AQA A-level Biology 7402 - Paper 1 - 6th June 2019

Anyone got advice on the questions about statistical tests? You know when they ask which test to use and why? Really been letting me down on the mocks

the only one i can remember is that when the question involves expected values and an observed values, it's chi squared

Anyone got advice on the questions about statistical tests? You know when they ask which test to use and why? Really been letting me down on the mocks

during transcription, is it RNA polymerase that breaks the hydrogen bonds between dna strands or is it DNA helicase? I've read different things in different textbooks and online

dna helicase

DNA Helicase, try and think H for hydrogen
RNA polymerase forms the phosphodiester bonds, similarly, think P for Phosphate.

hope that helps

so is the CGP revision guide wrong? it says "Transcription starts when RNA polymerase attaches to the DNA double-helix at the beginning of a gene. The hydrogen bonds between the two DNA strands in the gene break, separating the strands." later on it talks about the RNA polymerase also joining up the nucleotides... so they say it does both?

so is the CGP revision guide wrong? it says "Transcription starts when RNA polymerase attaches to the DNA double-helix at the beginning of a gene. The hydrogen bonds between the two DNA strands in the gene break, separating the strands." later on it talks about the RNA polymerase also joining up the nucleotides... so they say it does both?

What type of topics came up?

In AQA PPQ I have done it's always DNA Helicase to unwind the DNA strand and RNA polymerase to join the nucleotides together by reforming the H bonds

so is the CGP revision guide wrong? it says "Transcription starts when RNA polymerase attaches to the DNA double-helix at the beginning of a gene. The hydrogen bonds between the two DNA strands in the gene break, separating the strands." later on it talks about the RNA polymerase also joining up the nucleotides... so they say it does both?

this is correct but it doesn't reform h bonds, phosphate bonds

can someone confirm this?

RNA polymerase forms the phophodiester bonds between the free-floating RNA nucleotides, there wont be any hydrogen bonds formed because resulting mRNA/pre-mRNA strand in prokaryotes/eukaryotes respectively is single stranded.
Also just to note, RNA polymerase does break the hydrogen bonds in prokaryotes only, it's DNA helicase in eukaryotes.

I though RNA polymerase helps reform the hydrogen bonds in the DNA strand so it is a double helix again

Thanks, I'll send the link they were posted on TSR. and don't worry about sending anything in return's fine. The booklets are REALLY useful i've used both AS ans A2 and practiced 2 paper 1 papers and got A grades on both really hoping for an A* but i guess maths and practicals are letting me down.
https://www.thestudentroom.co.uk/showthread.php?t=5062288

does anyone have any really hard data application questions for biology, like the xylem one from last year ??