AQA GCSE Combined Science Biology - Paper 2
Terms in this set (148)
What is homeostasis ?
keeping conditions inside your body.
What does the control system ?
keeps the conditions in your body steady.
What happens in the blood glucose level is too high ?
the control system decreases the level.
What happens in the blood glucose level is too low ?
the control system increases the level.
What does the nervous system mean ?
that humans react to their surroundings and coordinate their behaviour.
What does the Central Nervous System (CNS) consist of ?
brain and spinal cord.
What is the CNS connected to ?
the body by sensory neurones and motor neutrons.
What is are Sensory Neurones ?
These carry information as electrical impulses from the receptor to the CNS.
What are Motor Neutrons ?
These carry electrical impulses from the CNS to effectors.
What are Receptors ?
Cells that detect stimuli.
Examples of Receptors ?
Receptor in the ear detect sound.
What does Effectors responded to ?
Electrical impulses and bring about to a change.
Examples of Effectors ?
Muscles and glands.
What is the process of CNS ?
Stimulus - Receptor - Sensory Neurone - CNS - Motor Neurone - Effector - Response.
What is a Synapses ?
Is where two neurones join together.
What are Reflexes ?
an automatic responses to prevent injury.
What are hormones ?
Are chemical messengers sent in the blood.
What is another name for the Pituitary Gland
What does the Pituitary Gland produce ?
many hormones that regulate body conditions.
What do Ovaries produce ?
What is oestrogen involved in ?
What do Testes produce ?
What do Testes control ?
puberty and sperm production in males.
What does Thyroid produce ?
What is Thyroxine involved in ?
Rate of metabolism , heart rate and temperature
What does the Adrenal Gland produce
What is Adrenaline involved in ?
Prepare the body for a 'fight or flight ' response
What does the Pancreas produce ?
What is Insulin used in ?
Regulate the blood glucose level.
Characteristics of Nerves ?
- Very FAST action.
- Act for SHORT TIME.
- Act on a very PRECISE AREA.
Characteristics of Hormones ?
- SLOWER action.
- Act for a LONG TIME.
- Act in a more GENERAL way.
What does Insulin used for ?
Reducing blood glucose levels.
How many types of diabetes are there ?
What is type 1 diabetes ?
where pancreas produces little or no insulin.
How do you treat Diabetes type 1 ?
Need injections of insulin throughout the day.
What is type 2 diabetes ?
where a person becomes resistant to their own insulin this can be influences by lifestyle choices.
How do you treat Diabetes type 2?
eating a carbohydrate -controlled diet and controlled regular exercise.
How many different stages are there in a Menstrual Cycle ?
What is stage one of the Menstrual Cycle ?
When menstruation (blending) starts, uterus lining breaks down for about 4 days.
What is stage two of the Menstrual Cycle ?
The uterus lining builds up again from day 4-14.
What is stage three of the Menstrual Cycle ?
An egg develops and is released from ovary at day 14. This is called ovulation
What is stage four of the Menstrual Cycle ?
The wall is then maintained (kept the same) for about 14 days until day 28.
What happens to an un fertilised egg ?
The uterus wall by day 28 , the spongy lining starts to break down. The whole cycle starts again.
The Menstrual Cycle is controlled by 4 hormones which are?
- FSH ( Follicle-Stimulating Hormones )
- LH ( Luteinsing Hormone )
FSH ( Follicle-Stimulating Hormones ) what does this hormone do ?
Causes an egg to mature in one of the ovaries.
LH ( Luteinsing Hormone ) what does this hormone do ?
Causes the release of an egg (ovulation)
Oestrogen & Progesterone what does these hormone do ?
Are involved in the growth and maintenance of the uterus lining.
What is definition of Fertility ?
How easy it is for a woman to get pregnant.
What is definition of Contraceptives ?
Things that prevent pregnancy.
How can Hormones be used to prevent pregnancy?
