Paper 1 Flashcards
1
Q
nucleus
A
- contains genetic code; DNA nucleotide triplets code for mRNA codons, complementary to tRNA anticodons, code for an AA
- site of transcription
2
Q
rough endoplasmic reticulum/ free ribosomes
A
- site of translation
- synthesis of polypeptide chain, packaged into RER vesicle, transport to Golgi
- protein synthesis
3
Q
golgi
A
- modify (addition of carbohydrates)
- package in Golgi vesicles for exocytosis
- transports to cell membrane
4
Q
advantage of TEM over SEM
A
magnification
5
Q
maths
A
4.71 x 10^7
6
Q
DNA polymerase
A
- catalyses the condensation formation of phosphodiester bond between nucleotides, joining them together
- act on the leading strand
7
Q
percentage difference
A
(difference/original) x 100
8
Q
phosphorylation
A
- addition of a phosphate group by a catalyst
- changes the shape of the tertiary structure (bonds form in different places)
- makes active site complementary to specific nucleotides
- allows formation of ESCs
9
Q
graph of mitosis
A
- percentage of DNA undergoing mitosis
- uncontrollable cell division results in tumour suppression
- maximum 47%
- more DNA polymerase activated = faster DNA replication
10
Q
transcription
A
- DNA helicase breaks hydrogen bonds between complementary base pairs of DNA nucleotides
- (A-T, C-G)
- 1 template strand
- free, activated RNA nucleotides are attracted to exposed bases via hydrogen bonds in complementary base pairs
- (A-U, T-A, C-G, G-C)
- RNA polymerase catalyses the formation of phosphodiester bonds, joining nucleotides together
- Splicozomes splice the introns out of pre-mRNA to form mature mRNA
11
Q
translation
A
- mRNA leaves the nucleus via the nuclear pore
- mRNA attaches to the mRNA binding site of ribosome
- tRNA anticodons complementary to the mRNA codons attach to specific amino acids and transfer them to the ribosome, beginning at the start codon
- peptidyl transferase catalyses the formaiton of peptide bonds between adjacent carboxyl and amine groups of amino acids
- tRNA detaches and collects another amino acid; two tRNA molecules fit into the ribosome reading frame
- ribosome moves along mRNA until the stop codon is reached
- at the stop of codon, the polypeptide chain disconnects
- hydrogen bonds form in the secondary structure to form alpha-helices and beta-pleated-sheets
- hydrogen, ionic and covalent bonds form in the tertiary structure, creating the 3D shape for functionality
12
Q
gene mutation
A
a random and rare alteration in DNA nucleotide sequence
13
Q
gene mutations that have no effect
A
- occur in the intron region
- occur in the allosteric region
- occur via substitution mutation
14
Q
gene mutations that have a positive effect
A
natural selection
