Edexcel A level Biology pp1 marking scheme

Mark Scheme (Results)2022
Pearson Edexcel GCE
Biology
Paper 1: Advanced Biochemistry, Microbiology and Genetics

, Answer Additional Guidance Mark
Question
Number
1(a) An explanation that makes reference to two of the following:

• because DNA needs to be {amplified / replicated} (1)

• as only small samples are taken / to produce enough DNA (1)

• all copies of the DNA need to be identical (to the original sample) (2)
(1)


Question Answer Additional Guidance Mark
Number
1(b) An explanation that makes reference to two of the following:

• because of the {differences in / hypervariable regions} (in each ACCEPT unique DNA
individual's DNA) (1)

• so produce fragments of different lengths (1) ACCEPT each individual has different abundance of
different sized DNA (fragments) (2)
OR OR

• different {fragments / lengths} of DNA are separated out (1) ACCEPT fragments therefore move through gel at
different rates / smaller fragments move {further /
faster} / converse for larger

, Question Answer Additional Guidance Mark
Number
1(c)
The only correct answer is B

A is incorrect because child 2 has no matching bands with the father (1)
C is incorrect because child 2 has no matching bands with the father
D is incorrect because child 4 has no matching bands with either adult

Question Answer Additional Guidance Mark
Number
2(a)(i)
• glucose is a monosaccharide and maltose is {a disaccharide / ACCEPT maltose has a glycosidic bond and glucose (1)
made of two glucoses / made of two monosaccharides} (1) does not
glucose has 6 carbons and maltose has 12
glucose has the formula C6H12O6 and
maltose C12H22O11
ACCEPT a labelled diagram

Question Answer Additional Guidance Mark
Number
2(a)(ii) An explanation that makes reference to two of the following:

• neither sugars respired immediately because the yeast need to
{acclimatise / adjust to the conditions} (1)

• delay is longer for maltose as {enzymes need to be synthesised / ACCEPT glycosidic bonds have to be broken
maltose needs to be broken down into glucose} (1)

• respiration of maltose is faster (than glucose) as maltose has ACCEPT because maltose contains more energy /
{twice the number of sugar units / more glucoses / more maltose is a disaccharide and glucose is a (2)
hydrogens} (1) monosaccharide