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195 Cards in this Set
- Front
- Back
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What does the scientific theory help explain?
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Observations & make predictions - may need to be modified if further conflicting observations are made.
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What is the classification of living things based on?
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Their cell structure
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What happens when similar cells are grouped together?
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They form tissues, which combine to form organs.
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How do the lifetime of cells vary?
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Depending on function of cell. Cheek cells are continuously being replaced & would have much shorter life span than nerve cell which helps store information & is not replaced
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Why is cell division necessary?
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In order for cells to grow, repair & reproduce
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What is the chemical reaction that provides energy to cells?
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Respiration:
glucose+oxygen=carbon dioxide+water+energy |
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Where does photosynthesis occur?
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in plants, which are able to produce their food from carbon dioxide & water
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What coordinates body systems?
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Nervous system & endocrine system
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List 3 involuntary responses
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- laughing
- walking - talking |
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Describe the path of reflex actions
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Have nerve pathway that bi-passes brain.
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What happens when the body's environment changes?
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Control centre in brain releases hormones called hormones that act on target organs that may also release hormones which restore balance
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What causes infectious diseases?
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by micro-organisms known as bacteria, viruses, protozoa, or fungi
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When does immunity occur?
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When body has been exposed to micro-organisms that cause disease.
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How is natural protection against disease achieved?
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Following exposure
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How is artificial protection against disease achieved?
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Immunisation/vaccination
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List 3 examples of non-infectious diseases
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- ulcers
- haemophilia - diabetes |
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What is a karyotype?
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Chromosome map.
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What are egg & sperm cells also called?
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Gametes/sex cells.
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What is meiosis?
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Special process of cell division required in order to produce sex cells that have 23 chromosomes
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What are alleles?
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genes located on chromosome pairs.
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What does genotype give info about?
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Genetic makeup of individual. Phenotype gives info about physical appearance of individual
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What does a chromosome consist of?
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Long strand of DNA
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What would a nerve cell form?
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Tissue known as nervous tissue, which would form part of nervous system
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What is base adenine always paired w?
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thymine; & base cytosine is always paired w guanine
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What does a sequence of bases in DNA molecule provide?
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Triple code giving instructions to messenger RNA, for correcting sequencing of amino acids in proteins
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When do DNA mutations occur?
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When changes in sequence of bases cause wrong info to be given to messenger RNA, resulting in incorrect amino acid sequences in proteins
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What can cause DNA mutations?
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- radiation
- chemicals - by chance |
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What does biotech make use of?
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Living species to create resources - can be used in medicine, industry & agriculture
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List 3 benefits of biotech for humans
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- Genetic testing for disease
- Production of chemicals needed to treat disease - Future possibilities of cloning body tissues/organs |
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Why did Dolly sheep become famous?
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b/c clone of genetically identical sheep - DNA manipulated to make exact replica of donor animal
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Why has cloning of humans been banned in AUs?
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For ethical reasons
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Why is embryonic stem cell tech ethically questionable?
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b/c involves use of human embryos for research
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What can DNA profiles be used in?
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- Forensics to identify person responsible for crime
- To identify whether people related |
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WHat are genetically modified foods used in?
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Agriculture in order to create distant resistant crops or to create more desirable product
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What are some concerns about genetic modification of crops?
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- Possibility of contamination of other crops
- Reduction in biodiversity, which could cause species to disappear |
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List a medical use for biotech
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Production of hormones like insulin needed by diabetics
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What did the human genome project result in?
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Identity & sequencing of genes in human DNA
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What did Charles Darwin develop?
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Theoretical mechanism for evolution, based on natural selection
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What did Darwin & Wallace both publish?
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Similar findings in same yr.
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What did Darwin partially use for observation to support theory?
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Finches of Galapagos Islands.
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When can divergent evolution occur?
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Where common ancestor, but gelogical isolation leads to changes in species.
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What does a fossil record provide evidence for?
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evolution
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What do pentadactyls provide evidence for?
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Evolution as suggest diff organisms arose from common ancestor
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What do embryos of vertebates reveal?
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Common evolutionary past
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What does biogeographical evidence support?
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Theory of evolution
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What does DNA testing of genetic material show?
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Links w common ancestors
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What are abiotic components of organism's habitat
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Non-living components, whereas biotic components=living things
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Why is water purity important?
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in maintaining ecosystems
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What are laws & regulations needed for?
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To regulate & maintain water purity
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How do burning fossil fuels impact the carbon/oxygen cycle
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B/c gas carbon dioxide built up in atmosphere, causing enhanced greenhouse effect
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Describe food chains
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Begin w producers, which provide food for consumers.
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What are interconnecting food chains known as?
