Biology Paper 1

long protein strand that lashes about for movement

- lots of dendrites - make connections to other nerve cells
- axon that carries nerve impulses is very long
- myelin sheath for insulation
- lots of mitochondria to provide energy needed to make transmitter chemicals for synapses

- proteins that slide over each other - make fibres contract
- many mitochondria
- can store glycogen - can be broken down and used in respiration

- long tail for movement
- midpiece packed with mitochondria - for tail to work
- acrosome in head stores enzymes
- large nucleus for genetic info

- large SA - increase rate of absorption
- many mitochondria - energy for active transport
- large permanent vacuole - speeds up movement of osmosis

- positioned in continuous layers of the leaves / outer stem layers
- large permanent vacuole - keep cell rigid as result of osmosis - these rigid cells also help support the stem and keep the leaf spread out so it can absorb more light

- alive when first formed but chemical lignin builds up in spirals in the cell walls - cells then die and form long hollow tubes - allow passage of water and minerals
- spirals and rings of lignin make them very strong and support the stem - withstand pressure of water moving up them

- cell walls between cells break down to form sieve plates - allow water carrying dissolved food to pass through
- lose lots of their internal structures so companion cell mitochondria transfer energy needed to make dissolved food move up and down

O2, CO2, Urea

concentration of solutes outside cell = internal concentration

concentration of solutes outside the cell > internal concentration
- shrivels cells

concentration of solutes outside cell < internal concentration
Burst

- water moves into cell by osmosis
- vacuole swells, pressing cytoplasm against cell wall
- pressure builds up until no more water can enter
- makes cells hard and rigid

hypotonic - keep water moving towards cells and keep them turgid

- become flaccid as there is no pressure on cell walls
- plant wilts as there is no longer turgor to support the plant tissues

state of plant cells when so much water is lost by osmosis that the vacuole and cytoplasm shrink and the membrane pulls away from the wall

- mineral ions from very dilute solutions in soil
- sugar from the gut into the blood

- provide short diffusion paths
- rich blood supply

- grow bigger
- carry out normal cell activity
- replicate DNA to form 2 copies
- increase number of organelles

mitosis - DNA copies separate and nucleus divides

cytoplasm and cell membranes divide to form 2 identical daughter cells

unspecialised cells that can differentiate into many different types of cell

- active regions of stem and roots where stem cells are formed
- stem cells used to produce clones of a mature parent plant quickly and cheaply
- mitosis takes place almost continuously - cells then elongate and grow before they finally differentiate

- paralysis - spinal nerve cells can't repair themselves
- type 1 diabetes - specialised cells in pancreas don't work

- cells from adult patient used to produce cloned early embryo of themselves
- source of perfectly matched embryonic stem cells that wouldn't be rejected by patient

- embryonic divide and grow rapidly - could cause cancer
- adult could be infected with viruses or trigger immune responses

- muscular
- glandular - contains secretory cells that produce and release enzymes and hormones
- epithelial - covers outside of body and internal organs

carbon, hydrogen, oxygen

carbon, hydrogen, oxygen

carbon, hydrogen, oxygen, nitrogen

- structural components of tissues
- hormones
- antibodies
- enzymes

produces digestive enzymes and secretes them into small intestine through bile duct

faeces formed and water absorbed back into blood

mouth, pancreas, small intestine

stomach, pancreas, small intestine

pancreas, small intestine

metabolism

- shape of active site comes from forces between different parts of the protein molecule - change in pH affects these forces

- kills most bacteria
- gives protease an acidic environment to work in

- series of enzyme-controlled reactions that convert fibrinogen into fibrin
- this produces network of proteins that capture red blood cells and platelets to form a jelly-like clot

primarily made of water - many of the molecules it needs to transport are soluble in water

irregular shape - change shape to squeeze out of blood vessels and get to site of infection

proteins on surface allow them to stick to breaks in blood vessels and to each other

pumps blood around the body in a double circulatory system

blood from heart to body

from body to heart

pumps blood to the lungs for gas exchange

pumps blood to the rest of the body through aorta

- small lumen
- thick walls containing muscle and elastic fibres for protection
- can stretch to allow blood through them

- no pulse
- thin walls
- large lumen
- valves to prevent backflow of blood

- narrow lumen
- one cell thick walls - short diffusion pathway

- epidermal
- palisade mesophyll
- spongy mesophyll
- xylem and phloem
- meristem

- covers plant surfaces and protects them
- some secrete a waxy substance that waterproofs surface of the leaf

lots of chloroplasts

- some chloroplasts
- big air spaces and large SA to make diffusion of gases easier

- thick, waxy, waterproof cuticle
- most stomata on underside of leaf - protects them from direct sunlight and energy of sun
- wilting - leaves collapse and hang down - reduces SA available for water loss by evaporation
- stomata close - stops photosynthesis if risk of overheating present

