How to Answer Discuss Questions

Discuss Questions
Discuss questions need you to describe or explain several
points and link them together in order to answer one overall
question.
Even if you don’t believe that you can answer a question to
Excellence level; every question has an Achieved or a Merit
level answer so by using these steps you can increase your
chances of gaining a good grade
How to answer a Discuss question
1) Read over the question and what it is that they want you
to discuss. Keep this in mind as you write your answer
2) Go through the guidance points one by one and (where
you can) write bullet points or statements that give
some detail on each point (SHOW WHAT YOU KNOW!!!)
3) If you know extra detail that hasn’t been suggested by
the guidance points but still seems relevant – PUT IT IN.
4) Put everything you have together either with by writing
entire paragraphs or a final summary sentence.
Worked Example ONE: MICRO-ORGANISMS
Explain the factors that limit the size of bacteria colonies.
In your answer you should talk about:
The conditions bacteria need to survive
Their life processes
For Achievement you should give 2 – 3 points such as
Bacteria need enough food, moisture and warmth to survive
Bacteria reproduce by Binary fission
Bacteria feed by extra cellular digestion
Bacteria produce toxins which can kill them
For Merit at least one point should be explained in suitable detail
The factors that limit the size of bacteria colonies are the availability of food,
moisture and the presence of toxins. Unless there is sufficient food available for
bacteria to break down for nutrients the bacteria cannot make copies of itself and
increase its numbers by binary fission. This limits the numbers present.
As bacteria go through their life processes they produce and excrete toxins.
These toxins build up in the area and kill off the bacteria. The size of the colony
depends on the balance between the number of bacteria being produced and the
number of bacteria being killed off by the toxins.
Worked Example TWO GENETICS
A couple has four children, all girls. What are the chances that there
next child will be a boy? Explain your answer.
In your answer you should talk about:
What chromosomes are needed for a boy to be born
Which chromosomes are provided by each parent
For Achievement you should give at least 2 facts.
To be a boy the child needs to have received a Y chromosome (from the father)
The father produces equal numbers of sperm carrying either the X or Y
chromosome. The mother provides only X chromosomes
The chances are 50%.
For Merit you should have a reasonable explanation.
Each child is a single and unique genetic event. While random chance could lead
to a higher proportion of males and females, there is always a 50:50 chance of
having a boy or girl. It depends on whether the sperm that fertilizes the egg has
an X chromosome (girl) or a Y chromosome (boy). Half the sperm provided by
the father has X and half have Y.

Worked Example THREE GENETICS
Facial dimples are a dominant genetic trait, caused by shortened facial
muscles which pull on the overlying skin when a person smiles. The
recessive trait produces longer muscles, so no dimples appear. D =
dimples, d = no dimples.
A married couple, both with dimples, have four children. One child has
dimples, the other three do not.
(a)
(b)
Give the genotypes for both parents, and explain why you chose
this answer.
The parents are surprised that only one of their children has
dimples like they do, and wonder what they will get if they have
another baby.
Discuss how the process of meiosis functions to produce children
both with dimples and without. Include why the parents are
surprised and state the likely outcome if another child was born.
Include a punnett square in your answer. Diagram/s may be
used.
(a) For Achievement your answer should have the correct genotypes (a)
Dd or heterozygous (Allow other letters if clearly heterozygous)
For Merit your answer should explain why the genotypes must be Dd (m)
Eg:
Both parents have the dominant trait (dimples) so can be DD or Dd. (or parents
can’t be dd or would have no dimples)
They must both be Dd so they can produce a dd child with no dimples / each
provide a d allele to produce a child with dd genotype (no dimples)
(b) For Achievement your answer should have TWO correct statements
OR ONE statement AND the punnet square. Eg:
Description / diagram of meiosis (a)
Variation in meiosis can be caused by crossing over / shuffling/ independent
assortment (a)
D d
D DD Dd
d Dd dd
Defines 2 of allele (different versions of a gene), phenotype (physical/observed
trait), gene (length of DNA coding for a trait) (a)
Next child has ¾ chance of dimples (a)
Only 1 has dimples due to chance / each baby has same chances (a)
For Merit your answer should include a correct punnet square AND
explanation of outcomes of meiosis OR outcome related to chance. (m)
If you use the terms allele and gene correctly you must use them correctly.
Explains meiosis process (may be annotated diagram) (m) OR
Meiosis is the production of gametes / sex cells, so produces cells with half the
number of chromosomes. These mix at fertilization, the dominant D will show if
present (m)OR
Both parents have both alleles, D and d, how these combine is random for each
child / not related to previous events.
Chance of dimpled child phenotype is still ¾ as in punnet even though it hasn’t
shown up as often as this so far. 75% chance will only be displayed in a large
sample, not necessarily in only 4 children (m)
AND
Correct Punnett square. (as above)
For Excellence your answer should discuss how meiosis produces can be
produced AND links the outcome to the statistical probability of it
happening. MUST include punnet square. (e)
Because both parents are heterozygous, they carry both dominant and recessive
alleles for the gene. In meiosis, the homologous pairs line up and are pulled
apart, ie the alleles are separated. Each gamete receives one allele for each
gene, ie 1/2 the genetic material of the parent. This combines randomly at
fertilization with another gamete to give the various outcomes dd, DD and Dd.
For a child to have no dimples it must inherit the recessive allele from both
parents. As shown in the punnett this should statistically happen ¼ of the time,
but each time is random /unrelated to previous outcomes, so it is quite possible
to not get correct ratios unless a very large number of children are born.
AND
Correct Punnett square.
(a)