Used in contraceptive ( hormonal contraceptives)
What is Oral contraceptive ?
a pill that stops the hormone FSH from being released this stops eggs maturing. 99% effective. Can cause headaches and feeling sick.
Examples of Hormonal contraceptives ?
- Contraceptive patch.
- Contraceptive implant.
- Contraceptive injection.
What is a Contraceptive patch ?
A small patch that is stuck to the skin this slowly releases Progesterone (stops egg from maturing) , it lasts one week.
What is a Contraceptive implant ?
inserted under the skin of the arm this slowly releases Progesterone (stops egg from maturing) , can last for 3 years.
What is a Contraceptive injection ?
An injection this slowly releases Progesterone (stops egg from maturing) ,that can last 2/3 months.
What is an Intrauterine device (IUD) ?
An T-shaped device thats inserted into the uterus, this can stop fertilised eggs from implanting in the uterus wall.
Examples of non- hormonal contraceptives ?
Condom or Diaphragm.
What does a Diaphragm do ?
A shallow plastic cup that fits over the entrance to the uterus, this must be used with spermicide to allow the sperm to killed or disabled.
What does a Condom do ?
Worn over penis during sexual intercourse ( males) , worn inside the vagina ( woman). Protect against sexually transmitted diseases.
What are the other ways of avoiding pregnancy ?
Sterilisation , Naturel methods and Abstinence.
What is Sterilisation ?
involves cutting or tying the fallopian tubes (woman) , cutting or tying the sperm duct (males) , this is permeant (last for life).
What is an Naturel methods ?
Not having sexual intercourse when a woman is at the stages of the menstrual cycle she is like to get pregnant , but not very effective.
What is Abstinence ?
The only way to be sure that sperm and egg don't meet is to not have have intercourse , this is called Abstinence.
What are Chromosomes ?
Long molecules of DNA.
What is DNA ?
chemical that all genetic material in a cell is made up from.
What is it called when two strands of DNA are coiled together ?
What is an DNA strand called ?
Polymer that is made up of lots of smaller pieces joined together.
What are genes ?
Small sections of DNA found on a chromosomes.
What do genes codes do ?
are part of a particular sequence of amino acid, these amino acids doing together to make a protein.
What is a Genome ?
Fancy name for all the genetic materials in an organism.
How can Genomes be use in medicine ?
-By allowing scientists to know which genes link to inherited diseases , they can understand better this can help develop treatments.
-Look at different genomes of different people to help they find the migration (movement) of certain populations around the world over history.
What does asexual reproduction produce ?
Genetically identical cells.
What does sexual reproduction produce ?
Genetically different cells.
What does the mother and father produce in sexual reproduction ?
Gametes these are produced by meiosis. Gametes contain half the number of chromosomes of a normal egg.
What is the process of sexual reproduction ?
sperm ( half set of chromosomes )+ egg ( half set of chromosomes ) = offspring ( full set of chromosomes , genes are mixture of mother and father )
What does asexual reproduction happen by ?
What is the process of asexual reproduction ?
Parent cell ( full set of chromosomes ) = 2 new cells both contains the same genes of parent ( full set of chromosomes ). These are clones of the parent.
What is step one in the process of Meiosis ?
The parent cell has chromosomes in pairs. Half of the chromosomes have come from father and half come from mother.
What is step two in the process of Meiosis ?
The DNA in the parent cell is copied. It makes X- shaped chromosomes.
What is step three in the process of Meiosis ?
The cell divides and each new cell gets half of the chromosomes.
What is step four in the process of Meiosis ?
Each cell divides again. The X- shaped chromosomes are pulled apart. You end up with four daughter cells. These are the gametes.
What is in each gamete at the end of Meiosis ?
Only has one single set of chromosomes and is genetically different ( each has a different mix of the mother's and father's chromosomes).
How many pairs of chromosomes are there in every human body ?
How many of these pairs control your characteristics ?
22 matched pairs
To determine the sex of an offspring what chromosomes are present in a male ?
X and a Y
To determine the sex of an offspring what chromosomes are present in a female ?