- used to investigate effect of different factors on rate of transpiration
- shows uptake of water by plant with an air bubble
- gives a good idea of how much is lost in transpiration - almost all water taken up by a plant is lost in transpiration
- rate measured by distance travelled by air bubble

viral, can be fatal, spread by air

fever and red skin rash

reduces growth due to lack of photosynthesis

no treatment - spread can be stopped by good field hygiene and pest control

antiretroviral drugs

fever, abdominal cramps, vomiting, diarrhoea

easily treated with penicillin until resistant strains started to appear

fungal, spread by water and wind

purple / black spots on leaves

fungicides and removal of affected leaves

white blood cells ingest pathogens

- barrier
- blood clotting
- produces antimicrobial secretions to destroy pathenogenic bacteria
- covered in microorganisms that act as an extra barrier

hairs and mucus trap particles

secrete mucus which is wafted by cilia

virus

bacteria, viruses, fungal spores

- tiny piece of infected plant material left in a field can infect an entire new crop
- animal vectors

- fungal spores carried in splashes of water
- raw, undercooked or contaminated food
- water containing sewage

liquid / gel containing all necessary nutrients for cultivating microorganisms

- carbohydrate (energy source)
- minerals
- nitrogen source (protein synthesis)
- most also need warmth and oxygen to grow

- hot agar gel: first poured into a petri dish and then left to cool and set
- flask of sterile nutrient broth solution

- to investigate effects of chemicals eg. disinfectants / antibiotics
- risk that microorganisms will mutate to produce a new dangerous pathogen

= lower likelihood of growing harmful pathogens

enables faster growth - used in industrial settings and hospital labs (identify human pathogens as quickly as possible)

simple binary fission - can divide as often as every 20 mins with the right conditions

- doctor
- noticed that women delivered by medical students and doctors rather than midwives were much more likely to die from childbed fever after giving birth
- made link between dead bodies, no handwashing and then delivering babies

showed that microorganisms caused disease - developed vaccines

started to use antiseptic chemicals to destroy pathogens before they caused infection

- very few
- crown galls caused by a bacterium - mass of unspecialised cells that often grow at join between root and shoot
- bacteria insert plasmids into plant cells and cause a mass of new undifferentiated genetically modified cells to grow

sexual in female mosquito, asexual in human body

- insecticide - impregnated insect nests
- stop vectors breeding - remove standing water / spray with insecticides to kill larvae
- antimalarial drugs (for travellers)

- insect plant pest group
- sharp mouthparts penetrate phloem vessels and feed on sugar-rich phloem sap, depriving cells of photosynthesis products
- attack in large numbers
- can also act as vectors

- chemical pesticides in enclosed spaces
- biological pest control eg. ladybirds

- needed to convert sugars made in photosynthesis into proteins
- causes stunted growth

- aka chlorosis
- needed to make chlorophyll
- causes yellowing leaves

- stunted growth
- spots on leaves
- decay / rot
- growths
- malformed stems and leaves
- discolouration
- presence of visible pests

- expert
- gardening manual
- testing kit (monoclonal antibodies)
- DNA testing

- tree bark
- cellulose cell wall
- tough, waxy cuticle on leaf surface
- layer of dead cells on outside of stems
- leaf fall

- antibacterial chemicals
- poisons - herbivores learn quickly to avoid eating plants that make them feel unwell

- hairy stems / leaves
- thorns
- drooping / curling when touched
- mimicry - droop to mimic unhealthy plants and trick animals

- dead / inactive forms of pathogens injected
- antigens stimulate lymphocytes to produce antibodies
- if the same pathogen reenters the body, the white blood cells respond quickly
- can protect against both bacteria and viruses

heart drug - originates from foxgloves

originates from willow

- Alexander Fleming from the penicillium mould
- his culture plates had mould growing on them
- there were some clear rings in the agar gel around mould spots

toxicity, efficacy and dose

uses cells, tissues and live animals

- use healthy volunteers and patients
- very low doses given at start
- if safe, further clinical trials carried out to find optimum dose
- double blind trials - some patients given placebo to test for efficacy

25*C

if a large proportion of the population is immune to a pathogen, its spread is much reduced

- used in traditional medicine in some countries
- used as food and drink for centuries with no apparent problems
- recent research shows antibacterial properties

scientists collecting soil samples and searching for microorganisms to produce a new antibiotic against antibiotic-resistant bacteria

- produced from a single clone of cells
- each type is specific to one binding site on a specific protein antigen so they can target specific cells in the body / specific chemicals

- mouse lymphocytes stimulated to make a particular antibody
- lymphocytes combined with tumour cells to create a hybridoma cell
- hybridoma can both divide and make the antibody
- single hybridomas are cloned to produced many identical cells
- large amount of antibody is separated and purified

- HCG hormone in urine of pregnant women
- monoclonal antibodies bind to hormone
- dye attached to antibodies signals positive result

- monoclonal antibodies bind to antigens on pathogens, blood clots or cancer cells
- may carry markers - easier for doctors to see where they have built up
- used in blood test for prostate cancer

- monoclonal antibodies locate specific molecules in cell / tissue
- linked to a fluorescent dye

