Core Science Flashcards
What are characteristics?
The features of an organism
What is a species?
Organisms with many characteristics in common
What are the 5 kingdoms?
Animalia, Plantae, Fungi, Protoctista, Prokaryotae
What are the features of animalia kingdom?
Multicellular, heterotrophic, no cell walls, nucleus
What are the features of the Plantae kingdom?
Multicellular, autotrophic, cell walls (made of cellulose), nucleus
What are the features of fungi kingdom?
Multicellular, cell walls, saprophytic, nucleus
What are the features of protoctista kingdom?
Mostly unicellular, nucleus
What are the features of Prokaryotae kingdom?
Unicellular, no cell walls
Define heterotrophic
Getting food and digesting the tissues of of other organisms
What does autotrophic mean?
Make food from small molecules using an energy source, such as light in photosynthesis
What does saprophytic mean?
Getting food by digesting the tissues of other organisms outside the body and absorbing the digested food
Define vertebrate
Has a back bone
Define invertebrate
Has no back bone
Describe the features of a fish
Gills, poikilotherm, oviparous, external fertilisation
Describe the features of an amphibian
Gills, poikilotherm, lungs, oviparous, external fertilisation
Describe the features of a reptile
Lungs, poikilotherm, internal fertilisation, oviparous
Describe the features of a bird
Lungs, internal fertilisation, homeotherm, viviparous
Describe the features of a mammal
Lungs, internal fertilisation, homeotherm, viviparous
Define viviparous
Gives birth to live young
Define oviparous
They lay eggs
Define poikilotherm
A species in which its body temperature is dependent on its surrounding environment
Define homeotherm
A vertebrate which has a regular body temperature
Define a species (in terms of reproducing)
A group of organisms that can interbreed to form fertile offspring
What is a hybrid?
Offspring produced from two closely related species that isn’t fertile itself (with the exception of Mallard Ducks)
What is a ring species?
A ring of populations, where neighbouring populations can interbreed
What is the binomial system?
The naming system for an organism, made up of two Latin words, genus and species
What is variation?
Differences in characteristics
What is the importance of classification?
To identify species (new and existing)
See how organisms are related
To identify areas of greater and lesser biodiversity
Define biodiversity
A measure of the total number of species in an area
Why is biodiversity important?
To have foods and medicine
Define adaptation
When an organism has characteristics that make it best suited for its habitat
What is genetic variation?
Variation in characteristics caused by DNA
Give an example of continuous variation
Height
What is an acquired characteristic
A characteristic cause by the environment
What is classification?
The process of sorting organisms based on their characteristics
Why is there competition among a species?
Lack of resources
What is natural selection? (Survival of the fittest)
When those with the best adaptations within a species will survive and produce offspring
How does evolution occur?
When natural selection happens over an extensive period of time
Define speciation
Formation of a new species as when populations of a species are separated geographically and evolve until they are no longer able to reproduce with one another
Development of what supports Darwin’s theory of evolution?
Resistant organisms
What are the 3 main parts of a cell?
Cell membrane, cytoplasm and nucleus
Where is DNA found?
In the nucleus
What does DNA contain?
Chromosomes
Chromosomes are divided up into what?
Genes
What is inherited variation?
Variation caused by genes
Sort ‘eye colour’ and ‘blue’ into allele and gene
Gene - eye colour
Allele - blue
What is a gamete?
Sex cells
How many pairs of chromosomes does a gamete have?
23
Show the way that a dominant and recessive allele is shown with the letter B
B - dominant
b - recessive
What is the difference between homo and heterozygous?
Homozygous is when a person has 2 of the same alleles and heterozygous is when they have 2 different alleles
Define genotype
The alleles for a certain characteristic found in an organism
Define phenotype
The characteristic that is caused by the genotype (e.g. Blue eyes)
What is sickle cell anaemia?
A genetic disorder that is caused by faulty alleles
What are the symptoms of sickle cell anaemia and why does this happen?
People with the disease become tired very easily and often have pain in their joints and their red blood cells are sickle shaped so therefore carry less blood and can sometimes block blood vessels as they stick together
What is cystic fibrosis and what does it cause?
A genetic disorder which causes mucus to clog the lungs and enzyme passages which can cause weightloss
What is a family pedigree chart used for?
To determine how likely it is for someone to give birth to someone with a certain disease and from there doctors can advise courses of action
What is the internal environment?
Conditions inside the body
What is the term for keeping the internal environment stable?
Homeostasis
What is osmoregulation?
Water control
What is blood glucose regulation?
Blood sugar control
What is thermo regulation?
Temperature control by the hypothalamus
What is the hypothalamus?
The part of the brain the controls temperature
Describe was happens to the erector muscles when:
A) you are hot
B) you are too cold
A) the muscle is relaxed so the hair lies flat
B) the muscle contracts so the hair is upright and acts as an insulator of heat
Describe vasoconstriction and vasodilation and when and why they happen?