X and X
What are Punnett squares ?
A genetic diagram to determine the probability of something.
If its a dominant alleles what type of letter do you put in a Punnett squares ?
If its a recessive alleles what type of letter do you put in a Punnett squares ?
Advantages of Embryo screening ?
Help stop people suffering. Treating disorders cots a lot of money. No laws to stop it going to far.
Disadvantages of Embryo screening ?
People with genetic problems are not wanted, this can lead to unfair treatment. In the future people might be able to pick the features and prefers. Screening is expensive.
How can variations be effected ?
By genetics ( differences in genes that are inherited) and environmental ( by the conditions in which an organism lives in).
How are most variations caused by ?
Phenotype by a mixture of genes and the environment.
What are mutations?
Change to the genome
What is the Theory Of Evolution ?
All of today's species have evolved from simple life forms that first started codevelop over 3 billion years ago.
Who came up with evolution of natural selection ?
What can evolution lead to ?
New species developing
What is the definition of extinction ?
Is when no individual of species are left.
How can bacteria evolve ?
To become antibiotic-resistant
Process of antibiotics evolving ?
variation in the population(bacteria exposed to antibiotics) - Survival (resistant bacteria ae more like to survive , non resistant bacteria die , reproduce and pass on resistance) - Reproductions (resistance becomes more common in the population)
What is the problem with antibiotic - resistant bacteria
Spread easily , no effective treatment for the infection , not immune to the new strain.
What is a superbug ?
Bacteria that are resistant to most known antibiotics. This is becoming more common.
What is an example of a superbug ?
How do avoid antibiotic-resisnat bacteria forming ?
1) take all the antibiotics
2) only get prescribed when you really need them
How are antibiotics used in farming ?
1) to animals to prevent them becoming ill and to grow faster. this can lead to development of antibiotics - resistant strains which can spread to humans.
What is the problem with developing drugs ?
1) development rate is slow
2) process is really expensive
What is selective breeding ?
When humans choose which plants are going to breed. Another name for this is ' artificial selection '
Example of selective breeding ?
A farmer wants his cattle to produce more meat. The farmer could us selective breeding to elect the largest cows and bulls and breed them together. After generations of these breeding together this would produce very high meat yield.
Disadvantages of selective breeding ?
- reduce the number of different alleles in a population
- if closely related this can be known as inbreeding
- heath problems within genes by genetic defects passed on
What does Genetic Engineering involve ?
By cutting a gene out if one organism and putting it into another organism's cells. Organisms that have had a gene inserted are called genetically modified(GM) organisms.
How is genetic engineering used in agriculture ?
by crops being genetically engineered to be resistant to insect or disease or they can be made to grow bigger and better fruit. Also be resistant to herbicides ( a chemical that kills plants).
How is genetic engineering used in medicine ?
By having bacteria produced human insulin , this can be used to treat diabetes. Also used in inherited diseases by being researched.
Concerns within GM in animals ?
1) hard to predict how chaining an animal DNA will affect the animal
2) some embryos don't survive
3) GM animals some suffer from health problems later in life.
Concerns within GM in crops ?
1) affect the number of wild flowers , also affect the population of insects
2) some people are worried that we might not understand the effect of GM crops on human health.
What are fossils ?
Remains of plants and animals
How many ways are there that fossils can be formed ?
three ways - gradual replacement by minerals , casts and impressions and preservation in places where no decay happens.
What is the process where fossils are formed by gradual replacement by minerals ?
This is how most fossils are formed. ~Shells , teeth and bones don't decay easily this mean they can last a long time when buried, from them not decaying they get replaced by minerals. This forms a rock-like substance shaped like the original hard part.
What is the process where fossils are formed by casts and impressions ?
By organisms being buried in a soft martial like clay. This substance creates a barrier around the organism , the organism leaves a clay cast of itself. An animal's burrow or a plant's roots can also be preserved as cats. Think of this process like a footprint.
