1. Nicotine and alcohol are drugs that affect the brain.
1. (a) (i) What is the correct description of both nicotine and alcohol?
[1 mark]
Tick () one box.
illegal, medical drugs
illegal, recreational drugs
legal, medical drugs
legal, recreational drugs ✔
1. (a) (ii) Why do people find it difficult to stop smoking?
[1 mark]
_Ans: A cigarette is a drug. People can becomeaddicted to it. People who try to stop smoking may develop withdrawal symptoms if they have smoked heavily for a long time. _____________________
1. (b) (iii) Some scientists believe that the part of the brain sensitive to alcohol is the same as the part of the brain sensitive to nicotine.
Explain why the n new drug might be useful for treating people who find it difficult to stop drinking alcohol.
Ans: 1. Reduce feeling of pleasure
2. Less likely to drink alcohol.
1. (c) Figure 1 shows the results of a survey into the different types of alcoholic drinks consumed by one hundred 15-year-old boys and one hundred 15-year-old girls in the UK.
1. (c) (i) Describe the differences between the types of alcoholic drink consumed by boys and by girls.
7. (c) (ii) Give one different method of measuring the environmental factor you gave in part (c)(i).
[1 mark]
Ans: oxygen meter
AQA GCSE BIOLOGY-2016 Higher Tier B2
1. An athlete ran as fast as he could until he ran was exhausted.
1. a) Figure 1 shows the concentrations of glucose and of lactic acid in the athlete's blood at the start and at the end of the run.
1. a) i) Lactic acid is made during anaerobic respiration.
What does anaerobic mean?
Ans: without oxygen
ii) Give evidence from Figure 1 that the athlete respired anaerobically during the run.
Ans: increased lactic acid
1. b) Figure 2 shows the effect of running on the rate of blood flow through the athlete's muscles.
1. b) i) For how many minutes did the athlete run?
Time = 1.5 minutes
ii) Describe what happens to the rate of blood flow through the athlete's muscles during the run.
Use data from Figure 2 in your answer.
Ans: Increases at first and leveling off suitable use of numbers
e.g. rises to 10/by 9 (dm3 per min)
iii) Explain how the change in blood flow to the athlete's muscles helps him to run.
Supplies oxygen
supplies glucose
for respiration
releases energy (for muscle contraction)
2. In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate.
Light intensity, CO2 concentration and temperature are three factors that affect the rate of photosynthesis.
How would you investigate the effect of light intensity on the rate of photosynthesis?
Figure 3 shows some of the apparatus you might use.
You should include details of:
*How you would set up the apparatus and the materials you would use
* the measurements you would make
* How you could make this a fair test
Ans: apparatus set up:
- Weed in water in beaker
- light shining on beaker
- method of varying the light intensity- eg. changing distance of lamp from plant.
method of controlling other variables
- use same pond weed or same length of pond weed.
Temperature: water bath or heat screen CO2
Leave sufficient time at each new light intensity before measurement taken.
- method of measuring photosynthesis.
3. Enzymes are made and used in all living organisms.
3. a) What is an enzyme?
Ans: Enzymes are protein molecules which can be defined as biological catalysts. A catalysts is a molecule which speeds up a chemical reaction but remains unchanged at the end of the reaction.
b) Many enzymes work inside cells.
In which part of a cell will most enzymes work?
Draw a ring around the correct answer.
cell membrane cytoplasm nucleus
3. c) We can also use enzymes in industry.
Hydrogen peroxide is a chemical that can be used to preserve milk.
Adding a small amount of hydrogen peroxide to the milk kills the bacteria that cause decay. Hydrogen peroxide does not kill all disease- causing bacteria.
The enzyme catalase can be added later to break down the hydrogen peroxide to oxygen and water.
A different way of preserving the milk is by heating it in large machines to 138⁰С for a few seconds.
Suggest one advantage and one disadvantage of using hydrogen peroxide and catalase to preserve milk instead of using heat treatment.
Advantage of hydrogen peroxide and catalase
......heat would....denature protein...
The disadvantage of hydrogen peroxide and catalase......
b) The stomach wall contains the following types of tissue.
* epithelial tissue
* glandular tissue
* muscular tissue
b) i) What is the function of epithelial tissue in the stomach?
Ans: Produce enzyme/protease
* (digestive juice/enzyme) digests/ breaks down protein
* produces HCl/ acid
*kills bacteria/ pathogens or provides optimum pH
iii) Describe how muscular tissue helps the stomach to function.
* Contracts
* Churns/mixes/moves/stomach contents
5. Figure 4 shows the production of human sperm cells.
a) Name the organ where the processes shown in Figure 4 take place.
Ans: testis
b) i) Not every cell in Figure 4 contains the same amount of DNA.
Cell A contains 6.6 picograms of DNA (1 picogram = 10¯¹² grams).
How much DNA is there in each of the following cells?