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Food webs
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WHy are food webs helpful?
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b/c can be used to explain & predict changed within community
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WHat are biomass & energy pyramids used to explain & predict?
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Changed in community.
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What are waves able to transport?
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Energy, but not matter
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Select the most correct statement about transverse waves:
a) the particles in the wave move up & down, perpindicular to the wave direction b) energy is transferred from one place to another c) wavelength is measured in metres d) all of the above |
D
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Use the formular speed = wavelength x frequency, to calculate the speed of a wave with wavelength 10m, & frequency 0.5Hz
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5m/s
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What does the electromagnetic spectrum consist of?
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Waves of diff wavelengths.
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Define speed
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distance travelled by body in unit time.
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Define force
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Push/pull
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What does Newton's 1st law of motion state?
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That object in motion will continue to move w constant speed in straight line, unless acted upon by opposing force.
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What do passengers have the tendenacy to do when a car stops?
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Move forward.
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Select most correct answer describing mass of object:
a) same as weight b) dependent upon size c) amount of matter in object d) all of above |
C
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Define acceleration
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Change in speed in unit of time
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What does acceleration of object depend on?
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Strength of force acting on it & it will accelerate more slowly larger its mass
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What does the weight of object depend upon?
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Gravitational field of Earth
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For every action, there is _____________ & _________ reaction
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equal & opposite
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Define electricity
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flow of electrons.
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Where do electrons travel when electric current flows through piece of metal?
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Travel towards end w positive charge
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What does flow of electric current depend on?
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Pot diff of electric circuit, how fast current flows & any resistance current meets in conductor
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What is used to measure pot diff of current & gives reading in volts?
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Voltmeter
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What is current flowing around circuit measured in?
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Amps using ammeter
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What does electric current meet as flows through conductor>
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Resistance.
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What happens to current as number of volts increases?
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Increases & resistance increases
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How fast does light travel?
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300 000km/sec, in vaccuum, in form of waves.
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How do objects appear when absorb all light?
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Black & white if reflect all light
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When do objects appear particular colour?
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When some wavelengths of light are absorbed but colour of object is reflected back to eye
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What is meant by refraction?
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As light passes from gas to liquid, light rays bend
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How can short-sightedness be corrected?
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Convex lenses whereas long-sightedness is corrected by concave lenses
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Name colours of visible spectrum beginning w longest wavelength
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red, orange, yellow, green, blue, indigo, violet
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List 3 uses components of electromagnetic spectrum have?
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- Communications
- Medicine - Exploring universe |
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What waves have lowest frequency & longest wavelength of all waves in electromagnetic spectrum?
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Radio
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What are shorter low frequency radiation called?
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Microwaves
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What are ultra high frequency waves which can pass through ionsphere useful for?
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Satellite communication
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What do mobile phones use?
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Electromagnetic waves in radio wave frequency.
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What absorbs infrared radiation?
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Certain materials & infrared transforms into heat energy.
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What did invention of laser make possible?
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to use visible light to create high intensity beam of light
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What do optical fibres make use of?
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Visible light to transmit messages over long distances.
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What is short wavelength radiation?
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Ultraviolet light.
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WHat do CAT scans make use of?
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X-ray radiation to image combination of soft tissue, bone & blood vessels
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Describe gamma rays
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Have high energy & very short wavelength & can be used for gamma ray imaging of body organs
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What do isotopes of same element have?
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Same number of protons but diff number of neutrons.
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Who was 1st person to discover radioactivity?
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Albert Einstein
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True of false?
a) Gamma rays are positively charged particles b) Alpha, beta & gamma rays are all particles c) Alpha particles can be stopped by piece of paper |
a) false
b) false c) true |
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What is nuclear fission?
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When heavy atoms are split into lighter new elements
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When does radioactive decay occur?
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When nucleus of atom breaks down b/c its neutron to proton ratio is larger than 1:1
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Carbon-14 decays radioactively to nitrogen-14 with half-life of 5730 yrs. If wood from ancient boat is found to contain 50% carbon-14 & 50% nitrogen-14, how old is boat?
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5730 yrs as it has undergone one halflife
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What are nuclear reactions occuring in Sun?
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Nuclear fusion
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What can nuclear energy be used to produce?
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Electricity.
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List 3 disadvantages in using nuclear energy to produce electricity.
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- it is difficult to store nuclear waste like plutonium which has half-life of 24 000 yrs
- Expensive to construct - Always danger of accident |
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What can radioisotopes for medical & industrial purposes be produced in?
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Nuclear reactor such as ANSTO reactor at Lucas Heights in Sydney.
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How is diagnosis of diseased body organs made?