- trigger immune system to recognise, attack and destroy cancer cells
- block receptors on cancer cell surfaces to stop them growing and dividing
- carry toxic drugs / radioactive substances / chemicals to attack cancer cells, without damaging healthy cells

initially created more side effects than expected - mouse antibodies triggered an immune response in humans

explains how one factor influences another through a biological process

similarity in the patterns between non-communicable diseases and lifestyle factors - doesn't prove one thing is the cause of another

- growth of abnormal cells contained in one place, usually within a membrane
- can grow very large very quickly but don't invade other parts of the body
- can be life threatening if they cause pressure or damage to an organ eg. brain

- cancer - invades neighbouring tissues and spreads to different parts of the body through the blood, where it form secondary tumours
- cells divide more rapidly and live longer than normal cells, so completely disrupt normal tissue

- don't respond to normal mechanisms that control the cell cycle
- divide very quickly with little time for growth between each division

- fetus may not get enough oxygen to grow properly
- premature, low weight and still birth

- chemicals in tobacco smoke anaesthesise cilia
- dirt and pathogens in lungs - high risk of infection
- mucus build up causes coughing

- turns lungs from pink to grey
- increases risk of bronchitis
- build up of it in the delicate lung tissue can lead to a breakdown of alveoli structures, causing COPD - this reduces SA:V of lungs
- carcinogen - acts on delicate lung cells, causing mutations

- narrows blood vessels and damages artey lining
- nicotine increases heart rate
- coronary heart disease more likely
- chemicals increase blood pressure

- builds more muscular tissue, which needs more food transferred energy than body fat - increases metabolic rate and decreases likelihood of being overweight
- fitter heart and better blood supply
- bigger lungs
- lowers blood cholesterol - less risk of fatty material deposit in coronary arteries

- arthritis
- high blood pressure and heart disease
- type 2 diabetes (due to abnormal blood glucose balance)

poisonous but removed by liver before permanent damage / death

- cirrhosis of the liver - destroys liver tissue - active cells replaced with scar tissue that can't carry out vital functions
- liver cancer
- brain becomes soft and pulpy so brain structures are lost and it can no longer work properly

- passes through placenta to foetus - developing liver can't cope
- Fetal Alcohol Syndrome (FAS), miscarriage, stillbirth, premature and low weight birth

carcinogen - radiation penetrates cells and damages chromosomes, causing mutations in DNA

6CO2 + 6H2O (light) ---> C6H12O6 + 6O2

- respiration
- conversion into insoluble starch for storage - insoluble so has no effect on water balance of plant - energy store for darkness and winter
- produce fat or oil for storage
- produce cellulose to strengthen cell walls
- amino acid production - combine the sugars with mineral ions from the soil

- very few plants survive well
- some carnivorous plants adapted to living in nitrate-poor soil
- produce enzymes to digest the insects that they trap
- use nitrates and other mineral ion from them

endothermic reaction - energy transferred from the environment to the chloroplasts by light

- broad - big SA for light to land on
- thin - diffusion distances for gases are short
- chlorophyll in chloroplasts absorbs light
- veins - water supply and remove products of photosynthesis
- air spaces and stomata

when light, warmth or CO2 are in short supply

speeds up reaction but photosynthesis is controlled by enzymes that can denature

- increase at night because plant respires but doesn't photosynthesise
- as light intensity and temp increase in the morning, most of the CO2 is used up

$Light \space Intensity =\frac{K}{Distance^2}$

- plants grown in water with a perfect balance of nutrients instead of soil
- conditions controlled by computer software
- crops are clean and soil free, no need to plough and prepare land

exothermic, occurs continuously

C6H12O6 + 6O2 ---> 6CO2 + 6H2O + (energy transferred to the environment)

DELETE

turns limewater cloudy

turns cobalt chloride from blue to pink

- building / breaking molecules
- muscle contraction
- maintain body temperature
- active transport

folded inner membrane provides large SA for enzymes involved

- heart rate increases and arteries supplying blood to muscles dilate - so flow of oxygenated blood to muscles increases
- breathing rate and depth increase

incomplete breakdown / oxidation of glucose

glucose ---> lactic acid + (energy transferred to the environment)

muscles stop contracting efficiently after being used vigorously for a long time

- muscle fatigue
- oxygen debt

amount of oxygen needed to oxidise lactic acid

- blood transports lactic acid to the liver, where it's converted back into glucose
- glucose is then converted aerobically into CO2 and H2O

- glucose ---> ethanol + CO2
- C6H12O6 ---> 2C2H5OH + 2CO2

- detoxify poisonous substances eg. ethanol
- pass breakdown products into the blood so they can be excreted in the urine via the kidneys
- breakdown old, worn out blood cells and store the iron until it is needed to synthesise more blood cells
- remove lactic acid

- iodine solution (yellow / red solution)
- turns blue / black

- Benedict's test (blue solution)
- turns brick red on heating

- Biuret test (blue reagent)
- turns purple
- corrosive - eye protection

- ethanol test
- gives a cloudy white layer
- highly flammable and harmful