MOCKS (NOV)

• nerve cell adaptations: Long axons carry impulses, myelin insulates and speeds up, synapse allow impulses to move, contains egg digesting enzymes
• muscle cell adaptations: Special proteins that contract, many mitochondria, store glycogen
• xylem cells: - thick walls containing lignin, strengthens and supports plants

  - end walls between cells broken down and no internal structure (e.g. nucleus) so cells forms long tube and H2O and minerals can flow more easily
• Phloem cells: - no nucleus and limited cytoplasm

  - sieve plates on end walls of vessel cells, both features let dissolved sugar move through interior

  - companion cell connected to vessel cell has mitochondria and provides energy to vessel cell
• Mitosis: 1. DNA replicates to form 2 copies of each chromosome, also grows and copies internal structure

  2.MITOSIS occurs, 1 set of chromosomes is pulled to each end of the cell and nucleus divides

  3. cytoplasm and cell membrane divide to form 2 identical cells
• Bone marrow transplants (leukemia cancer of bone marrow): 1. existing bone marrow destroyed using radiation

  2.recoeves transplant of bone marrow from a donor

  3. stem cells in bone marrow divide to form new bone marrow, also differentiated to form blood cells

  PROBLEM: donor must be compatiable with patients or white blood cells from donor bone marrow will attack donors body
• THERAPUDIC CLONING (e.g. paralysis or diabetes): 1. embryo produced with same genes as patient

  2. embryo stem cells transplanted to patient w/out rejection by patients immune system

  3. in patient stem cells can differentiate to replace cells which have stopped working
• gas exchange in animals: have structures for gas exchange with very high S.A:V e.g. lungs

  have transport system to carry gasses around body
• gas exchange in fish: 1. O2 rich water passes mouth, flows over gills where O2 transported to blood stream

  2. gills covered in lots of fine fillaments where gas exchange occurs

  3. deoxygenated blood flows into filament, O2 diffuses from water to blood, oxygenated blood returns to body
• filament adaptations: give gills massive surface area

  thin membrane provide short diffusion pathway

  efficient blood supply takes oxygenated blood away, ensures concentration gradient is always high
• plant root hair cell: root hair cell transports ions (e.g. Mg) into plant from soil (Mg needed to make chlorophyll)

  conc of ions in soil lower that in root air cell so active transport moves ions into cell then ions transported to Xylem to leaf
• digestive system: 1. mouth- chew, enzymes in saliva digest starch similar to simple sugars

  2. passes down oesophagus into stomach whre enzymes begin the digestion of protiens and HCL acid help enzymes digest protiens, churning action of stomach muscles turns food into fluid increasing surface area for enxymes to digest

  3. fluid passes into small intestine, pancreas releases enzymes to s.i, continues digestion of starch and protiens also starts digestion for lipids (liver releases bile)

  4. fluid travels to rest of si, walls of si release enzymes to continue digestion of protiens and lipids

  5. in si small food molecules produced by digestion are absorbed into blood stream by diffusion or active transport

  6.fluids enter large intestine, water absorbed itno blood stream and faeces released
• circulation in fish (single): - deoxygenated blood pumped from heart to gills, becomes oxygenated, blood passes from gills to organs, O2 diffuses out of blood to body cells, blood returns to heart

  PROBLEMS- blood loses lots of pressure as it passes through gills before reaching organs so travels slowly so cant deliver lots of oxygen
• the blood through the heart: vena carva

  right atrium (where pacemaker is )

  right ventricle

  pulmonary artery

  lungs

  pulmonary vein

  left ventricle

  left atrium

  aorta
• what does the plasma carry: - soluable digestion products from si to other organs

  - CO2 from organs to lungs (to breathe out)

  - urea from kidneys excreted as urine

  - blood components
• CHD: fatty material builds up in cornonary arteries causing it to narrow, which reduces blood flow so lack of O2 for heart muscle (can result in a heart attack and the heart is starved of O2)
• Treatments of leaky valves: mechanical valves (last a lifetime, increase risk of blood clots so have to take anticlotting drugs )

  animal valves (dont last as long and may need replaceing but patients do not need to take drugs )
• epidermis tissue: the outside layer of cells on the top and bottom of a leaf, protects surface of leaf, upper epidermis transparent to allow light to pass through
• waxy cuticle: Forms a waterproof layer to stop water loss due to photosynthesis
• stomata: Small openings on the underside of a leaf through which oxygen and carbon dioxide can move
• palisade mesophyll: photosynthetic tissue below the epidermis in a leaf. (contains lots of chloroplasts)
• spongy mesophyll: Loose tissue beneath the palisade layer of a leaf; has many air spaces between its cells to allow for diffusion of gasses
• Transpiration stream: the movement of water through a plant from the roots until it is lost by evaporation from the leaves.
• factors affecting rate of transpiration: 1. Temperature (high = faster)

  2. Humidity (dry = faster)

  3. Light intensity (bright = high)

  4. Wind (windy = faster)
• stomata and guard cells
• non specific defense systems (human): skin- protective layer, dead cells on outer layer so its difficult for pathogens to penetrate

  nose- hair and mucus trap pathogens before they enter the breathing system

  stomach- HCL acid kills pathogens
• TMV: Virus affecting plants causing a mosaic pattern on leaves, rate of photosynthesis reduced so plant growth reduced
• rose black spot: fungus

  causes leaves to develop black spots then turn yellow and fall off

  rate of photosynthesis falls reducing growth

  treatment: spray fungacides or remove infected leaves
• nitrate deficiency: Plants have stunted growth and older leaves turn yellow because these ions are required to make amino acids, proteins, chlorophyll and DNA.
• magnesium deficiency: Plant leaves turn yellow because these ions are needed to form part of a chlorophyll molecule.
• aspirin


  willow trees
• heart drug (digitalis)


  foxglove
• pathogens: bacteria- once in body reproduces rapidly

  virus- cannot reproduce by themselves, must infect a host cell

  protists

  fungi
• measles: virus

  fever, skin rash

  infected persons cough or sneeze droplets

  can cause damage to brain and breathing system
• HIV: A virus that attacks and destroys the human immune system.

  leads to aids in untreated

  spread by bodily fluids
• malaria: - protist

  - infected person bitten by a mosquitoe and protist passes into it

  - mosquito bites a different person and passes malaria protist to them

  - mosquito is the vector
• salmonella: Bacteria that causes food poisoning by producing toxins

  Symptoms: fever, stomach cramps, vomiting and diarrhoea

  Caused by eating food contaminated with salmonella e.g. uncooked chicken

  In the UK, most chickens are vaccinated against salmonella
• gonorrhoea: Bacterial disease

  Sexually transmitted disease (STD) caused by sexual contact e.g. unprotected sex

  Symptoms: pain when urinating; thick yellow/green discharge from the vagina/penis

  Originally treated with penicillin - now some strains have become resistant to it

  Treatment with antibiotics and using barrier methods of contraception (e.g. condoms) help prevent the spread of it
• Uses of monoclonal antibodies: pregnancy tests, diagnosis of disease,reasearch, measuring and monitoring, treating disease
• monoclonal antibodies in pregnancy tests: Monoclonal antibodies are attached to the end of a pregnancy test stick onto which a woman urinates. If she is pregnant, HCG will be present in her urine and will bind to the monoclonal antibodies on the test stick. This will cause a change in colour or pattern which will indicate pregnancy.