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BMAT Section 2 2021 Answers Explained
Thank you for using this document to aid your revision for the BMAT
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This document contains in-depth explanations for
the answers to the BMAT 2021 Section 2 paper
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The author assumes no responsibility or liability for any errors or
omissions which may be present in this document
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1
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In the arteries,
atherosclerotic plaques can form and this narrows the lumen of such arteries, thus
reducing blood flow to the organs it supplies
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Stem cells are cells which don’t belong to any specific, functionally active cell type
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The
crucial aspect is that they’re capable of self renewal, which means they can replenish
the “pool” of stem cells as they differentiate
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e
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Multipotent: Even more differentiated stem cells, and can only differentiate
into closely related family of cells
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Unipotent: the most differentiated stem cells which can only differentiate to
a particular cell
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Communicable diseases are diseases which can spread from an
infected host to another unaffected individual e
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infectious diseases
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Created in 2022
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2
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Since the electronic
configuration of Z3- is 2,8,8, then atom Z must have the configuration 2,8,5
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Z must be a p block element as the 3rd shell has 5 electrons, and this can be
rewritten as:

(where the squared bracket tells us the electron configuration of the noble gas element
before addition of further electrons in the next highest shell)
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- S block: group number is either 1 or 2 (depending on number of outer shell
electrons)
- P block: group number is the number of outer shell electrons, plus 10
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Imagine the following scenario:

3
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Author: Shyam Parmar
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The weight of the ball is 50N whilst the magnitude of air resistance is 50N (stated in
question)
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e
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Since these 2 forces oppose each other then the net (resultant) force is 0N (they
cancel each other out)
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A net (non-zero) resultant force causes the object to accelerate (i
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increase it’s
speed in a given direction) in the direction of the net force
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e
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So statement 3 is
correct
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There are many ways to simplify this expression
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i
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If a term
with a power is itself raised to a power then the powers are multiplied together
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The x in the 3xy term increases the power of the x
in the numerator (x6) leaving x7
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4
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Author: Shyam Parmar
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5
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Statement 1 is wrong because at pH 9 (weakly alkaline) the time taken for browning
(pH9 – 6s) is much less than if the enzyme was placed in more acidic conditions (pH3
– 22s; pH5 – 10s) meaning the enzyme ‘works’ faster at a weakly alkaline condition
than in acidic condition (all else being equal)
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There is no data in the table showing how well the enzyme works (i
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time taken) in
between these 2 pH values
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Hence we can’t
conclude what the optimum pH is from the data availble
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Le Chatelier’s law essentially states that If you change the conditions in an
equilibrium reaction, then the position of equilibrium will change to counteract the
change you induced
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e
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e
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So increasing pressure in this case, will favour the forward
reaction (i
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the reaction which produces the fewest moles) to reduce pressure
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Statement 2 is wrong; the forward reaction is exothermic (releases heat) given the
negative enthalpy change, and the backward reaction is endothermic (absorbs heat)
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6
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Author: Shyam Parmar
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Statement 3 is wrong; the addition of a catalyst doesn’t change the position of
equilibrium, it just speeds up the rate of the forward and backward reaction equally
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The detector’s count rate, at any one time, is the sum of the background count rate
and the sample count rate
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Then 48 hours later, the count rate being displayed was 31/minute, hence the count
rate of the sample was 7/minute
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e
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6 hours
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D

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●
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8
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Simplifying the above gives:

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Going back to the first rule of surds, we can rewrite this as:

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The 3 statements given in the question are all consistent with an erythrocyte
(mature red blood cell)
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Taking each statement in turn:
- Statement 1 is correct; the solution carrying erythrocytes is the plasma
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9
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Author: Shyam Parmar
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-

10
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H
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This question tests factual recall of interpreting chemical test results
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Here are flame test colours for other metals:

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Potassium

Lilac

Sodium

Yellow/Orange

Lithium

Red/Crimson

Calcium

Orange/Red

Copper

Green

The fact that a green precipitate was formed upon addition of aqueous sodium
hydroxide shows that the inorganic salt must contain ferrous ions - Fe(II)
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Here are some
tests for identifying other anions:
Halide

Add aqueous silver nitrate and dilute
nitric acid
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Carbonate

