AQA A-level Biology paper 1 Exam 2024 Exam QUESTIONS & ANSWERS ( A+ GRADED 100% VERIFIED)

AQA
A-level
Biology
paper
1
Exam
2024
large
molecules
often
contain
carbon.
why?
-
CORRECT
ANS
they
can
readily
form
bonds
with
other
carbon
atoms.
this
forms
a
'backbone'.
other
atoms
can
then
attach.
describe
benedicts
test
for
reducing
sugars
-
CORRECT
ANS
add
equal
volumes
of
the
sugar
sample
and
benedicts
reagent.
heat
the
mixture
in
a
water
bath
for
5
minutes.
brick
red
precipitate
will
form.
what
is
a
reducing
sugar
?
-
CORRECT
ANS
a
sugar
that
can
reduce
(give
electrons
to)
another
chemical.
describe
the
benedicts
test
for
non
reducing
sugars
-
CORRECT
ANS
with
food
sample,
add
an
equal
volume
of
dilute
hydrochloric
acid
in
a
test
tube.
place
test
tube
in
water
bath
for
5
mins.
add
sodium
hydrogencarbonate
solution.
heat
resulting
solution
with
an
equal
volume
of
benedicts.
solution
for
5
minutes.
turns
orange/brown.
what
does
dilute
hydrochloric
acid
do
in
the
benedicts
test
for
non
reducing
sugars?
-
CORRECT
ANS
it
hydrolyses
any
disaccharide
into
monosaccharides,
thus
also
forming
reducing
sugars.
describe
the
structure
of
starch
-
CORRECT
ANS
chains
of
alpha
glucose
some
chains
are
branched=
amylopetcin
some
chains
are
coiled=
amylose
what
purpose
does
the
structure
of
amylose
serve?
-
CORRECT
ANS
makes
the
molecule
compact
so
it
is
stored
more
easily.
what
purpose
does
the
structure
of
amylopectin
serve?
-
CORRECT
ANS
more
surface
area
for
enzymes
to
work
on,
thus
glucose
molecules
can
be
released
at
a
much
quicker
rate. how
is
the
structure
of
starch
suited
to
its
function?
-
CORRECT
ANS
1.
starch
is
insolube
so
it
doesnt
affect
water
potential
2.
it
is
large
enough
that
it
doesnt
diffuse
out
of
cells
3.
compact
enough
so
that
a
lot
of
it
can
be
stored
in
a
small
space
4.
branched=
each
end
can
simultaneously
be
acted
on
by
enzymes,
so
glucose
is
quickly
released
how
is
the
structure
of
glycogen
suited
to
its
function?
-
CORRECT
ANS
1.
insoluble,
so
no
effect
on
water
potential
of
cell
2.
insoluble,
so
doesnt
diffuse
out
of
cells
3.
compact,
a
lot
of
it
can
be
stored
in
a
small
space
4.
very
highly
branched=
each
end
can
simultaneously
be
acted
on
by
enzymes,
so
glucose
is
quickly
released
why
do
animals
need
highly
branched
glycogen?
-
CORRECT
ANS
because
animals
metabolic
rate
is
faster
than
plants
and
so
needs
glucose
to
be
released
quicker.
describe
the
structure
of
cellulose
-
CORRECT
ANS
made
up
of
straight
chains
of
beta
glucose
the
chains
are
parallel
to
each
other,
so
H
bonds
form
cross-linkages
all
the
H
bonds
together
strengthens
the
cellulose
forms
microfibrils
draw
alpha
and
beta
glucose
-
CORRECT
ANS
how
does
the
structure
of
triglycerides
relate
to
their
properties?
-
CORRECT
ANS
1.
triglycerides
have
a
high
ratio
of
energy-storing
carbon-hydrogen
bonds
to
carbon
atoms,
so
its
a
good
source
of
energy.
2.
low
mass
to
energy
ratio,
so
theyre
good
energy
storage
molecules.
3.
large
and
non-polar,
therefore
insoluble,
therefore
don't
affect
osmosis.
4.
high
ratio
of
hydrogen
to
oxygen
atoms,
so
can
release
water
when
oxidised,
hence
provide
a
source
of
water what
are
the
roles
of
lipids?
-
CORRECT
ANS
1.
source
of
energy
2.
waterproofing
3.
insulation
4.
protection
how
does
the
structure
of
phospholipids
relate
to
their
properties?
-
CORRECT
ANS
1.
polar,
therefore
will
position
itself
to
form
a
bilayer
2.
the
structure
allows
them
to
form
glycolipids
by
combining
with
carbohydrates
within
the
cell-surface
membrane.
these
are
important
in
cell
recognition.
draw
the
structure
of
an
amino
acid
-
CORRECT
ANS
draw
how
a
dipeptide
forms
-
CORRECT
ANS
what
is
meant
by
'primary
sequence'
of
a
protein
-
CORRECT
ANS
The
unique
sequence
of
amino
acids
that
make
up
a
protein
or
polypeptide
chain
what
is
meant
by
'secondary
sequence'
of
a
protein
-
CORRECT
ANS
The
way
in
which
the
primary
structure
of
a
polypeptide
chain
folds
e.g.
alpha
helix
or
beta
pleated
sheets.
shape
is
held
by
H
bonds.
what
is
meant
by
'tertiary
sequence'
of
a
protein
-
CORRECT
ANS
This
is
the
overall
3-D
structure
of
the
protein.
The
shape
of
the
protein
is
held
together
by
H
bonds
and
ionic
bonds
and
disulfide
bridges.
what
is
meant
by
'quaternary
sequence'
of
a
protein
-
CORRECT
ANS
If
a
protein
is
made
up
of
several
polypeptide
chains
that
are
linked
in
various
ways,
the
way
they
are
arranged
is
called
the
quaternary
structure.