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By injecting patient w radioisotope havingshort half0life, this reducing exposure to radiation.
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Why is iodine-131 suitable isotope for diagnosis of thyroid disease?
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b/c images of iodine-131 are obtained by scanning thyroid for radiation
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List 3 possible industrial uses of radioisotopes
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- thickness gauges for great accuracy
- leak detectors - irradiation of medical supplies & food for sterilisation |
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What is the universal radiation symbol used to warn people?
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That radioactive material is present
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What is a large cloud of cosmic dust & gases known as?
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nebula
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When a cloud of dust & gases cools & collapses & then begins to heat up, what is it known as?
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protostar
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What are the size of stars compared to?
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That of Earth's SUn, so that one solar mass is equivalent of mass of SUn
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What so protostars do?
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contract & spin & throw out fragments that give rise to planets
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What colour are higher temp, more luminour stars?
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blue
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How do massive stars end their lives?
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Either as neutron star or black hole
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Describe black holes.
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Thought to exist at centre of galaxies & have such strong gravitational attraction that not even light can escape from them.
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What are most brilliant & remote objects in Universe?
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quasars
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What is the current theory about origins of Universe called?
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Big bang theory
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What did steady state theory predict?
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That amount of matter in Universe would remain constant
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List 2 possible alternatives for ultimate fate of Universe
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- conitnuously expanding theory
- pulsating universe theory |
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Where is the star moving if found to have red shift?
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away from Earth
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How does cosmic background radiation contribute to predictions about origins of Universe?
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It supports big bang theory which predicts presence of background cosmic radiation
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What is amount of hydrogen & helium foud in Universe today consistent with?
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its formation durin big bang
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What is electromagnetic radiation detected from outer space used for?
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To gather evidence about universe.
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How are long wavelength radio waves collected?
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Using radio telescopes w large curved dishes & give info about objects hidden by visible light
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How is info about thermal energy from objects in Universe collected?
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Using infrared part of electromagnetic spectrum
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What is Hubble Space Telescope?
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Optical telescope orbiting 600km above Earth, collecting visible light from many diff kinds of celestial bodies.
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What does extreme UV radiation give info about?
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OBjects that are hot like normal stars
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What do X-ray satellites detect?
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High energy radiation
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What is the Compton Gamma-Ray Observatory able to detect?
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Gamma rays given off by violent process like supernovae explosions
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Why is travelling outer space hindered?
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Distance, food & oxygen
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What do scientists believe about origins of continents on Earth?
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All continents once joined together to form one giant landmass called Pangaea
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What did Wegener suggest in 1915?
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COntinents once joined - continental drift
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What did further observations about changes in Earth's crust support?
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Wegener's hypothesis, & became known as theory of plate tectonics
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Why does movement of plates in Earth's crust occur?
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Due to convection currents in mantle & to gravitational forces
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Where does word 'tectnoic' come from?
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Greek word 'to build'
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Name changes that occur to landmasses as plates collide in:
a) spreading zones b) subduction zones c) collision zones d) fault zones |
a) islands
b) volcanoes & earthquakes c) mountain ranges d) earthquakes |
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What is likely to occur where earth's plates meet?
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volcanoes & earthquakes
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What are fossils?
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Plant preserved remains or imprints of plants & animals that lived >10 000years ago.
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Where are fossils found?
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In sedimentary rocks, where they have become compacted & hardened as layers of sediments have built up over time.
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What can changes in Earth's crust over time lead to?
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exposure of sedimentary layers of rock & reveal fossils trapped within them
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What does law of superposition say?
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In sequence of sedimentary rock strata, youngest are on top.
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Describe the structure of Earth
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Dynamic which menas that it constantly changes.
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What does dot in middle of cyclone represent?
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Eye of cyclone
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How can cyclones lead to changes in hydrosphere?
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By causing high seas, to changes in biosphere by threateneing plants & animals & to changes in lithosphere by causing erosion
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What is in mantle?
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Molten magma.
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When do volcanoes lead to changes in lithosphere?
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When lava flows create new land masses or when gases escape into atmosphere & cause global cooling
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What could a fault in lithosphere result in?
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Earthquake
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How do earthqyakes impact lithosphere?
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By creating valleys & landslides & impact on hydosphere by creating tsunamis
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What does atomic number of element give number of?
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protons
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What number does mass number of element give?
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protons & neutrons
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How do electrons orbit nucleus?
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In discrete energy levels or shells.
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What will atom w one electron in outer shell do?
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lose one electron in order to gain full outer shell of 8 electrons
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What will atom w 7 electrons in outer shell do?
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gain one electron in order to have full outer shell of 8 electrons
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Why do chemical reactions take place?
