GSCE Biology Paper 1 Exam Notes 2023/2024, Exams of Nursing

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what is a eukaryote - correct answers organism made up of eukaryotic cells what is a prokaryote - correct answers a prokaryotic cell purpose of nucleus - correct answers contains genetic material (arranged in chromosomes) that controls activities of the cell purpose of cytoplasm - correct answers where chemical reactions take place and contains enzymes to control these purpose of cell membrane - correct answers holds cel together and controls what foes in and out purpose of mitochondria - correct answers where respiration takes place to transfer energy for cell functions purpose of ribosomes - correct answers involved in translation of genetic material in protein synthesis what extra subcellular structures do plants have that animals cells do not - correct answers cell wall, vacuole, chloroplasts purpose of cell wall - correct answers support and strength (made of cellulose) purpose of vacuole - correct answers maintains internal pressure to support purpose of chloroplasts - correct answers where photosynthesis occurs (contain chlorophyll)

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2023/2024 graded A+

purpose and location of chromosomal DNa in a bacteria - correct answers control's cell activities and replication, cytoplasm purpose of flagellum - correct answers hair-like structure that rotates to move bacterium away from harmful substances or towards beneficial things purpose of plasmid DNA - correct answers small loops of extra DNA that contain genes for things like drug resistance (can be passed between bacteria) name of a developed egg - correct answers embryo what does haploid mean - correct answers half the normal number of chromosomes adaptions of the egg cell - correct answers nutrients in cytoplasm, haploid nucleus, membrane structure changes on fertilisation adaptions of sperm cell - correct answers tail, mitochondria (in middle section), acrosome enzymes, haploid nucleus specialisation of epithelial cells - correct answers cilia move substances in one direction across the surface of the tissue (e.g. moving mucuc=s in airways) what does resoltuion mean - correct answers how wel a microscope distinguished between two points close together when were light and electron microscopes invented - correct answers 1590s, 1930s how does a light microscope work and what can we see in a cell - correct answers passes light through specimen, nuclei and chloroplasts

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how does an electron microscope work and what can we see - correct answers uses electrons, internal structure of mitochondria and chloroplasts total magnification = - correct answers eyepiece lens x objective lens magniication = - correct answers image/real to convert from mm to Um - correct answers x to convert from mm to nm - correct answers x to convert from mm to pm - correct answers x enzymes are said to have a ... for their substrate - correct answers high specificity metaphor for enzymes - correct answers lock and key what affect does a higher substrate concentration have on the reaction - correct answers faster to a point (more likely to two will meet up) rate = - correct answers 1000/time why must big molecules like protein be broken down - correct answers too big to pass through walls of cells in digestive system to be absorbed into bloodstream carbohydrates: enzyme and smaller molecule - correct answers amylase, simple sugars (e.g. maltose)

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proteins: enzymes and smaller molecule - correct answers protease, amino acids lipids: enzyme and smaller molecule - correct answers lipase, glycerol and fatty acids what is it called when you join smaller molecules together to make a bigger one - correct answers synthesising what is used to test for sugars and what is a positive test - correct answers Benedict's reagent, coloured precipitate (from blue to green to yellow to orange to red) what is used to test for starch and what is a positive test - correct answers iodine, from brown orange blue black colour what is used o test for Lipids and what is a positive test - correct answers Emulsion test(with ethanol), milky emulsion what is used to test for protein and what is a positive test - correct answers Biuret test (with potassium hydroxide and copper sulphate), blue to purple energy in food (J) = - correct answers mass of water x temperature change x 4. how can you compare energy in food fairly - correct answers energy per gram what is diffusion - correct answers net movement of particles from an area of high concentration to an area of power concentration

