will find their complementary strands measure fraction remaining single stranded