11
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Gas (carbon dioxide) given off
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Author: Shyam Parmar
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●

Consider the following:

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The question is asking for the pressure when one of the largest sides of the cuboid is
resting on the horizontal ground
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Fortunately we can calculate the mass as we know the density and volume of
the object
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2m X 0
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(0
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1m X 0
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Created in 2022
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A
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Since the larger rectangle and small rectangle are similar, then all corresponding
sides will be in the same ratio
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Also lets compare the large rectangle with another small rectangle, side by side, so
that they’re both orientated in the same way:

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Since the top and bottom rectangles are similar, their corresponding sides will have a
common enlargement factor, which can be rewritten as follows:

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This then gives us:

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If we then substitute y in terms of x in the smaller rectangle we get the following,
with the ratio of the smaller side to the larger side apparent:

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Created in 2022
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A
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During the menstrual phase of the uterine cycle, there are low levels of
progesterone, which causes vasoconstriction of the arterioles which supply the lining
of the uterus (endometrium)
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During the luteal phase, there are high levels of progesterone, which maintains the
thick endometrium for possible pregnancy
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When oestrogen levels are high enough, there is an LH surge due to a switch from
negative feedback to positive feedback (usually oestrogen has a negative feedback
effect on LH) which causes ovulation
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Consider the following which shows the overall reaction in forming esters
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H

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Created in 2022
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Hence everything to the left of the

group of the ester (including the COO

group itself) was part of the carboxylic acid molecule, whilst everything to the right
was part of the alcohol molecule
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Using this principle, when looking at the specific ester in the question, we can
therefore say that the alcohol looked like this:

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The hydroxyl group is on carbon number 2 (centre of structural formula)
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Hence this
molecule is called propan-2-ol
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The question is asking how much work is done by the escalator when the person is
moved up the escalator
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Author: Shyam Parmar
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The height of the escalator is 6m (given that each step is 30cm tall and there 20 of
them), whilst the weight of the person is 800N
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e
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Hence work done is 4800J
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This
is because the depth (of the step) doesn’t go in the same vertical direction as the
height; it’s this vertical direction where the force is acting along
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e
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This automatically excludes options A-D as the gradient for these are
-0
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With this information, we can say the equation of the reflected line is:

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Where c is the y-intercept, which is to be determined
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Fortunately, we can use the coordinates (2,-3) which lies on the original line, as this
is a common coordinate in both equations (Think: the original line is reflected at x =
2, so the reflected line will intersect the original line at this x value, simply for the
fact that this is where the “mirror line” is)
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E

is reflected in a vertical “mirror line”

17
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Author: Shyam Parmar
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This question tests understanding of key ecological terms
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These include:
availability of food (whether that be plants or other animals); presence of parasites
or predators; competition between species (intra and inter-specific)
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These include:
light; temperature; oxygen; soil composition; water
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An example of this is between humans and the gut microbiota (since the gut
microbiota benefits from the environmental conditions and nutrients, whilst humans
benefit from microbiota producing essential vitamins and preventing pathogens from
colonising the large bowel where they mostly reside)
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Other ecological terms:

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Community: All populations of all the different species in a given habitat at a given
time
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Niche: The role that the organism has within the ecosystem
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Taking each statement in turn:
- Statement 1 is incorrect; temperature is an abiotic factor
- Statement 2 is correct; as the bacteria benefit from the nutrients in the
salivary glands of the octopus whilst the octopus benefits from the toxins the
bacteria produce (to kill prey and defend against predators)
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This statement would make
sense if it mentioned these species contributing to the community of
species
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D
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This question involves using the ideal gas law equation and realising what the
appropriate constants are at room temperature and pressure

where:

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Created in 2022
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31 (a constant)
T is temperature of a gas mixture or pure form (273K at room temperature)
n is number of moles

Start by taking a mental note of this formula but applied to this scenario:

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Some important points need to be addressed before progressing any further:
- In the exam, you won’t have the luxury of time nor a calculator in your
favour
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- 1 mole of any ideal gas occupies 22
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Hence there will be about 1 mole of
oxygen in 25 cubic decimetres as mentioned in the question (under STP)
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However, it is common
knowledge that oxygen makes up about 20% of an air mixture, so we can go in
reverse and divide 24 by 20%(or 0
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Note how the options (in the question) were largely
different from each other; this allowed us to round those complicated numbers to 1
significant figure and still choose the right answer
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This question requires us to use the formula:

