Biology Paper 2 AQA GCSE

what happens to enzymes if temperature becomes too high or pH becomes too high or low

conditions in which enzymes work best

the regulation of the internal conditions of a cell or organism

involves responses to the ___ or ___ conditions

many conditions are controlled in the human body, including: body ___

blood ___ concentration

___ levels

homeostasis uses automatic control systems such as: hormonal (___) responses

nerve responses (___ system)

all control systems have 3 main parts. 1) ___ which are cells that detect stimuli

receive information and process it

bring about responses needed

cells in the nervous system

carry electrical impulses from receptors to CNS: ___ neurone

dendrites collect impulses from ___ cells

has a long dendron and ___ to carry impulses distances

has a fatty ___ ___ to insulate the neurone, as the impulse can't cross this

carry impulses from sensory to motor neurones, found in CNS: ___ neurone

dendrites collect impulses from ___ neurone

axon ___ pass impulses to other neurones

carry impulses from CNS to effectors: ___ neurone

___ actions don't involve the conscious part of the brain

they are automatic and ___ - not learned responses

a reflex arc:

 

 

 

 

 

 

the point where 2 neurones meet

electrical impulses can't cross the gap in these, so the signal is transmitted by:

this process works in one direction and allows nerve impulses to produce impulses in several other neurones, but is ___ than nerve impulses

investigating reaction times RP: sit on stool and rest ___ on bench with hand hanging over edge

open thumb and forefinger, and get a partner to hold the ruler upright so the ___cm mark is level with the top of your thumb

without ___, the partner should release the ruler for you to catch

record the reading, repeat 2-___ times

plot reaction time on the ___ axis

plot drop number on the ___ axis

the ___ system comprises of glands that secrete hormones directly into the bloodstream

a hormone is secreted by a gland, transported in the ___ and affects a target organ or another gland

the ___ gland secretes several hormones which act on other glands, stimulating the release of other hormones

hormones have a ___ speed and ___ duration (opposite to nerves)

secretes TSH, ADH, FSH and LH

secretes thyroxine

secretes insulin and glucagon

secretes adrenaline

secretes testosterone

secrete oestrogen and progesterone

blood glucose concentration rises: pancreas increases secretion of ___ and decreases secretion of ___

insulin causes muscle and liver cells to remove glucose from blood and store as ___

concentration falls: pancreases increases secretion of ___ and decreases secretion of ___

glucagon causes liver cells to convert ___ to ___ and release into blood

___ is a disease where the body can't properly control BGC

in type ___, pancreatic cells are destroyed by immune system. no longer produce insulin/not enough insulin. treated by insulin injections

in type ___, liver and muscle cells no longer respond to insulin, or pancreas doesn't produce enough insulin

treated by carbohydrate-controlled ___ and exercise

menstrual cycle: day 1-5, the breakdown and shedding of uterus lining along with blood

8-14 uterus lining is ___ ___

day 14

14-16: where ___ is most likely to take place

up to day ___: lining of uterus continues to build up

___ causes eggs in the ovaries to mature

___ causes an ovary to release an egg

___ and ___ maintain uterus lining

oral ___ may contain oestrogen and progesterone

inhibits release of FSH meaning eggs don't ___

risk of side effects, such as raised blood pressure, breast cancer and blood clots (___)

surgical ___: women are sterilised by blocking oviducts that lead from the ovaries to the uterus

men get ___ where sperm ducts are cut, stopping sperm getting into the semen

IUD or ___ ___: stops sperm/eggs surviving in the uterus and oviducts

doses of ___ and ___ help women with low levels become pregnant normally

FSH given to stimulate egg ___ and oestrogen production

LH given to trigger ___ of the egg

doses are controlled to avoid ___ births

in in vitro fertilisation, or ___, mature eggs are fertilised outside the woman's body

used when ___ are damaged/blocked

or when the man has a ___ ___ ___ or malformed sperm

___ is given to cause an egg to mature

then the eggs are taken from the ovaries, mixed with sperm in a dish for ___, then implanted into the womb

hormone produced by adrenal glands in times of fear/stress

converts glycogen into glucose, ___ heart/breathing rate

hormone that controls how much energy your body uses

including rate of ___ in cells, how quickly substances break down or are synthesised

key role in ___ and ___

regulates growth of ___ and how the brain matures

sexual reproduction

parent cell has 2 sets of chromosomes, a ___

divides in 2 then in 2 again. each daughter cell has 1 set of chromosomes: ___

in fertilisation, male and female ___ join to form zygote

zygote divides by mitosis, forming an ___

number of cells increases and cells ___ as this develops

in plants, fertilisation involves ___ and egg cells fusing

___ are different versions of the same gene

the ___ is the alleles of a particular gene present in an individual

the ___ is the observed characteristics or traits of the individual produced by the allels working at a molecular level

most characteristics are a result of multiple genes ___

___ is where a person has extra digits. dominant allele causes it

___ ___ is an inherited disorder of cell membranes

caused by ___ allele. only homozygous cc will give cystic fibrosis

people who are heterozygous for the trait are ___: they can pass the allele to their children but don't have the disorder themselves

the difference in characteristics of individuals in a population

can be caused by ___ or ___ factors

evolution: individuals in a population show variation and some have ___ that make them better suited to the environment

more likely to survive and ___ and pass alleles to their offspring

these offspring are likely to have phenotypes that make them better suited to the environment, making them more likely to ___

