Revision 2 Flashcards
What did the Human Genome Project aim to do?
2 marks
The Human Genome Project aimed to find every single human gene in order to make a complete map of the Human Genome.
True or false? Scientists have discovered the function of every human gene.
(2 marks)
False. Scientists are still trying to find out what all the genes do.
Describe how the Human Genome Project can help to improve Testing for inherited disorders, such as Cystic Fibrosis.
(5 marks)
Scientists are now better able to identify the Genes and Alleles that are suspected of causing an inherited disorder. Once an Allele that causes an inherited disorder has been identified, people can be tested for it.
Genome research has found that there are some common genetic variations in people.
Suggest how this knowledge how this knowledge can be used to tailor treatments to specific people.
(3 marks)
Scientists can use this knowledge to design new drugs that are specifically tailored to people with a particular Genetic Variation.
They can also determine how well an existing drug will work for an individual.
The Human Genome Project may allow doctors to know what genes predispose people to certain diseases.
Give 1 advantage and 1 disadvantage of this knowledge.
(6 marks)
It would enable people to get individually tailored advice on the best diet and lifestyle to help avoid their likely health problems.
However, it might allow employers and insurers to discriminate against those people who are genetically likely to get a disease.
Give 2 Selection pressures that could affect an individuals chance of survival.
(6 marks)
E.g. predation, competition for resources (e.g food, water, mates etc.) and Disease.
MRSA is a bacterium that is resistant to antibiotics. What does this mean?
(2 marks)
The Bacteria cannot be killed by antibiotics.
Why can Bacteria evolve rapidly?
2 marks
Bacteria reproduce at a fast rate.
What is meant by ‘natural selection’?
6 marks
Individuals with characteristics that make them better adapted to the selection pressures in their environment have a better chance of surviving and reproducing successfully.
This means the Alleles that are responsible for the useful characteristics are more likely to be passed on to the next generation.
A population of lizards live in a desert and are preyed on by eagles. Some of the lizards are brown and difficult to see. Others are bright pink and stand out against the sand.
Which characteristic is likely to become more common in the population? Explain your answer.
(8 marks)
The brown colour is likely to become more common in the population due to natural selection. This is because the brown lizards are better adapted to their environment as they are less likely to be spotted and eaten by eagles.
More of the brown lizards will survive and breed and pass the Allele for their brown colour to the next generation.
Describe how a population of bacteria can become resistant to a particular antibiotic.
(7 marks)
Bacteria can develop random mutations in their DNA that make them resistant to a particular antibiotic.
Antibiotic-resistant bacteria are more likely to survive and reproduce, passing on the gene for resistance.
The gene for resistance becomes more common in the population due to natural selection.
Which scientist organised the expedition that found the 1.6 million year old Homo erectus fossil skeleton called ‘Turkana Boy’?
(1 mark)
Richard Leakey
True or False? ‘Turkana Boy’ is older than the fossil skeleton of ‘Ardi’.
(3 marks)
False. The fossil skeleton of ‘Ardi’ is 2.8 million years older than that of ‘Turkana Boy’.
What have fossils of hominids (human beings and their ancestors) taught us about the evolution of the brain in humans?
(4 marks)
Older hominids had smaller brains. This tells us that brain size has increased as humans have evolved.
Brains aren’t preserved in fossils.
Suggest how scientists have been able to use fossil skeletons to learn about the evolution of the brain in humans.
(2 marks)
They measured the space taken up by the brain in the skull to find our the brain size.
Give 2 ways in which ‘Lucy’ (a fossil of the Species Australopithecus afarensis) is different from ‘Ardi’ (a fossil of Ardipithecus ramidus).
(9 marks)
‘Lucy’ didn’t have an ape-like big toe.
‘Ardi’ did.
The size of Ardi’s arms and legs were more like an ape than a human, while the size of Lucy’s arms and legs were between what you would expect to find in apes and humans. Lucy had a larger brain.
The structure of Lucy’s leg bones and feet suggest that she walked upright more efficiently than Ardi.
Axel is studying the fossil skeletons of ‘Ardi’ and ‘Lucy’. He suggests that Ardi was better at climbing trees than Lucy was.
Why does Axel think this?