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what is osmosis - correct answers net movement of water molecules across a partially permeable membrane from an area of high water potential to an area of lower water potential what is active transport - correct answers movement of particles across a membrane against a concentration gradient which process of transport requires energy - correct answers active transport why do potato cylinders gain mass - correct answers high water potential outside what do potato cylinders have np change in mass - correct answers water potential same inside and out (isotonic) why do potato cylinders loss mass - correct answers lower water potential outside what does diploid mean - correct answers two copies of each chromosome what is created from mitosis - correct answers two genetically identical daughter cells stages of mitosis - correct answers interphase, prophase, metaphase, anaphase, telophase, cytokinesis what happens in interphase - correct answers increase ins subcellular structures, duplicates DNA what happens in prophase - correct answers chromosomes condense, nucleus membrane breaks down

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what happens in metaphase - correct answers chromosomes line up at middle of cell what happens at anaphase - correct answers spindle fibres pull chromosomes apart to poles what happens in telophase - correct answers nucleus membranes form around each set of chromosomes what happens in cytokinesis - correct answers cytoplasm and cell membrane divide number of cells after divisions in mitosis = (formula) - correct answers 2(to the)n two processes of growth - correct answers cell differentiation, cell division what is cell differentiation - correct answers when a cell changes to become specialised for its job to be more efficient what is cell division - correct answers mitosis what is cell elongation (only plants) - correct answers where a plant cell expands where does cell diviosn happen on a plant - correct answers meristem (roots and shoots) do animals or plants continue to differentiate all life - correct answers plants

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what is cancer - correct answers when a tumour invades and destroys surrounding tissue what is a tumour - correct answers a mass of undifferentiated cells (created by rapid division) what are growth charts used for - correct answers asses a child's growth to highlight any problems three measurements taken for growth charts - correct answers length, mass, head circumference what are stem cells - correct answers undifferentiated cells what potential to embryonic stem cells have and where are they found - correct answers in embryos, become anything what potential do adult stems cells have and where are they found - correct answers certain places e.g. bone marrow, become certain cells (to repair) what potential fo meristem cells have and where are they found - correct answers roots and shoots, become any cells (e.g. xylem or phloem) disease traced with adult stem cells - correct answers sickle cell anaemia risks of stem cell treatment - correct answers tumour development, disease transmission, rejection what is the spinal cord - correct answers a long column of neurones

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where is the cerebrum and what does it do - correct answers top, movement, memory, vision, language where is the cerebellum and what does it control - correct answers muscle coordination, balance where is the medulla oblongata and what does it control - correct answers bottom middle, unconscious activities (e.g. breathing) what does a Ct scan: use, show - correct answers x-rays, structure what does a PET scan: use, show - correct answers radioactive chemicals, brain activity difficulties with treating problems to the CNS - correct answers can't repair, hard to access, could be damaged further what is a sensory receptor - correct answers groups of cells which can detect a stimulus how does the nervous system send messages - correct answers as electrical impulses order of a nervous response to a stimulus - correct answers stimulus, receptor, sensory neurone, relay neurone, motor neurone, effector, response what is the purpose of a myelin sheath - correct answers electrical insulator to speed up electrical impulses what carroies impulses towards a cell body and what carries impulses away - correct answers dendrites and dendrons, axons

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features of the structure of a sensory enurone - correct answers one long dendron, one short axon features of a motor neurone - correct answers many short dendrites, one long axon features of the relay neurones - correct answers many short dendrites, one axon what is a synapse - correct answers the connection between two neurones how does a synapse work - correct answers chemicals called neurotransmitters diffuse across the gap which are detected on the other side and trigger a new electrical signal what is a reflex - correct answers automatic, rapid responses to stimuli to reduce the chance of injury what is the passage of information in a reflection called - correct answers reflection arc order of a reflex arc - correct answers stimulus, receptor, sensory neurone, relay neurone (through unconscious part of CNS), motor neurone, effector, response what is the reflex in the eye - correct answers light receptors detect very bright light which triggers circular muscles in the iris to contract function of the cornea - correct answers refracts light function of the iris - correct answers controls how much light enters pupil

