clazah attached might be referring to membrane bound antibody receptors (like God said). That would include B cell receptors (not T cell receptor though because they're not a type of antibody). Free antibodies would just be the antibodies produced by plasma B cells to target specific antigens, causing opsonisation, agglutination, neutralisation, etc.

Edit: Haha bioho4! Two minds think alike!

        clazah 26 or 28 ATP (it's on the biology FAQ document on the VCAA website, as most textbooks have the numbers wrong).

          can somebody please explain this multiple choice question: The insulin produced by recombinant DNA technology is.. the answer was; produced from human insulin mRNA.

            clazah
            Universal = Same codons code for the same amino acids in different species. This is all about the "universal" nature of the codon to amino acid system.

            Degenerate = Multiple codons code for the same amino acid -> Results in a level of redundancy, whereby some mutations won't actually alter the amino acid (silent mutation)

              I was doing a multiple choice question from the practice exams Nelson net provided, and one of the questions implied that you knew the difference between degeneracy and redundancy.
              Is there a difference at all?

              Thanks

                Christ I know which question your talking about, and I was suggested to ignore this question, but just searching it on google wasn't much help and seems like more of a niche thing rather than something were likely to be assessed on

                  chemistry1111 No, trp is an amino acid and its not because of its toxicity the trp operon exists, but rather its synthesis is very energy costly, so continual expression of the trp genes could deplete the cell of ATP. And that's why these structural genes are regulated in an operon to conserve this ATP when trp is already present

                    clazah I was confused about this trial question too, and instead I chose C, and I confirmed with my teacher that B wasn't the best answer out of them

                        tubes
                        B is the best answer and here is why.
                        When DNA is needed to be inserted into the plasmid of a bacteria, it must not contain the introns. This is due to the prokaryotic DNA not containing introns and hence does not undergo RNA processing.
                        The reason the human insulin is produce by the human insulin mRNA is because the human mRNA does not contain introns. The enzyme invertase is then used to convert the intron free mRNA in to DNA strand, that does not contain introns. Hence DNA is able to be inserted into the bacterial plasmid to produce the correct gene produce, insulin.

                        I hope this makes sense

                            Hey i need help with the answer for 9a for the sample exam, my teacher said it was homo erectus but im still confused

                              Also for 10d im unsure about the marking

                              vcaa exam 2018 question 4a.
                              Draw a labelled diagram to illustrate endocytosis of botulinum toxin into nerve cells.

                              Is this still required to know or not?
                              Thanks

                                chemistry1111 I believe endo and exocytosis is still required knowledge, haven't seen any information saying it isn't needed anymore

                                  md2112 what was the explanation given for saying it's homo erectus? Denisovans makes the most sense imo because its the only ancestral species that shares DNA with Indigenous Australians, as said in the article in the question

                                    Christ Hi! Yes I understand the fact about the mRNA not containing introns, however if you read the entire sentence together "The insulin produced by recombinant DNA technology is produced from human insulin mRNA," though accurate is not as good as "The insulin produced by recombinant DNA technology is produced by a cloned human insulin gene."
                                    And the reason why C is a better answer is because the mRNA undergoes further processing as you mentioned to convert into into DNA, and hence its not actually the mRNA producing the insulin but rather the copy DNA produced by Reverse transcriptase (invertase in an enzyme that catalyses sugar btw). Thus C would be a better answer