Cell B 13.2 picograms
Cell C 6.6 picograms
Cell E 3.3 picograms
5. b) ii) How much DNA would there be in a fertilized egg cell?
Ans: 6.6 picograms
iii) A fertilized egg cell divides many times to form an embryo.
Name this type of cell division.
Ans: mitosis
5. c) After a baby is born, stem cells may be collected from the umbilical cord. These can be frozen and stored for possible use in the future.
i) What are stem cells?
Ans: A stem cell is a cell that can divide an unlimited number of times (by osmosis). When it divides, each new cell has the potential to remain a stem cell or to develop (differentiate) into a specialised cell such as a blood cell or muscle cell.
ii) Suggest why it is ethically more acceptable to take stem cells from an umbilical cord instead of using stem cells from a 4-day-old embryo produced by in Vitro Fertilisation (IVF).
Ans: 4 - day embryo is a potential) human life
iii) Stem cells taken from a child's umbilical cord could be used to treat a condition later in that child's life.
Give one advantage of using the child's own umbilical cord stem cells instead of using stem cells donated from another person.
Ans: perfect tissue match
The zygote formed by the fusion of a sperm with an egg at fertilisation is totipotent, as are the cells up to the 16-cell stage of development in humans. After that, some cells become specialised to form the placenta, while others lose this ability but can form all the cells that will lead to the development of the embryo and then the adult. These embryonic stem cells are described as pluripotent.
iv) Why would it not be possible to treat a genetic disorder in a child using his own umbilical cord stem cells?
Ans: Stem cells have same faulty gene/allele/DNA/chromosomes
6. a) Polydactyly is an inherited condition caused by a dominant allele.
Figure 5 shows the hand of a man with polydactyly. The man has an extra finger on each hand.
The man's mother also has polydactyly but his father does not.
i) The man is heterozygous for polydactyly.
Explain how the information given above shows that the man is heterozygous for polydactyly.
Ans: man has (inherited) polydactyly (PD) allele (from mother)
man has (inherited) other/normal/recessive allele from father
Because father does not have PD allele or if the father had it father would have had PD or father only has normal alllele.
ii) The man marries a woman who does not have polydactyly.
What is the probability that their first child will have polydactyly?
Ans: 0.5/1:1/50%
6.b) The man has red hair. His sister has brown hair.
Both of their parents have brown hair.
Brown hair is caused by the dominant allele B.
Red hair is caused by a recessive allele b.
Complete the genetic diagram below to show how the man's parents were able to have some children with red hair and some with brown hair.
Father Mother
Parental phenotypes: both brown
Parental genotypes: Bb Bb
Gametes B b B b
offspring genotypes: BB (2) Bb bb
Offspring phenotypes; BB & Bb = brown bb = red
7. Some students wanted to estimate the number of plants in a grassy field.
The field measured 100 meters x 50 meters.
The students:
* chose areas where plantains were growing
* placed 10 quadrats in these areas
* counted the number of plantains in each of the 10 quadrants.
Each quadrat measured 25 cm x 25 cm.
Table 1 shows the students' results.
Table 1
Quadrat Number of plantain
number plants
1 2
2 1
3 4
4 1
5 3
6 2
7 4
8 1
9 1
10 1_____
Total = 21
a) Complete the following calculation to estimate the number of plantain plants in the field.
Use the students' results from Table 1.
Total number of plantains in 10 quadrats = _______________
Total area of 10 quadrats = ______________________
Mean number of plantains per m² = _____________________
_________________________________________________
Area of field = 5000 m²
Therefore estimated number of plantains in field =_____________ ___________________________________________________
mean = total number/area of 10 quadrats
= 20/0.625
= 32
mean x field area = mean x 5000
b) The students' method would not give a valid estimate of the number of plantain plants in the field.
Describe three improvements you could make to the students' method.
For each improvement, give the reason why your method would produce more valid results than the students' method.
Improvement 1 Place quadrats randomly
Reason avoid bias/representative/reliable
Improvement -2: more quadrate
Reason: over come random variable/ typical/ representative
Improvement-3; larger quadrats/ repeat when plants are bigger
Reason: less likely to miss plants.
8. Figure -6 is a map showing a group of islands in the Pacific Ocean, near the coast of California, USA.
A species of fox, called the island Fox, lives on each of the six islands shown in Figure 6.
Figure 7 shows an island Fox.
The foxes on each island are slightly different from those on the other islands.
The island Foxes are similar to another species of fox, called the Grey Fox.
The Grey Fox lives in mainland California.
8. a) Suggest how scientists could prove that the six types of Island Fox belong to the same species.
Ans: reference to interbreeding successfully between Island types
8.b) Scientists believe that ancestors of the modern Island Fox first colonised what is now Santa Cruz Island during the last Ice Age, approximately 16,000 years ago. At that time, lowered sea levels made the three northernmost Islands into a single island and the distance between thsi island and the mainland was reduced to about 8 km.
8. b) i) How could the island Fox have developed into a completely different species from the mainland Grey Fox?