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function of the lens - correct answers refracts light to focus on the retina function of retina - correct answers covered in cones and rods what do rods detect - correct answers sensitive in dim light what do cones detect - correct answers colour function of the optical nerve - correct answers carries the electrical impulses of the light information to the brain how do you focus on distant objects - correct answers ciliary muscle relaxes, suspensory ligaments pull tight, lens less round, light refracted less how do you focus on close objects - correct answers ciliary muscles contract, suspensory muscles relax, lens more round, light refracted more when does long sidedness occur - correct answers eyeball too short, lens the wrong shape where is the image for someone longsighted - correct answers behind retina which lens does longsighted person need - correct answers convex when does short sightedness occur - correct answers lens the wrong shape, eyeball too long

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where is the image for someone with shortsightedness - correct answers infront of retina which lens does a shortsighted person need - correct answers concave what causes colourblindness and why can't it be cured - correct answers faulty cones, can't be replaced what is cataract and how can it be treated - correct answers a cloudy patch on the lens, replacing lens with an artificial one what is sexual reproduction - correct answers where genetic information from two organisms is combined to produce offspring which are genetically different to both what are the reproductive cells called - correct answers gametes what is fertilised egg called - correct answers zygote what is a normal number of chromosomes for a human - correct answers 46 what is the cell division in sexual reproduction called - correct answers meiosis the process of meiosis - correct answers DNA duplicated, chromosomes line up in pairs at centre (mixture of mother and fathers), pairs are pulled apart, chromosomes line up again at centre, arms of chromosomes pulled apart what are the products of meiosis - correct answers four genetically different haploid daughter cells

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advantages of asexual reproduction - correct answers fast, no need to find mate advantages of sexual reproduction - correct answers genetic variation, natural selection disadvantages of asexual reproduction - correct answers no genetic variation disadvantages of sexual reproduction - correct answers more time and energy, two organisms needed DNA tornados are polymers made up of - correct answers nucleotides structure of a nucleotide - correct answers sugar and phosphate back-bone (alternating), one base attached to the sugar 4 bases - correct answers adenine, thymine, cytosine, guanine what are the complementary base pairs - correct answers AT, CG what joins the base pairs - correct answers weak hydrogen bonds what is agene - correct answers a section of DNA which codes for a particular protein what is a genome - correct answers all of an organism's DNA what must be added to fruit to extract DNA and why - correct answers deterrent to break down cell membranes, slat causes DNA to stick together, cold alcohol because DNA is insoluble in it

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what are proteins made from - correct answers amino acids amino acids are read in groups of - correct answers 3 what is a mutation - correct answers a rare random change to an organism's DNA base sequence what affect can a mutation have - correct answers change sequence of amino acids, change final protein, change its activity, change phenotype what is mRNA - correct answers a polymer of nucleotides difference between DNA and mRNA - correct answers double strand, uses Uracil instead of thymine two stages of protein synthesis are - correct answers transcription, translation how does transcription work - correct answers RNA polymerase binds to non- coding DNA, DNA unzips, moves along creating the mRNA to complement, leaves nucleus through pores how does translation work - correct answers joins with ribosome, amino acids brought by tRNA to match codons on mRNA, joined by ribosomes to form polypeptide how can a mutation in non-coding DNA affect protein synthesis - correct answers RNA polymerase unable/more difficult to bind to DNA, change protein, change phenotype

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what was the gist of Mendel's work - correct answers characteristics were passed on from one generation to the next Mendel's 3 conclusions - correct answers characteristic determined by hereditary units, passed on one unit from each parent, units can be dominant or recessive what are alleles - correct answers different versions of a gene what is genotype - correct answers the combination of alleles the inheritance of a single characteristic is called - correct answers monohybrid inheritance what chromosomes do males and females have - correct answers XY, XX what determines sex in humans - correct answers the sperm because it can carry X or Y is cystic fibrosis recessive or dominant - correct answers recessive what are disorders caused by faulty alleles on the sex chromosomes called and who are more likely to have them nd why - correct answers sex-linked genetic disorder, men, Y chromosome is smaller examples of a sex linked genetic disorder - correct answers colour blindness, haemophilia what is the relationship between Ia and Ib? - correct answers co-dominance