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For atoms to gain full outer shell of electrons
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Who presented the current model of atom?
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Bohr
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What is smallest unit of element still w properties of element?
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Atom
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All elements contain only one type of __________
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atom
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What is molecule?
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group of two or more atoms joined togther by chemical bond
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What does compound contain?
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two or more diff elements joined together in definite ratio
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In experiment student heats 1.00g of blue compound & obtains 0.64g of black compound & 0.36g of colourless gas. What law demonstrated by experiment?
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Law of conservation of Mass
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When does chemical bond form between elements?
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When metals give electrons to non-metals, or when non-metals share electrons
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When does ionic bond form?
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When metal atoms lose electrons, & non-metal atoms gain electrons
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Describe at least 2 features of ionic bonds
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- metals have positive charge
- non-metals have negative charge - ions electrostatically attracted - ions build up into crystal lattice |
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What must do when naming ionic compounds?
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Metal name written 1st, followed by non-metal name. Non-metal keeps 1st part of name & ends in -ide
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Write chemical formulas for following compounds:
a) Potassium nitride b) Aluminium chloride c) Barium oxide d) Sodium sulfide |
a) K3N
b) AlCl3 c) BaO d) Na2S |
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Write chemical formula for carbon tetrachloride
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CCl4
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What is carbon compound C2H4 used for making plastics called?
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Ethene or ethylene
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Name & write chemical formulas for following compounds:
a) acid found in digestive system b) acid used in batteries c) base used for cleaning |
a) Hydrochloric acid (HCl)
b) Sulfuric Acid (H2SO4) c) Sodium hydroxide (NaOH) |
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When does combustion occur?
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When substance reacts w oxygen & releases energy in form of heat or light
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What is eg of corrosion?
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Silver tarnishing
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What happens when solution of lead nitrate reacts w solution of potassium iodide?
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Bright yellow solid forms - known as precipiation reaction
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What is observed when hydrochloric acid is added to marble chips?
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Fizzing.
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What does person take when has heartburn?
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Antacid tablets to relieve pain.
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Write balanced word equation for what happens to mercury (II) oxide is heated?
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2 mercury (II) oxide = 2 mercury + oxygen
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Classify following substances as acidic, basic or neutral:
a) tap water b) cloudy ammonia c) vinegar d) sodium hydroxide e) sulfuric acid |
a) neutral
b) basic c) acidic d) basic e) acidic |
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Which elemnt do following acids have in common?
Hydrochloric acid (HCl), sulfuric acid (H2SO4), acetic acid (CH3COOH) |
Hydrogen
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What does pH scale indicate??
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Whether substances are acidic, basic or neutral.
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What are acid-base indicators?
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Chemicals that help to identify acids & bases by changing colour
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Give example of following:
a) weak base b) strong acid c) neutral substance |
a) cloudy ammonia
b) hydrochloric acid c) pure water |
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Name a natural substance that can be used to make indicator.
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Coloured vegetable like red cabbage or glower like geranium
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Name one everyday use for indicator.
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testing pH of swimming pool water, aquarium water or soil
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What is energy in mechanical systems?
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Capacity to do work
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Give example of non-renewable resource
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Coal
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What are main products when fossil fuels are burnt?
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Carbon dioxide & water - known as greenhouse gases & contribue to global warming
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What are wind, water, sun & biomass known as?
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renewable resources
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What can wind energy be used for?
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To produce electricity when wind turns blades & turbines which are attached to genertor
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Propose 2 limitations for use of wave energy for production of electricity.
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- only suitable near sea
- low tides limit electricity production |
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Propose reason why only 1.5% of Aus' power production comes from hydro-electricity.
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Aus has limited mountainous areas
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Why do geothermal power station heat water?
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To produce electricity by using water that comes from hot springs
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What is advantage of using solar energy?
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It is free & disadvantage is that it is limited to daylight hours
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Describe biomass
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- comes from plant & animal material
- can be produced from household waste - is waste from sawmills & food prodution |
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What do materials tech investigate?
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Ways of researching & developing new materials that have desirable physical properties
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List 3 most useful properties of metals
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- malleable
- ductile - Conduct electricity |
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What are superconductors able to do?
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To conduct electricity w 0 resistance
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What are optical fibres useful in?
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Communications becaise able to transmit 1000s more messages than copper wires
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What are plastics?
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Long chain molecules made out of 1000s of monomer units that join together to form polymer
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What is the name of the molecule that was discovered late last century & is allotrope of carbon?
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- bucky ball
- buckministerfullerene - fullerene |
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Why are batteries useful?
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b/c they use chemical reactions to produce electricity
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