Vasoconstriction is when the blood vessels tighten to keep the blood flowing through deeper vessels to prevent heat loss through the skin
Vasodilation is when the blood vessels dilate to allow the blood to flow through vessels closer to the surface of the skin to allow the body to lose heat and cool down
What do sense organs contain and what do they detect?
They contain reception cells which will detect a stimulus
What is an impulse?
And electrical signal created by a receptor cell
What do impulses do?
Impulses travel to the brain which can alter things accordingly
Impulses travel along neurones, what is this called?
Neurotransmission
What do the dendrites do?
They collect impulses from the skin receptor cells
What do the impulses travel on before reaching the cell body?
The dendron
What do the impulses travel on after passing through the cell body?
The axon
What is a nerve?
A bundle of neurones
What are the 2 parts of the central nervous system?
The spinal chord and the brain
What happens when the brain receives an impulse?
It coordinates a response
What happens in a response?
Impulses are sent to effectors to carry out an action
What is a sensory neurone?
A neurone that receives impulses
What is a motor neurone?
A neurone that carries impulses to effectors
What is a relay neurone?
The neurone between the sensory and motor neurone (they make up the spinal chord and the brain)
What is the myelin sheath and what does it do?
It is a fatty layer around the neurones to insulate them and carry impulses faster
What is a synapse?
A small gap between neurones
What are the impulses transmitted across the synapses called?
Neurotransmitters
What do synapses do?
They slow down impulses and allow them to only travel in one direction
What is a reflex?
An automatic response that bypasses conscious thought (the brain)
What is the reflex arc?
When a sensory neurone directly controls a motor neurone (bypasses the brain which is made up of relay neurones)
What are hormones produced by?
Endocrine glands
What is the name of an organ that responds to hormones?
Target organ
What does the pituitary gland do?
It causes the kidney to release concentrated urine
Where is adrenaline released from and what does it do?
It is released from the adrenal glands and speeds up our heartbeat
Where is oestrogen made and what does it do?
Made in the ovaries and causes female reproductive development
Where is testosterone made and what does it do?
Made in the testes and causes male reproductive development
What does the pancreas do when blood sugar is too high?
It secretes insulin which will convert glucose into glycogen (a store of glucose) to lower blood levels, this happens in the liver
What is the role of glucagon and where is it made?
It breaks down glycogen into glucose when blood sugars are low, it is made in the pancreas
What is diabetes?
It is a disease caused by the inability to control blood glucose levels as the body either has no insulin or doesn’t respond to it
What is type 1 diabetes?
Type 1 is when the pancreas doesn’t produce insulin, people with type 1 need to inject insulin daily into the subcutaneous fat layer
What is type 2 diabetes and what causes it?
Type 2 diabetes occurs when the persons body no longer responds to insulin, it is caused by high fat diet, lack of exercise, getting older and being obese
What do doctors class as obese?
Someone with a BMI over 30
How do doctors work out BMI?
Weight (kg) / height squared (m^2)
Define tropism
Growing towards or away from something
What is a phototropism?
A tropism caused by light
What is the name of the plant hormone that causes phototropism?
Auxins
How do auxins cause phototropism?
They move to the shaded side of the plant and cause cell elongation
What type of tropism do plant roots have?
Gravitropism
What do the auxins in roots do?
They follow the direction of gravity and prevent cell elongation in this area so the root grows in the direction of gravity
What do gibberellins do and when?
After a period of germination and the plant has had time to grow, the gibberellins will be released to turn starch into sugar and stimulate flower or fruit production
Name four uses for plant hormones
Selective weed killer
Rooting powder
Seedless fruit
Fruit ripening
Describe how selective weed killers work
Artificial auxins are used to make broad leaf plants grow out of control and die but leave narrow leaves plants unaffected
How do rooting powders work?
Plant cuttings are dipped into the rooting powder (which has synthetic auxins in) which makes them develop roots quickly
Explain how we get seedless fruit
Flowers are strayed with plant hormones so that the fruit develops without seeds, they can also make small seedless fruit bigger (e.g. Grapes)
How are plant hormones used to ripen fruit?
They (gibberellins and ethylene) are sprayed onto fruit trees to prevent the fruit from falling also they are sprayed to make them ripen so the fruit gets to the shops in perfectly ripe condition
What is a drug?
A chemical substance that changes how the body works
What do narcotics do?
They make us sleepy
What’s a hallucinogen?
A drug which changed how our brain responds to what we see, hear or feel (e.g. LSD distorts our sense of colour, time and space)
What does a stimulant do?
Speeds up Neurotransmission thus speeding up reaction time
What does a painkiller do?
They block nerve impulses so we feel less pain
What is a depressant?
A drug that slows down neurones in the brain to help relaxation
What does tar contain and what is the harm?
Tar contains carcinogens which can cause cancers in the mouth and lungs
What are the dangers of carbon monoxide?