___ ___: individuals with the desired characteristic are selected and bred

the best of their offspring is then bred again, and this is repeated over many ___ until all offspring share this characteristic

GM crop advantages: ___ to diseases and pests

resistant to ___ so fields can be sprayed to kill weeds but not crop plants

help produce increased ___, including bigger and better fruits

___ value increased: eg golden rice with more beta-carotene for vitamin A production

GM crop concerns: concerns on effects on populations of wildflowers due to herbicide use, and populations of ___ if there's less food for them

if the human ___ impact of eating GM crops has been researched enough

some people have an inherited disorder that stops them making a protein which causes problems with the ___ and liver

___ can be engineered to produce this protein in their milk, which can be used to treat them

when an organism's genome is modified to give a desired characteristic by introducing a gene from another organism

process: enzymes are used to ___ the gene

transferred to a ___ or virus

the gene is then transferred into the cells of a target organism at an ___ stage of the organism's development

this ensures ___ cells receive the transferred gene and the organism develops with the desired characteristic

can be used to modify the genome of a ___ to include a human gene

eg. the insulin production gene, then the insulin can be ___ and used to treat diabetes

cloning animals: remove nucleus from ___ cell of animal A and insert into unfertilised egg cell from animal B

use an ___ ___ to start division and form an embryo. the animal will be a clone of animal A

individual organisms within a species show a wide ___ of characteristics

who came up with the theory of evolution by inheritance of acquired characteristics?

useful body parts become ___ and ___ while unused ones grow smaller or disappear

changes to an organism during its ___ are passed to the offspring

explains evolutions of ___ ___ in giraffes

had to stretch to reach high leaves on trees for ___

those with characteristics best suited to the environment are most likely to breed successfully and pass on their characteristics. this is known as ___ by ___ ___

who came up with this theory?

published the theory in his book ___ ___ ___ ___ ___ (1859)

this idea faced opposition: challenged the idea that ___ made all living things

there was not enough ___ and the mechanism of inheritance and variation wasn't known at the time

was a result of scientific research: eg. observations made on his 1836 expedition around the world on the HMS ___

also worked with ___ ___ ___

he developed the same theory independently from ___

also known for his theory of ___ (the formation of new species) and work on warning colours on animals

speciation: populations of the same species are ___ somehow

eg. due to a change in the environment producing a ___ to movement

___ ___ favours different characteristics in each area

therefore the characteristics of each population become ___ over time

eventually they are so different that populations become new ___

they can no longer breed together to produce ___ offspring

man who came up with the basics of inheritance

pure-bred ___ ___ would produce identical offspring when bred with the same type of ___ ___

when a tall plant was crossed with a dwarf, the offspring was tall, so the dwarf trait was ___

cross-bred plants from the first generation of offspring with each other and about one ___ were dwarf

this trait had been passed ___ from the parents

fossil formation: ___ of the organism are preserved such as burrows, root traces and footprints

parts of the organism (eg. bones and teeth) are replaced by ___ as they decay

___ tissues don't decay because on or more of the necessary conditions is missing

causes of extinction: new ___ eat all the individuals

a new ___ kills the population

new ___ take up all of a resource

there is a change to the ___ that the organisms can't adapt to quickly enough

single ___ event (eg asteroid collision, volcano eruption)

Swedish scientist who classified organisms into groups by structure and characteristics

classification system:

 

 

 

 

 

 

each species has a ___ name (genus then species) and closely related species have the same genus name

who proposed the three domain system?

plants, animals, fungi and protists

true bacteria and cyanobacteria which photosynthesise

primitive bacteria that usually live in extreme environments like very hot or salty water

evolutionary ___ show evolutionary relationships between species

___ data can be used to work out relationships between extinct species

modern data, eg. ___ analysis, can be used to work out relationships between living scientists

single living individual

all the organisms of the same species in a habitat

populations of all the different species in a habitat

the interaction of a community of living organisms with living and non-living parts of the environment

non living

includes: ___ intensity, temperature, moisture levels, pH

mineral content of ___

___ concentration

living. includes: food, predators, pathogens, competition

where each species in a community depends on others for resources

in a ___ community, all the species and environmental factors are balanced

___ are relatively constant in size

plant reproduction: male gametes (pollen cells) are transferred to female egg cells by ___

some species of plant rely on the wind to carry ___ from one place to another

others rely on ___ such as bees

many plants rely on the wind to ___ seeds from parent plants

others use ___, eg. eating fruits, carrying seeds on fur

animal adaptations to the cold: polar bears have a white colour for ___

thick fur and fat below skin to ___

___ feet for a better grip on ice and to stop the bear sinking in the snow

adaptations to hot/dry conditions: camels have a ___ of fat

this acts as a ___ store without insulating the rest of the body against heat loss