(5 marks)
The structure of Ardi’s feet suggests they were well adapted for climbing trees.
For example - she had an ape-like big toe to grasp branches. Lucy had feet that are more adapted to walking than climbing and did not have an ape-like big toe.
What does the complexity of a stone tool suggest about its age?
(2 marks)
The simpler a stone too, the older it’s likely to be.
True or false? The movement of rock layers can affect the accuracy of dating stone tools.
(5 marks)
True. Dating stone tools using stratigraphy (the study of rock layers) can be inaccurate if the rock layers have moved over time.
A diagram shows the position of stone tools within layers of rock underground.
Which tool (on flash card 23) A, B, or C, is likely to be the oldest? Explain your answer.
(6 marks)
Tool C is likely to be the oldest because it is found in the deepest layer. The deeper the layer of rock that a stone tool is found in, the older the tool is likely to be. This is because older rock layers are normally found below younger layers.
Apart from stratigraphy (the study of rock layers), give 1 other method of dating stone tools.
(4 marks)
Stone tools found with Carbon-containing material, e.g. a wooden handle, can be dated using carbon-14 dating.
Explain why differences between the stone tools used by each Homo species provides evidence for human evolution.
(5 marks)
The stone tools used by different Homo species became gradually more complex over time. This suggests that their brains were getting larger, providing evidence for evolution.
What does classification mean in Biology?
2 marks
The organisation of living organisms into groups.
Name the 5 kingdoms traditionally used in classification.
5 marks
- Animals
- Plants
- Fungi
- Prokaryotes
- Protists.
Archea are 1 of the 3 domains proposed for use in classification instead of the 5 kingdoms.
Name the other 2.
(2 marks)
Bacteria and Eukarya.
What type of organisms are in the domain Archaea?
3 marks
Prokaryotes. (They look similar to prokaryotes in the Bacteria domain, but are actually quite different.)
How can the genes of an organism be used to determine how closely related it is to other organisms?
(5 marks)
The sequence of DNA bases in the genes can be determined, and then the sequence can be compared to other organisms.
Those with more similar DNA sequences are more closely related to each other.
Explain how developments in technology have led to the proposal of splitting the Prokaryote kingdom into 2 domains.
(6 marks)
Developments in technology have led to the use of RNA sequencing.
This has been used to show that some members of the Prokaryote kingdom were not as closely related as first thought, leading to the proposal that the kingdom should be split into separate groups (Archaea and Bacteria).
Suggest 2 characteristics that a cattle farmer might want to develop in her cows over time using Selective Breeding.
(3 marks)
They might want to increase the size of the cattle, so that they produce more meat, and to increase the amount of milk produced by the cows.
What is ‘inbreeding’?
2 marks
Inbreeding is when closely related organisms are bred together.
There is some variation in size of the leaves produced by spinach plants. A farmer wants to grow spinach plants with particularly large leaves because they produce more food.
Describe how this could be achieved.
(6 marks)
Select the individuals that produce the largest leaves. Breed these together. Then select the individuals of the offspring that produce the largest leaves and breed these together.
Continue doing this with each new generation until the trait gets stronger. Eventually all of the plants will produce large leaves.
A farmer has used Selective Breeding to increase the yield from his tomato plants. A new Disease gets into the greenhouse. The first plant to be infected dies.
Suggest what might happen next and why.
(6 marks)
The other tomato plants in the greenhouse are also likely to die from the Disease. This is because Selective Breeding results in populations of closely related organisms with little genetic variation.
Therefore, if 1 plant has died from this disease, it is unlikely that there will be Alleles for resistance to the disease in the other tomato plants in the greenhouse.
What is Genetic Engineering?
2 marks
Genetic Engineering involves modifying an organism’s Genome to introduce desirable characteristics.
Give 1 useful substance that Bacteria have been Genetically modified to produce.
(2 marks)
Insulin. This can be used to treat Diabetes.
How can Genetically Engineered animals be used in Medicine?
7 marks
Human Genes that produce useful proteins can be transferred to animals such as sheep or cows. These proteins can then be extracted from the animal’s milk and be used to treat patients.
Animals that have organs suitable for organ transplantation into humans might also be produced in the future.
