is it for dna replication, protein synthesis or both, like which specific bits
i just kept reading over it tbh it was one of the easier parts of mod 5 for me because we had a whole assessment just on polypeptide synthesis and i did a lot for that (still struggling with mitosis and meiosis though)
You need to remember all of them
DNA replication - I’ll make a step by step list on how it goes:
1. Helicase enzyme unzips the double stranded DNA molecule on one strand. The separated strands are the template strand, which will form the basis of what the new strand will be. The gap between the strands is called replication fork
(fork in the road).
2. Primase enzyme adds primers to the broken up nucleotides, where free-floating nucleotides can join to the strands.
(Think of priming before painting).
3. DNA polymerase adds these nucleotides to the strands, starting from 5’-3’ (this is the leading strand, as it moves towards the direction of DNA with 3 carbon molecules on the phosphate group. Polymerase adds this pretty straightforwardly to the leading strand, and checks for any errors.
4. The other direction from 3’-5’ is known as the lagging strand. DNA polymerase adds these differently by segmenting the lagging strand into ‘
Okazaki Fragments.’ These have primers on them and are done a few at a time from the phosphate end so that both the parent and daughter strands can have nucleotides attached.
5. Exonuclease enzyme removes the primers
(think ex like the X as a delete button).
6. Ligase enzyme
(the gluing enzyme) joins the strands together securely, which reconnects the daughter strands to form a functional DNA molecule. Same as for the parent strand.
———
we call this process semi-conservative cause it uses the original DNA molecule as a template to create a new one.
Protein synthesis is pretty much polypeptide synthesis (polypeptide = many peptides or amino acids in a long chain. Once it is complete, it folds into the protein.)
that’s usually a big part when they have a question about like a genetic disorder caused by a mutation to the nucleotides affecting proteins. You should be familiar with how that works since u did an exam.
Meiosis and mitosis i gotta revise a bit more, but way I remember it.
MITOSIS = only 1 phase, used for somatic cell replication and repair. Basically it has all the traditional steps (interphase, prophase, anaphase, metaphase, telophase, cytokinesis). The cells created from this are called
diploid cells that are created, because two are made.
MEIOSIS = OCCURS BEFORE FERTILISATION; THERE ARW TWO PHASES.
-during prophase I, the homologous chromosomes randomly cross over to create new alleles. then, during meiosis II the chromosomes split into four haploid (haploid = half a chromosome) cells (individual sister chromatids) which form your gametes (sex cells—> sperm/ova depending on sex)
hope this helps
its okay we CAN DO THIS