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how does Io blood group interact - correct answers recessive 2 types of variation - correct answers genetic, environmental what causes genetic variation - correct answers mutations, sexual reproduction what causes environmental variation - correct answers the conditions in which an organism lives what is cystic fibrosis - correct answers the protein which controls the movement of salt and water in and out of cells stops working, leading to the production of a thick, sticky mucus in the lungs and digestive system aim of Human Genome project - correct answers find every human gene (20500) how can the HGP help in prediction and prevention of disease - correct answers individually tailored advice on diet and lifestyle to avoid likely diseases, regularly checks for early treatment how can the HGP help in testing and treatment of inherited disorder - correct answers identify genes causing a disorder, tested for gene and develop treatments how can the HGP help in new and better medicines - correct answers variation affects how the body reacts to medicine, tailored medicine for genetic variations, dosage, side effects disadvantages of the HGP - correct answers increased anxiety, gene-ism (pressure on those with a disorder), discrimination (by employers or insurers)

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what are some selection pressures - correct answers predation, competition for resources, disease how does natural selection work - correct answers those organisms with alleles which make them better adapted are more likely to pass on their genes so the characteristic becomes more common how do bacteria show evidence for evolution - correct answers mutations cause antibiotic resistance, these genes are more likely to be passed on, natural selection makes the characteristic more common in the population how do fossils provide evidence for evolution - correct answers arranging fossils in chronological order shows gradual which two scientists came up with the theory or evolution - correct answers Darwin and Wallace what did Darwin discover - correct answers variation in species, organisms with the best characteristics were most likely to survive, characteristics could be passed on effect of the theory of evolution - correct answers classification (we must have all descended from one organism so we are classed depending how closely related they are), antibiotic resistance (finishing drugs courses), conservation (importance of genetic diversity to help populations adapt) what are humans and their ancestors known as - correct answers hominids what species is the Ardi fossil and how old is it - correct answers ardipithecus ramidus, 4.4 million

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what did ardi fossil show - correct answers ape-like toes for tree climbing, long arms, short legs, walked upright what species is the Lucy fossil and how old is it - correct answers Australopithecus afarensis, 3.2 million what did Lucy fossil show - correct answers feet for walking not climbing, changes to arm and leg length, larger brain, more efficiently walked upright what species was the Turkana boy and how old is it - correct answers homo erectus, 1.6 million what did the Turkana boy fossil show - correct answers short arms, long legs, large brain, walked upright most efficiently fossils in order - correct answers Ardi, Lucy, Turkana Boy homo species in order with age - correct answers habilis 2.5million, erectus 2million, neanderthalis 300000, sapiens 200000 how did tool use develop over time - correct answers scrape meat off bones, dig or hunt, weapons ways to age a fossil/tool - correct answers structure of tool, stratigraphy (layers of rock), carbon-14 dating what is a limb with 5 digits called - correct answers pentadactyl limb how does the pentadactyl limb provide evidence for evolution - correct answers similar bone structure with different function (e.g wing or hand), evolved from common ancestor

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why has animal classification changed - correct answers traditional based on observable characteristics, technology improved to use things like DNA (e.g cell structure), members of the prokaryotes group not as closely related as originally thought what was the old classification system called and what were the 5 groups - correct answers five kingdom classification, animals, plants, fungi, prokaryotes, protists what is a protist - correct answers eukaryote single cell what are the small subcategories in the old classification system - correct answers phylum, class, order, family, genus, species what is the new classification system - correct answers three domains what are the three domains in classification - correct answers archaea, bacteria, eukarya what is selective breeding - correct answers when humans artificially select plants or animals to breed with favourable characteristics how to selectively breed - correct answers chose organisms with characteristic, breed them, select best offspring, breed them, repeat over generations importance of selective breeding in agriculture - correct answers genetic variation means some animals have better characteristics (e.g. larger meat) so farmer can maximise profit/yield