Give 1 ethical concern with using animals in Medicine (Genetically Engineered).
(4 marks)
Many Genetically Modified Embryos don’t survive and some Genetically Modified animals suffer from health problems later in life.
Many Genetically Modified crops contain transplanted genes that make them resistant to weedkiller.
Suggest why it could be a problem if these genes got out into the environment.
(4 marks)
The transplanted genes could be picked up by a weed. This would make the weed resistant to weedkiller, which would be a big problem for farmers if the weed spreads.
Describe how a scientist could insert a useful human gene into bacteria.
(9 marks)
A Restriction Enzyme is used to cut out the useful gene from the Human DNA.
The same Enzyme is used to cut open the Vector DNA, leaving both the Vector DNA and the Human DNA with sticky ends.
Ligase Enzymes are then used to join the 2 pieces of DNA to make Recombinant DNA, which is then inserted into the bacteria.
What is Recombinant DNA
5 marks
DNA produced by joining 2 pieces of DNA (Vector DNA and Human DNA) with the help of Ligase Enzymes.
Restriction Enzyme
2 marks
Enzyme that cuts out genes/fragments out of DNA for other use.
True or False? Communicable Diseases can be spread between people.
(3 marks)
True. Communicable Diseases can be spread between people, Non-Communicable Diseases cannot.
Give 2 Examples of Non-Communicable Diseases.
2 marks
Cancer and Heart Disease.
Bacteria, Viruses and Fungi are examples of Types of Pathogens.
Give 1 other example of a type of Pathogen.
(1 mark)
Protists
What are Pathogens?
2 marks
Pathogens are organisms that cause (Communicable) Diseases.
Give the definition of ‘Health’.
4 marks
A state of complete physical, mental and social well-being (not just the absence of disease or infirmity).
Explain how having 1 disease can affect the likelihood of a person getting another, different disease.
(3 marks)
Having 1 disease can increase the likelihood of a person getting another disease.
This is because their body may have become weakened by the first disease, so it’s less able to fight off other diseases.
Which type of Pathogen causes Malaria?
1 mark
Malaria is caused by Protist.
Give 1 effect that Tuberculosis has on the body of an infected person.
(2 marks)
E.g. Coughing and lung damage.
What would an ash tree infected with Chalara ash dieback look like?
(2 marks)
It would have lost leaves and have lesions on its bark.
Cholera is a disease that is spread by water.
How could a person pick up the Pathogen that causes Cholera?
(2 marks)
The Pathogen could be picked up by drinking or bathing in contaminated water.
Give 2 other ways that Diseases can be spread.
5 marks
E.g. Diseases can be spread through the air, through eating contaminated food (oral transmission), through exchanging infected bodily fluids and by being carried by an Animal Vector.
Why are people infected with Tuberculosis advised not to go to work or school, even if they feel well enough to go?
(4 marks)
Tuberculosis is spread through the air (air borne), so people with Tuberculosis should avoid crowded public spaces in case they spread the disease by coughing near others.
Explain how you can reduce the spread of Malaria.
4 marks
Malaria is carried by mosquitoes, so using mosquito nets and insect repellant can help reduce the spread of Malaria by preventing mosquitoes from biting people, therefore preventing people from becoming infected.
What is Malaria?
3 marks
A serious and sometimes fatal disease caused by a parasite that commonly infects a certain type of mosquito which feeds on humans.
Symptoms of Malaria
7 marks
- High temperature of 38C or above
- Feeling hot and shivery
- Headaches
- Vomiting
- Muscle pains
- Diarrhoea
How many types of Malaria parasites infect humans?
1 mark
4
What is Tuberculosis (TB)?
3 marks
TB is a bacterial infection spread through inhaling tiny droplets from the coughs or sneezes of an infected person.
Where does TB affect the Human Body?
5 marks
TB mainly affects the Lungs, but it can affect any part of the body, including the tummy (Abdomen), Glands, Bones and Nervous System.
Symptoms of Tuberculosis (TB)
9 marks
- Persistent cough; lasts more than 3 weeks and usually brings up phlegm, which may be bloody
- Weight loss
- Night sweats
- High temperature
- Tiredness and fatigue
- Loss of appetite
- Swellings in the neck
How can TB be treated?
