AQA GCSE Combined Science: Trilogy Biology Paper 2 (Foundation), 2022: Question 1

11 marks · Low Demand difficulty · Short Answer

Identify characteristics and concerns of GM crops, define genetic terms, and complete a Punnett square for cystic fibrosis inheritance.

Practise this question

Question

A multi-part biology exam question about genetics. It includes multiple-choice questions on GM crops, DNA coding for proteins, and genetic terms like recessive and heterozygous. It also features a Punnett square to complete for the inheritance of cystic fibrosis (Hh x Hh) and asks for the probability of a child having the disorder.
Question text

01 This question is about genetics.

01.1 Crop plants are genetically modified (GM) for useful characteristics.

Which useful characteristic are crops genetically modified for?

[1 mark]

Tick ( ) one box.

Fewer roots

Larger yields

Smaller fruits

01.2 What is one concern about GM crops?

[1 mark]

Tick ( ) one box.

GM crops will add to global warming.

GM crops will cause air pollution.

GM crops will harm wildlife.

GM crops will produce too much food.

Some inherited disorders are caused by a faulty piece of DNA.

01.3 What is the name of a piece of DNA that codes for a characteristic?

[1 mark]

01.4 DNA contains a code for making substances in the cell.

What type of substance is made using the DNA code?

[1 mark]

Tick ( ) one box.

Fat

Protein

Starch

Sugar

Cystic fibrosis (CF) is an inherited disorder.

The allele for having CF is recessive (h).

The allele for not having CF is dominant (H).

01.5 What is a recessive allele?

[1 mark]

Tick ( ) one box.

An allele that is always expressed.

An allele that is expressed if only one copy is present.

An allele that is only expressed if two copies are present.4

A man and a woman do not have CF. The man has the alleles Hh.

01.6 What word describes the alleles of the man?

[1 mark]

Tick ( ) one box.

Heterozygous

*03* Homozygous

Phenotype

01.7 The man and the woman want to have a child.

Complete Figure 1 to show the possible genotypes of the child.

Draw a ring around the genotype of a child who will have CF.

[3 marks]

Figure 1

Woman

H h

H

Man

h hh

01.8 What is the chance that a child of the man and the woman will have CF?

[1 mark]

Tick ( ) one box.

25% 50% 75% 100%

01.9 The woman is pregnant.

The woman can have embryo screening to find out if the child will have CF.

Suggest one reason why the woman might not want to have embryo screening.

[1 mark]

Mark scheme

Show the mark scheme The mark scheme for Question 1 provides the correct answers for each part. Key answers include 'larger yields' for GM crops, 'gene' for the DNA segment, 'protein' for the DNA product, and 'heterozygous' for the Hh genotype. It shows the completed Punnett square with genotypes HH, Hh, Hh, and hh, with 'hh' circled to indicate the child with cystic fibrosis, leading to a 25% probability.

Question 1

AO /

Question Answers Extra information Mark

Spec. Ref.

01.1 larger yields 1 AO1

4.6.2.4

AO /

Spec. Ref.

01.2 GM crops will harm wildlife 1 AO1

4.6.2.4

AO /

Spec. Ref.

01.3 gene(s) allow allele(s) 1 AO1

4.6.1.3

4.6.1.4

AO /

Spec. Ref.

01.4 protein 1 AO1

4.6.1.3

AO /

Spec. Ref.

01.5 an allele that is only expressed if 1 AO1

two copies are present– OMBINED SCIENCE: TRILOGY – – 4.6.1.4

AO /

Spec. Ref.

01.6 heterozygous 1 AO2

4.6.1.4

AO /

Spec. Ref.

01.7 offspring genotypes correctly allow 1 mark for 1 or 2 correct 2 AO2

mark with derived genotypes 4.6.1.4

1.8

hh circled 1

Woman

H h

H HH Hh

Man

h Hh hh

AO /

Spec. Ref.

01.8 25% probability must match 1 AO3

mark with – OMBINED SCIENCE: TRIderivations(hh)inquestionLOGY01.7– – 4.6.1.4

01.7

AO /

Spec. Ref.

ignore cost

01.9 any one from: 1 AO3

• it might harm the embryo / ignore harmful / dangerous 4.6.1.4

baby / mother unqualified 4.6.1.5

• it might cause a miscarriage

• they do not want to make a

choice about having an

abortion

• it is against their religious allow against their religion

beliefs

Total Question 1 11

How to answer it

Genetics, GM Crops and Inherited Disorders

What this question tests

This question assesses your understanding of Genetic Modification (GM), the basic structure of DNA and genes, and the use of Punnett squares to predict the inheritance of disorders like Cystic Fibrosis. It also touches on the ethical considerations of embryo screening.

Parts 01.1 & 01.2

Genetically Modified (GM) Crops

Correct Answers

  • 01.1: Larger yields
  • 01.2: GM crops will harm wildlife

Key Knowledge

GM crops are engineered to be "better" for farmers. This usually means:

  • Resistance to pests or weedkillers.
  • Higher yield (more food per plant).
  • Improved nutritional value.

Exam Technique

When asked for a "concern," think about biodiversity. A common worry is that GM crops might cross-breed with wild plants or reduce the number of insects/wildflowers in a field.

Parts 01.3 & 01.4

DNA and Genes

Correct Answers

  • 01.3: Gene (or Allele)
  • 01.4: Protein

The Central Dogma

DNA is the master code. A small section of DNA is called a gene. Each gene provides the instructions to build a specific protein.

Common Errors

Don't confuse starch or fat with the DNA code. DNA only codes for proteins (which then act as enzymes to make other things like fats).

Parts 01.5 & 01.6

Genetic Vocabulary

Correct Answers

  • 01.5: An allele that is only expressed if two copies are present.
  • 01.6: Heterozygous

Key Terms

  • Dominant (H): Expressed even if only one copy is present.
  • Recessive (h): Only expressed if two copies are present (hh).
  • Heterozygous: Two different alleles (Hh).
  • Homozygous: Two of the same alleles (HH or hh).
Parts 01.7 & 01.8

Inheritance Calculation

Predicting Cystic Fibrosis (CF)

Step-by-Step Punnett Square

The man is Hh . The woman is also Hh (she does not have CF but must have the 'h' allele for the question to work, though the diagram provides the letters for you).

H (Woman) h (Woman)
H (Man) HH Hh
h (Man) Hh hh
  1. Fill the boxes: Combine the top letter and side letter for each square.
  2. Identify the disorder: CF is recessive, so only hh will have the disorder.
  3. Calculate Probability: There is 1 hh box out of 4 total boxes.
  4. Convert to %: 1/4 = 25%

Mark Breakdown

01.7: You get 2 marks for correctly filling the genotypes (HH, Hh, Hh) and 1 mark for drawing a ring around hh .

01.8: This mark is "consequential"—it must match your drawing in the table!

Part 01.9

Ethical Considerations

Acceptable Answers

  • Risk of miscarriage.
  • Potential harm to the embryo or mother.
  • Religious or ethical objections to abortion (if the test is positive).

What NOT to write

Examiners will ignore mentions of "cost" or "expense." They also won't give marks for just saying it's "harmful"—you must specify what is being harmed (the embryo or the mother).

Topics

Biology · B6: Inheritance, Variation and Evolution

Question and mark scheme from the AQA GCSE Combined Science: Trilogy examination, Biology Paper 2 (Foundation), 2022. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.