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Edexcel iGCSE Biology 1B 16th May 2017 Unofficial Markscheme

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Unofficial Markscheme??
1a) Parts of the lung.
A: Trachea, bronchi, bronchioles
1b)How can a lung be described as a tree? A:Branches out smaller and smaller
1c)How do the lungs move when a person breathes in?
A: Intercostal & diaphram contact, pressure lower
1d)Why is smoking banned in public buildings?
A: Enclosed space, lots of people, emphysema, cancer, CO, tar
1e)Why are children harmed more by smoke?
A: More fragile, less developed lungs easily damaged

2a) Table about visking tubing.
A: Example: No No
Starch+Maltase: No No
Starch+Glucose: No Yes
Starch+boiled amylase:No No
2b) How does the volume change?
A:Increases: osmosis
2c)Test for glucose?
A: Benedicts solution dark to brick red
d)How would you use this equipment for bile/lipids?
A: Place in visking tube Test water for glycerol/fatty acids

a) Genetic tree questions.
A:8,4,25%
3b) Define ‘mutation’.
A:Change in the genetic code
3c)Example of good mutation.
A : Antibiotic resistance, giraffe long neck etc
3d) How would the frequency of alleles change if medical care was not avaliable?
A: Would decrease; people with the fatal allele would die before they can reproduce without medical help, and wouldnt pass on allele

4a) Does the father determine gender?
A: Yes, father has XY, mother has XX Y decides whether child is boy or girl
4b)Man A vs B.
A: More sperm, healthier sperm
4c)Smokers and non smokers graph.
A: 45% of 55m=24750000
4d)Why are smokers less fertile, using the graph?
A: Have less moving sperm, more mutated sperm

5a) Balanced photosynthesis equation.
A: 6H20 + 6CO2 > C6H12O6 +6O2
5b)Why are the leaves darker?
A: More chlorophyll so they can absorb more sunlight
5c)Why are the leaves thinner?
A: So light can penetrate to other layers of leaves
5d&e)Morning vs night; effect on rate of photosynthesis.
A: Morning = colder, less light, slower
A: Opposite for afternoon
5f) Describe a test to compare the rate of photosynthesis for 2 plants.
A: Measure amount of O2 produced by 2 different types of pondweed with gas syringe

6a) What is used?
A: Quadrat
6b) Frequency of plants.
A: 8,22%
6c) Number of squares plants are in.
A: 4,11%
6d) How would you calculate the average for a very large field?
A: Use lots of quadrats
Find average of plantains
Multiply by area of field

7a) Young plants in mineral solutions: describe pattern in both plants.
A: In all minerals solution the plant grew to 163mm Plants without nitrate grew to 37-38mm and began to shrink
7b)Why was air bubbled through?
A: More oxygen, more respiration respiration, more energy for active transport
7c)Why was it covered with cardboard?
A: Mimic underground conditions
7d) Why was the solution sterile?
A: So no microorganisms outcompeted the plants

8a) Draw a graph generation/cloning.
8b)Describe pattern.
A: More older people supported cloning
8c)Using a named example, explain cloning.
A: Dolly the sheep, mature udder cell into enucleated cell, implanted into uterus of another sheep

9a) Label motor neurone.
A: nucleus, axon
9b)Describe role in the body.
A: Connects relay neurone to muscle/effector
9c) 3 Differences in hormonal and nervous?
A: Slower/faster
Small area/big area
Electrical/chemical
Nerves/Bloodstream

10) Fill in blanks: Chloroplasts, cellulose, starch, glycogen, consumer, chromosome, plasmid, photosynthesis, yoghurt, pneumonia

11a) How do fungi digest logs?
A: Saprotrophic nutrition: secrete enzymes and absorb
11b) Design experiment to find best fungicide. (CORMS)
A: Take 50 logs
Same weight, surface area, species
Split into 5 groups
Treat 4 groups with different fungicides, leave 10 as a control
Leave all logs on forest floor: same conditions Wash to remove fungi
Weigh and average groups to find loss in mass from each fungicide
Compare results

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Could you add how many marks was each question worth