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how is selective breeding used in medical research - correct answers studies into alcoholism breed rats with strong or weak preference to alcohol compare difference in behaviour and brain function disadvantages of selective breeding - correct answers reduced gene pool, inbreeding, ethical considerations (e.g pug dogs and breathing), no disease resistance what is tissue culture - correct answers growing cells on an artificial growth medium advantages of tissue culture in general - correct answers quick, all year round, little space needed what is the name for plants produced in tissue culture - correct answers clones how to tissue culture plants - correct answers choose plants based on characteristic, remove small part of shoot or root, grow on medium containing nutrients and hormones in aseptic conditions, move to compost why must tissue culture be done in aseptic conditions - correct answers to prevent growth of microbes that could harm the cells advantages of tissue culture in medical research - correct answers experiment on tissue in isolation (without complications of the rest of the body) how to tissue culture animals - correct answers sample of tissue, separate cells using enzymes, place in culture vessel with growth medium containing nutrients, separate into separate vessels, store what do restriction enzymes do - correct answers recognise specific sequences of DNA and cut the DNA at this point leaving sticky ends

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what enzyme is used to stick DNA together - correct answers ligase what are two pieces of DNA joined together called - correct answers recombinant DNA what is a vector and what are the two sorts - correct answers something used to transfer DNA into a cell, plasmids, viruses how does genetic engineering work - correct answers use restriction enzyme to get DNA you want, vector DNA cut leaving sticky ends, join vector and DNA with ligase, insert recombinant DNA into cell how is genetic engineering useful in agriculture - correct answers crops can be modified to be resistant to herbicides to increase yield how can genetic engineering be used in medicine - correct answers production of insulin, organ transplant, proteins used in cancer treatment disadvantages of genetic engineering - correct answers unpredictable, (many embryos dont survive), transplanted genes may get out into the environment, effect of food chains and human health, developed resistance what is the name of the bacteria which produces a toxin to kill insect larvae harmful to crops - correct answers bacillus thuringiensis how can GMO help with the growing pollution - correct answers increase food production, combat deficiency disease (e.g. by providing a nutrient) problems with GM food - correct answers need to tackle poverty first, dependance on GM, poor soil so even GM won't survive

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other techniques to increase food production - correct answers fertilisers, biological control (e.g cane toads) how does the WHO define being healthy - correct answers a state of complete physical, mental and social well-being what is a disease and what are the two types - correct answers where part of an organism doesn't function properly, communicable, non-communicable what are non-communicable diseases - correct answers diseases that cannot be transmitted between organisms what are pathogens and list them - correct answers organisms that cause communicable diseases, fungi, viruses, protists, bacteria cholera: pathogen, symptoms, spread, prevention - correct answers vibrio cholerae (bacterium), diarrhea, water, clean water supplies Tuberculosis: pathogen, symptoms, spread, prevention - correct answers Mycobacterium tuberculosis (bacterium), lung damage, air, avoid crowded places/sleep alone malaria: pathogen, symptoms, spread, prevention - correct answers protist, red blood cell damage, mosquitoes (act as vectors), mosquito nets stomach ulcers: pathogens, symptoms, spread, prevention - correct answers Helicobacter pylori (bacterium), vomiting, oral, clean water ebola: pathogens, symptoms, spread, prevention - correct answers virus, hemorrhagic fever, bodily fluids, sterilization

