Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
161 Cards in this Set
- Front
- Back
|
B1 |
B1 |
|
|
Definition of Genotype
|
Genetic makeup, determines the phenotype.
|
|
|
Definition of Phenotype
|
Observable/physical features and characteristics, depends on genotype.
|
|
|
What do structural proteins do?
|
Give body: structure, rigidity and strength. Examples include keratin in skin.
|
|
|
What do functional proteins do?
|
Enables body to function. Examples include enzymes, antibodies and hormones.
|
|
|
What do genes do?
|
-Carry instructions that control how you develop and function.
-Tells cells what proteins needed to make body work |
|
|
Put into order from largest to smallest:
Chromosomes DNA Base Cell Gene Nucleus |
Cell
Nucleus Chromosomes DNA Gene Base |
|
|
Why will variation in offspring always different? Any exceptions?
|
Variation always different because the combination of chromosomes in the egg and sperm will be different. Exceptions include identical twins as they come from the same fertilised eggs. However environmental factors also add to variation.
|
|
|
Definition of allele.
|
Different forms of a gene.
|
|
|
Definition of homozygous.
|
Two alleles of a gene are the same.
|
|
|
Definition of heterozygous
|
Two alleles of a gene are different.
|
|
|
How many chromosomes does a human have?
|
23 pairs (46 in total)
|
|
|
What does a dominant allele do?
|
There only needs to be one dominant allele present for that certain characteristic to show.
|
|
|
What does a recessive allele do?
|
There must two recessive alleles for that certain characteristic to show.
|
|
|
What does the 23rd pair of chromosomes do?
|
Determines gender.
|
|
|
Which pair is male and which is female?
XX XY |
XX = Female
XY = Male |
|
|
Is X or Y the sex determining gene? How?
|
Y is the sex determining gene because it triggers the development of testes in the embryo. In absence of the Y chromosome, ovaries develop.
|
|
|
What does Huntington's disease do?
|
Affects central nervous System, damages nerve cells. Gradual mental and physical changes.
|
|
|
Is Huntington's Disease dominant or recessive?
|
Dominant,
|
|
|
When does Huntington's Disease occur?
|
Middle age.
|
|
|
Symptoms of Huntington's Disease?
|
-Tremors
-Memory Loss -Inability to concentrate -Mood changes |
|
|
What does cystic fibrosis do?
|
Affects cells' membranes, production of thick sticky mucus on lungs and digestive system.
|
|
|
Is cystic fibrosis dominant or recessive?
|
Recessive therefore can be carrier.
|
|
|
Symptoms of cystic fibrosis?
|
-Weight loss
-Breathing problems -Repeated chest or lung infections -Persistent coughs |
|
|
When does cystic fibrosis occur?
|
Symptoms start during early childhood.
|
|
|
What is genetic screening?
|
It is when all newborn babies are tested for genetic disorders or if they are a carrier e.g 'blood spot test' used on majority of newborns to check for rare genetic disorders.
|
|
|
Why does genetic screening in pregnancy occur?
|
Hopes to minimises damage caused by genetic disorders, allows parents to prepare/get treatment.
|
|
|
Who usually is recommended to take genetic testing when in pregnancy?
|
People with known family history of disorder or if parent is a carrier.
|
|
|
What is embryo screening?
|
Usually done before get pregnant as it allows doctor to remove embryos with disorder and replace with healthy ones.
|
|
|
What is Amniocentesis?
|
A cell sampling method used on pregnant woman to find any genetic disorders in the foetus. It involves collecting cells from the developing foetus which is present in the amniotic fluid.
|
|
|
When can an amniocentesis be performed?
|
After 15 weeks of pregnancy.
|
|
|
Risks of an amniocentesis? |
1% chance of miscarriage. |
|
|
What is a chorionic villus sampling?
|
A cell sampling method used on pregnant woman to find any genetic disorders in the foetus. It involves testing samples of cells from the placenta.
|
|
|
When can a chorionic villus sampling take place?
|
During 10-14 weeks of pregnancy.
|
|
|
Risks of a chorionic villus sampling?
|
0.5% chance of miscarriage.
Small chance of infection. |
|
|
What is IVF?
|
It is short for in vitro fertilisation. It is when the sperm and egg meet in a test tube. The fertilised egg divides and then embryo is implanted in mother's uterus.
|
|
|
What is Pre-implantation Genetic diagnosis?
|
It is a type of embryo screening. IVF occurs with 10 eggs being fertilised. Each egg is sampled and 3 'genetically healthy' embryos are implanted.
|
|
|
What are clones?
|
Individuals with identical genes.
|
|
|
What is asexual reproduction? Examples?
|
Where only 1 parent is needed to reproduce, offspring has identical genes with the parent. Examples include plants, bacteria and simple animals.
|
|
|
How do plants reproduce?
|
They reproduce asexually in 2 ways:
-Using runners, where shoots are sent out and grow into identical plants (e.g strawberries). -Producing bulbs (e.g daffodils). |
|
|
How can clones have variation?
|
Since clones have identical DNA, the only variation can come from environment.
|
|
|
What the advantages of asexual reproduction?
|
-Success characteristics are seen in offspring.