___ fur at the top of the body to insulate against heat from the Sun, ___ fur everywhere else to allow heat loss

have the ability to tolerate ___ body temperature and ___ water content

organisms that make their own food

eaten by ___ consumers

eaten by ___ consumers (and so on)

a consumer of other animals that has no predators of its own

in predator-prey cycles: prey population ___ if there's plenty of food/few predators

many survive to ___ and therefore there's more available food for the predators

their population rises and they eat a greater ___ of the prey so the prey population falls

as this falls, there's less food for the ___, so their population falls

abundance RP: place ___ in randomly selected areas in a region

count number of organisms in each quadrat and find the ___

___ to apply to the whole area

only really useful for ___ or slow moving animals

the water cycle: ___ from bodies of water, respiration and transpiration = water vapour

this ___ to form clouds

falls back to Earth as ___ and some rejoins water bodies, some trickles through the soil

carbon cycle: plants absorb ___ ___ and convert it to carbon compounds

passed to animals when they ___ plants, and then from animal to animal along the food chain

carbon dioxide is released during ___

dead plants and animals are eaten by ___

dead organisms that aren't broken down may eventually form ___ ___

when these are ___, carbon dioxide is released

factors increasing rates of decay: ___ temperatures increase the rate of chemical reactions in microorganisms

decay happens faster in ___ conditions as microorganisms need water for cell processes

most decomposers use ___ respiration so decay is faster with the presence of oxygen as they can respire

some decomposers use anaerobic respiration and produce ___ gas

used as ___

a biogas generator uses animal ___ to produce large volumes of methane to burn

gardeners produce ___ from plant waste. it acts as a natural fertiliser

farmers also use ___ as a natural fertiliser

when harmful/poisonous substances are released into the environment

kills animals and plants, reducing ___

land pollution includes: toxic chemicals such as ___ and ___

dumping waste in ___ sites

air pollution: smoke/gases, ___ dioxide (part of acid rain) released when coal is burnt

water pollution: polluted with sewage, fertilisers, ___ chemicals washed in from land

rapid ___ growth and a better standard of living leads to more waste

if not handled properly, this causes ___

more people also means more land used for building, ___ for building materials, ___ to produce food

leads to less ___ for other animals and plants

destruction of forest land to make land available for other uses

need land for: ___ (either food crops or grassland to feed cattle)

___ for building and other uses

growing crops for ___ such as ethanol for cars

problems: burning the trees leads to ___ ___ release

increased activity of ___ that decay chopped wood so more CO2 released

fewer trees so less carbon "___ ___" in wood or removed from the air

partially decomposed plant material found in peat bogs and peatland

useful to make fuel and garden ___, but carbon dioxide is released when peat decays or is burnt as fuel

destruction of habitats containing peat reduces ___

variety of all the different species in an ecosystem or on Earth

a high level of this keeps ecosystems ___ by reducing interdependence

reasons to maintain this: ___, to respect other species

___, to enjoy seeing them

some are ___, for example plants being a source of new medicines, and some species provide opportunities to make money off tourism

programs to help it include: protecting and ___ rare habitats such as wetlands

replanting hedgerows in ___

___ resources to reduce waste in landfill and reduce quarrying

benefits of ___ (opposite of deforestation): restores habitats

reduces effects of soil ___ as tree roots bind soil together

helps reduce carbon dioxide concentration as trees ___

___ ___ absorb infrared radiation emitted by the Earth's surface and release it in all directions

helps to keep the Earth warm, allowing species to ___ here

___ activities increase levels of greenhouse gases

___ is produced by waste decay, rice paddy fields, and cattle

carbon dioxide is produced by the ___ of fuels

increasing levels of greenhouse gases enhance the ___ effect

leads to ___ ___/climate change (we know this based off peer-reviewed publications and systematic reviews of these papers)

effects of global warming: periods of low or no rainfall: ___

___ winters and ___ summers

rise in ___ ___ due to ice melting and warmer sea water

changes in bird ___ patterns

changes in ___ of species

___ ___: bacterial strains resistant to an antibiotic can spread through a population

these strains are caused by ___ and are more likely to survive and reproduce

eventually the ___ of resistant strains increases, while non resistant strains are killed

methicillin-resistant Staphylococcus aureus or ___ is an example of one of these strains

the Staphylococcus aureus bacterium causes skin/respiratory infections and food ___

used to be treated by ___ but it's not effective against MRSA

problem in ___ as patients may have wounds/weak immune systems and people transfer the bacteria from place to place easily

reducing antibiotic resistance: don't prescribe antibiotics to treat non-___ infections

restrict antibiotic use in ___

patients should finish antibiotic courses to all bacteria are killed, leaving none to form ___ strains