What is the process where fossils are formed by preservation in places where no decay happens ?
Decay microbes only work if there is oxygen , moisture , warmth and the right pH. if there conditions aren't all present , decay doesn't happen. Example , theres no oxygen or moisture in amber so decay organisms can't survive.
Living things are divided into 5 groups called kingdoms , which are ?
Animals (fish , mammals , reptiles , etc) , Plants (grasses , trees , etc) , Fungi (mushrooms and toadstools , yeast), Prokaryotes ( all single celled organisms without a nucleus) and Protists (eukaryotic single-celled organisms).
These groups are then split into smaller groups which are called ?
phylum , class , order , genus and species.
Classification systems change over time , what were the original classes ?
All organisms are divided into 3 big groups called domains. Eukaryota ( wide range of organisms, fungi , plants n animals and protists). Archaea ( primitive bacteria , usually live in extreme places , hot spring). Bacteria ( domain contains true bacteria
How are organisms named ?
What is the definition of habitat ?
The place where an organism lives.
What is the definition of population ?
all the organism of one species in a habitat.
What is the definition of community ?
all the population of different species in a habitat.
What is the definition of ecosystem ?
the interaction of community of organism with the non living parts of their environment.
What are abiotic factors ?
Non living factors eg. light intensity and temperature.
What are biotic factors ?
living factors eg. new pathogens and new predators.
Animals can adapt to their environment , what type of adaptations can happen ?
Structural , behavioural snd functional.
What are extremophiles ?
Microorganisms that live in extreme conditions. for example live in high temperature ( volcanic vent) , high salt concentration ( salty lakes) and high pressure ( deep sea vent).
What does the food chain look like ?
Producers - primary consumers - secondary consumers - tertiary
Definition of the Water Cycle ?
Water on Earth is constantly moving. It is recycled over and over again.
Water cycle in plants ?
Some water is absorbed by the soil , this is taken up by the plant through their roots. The plant needs water for things like photosynthesis. Some water becomes part of the plants' tissues , it passes to animals when plants are eaten.
Water cycle in animals ?
Water is need for the chemical reactions in their bodies , they return water to the soil and atmosphere in their waster ( sweat and urine).
Definitions of the Carbon Cycle ?
hows how carbon moves from the atmosphere, through various animals and plants, then back into the atmosphere again.
Definitions of biodiversity ?
The variety of different species of organisms on Earth , or within an ecosystem.
Why is biodiversity so important ?
- high biodiversity means that the ecosystem is more stable.
- human species to survive ecosystem must be maintained.
More people means greater demand on the environment , why is this bad ?
more resources are needed to survive. More raw materials are need to produced luxury ideas (cars) this requires energy. Resources are being used more quickly then they are being replaced.
What can pollution affect ?
Water , land and air
What are the 4 results of global warming ?
Flooding , Change in the distribution of species, less biodiversity and change in migration patterns.
What can deforestation cause ?
Less carbon dioxide taken in , more carbon dioxide ( causes more global warming ), released and less biodiversity.
How can you protect ecosystems and biodiversity ?
By breeding programmes , habitat protection , reintroducing hedgerows and field margins, recycling and government programmes.
What does breeding programmes involve ?
Animal species that are at risk are called endangered species. These can be bred in captivity. This can boost a population or replace species that has been wiped out.
What does habitat protection involve ?
Protecting and regenerating (rebuilding) rare habitats helps to protect the species that live there.
What does reintroducing hedgerows and field margins involve ?
Field margins are areas of land around the edge of fields. Hedges can be planted around fields to form hedgerows. These provide habitat and lots of types of organisms. This can be useful for only have one type of crop this is from frills having low biodiversity.
What does recycling involve ?
Reduces the amount of waste that gets dumped in landfill sites. This could reduce the amount of land taken over a landfill so ecosystems can be left alone.
What does government programmes involve ?
By deforestation increasing the amount of co2 in the atmosphere the government have made rules to reduce this. This could help to stop global warming increasing.