-Useful for animals who live in isolation. |
|
|
What are the disadvantages of asexual reproduction?
|
No genetic variation if conditions change or disease occurs then the whole population dies.
|
|
|
At what point does an embryo contain stem cells?
|
Embryo becomes ball of cell containing embryonic stem cells at 5 days.
|
|
|
What two types of stem cells are there and what are the differences? |
Embryonic - from embryo |
|
|
Why is the use of embryonic stem cells controversial? |
Usually taken from unused embryos after fertility treatment & their use involves destruction of embryos. |
|
|
What are stem cells used for? |
-Renewing damaged/destroyed cells in spinal injuries. |
|
|
What does gene therapy involve?
|
Uses healthy copied genes and inserted as modified virus which infects patient. Genes become incorporated into patient cells connecting the faulty allele.
|
|
|
B2 |
B2 |
|
|
What is a pathogen?
|
Microbes that make you feel I'll and cause disease.
|
|
|
Examples of pathogen |
-Bacteria |
|
|
What does bacteria do in the human body?
|
Releases poisons/toxins.
|
|
|
What do viruses do in the human body? |
Can only reproduce in host cells Take over cell and make copies Virus copies fill host cell and bursts open |
|
|
How does bacteria reproduce? |
Asexual reproduction Reproduced rapidly (exponential growth) if in ideal conditions. |
|
|
What are the passive immunity defences? |
-Skin |
|
|
What is the internal and active human defence?
|
Immune system.
|
|
|
Where are white blood cells made?
|
In your bone marrow.
|
|
|
What are the functions of white blood cells? |
-Ingest pathogens and destroy them -Produce antibodies to destroy pathogens -Produce antitoxins that neutralise the toxins released by pathogens |
|
|
What are the two main types of white blood cell? |
-Surrounds and digests bacteria -Produces antibodies to label microorganisms Specific antibody for antigen |
|
|
How can a person be immune to a disease?
|
After fighting that particular disease, memory cells remain in bloodstream so can produce large no. of antibodies quickly if micro-organism enters again.
|
|
|
What do phagocytes do?
|
White blood cell. Goes through phagocytosis, this is where it goes around body looking for bacteria. It 'eats' pathogen and breaks it down with enzymes and other chemicals.
|
|
|
What is an antimicrobial?
|
Chemicals that slow down growth of micro-organism or kill micro-organism.
|
|
|
Examples of antimicrobials
|
Cleaning products (antiseptics, disinfectants), antibiotics, antifungals, antivirals.
|
|
|
What is an antigen?
|
Foreign organisms that get in to the body, and trigger an immune response..
|
|
|
What are antibodies? |
Proteins produced by the body's immune system that attack antigens that get in to the body. |
|
|
How are resistant micro-organisms created? |
Bacteria or fungus can get random mutation in gene which allows it to develop resistance against antimicrobials. Bacteria without mutation die or can't reproduce. Resistance is passed on due to less competition and rapid reproduction |
|
|
What has antibiotic resistance led to? |
Strains of bacteria which are hard to eradicate |
|
|
What is a blind study?
|
Trial where patient doesn't know which drug they are given but doctor does.
|
|
|
How are drugs tested? |
Human cells grown in labs Tested on animals Used in clincal trials (healthy and ill people) |
|
|
What is drug testing?
|
Trials which investigate drugs over long time to look for side effects which may increase/appear or if drug becomes less effective.
|
|
|
Why are healthy and ill people both can volunteer? |
Healthy = Safety. |
|
|
What is a placebo?
|
A tablet/liquid made to look like drug but does not have active ingredients.
|
|
|
How you slow down or stop the development of resistant bacteria? |
Avoid unnecessary usage of antibiotics Complete full course of antibiotics |
|
|
What is a vaccination? |
Safe/dead form of the pathogen. |
|
|
What is an open label trial? |
Trial where both doctors & patients know what drug patient is receiving. |
|
|
What is a double blind study?
|
Neither patient nor doctor knows which drug is being given.
|
|
|
Why are new vaccines developed for same pathogens?
|
Some pathogens (e.g. flu) keep changing rapidly.
|
|
|
Why is only a herd immunity needed and not the whole population?
|
More people vaccinated = less risk of vaccinated approaching each other. Will not cause epidemic as that would mean it would go through rapidly through large no. population.