19
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Author: Shyam Parmar
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20
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By substituting the relevant numbers and following through you should arrive as
follows:

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This question may look daunting at first, but it is a lot simpler to answer because the
question provides the cosine of the theta as ¾
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The benefit of this will becomes apparent
when you draw it out as follows:

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Remember that the cosine of an angle is the ratio of the adjacent side to the
hypotenuse, so cosine of theta in this case means that the ratio of the adjacent to
hypotenuse is 3:4 (see diagram)
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Author: Shyam Parmar
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21
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Let’s break it down:

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The question starts off by saying that a nucleotide has 3 subunits
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The question then goes on to say that a section of double stranded DNA has 600 of
these subunits, in other words this DNA section has 200 nucleotides (due to the 3:1
ratio)
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That means there are 144 guanine and cytosine nucleotides, so there must be 72
guanine nucleotides and 72 cytosine nucleotides (again, due to the complementary
pairing of these 2 bases)
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Author: Shyam Parmar
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22
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The question wants to use the most reactive group 1 metal (from the table)
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The question also wants to use (from the table) the group 17 element with the
highest boiling point
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We can write the balanced equation between Potassium and Bromine as follows:

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There will be 1 mole of potassium and 1 mole of Bromine at the start of the reaction
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5 moles of Bromine left after the
reaction, whilst all the Potassium will have reacted
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1 mole of Potassium Bromide has a weight of 119g (1 mole of a compound has a
mass equivalent to its relative formula mass expressed in grams)
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Author: Shyam Parmar
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23
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First calculate the weight of the cable:

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To calculate the magnitude of magnetic force we need to use the following formula:

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This gives us (writing in standard form can help so we can add all the indices up in
one attempt rather than having to deal with fractions):

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It’s obvious that the direction of the cable weight will be towards the ground; but
determining the direction of the magnetic force requires use of Fleming’s Left Hand
Rule:

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Align the first finger in the North direction and the second finger in the East direction
(due to the directions stated in the question) and you will find that the thumb will
point upwards
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So the magnetic force is -2N
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24
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Author: Shyam Parmar
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For these types of graphical questions, it may be helpful to draw a rough sketch to
visualise the information given
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This would look like the following:

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(note that it isn’t important to draw an X axis or Y axis here, as you just want a
mental picture of where the circle and tangent are located relative to each other in
2D space)
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We can work out the gradient of the radius that connects the
centre to the meet up point (6,7)
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Author: Shyam Parmar
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25
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This means that because the condition is autosomal recessive, then the
genotype responsible for suffering the disease is hh
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Therefore, both of their parents must have an h allele,
but as neither parent suffers from the disease, then they both must also have the H
allele i
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they’re heterozygous
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Hence both children must have inherited this h
allele from their father, and because neither child suffers from the disease they must
also have inherited the H allele from the mother i
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they’re both heterozygous
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Author: Shyam Parmar
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1) The “zoomed in” version of the pedigree diagram originally in the question,
shows that one of the sons suffers from the disease hence has the genotype
hh; he is homozygous recessive
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3) Drawing a Punnett square shows the likely genotype combinations for the
other children, but note that since none of the other children suffer from the
disease, they cannot be homozygous recessive (i
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hh)
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So the probability of childrens 5 and 6 being
heterozygous is ⅔ not ½
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C

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The oxidation state of nitrogen in
is 3-, as Calcium has a 2+ oxidation
state so that means both nitrogens need to ‘cancel out’ the total 6+ charge of the
calciums
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There the empirical
formula is

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The oxidation state of an ion is simply the charge of that ion, whereas in molecules,
the oxidation state is the hypothetical charge of the atoms, had the bonding been
ionic instead
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Likewise, if the source was accelerating and moving away from the observer then the
perceived frequency decreases whilst the wavelength increases
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e
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The train is approaching an observer
at a platform and is slowing down
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F

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Created in 2022
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Hence the frequency would be decreasing
towards
, which is the actual frequency being generated by the horn
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As the train is approaching, the perceived amplitude of the sound by the observer
will increase
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Author: Shyam Parmar
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