It reduces oxygen
Makes blood vessels narrower which can kill tissues which are then more vulnerable to infection
Can cause heart attacks and cause respiratory diseases
What is the problem with nicotine?
It is the addictive drug in tobacco, people can become addicted after just 4 cigarettes
Describe the short term effects of alcohol?
Slows down brain and CNS, slows reaction times, lowers inhibitions, blurred vision, poor coordination and can cause unconsciousness
What are the long term effects of alcohol?
Cirrhosis of the liver (the normal tissue is destroyed so it cannot function properly), brain damage, clotting in the brain and alcoholism
What happens in a transplant?
A healthy organ is taken from a donor and put into a patient to replace non-functioning organs
What are the 4 main points doctors have to follow when finding a donor?
Similar tissue types
Similar age
Geographically close
How ill the patient is
What is an ethical decision?
A decision made that uses a criteria to reach a solution that most people think are fair
What is a pathogen?
A harmful microbe which carries infectious diseases
What 4 things are diseases caused by?
Bacteria, viruses, fungi and protoctists
Name the 6 ways that disease are spread
Water Vectors: mosquitoes/houseflies Food Contact Airborne Body fluids
What two methods do animals have to fight pathogens?
Physical barriers and chemical defences
Define antiseptic
A substance that kills microbes from out side the body
What do plants use to prevent pathogens from causing harm?
Anitbacterials
Give two examples of how humans use antibacterials
Witch hazel - used in aftershaves to prevent infection
Mint - used in toothpaste
Give some examples of physical barriers in humans
Skin, sweat, cilia (tiny hairs that sweep away mucus and microbe from the lungs), mucus to trap microbes
Give some examples of chemical defenses
Hydrochloric acid in the stomach and lysozyme in tears
Name one example of a resistant bacteria and why it is resistant
MRSA - because antibiotics have been over used
What is a producer?
Something that makes its own food (e.g plants)
What is a primary consumer?
Something that eats producers
What is a secondary consumer?
Something that eats a primary consumer
What is a trophic level?
A level on the food web (e.g. Primary consumers)
Why are food webs useful?
They show feeding relationships and that animals are interdependent
What is a pyramid of biomass?
It shows the biomass (that quantity of organism and the energy that it can transfer) of organisms in an area at each trophic level
What is parasitism?
When two organisms live together, the parasite feeds on the host and harms it
What do fleas and headline do that classifies them as a parasite?
They bite on animals to feed on their blood
What do tape worms do?
They live in intestines and eat the hosts food causing weightloss, they can sometimes even block intestines
What are the adaptations of a tape worm that makes it suitable for living in the intestine?
Flat body which results in a large surface area for maximum food absorption, it has substances on its skin to prevent it being digested, hooks and suckers instead of eyes, and there are male and female reproductive parts on each segment
What does mistletoe do?
The roots grow into the host’s vessels (tree) to absorb water and mineral salts
Describe a mutual instil relationship
When two organisms live together and both benefit from the relationship
What do oxpeckers do?
They feed on parasitic insects off the herbivore
What do cleaner fishes do? (Mutualism)
They feed on parasitic organisms on the surface of shark skin
What does nitrogen fixing bacteria do in terms of mutualism?
Feeds on chemicals for food and produces the nitrogen compounds that the legumes need to grow
What does chemosynthetic bacteria do?
It gets the substances needed from the tube worms and the tube worm will feed on the waste from the bacteria
What are fertilisers made up of?
Phosphates and nitrates
Describe eutrophicationi
1) fertiliser added 2) rain washes fertiliser off 3) phosphates and nitrates dissolve in soil water 4) phosphates and nitrates wash into flowing water 5) high levels of phosphates and nitrates encourage plant and algae growth 6) surface plants block the light so plants die 7) deco losers increase and use oxygen 8) oxygen decreases 9) animals die from lack of oxygen
What is an indicator species?
A species that can show where pollution occurs
How does black spot fungus in roses show areas of pollution?
Black spot fungus is killed by sulfur dioxide
How do lichens act as an indicator species?
Different species can to,erase different levels of sulfur dioxide so we can tell absence of these gases in air
How do stonefly larvae and freshwater shrimp show pollution on water?
They need lots of oxygen so would show an area with little pollution
How do bloodworms and sludge worms show us polluted areas of water?
Because they can survive in areas with little oxygen
Death and excretion leads to what stage in the nitrogen cycle?
Protein and urea
What happens to protein and urea to convert it to ammonia?
It is decomposed by soil bacteria
Ammonia is _____ by ____ to turn it into nitrates in the soil
A) oxidised
B) nitrifying bacteria
How are nitrates broken down into nitrogen in the air?
By denitrifying bacteria
Nitrogen fixing bacteria and lightning do what to nitrogen in the air?
Turn it into nitrates in the soil
Nitrates are _____ by roots
Absorbed
How does nitrogen in air lead to plants in the nitrogen cycle?
Nitrogen fixing by root nodule bacteria