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chalara ash dieback: pathogen, symptoms, pathogen, prevention - correct answers fungus, bark wounds, air, removing infected trees what is a virus - correct answers a protein coat around genetic material what are the two pathways of a virus - correct answers lytic, lysogenic what happens in the lytic pathway - correct answers attaches to host cell, injects genetic material, uses proteins and enzymes in cell to replicate DNA and virus components, components assemble, host cells splits (releasing virus) what happens in the lysogenic material - correct answers genetic material incorporated into DNA of host, genetic material replicated when cell divides (but virus is dormant), triggers causes genetic material to leave DNA (and start lytic pathway) chlamydia: pathogen, symptoms, prevention - correct answers bacterium (but can only reproduce in host cell), infertility, condom HIV; pathogen, symptoms, spread, prevention - correct answers virus, kills white blood cells, AIDS, weak immune system, bodily fluids (sex), condom plant physical protection against pathogens - correct answers waxy cuticle, cell walls made from cellulose chemical protection against pathogens and examples - correct answers antiseptics, quinine treats malaria, aspirin cures pain how can you determine whether a plant defect is disease or environmental - correct answers change the environment

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what does patches of diseased plants suggest about spread, or random distrbution - correct answers soil, air what can diagnostic testing involve (plants) - correct answers detecting antigens unique to diseases, detecting pathogen DNA in plant tissue physical barriers against disease on humans - correct answers skin, blood clots, hairs, mucus how do cells in the trachea and bronchi protect you against disease - correct answers mucus traps pathogens, cilia move the mucus to the throat to be swallowed what chemical barriers to disease do humans have - correct answers hydrochloric acid in stomach, lysozyme in tears what is a B-lymphoctye - correct answers a white blood cell involved in a specific immune response how do B-lymphoctyes work - correct answers pathogens have unique antigens (on their surface), (when detected lymphocyte) produces (proteins called) antibodies which bind to the pathogen (so it can be found and destroyed by white blood cells), antibodies produced rapidly (and search the whole body for the same pathogen) why is immune response slow first time you get a disease - correct answers not many b-lymphocytes to produce antibody needed what do memory lymphocytes do - correct answers remain in body and remember specific antigen

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why is the 2nd immune response quicker - correct answers memory lymphocytes recognise the pathogen what is immunisation - correct answers injecting dead or inactive pathogens into the body to trigger an immune response (and the production of memory lymphoctyes) advantages of immunisation - correct answers herd immunity, prevent epidemics, wipe out disease (e.g. smallpox) disadvantages of immunisation - correct answers doesn't always work, bad reactions what are monoclonal antibodies - correct answers clones of a single b- lymphocyte how are monoclonal antibodies produced - correct answers b-lymphocyte fused with myeloma (cancer tumour) cell to make a hybridoma which divides quickly to produce the same antigen, antigens can be extracted and purified what do you call a tumour cell used in monoclonal antibodies - correct answers myeloma what do you call and cancer cell fused with a lymphocyte - correct answers hybridoma what hormone is found in the urine of pregnant women - correct answers HCG how do pregnancy tests work - correct answers stick has antibodies to HCG with blue beads attached, test strip has antibodies on it

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how do you get a positive test on a pregnancy test - correct answers HCG binds to antibodies with blue beads, urine moves up stick carrying the beads, beads bind to antibodies on test strip (turn it blue) how do you get a negative test on a pregnancy test - correct answers urine moves up stick with blue beads, blue beads do not stick to test strip how can you identify a cancer cell - correct answers they have proteins on their cell membranes called tumour markers how can monoclonal antibodies be used to diagnose cancer - correct answers antibodies labelled with radioactive element, carried by blood around body, bind with tumour markers, image taken to detect radioactivity how can monoclonal antibodies be used to treat cancer - correct answers cancer drug attached to antibodies, antibodies bind to cancer cells, drug kills cancer cells (but not normal cells so less side-effects) problem with many cancer treatments - correct answers can affect normal cells as well as cancer cells how can monoclonal antibodies be used to find blood clots - correct answers antibodies labelled with radioactive element, antibodies bind to proteins (in clots), image taken to detect radioactivity how do antibiotics work - correct answers inhibiting the processes in bacterial cells (e.g. building of cell walls but not the host) why dont antibiotics work on viruses - correct answers viruses reproduces using body cells so cannot distinguish between what are the two stages of drug testing - correct answers pre-clinical, clinical