|
|
|
What do the happens at lungs? |
Blood absorbs oxygen & removes CO2, Lungs take in CO2 & release oxygen. |
|
|
What does the circulatory system consist of? |
Heart, Arteries, Veins& Capillaries |
|
|
Why is herd immunity needed?
|
To avoid an epidemic.
|
|
|
What is herd immunity?
|
High % of population is vaccinated.
|
|
|
How does a vaccination work?
|
Once vaccine is in blood stream, immune system attacks, it encourages to make the specific antibodies. Memory cells are left so body knows how to fight off disease.
|
|
|
What direction do arteries transport blood?
|
Away from heart.
|
|
|
What kind of walls do arteries have & why?
|
Thick, elastic and muscular so can withstand high pressure of blood.
|
|
|
What direction do veins transport blood?
|
Towards heart.
|
|
|
What kind of walls do veins have & why? |
Thin, elastic and muscular walls with valves in order to pump low pressure blood back to heart. |
|
|
What do capillaries do? |
Allow food and oxygen to diffuse to cells while waste is diffused from cells. |
|
|
What kind of walls do capillaries have & why? |
One cell thick walls to allow transfer of substances to and from blood. |
|
|
What blood vessels transport blood at high pressure?
|
Arteries.
|
|
|
What blood vessels transport blood at low pressure?
|
Veins.
|
|
|
What is coronary heart disease caused by?
|
Build-up of fatty deposits in coronary arteries.
|
|
|
What is a heart disease caused by?
|
Heart is unable to receive oxygen due to arteries being blocked by fatty deposits.
|
|
|
How is heart rate measured?
|
Through pulse rate (no. pulses as blood passes through artery close to skin).
|
|
|
What does blood pressure record?
|
Pressure of blood of walls of artery.
|
|
|
Why must blood be under pressure?
|
To reach every cell in body.
|
|
|
How can lower risk for coronary heart disease?
|
-Exercise = strengthens heart muscles, healthy weight & reduces stress.
- Healthy diet = lowers saturated fat so lowers blood cholesterol. |
|
|
Who must especially try to lower risk of getting coronary heart disease?
|
People with known family history of CHD.
|
|
|
What does the coronary arteries do?
|
Provide nutrients & oxygen that heart needs to contract & removes waste products.
|
|
|
Blood pressure is an important indicator of _______
|
health/fitness.
|
|
|
What does a high blood pressure do to body?
|
Damages arteries' walls & make more likely to develop fatty deposits - restrict blood flow and increases blood pressure
Blood clot may form if breaks artery lining - blocks artery |
|
|
What lifestyle factors increase the risk of heart disease?
|
Poor diet
-Cholesterol& Salt [High BP] Smoking -Oxygen& High BP& Carbon Monoside Misuse of illegal drugs Stress Alcohol (excessive) -High BP |
|
|
What is a epidemiological study?
|
Studies of occurrence of disease using large no. of people. Can help identify lifestyle factors
|
|
|
What is homoeostasis? Examples? |
Maintenance of a constant environment. Includes nervous and hormonal systems |
|
|
What is negative feedback? What is the process?
|
Counteracts changes
Receptors detect a change in environment [too high/low] Processing centre receives information and coordinates a response Effector produces a response, which counteracts change - the level decreases/increases |
|
|
Why is water level important? |
Maintain concentration of its cell contents at correct level for cell activity
|
|
|
What is concentration of blood plasma affected by?
|
External temperature
Exercise Intake of fluids & salt levels. |
|
|
What do kidneys help do?
|
Balance levels of water, urea, salts & other chemicals in blood.
|
|
|
How is water taken in by body?
|
Food and drink and is produced in respiration.
|
|
|
How is water lost? |
Urine, faeces, sweat and breathed out. |
|
|
How does alcohol affect kidneys/water balance?
|
Kidneys produce large volume of dilute urine & body becomes dehydrated.
|
|
|
How does ecstasy affect kidneys/water balance?
|
Kidneys produce very small volumes of concentrated urine. Body's cells swell with water.
|
|
|
What system are the kidneys in homeostatis?
|
Effectors.
|
|
|
Where is ADH released & why? |
Pituitary gland in response to changes in blood plasma. |
|
|
What does ADH do? |
Acts upon kidneys to reduce amount of water lost in urine. |
|
|
What does alcohol do to ADH & why? |
Suppresses release of ADH, so less water is reabsorbed by kidneys. |
|
|
What does ecstasy do to ADH & why? |
Increases production of ADH, so more water is reabsorbed by water. |
|
|
B3 |
B3 |
|
|
Definition of species. |
Group of organisms that can breed and produce fertile offspring. |
|
|
What does an adaptation mean?
|
Something special that helps organism survive.
|
|
|
Definition of extinction.
|
Where all the individuals of a species die.
|
|
|
What does interdependence mean?
|
When a species depends on another species (e.g. as food).
|
|
|
What causes extinction?