1 mark
Antibiotics
How can someone contract Malaria?
1 mark
Mosquito bite
What is Chalara Ash Dieback?
3 marks
Fungus, originating in Asia, that kills Ash trees.
Chalara Ash Dieback Symptoms
9 marks
Dark patches/wilting or black discolouration in leaves Leaves shedding Dieback if the shoots and leaves Lesions on trunk Discolouration on inner bark New growth from previously dormant buds
Cholera
4 marks
Cholera is an infection caused by contaminated water - it can cause severe diarrhoea. It’s not found in the UK, but there’s a very small risk of getting it while travelling in some parts of the world.
How can you catch Cholera?
4 marks
- Drinking unclean water
- Eating food (particularly shellfish) that’s been in unclean water.
- Eating food that’s been handled by an infected person.
Symptoms of Cholera
6 marks
- Profuse watery diarrhea, sometimes described as “rice-water stools”
- Vomiting
- Thirst
- Leg cramps
- Restlessness or irritability
True or False? Chlamydia is caused by a Bacterium.
1 mark
True
Which Disease is eventually caused by HIV?
5 marks
AIDS (Acquired Immune Deficiency Syndrome)
What Cells in the Body are killed by HIV?
1 mark
White Blood Cells
HIV can be spread by Sexual Contact.
Give 1 other way that HIV can be spread.
(3 marks)
E.g. The sharing of needles between drug users. This is because HIV spreads through the exchange of bodily fluids, and sharing needles can cause the exchange of blood.
The spread of HIV can be reduced by wearing a condom when having sex.
Give 1 other way of reducing the spread of HIV.
(4 marks)
Drug users avoiding sharing needles, using medication (to reduce the risk of infected individuals passing the virus on to others during sex or of infected mothers passing the virus to their babies during pregnancy).
Explain why someone infected with AIDS is very vulnerable to be infected by other Pathogens.
(4 marks)
AIDS causes an infected person’s Immune System to deteriorate and eventually fail. As a result, they are less able to fight off infections from other Pathogens.
When does HIV develop into AIDS?
1 mark
After the virus has severely damaged the Immune System.
What Chemical that kills Bacteria is found in tears?
1 mark
Lysozyme
Which Proteins on the surface of Pathogens trigger an immune response?
(1 mark)
Antigens
What is the role for the skin in protecting the body from Pathogens?
(2 marks)
The skin acts as a physical barrier that stops Pathogens from entering the body.
How does the Stomach help to defend the body against Pathogens?
(3 marks)
The Stomach produces Hydrochloric Acid, which kills most Pathogens that are swallowed.
How do Cells in the Trachea and Bronchi help to protect the Airway from Pathogens?
(5 marks)
Some cells in the Trachea and Bronchi produce Mucus, which traps Pathogens.
Other cells have Cilia, which move the mucus up to the back of the Throat so it can be swallowed.
Describe the role of Antibodies in the Immune System’s response to a Pathogen.
(3 marks)
Antibodies bind to the Pathogen so it can be found and destroyed by the WBC’s.
How is the Immune System able to attack only the invading Pathogen, and not other cells within the body?
(5 marks)
The Antibodies that are produced in an immune response are specific to the invading Pathogens.
This means that they will only bind to the Pathogen and not to other cells, so it is only the Pathogen that is then destroyed by WBC’s.
What are Antigens?
5 marks
Antigens are substances that cause an immune response in the body by identifying substances in or markers on cells.
Your body produces antibodies to fight antigens, or harmful substances, and tries to eliminate them.
What are Antibodies?
6 marks
Antibodies (aka immunoglobulin) are protective proteins produced by the immune system in response to the presence of a antigen.
Antibodies recognize and latch onto antigens in order to remove them from the body.
Give an Example of substances regarded by the body as Antigens.
(3 marks)
Disease-causing organisms and toxic materials such as insect venom.
What are foreign substances known as?
1 mark
Antigens
What is a foreign body (FB)?
2 marks
A foreign body is any object originating outside the body of an organism.
Immunisation involves injecting Pathogens into the body.
Why don’t these Pathogens cause Disease?
(2 marks)
Because the Pathogens that are injected into the body are dead or inactive.