|
- Environmental conditions
destruction of habitat - can't adapt -Competitor, disease or predator -Food web organism becomes extinct |
|
|
What is a habitat?
|
Where an organism lives.
|
|
|
Where do plants get energy from and how?
|
From sun, uses light in photosynthesis.
|
|
|
How does carbon leave the carbon cycle?
|
Photosynthesis - plants using carbon dioxide for energy
|
|
|
How is percentage efficiency calculated?
|
Energy transferred to next level/ Total energy in x 100
|
|
|
How can energy transfer still continue after death?
|
Micro-organisms such as bacteria or fungi feed on dead (decay)
|
|
|
When energy is passed down food chain, some of the energy is lost? How?
|
-Heat - Life processes - Uneaten parts - Excretion |
|
|
How does carbon leave carbon cycle?
|
Respiration.
Combustion of organic materials. Decomposition of soil micro-organisms. |
|
|
What are the four microorganisms used in the nitrogen cycle?
|
Decomposers - proteins [dead matter] and urea to ammonia
Nitrifying bacteria - ammonia into nitrates Nitrogen - fixing bacteria - N2 gas into nitrogen compounds Denitrifying bactera - nitrates to N2 gas |
|
|
What is Nitrogen fixation and how does it happen?
|
Atmospheric N2 into nitrogen compounds for plants
- Lightning = enough energy nitrogen + oxygen -Nitrogen - fixing bacteria |
|
|
What happens in nitrogen cycle?
|
Plants take nitrogen from soil through roots, in form of nitrates.
Converted to proteins which is passed through food chain. Nitrates released back into soil through excretion & after death and decomposition. |
|
|
How does nitrogen leave nitrogen cycle?
|
Denitrifying bacteria - nitrates intto N2 gas = denitrification
|
|
|
How can environmental change be measured?
|
-Direct, non-living indicators.
-Indicator species (biotic index). |
|
|
What are living indicators? |
Lichen - air pollution [sulfur dioxide] Mayfly Nymphs - level of oxygen in water Phytoplankton - water pollution (nitrates from fertiliser) |
|
|
What are non living indicators?
|
Temperature - climate change
Carbon dioxide levels - burning fossil fuels Nitrogen levels - sewage& fertiliser |
|
|
What is a mutation?
|
Change in genetic information in cell, results in change in characteristics.
|
|
|
Why is natural selection an important part of evolutionary process?
|
Allows organisms to survive better in terms of reproduction and competing with other animals.
|
|
|
When does a mutation occur?
|
Only happens to sex cells so mutation only seen in offspring.
|
|
|
What is evolution?
|
Change in organisms over time.
|
|
|
What were the first forms of life like?
|
Single celled, very simple.
|
|
|
When did life on earth start?
|
3500 mil yrs ago.
|
|
|
What is selective breeding?
|
Where humans deliberately choose desired characteristic for breeding of the next generation |
|
|
What is natural selection? |
Organism with adaptation most likely will survive passing on the characteristics to the next generation through reproduction |
|
|
How can evolution produce a new species?
|
- Mutations- Natural selection- Environmental changes e.g climate
|
|
|
What evidence is there for evolution?
|
-Fossil records, can see complexity range
-DNA (similarities and differences) |
|
|
What did Darwin observe? Example? |
Theory of evolution by natural selection |
|
|
What did Larmarck argue?
|
Believed animals acquired characteristics during lifetime that were then passed onto offspring. Not genetic.
|
|
|
What is biodiversity?
|
Variety of life on Earth & in different habitats.
|
|
|
What factors does biodiversity include? |
-No. different species. |
|
|
Why are species becoming more extinct recently?
|
Human activity such as hunting and deforestation.
|
|
|
How are organisms classified?
|
DNA sequence and similar features.
|
|
|
What is the classification of organisms? |
Bacteria, Algae, Fungus, Plants& Animals |
|
|
What resources do living things need from the environment?
|
- Light
-Food - Oxygen - Water |
|
|
What does life cycle assessment do?
|
Tracks environmental impact of product.
|
|
|
List steps in Life Cycle Assessment.
|
1) Sourcing of raw materials.
2) Manufacture. 3) Transport. 4) Use. 5) Disposal. |
|
|
What is Monoculture?
|
Continuous production of one type of crop that is often genetically uniform
|
|
|
What are the advantages and disadvantages of monoculture? |
Advantages: Efficiency in harvesting Disadvantages: When pests attack a lot of pesticides are used = bioaccumulation = not sustainable = reduces biodiversity Natural disaster removes crops |
|
|
Definition of sustainability.
|
Meeting needs of today without compromising future.
|
|
|
How can we improve sustainability?
|
Biodegradable packaging
-Decomposition needs oxygen - not present in landfills = methane Recycling packaging -Energy used e.g production, transport releases pollution -Creating less pollution |
