Yr 10 Half-Yearly Flashcards
Hypothesis
an ‘educated guess’ as to what a scientist thinks will happen during the investigation. Describes what kinds of results they think they will get.
Quantitative data
includes a number or some sort of measurement
Qualitative data
includes a description or an observation
Independent variable
the factor that changes during the experiment
dependent variable
the factor that is measured during the experiment
control variables
the factors which are kept the same throughout the experiment
Why do experiments need to be repeated?
to increase the reliability by finding the average of a series of repetitions of the same experiment.
Methods need to be written in:
- past tense
- passive voice
- numbered steps
Anomalous results
results that stand out or are significantly different from the others.
concordant results
results that are all similar
What to do with anomalous results
- circle them on graph
- ignore them when drawing line of best fit
- repeat the measurement to get a better result
Positive correlation
value on the x-axis and y-axis increase
negative correlation
value on the x-axis increases and the value on the y-axis decreases by the same amount. Always goes through (0,0)
Direct vs indirectly proportional results
Direct: positive correlation where the x and y-axis increase by the same amount. Always goes through (0,0)
Indirect: type of negative correlation where the value on the x-axis doubles and the value on the y-axis is halved. Line is often a curve.
Parts of scientific report in order
Background research aim hypothesis Risk Assessment Equipment Method Results (graph) Discussion (reliability, accuracy, validity, improvements) Conclusion
Reliability vs Accuracy vs Validity
Reliability: repeating experiment and getting same results each time
Accuracy: using appropriate equipment and techniques to obtain meaningful data
Validity: well-designed experiment, collects useful data, has one independent variable and others all controlled. Hypothesis can be supported or disproved.
What is an inference?
A statement that you can make after looking at the results and conclusion.
Gamete
sex cell containing half the information about an individual (sperm and eggs)
Fertilisation
the point at which the sperm and egg are joined together.
DNA
deoxyribonucleic acid
where is DNA found
in the nucleus of most cells
Gene vs Chromosome vs Allele
Gene: a unit of inheritance, specified by the code in a DNA molecule. E.g. eye colour
Chromosome: 23 pairs (46 in total), 44 called autosomes, 2 are sex chromosomes
Allele: different versions of genes. Receive one from each parent. E.g. blue and brown are alleles of the eye colour gene.
Karyotype
the number and appearance of chromosomes. E.g. Down’s Syndrome - additional chromosome 21
Inheritance
- passing on of information from parent to offspring.
- during fertilisation half of the genetic material is transferred from the male, half from the female.
Common genetic traits
- earlobes
- tongue rolling
- eye colour
- dimples
- thumb shape
- hairline
Gregor Mendel’s contribution
discovered the basic principles of genetics by cross-breeding pea plants.
Heterozygous vs homozygous
Heterozygous: the organism carries two different alleles for a gene. E.g. one blue and one brown eye allele.
Homozygous: organism carries two copie of the same allele for a gene. E.g. 2 blue eye alleles.
Dominant vs Recessive genes
Dominant will overpower the recessive gene and be the visible phenotypic characteristic. The recessive version of the gene is weaker and often hidden by other versions.
Watson, Crick and Franklin
Watson and Crick used research from various scientists to come up with the double helix structure of DNA (including the x-ray photography from Franklin)
DNA bonds and base pairing
DNA is made up of 4 different bases: - Thymine - Adenine - Guanine - Cytosine These are arranged to form long genetic codes which determine an organism's physical characteristics. Cytosine + Guanine Adenine + Thymine
DNA Replication
The process by which a strand of DNA is copied to make an exact replica.
- the double helix is unwound and unzipped by the enzyme helicase
- the DNA unzips forming two single strands
- SNA polymerase adds nucleotides to the single strands resulting in two identical strands of DNA
DNA mutation and how it occurs
change in the DNA sequence
- are random
- can occur when DNA does not copy correctly
- can be caused by exposure to chemicals or radiation
Types of mutation
substitution: one base is exchanged for another. E.g. sickle cell anaemia
insertion: where extra bases are inserted into the DNA. E.g. Huntington’s disease
Deletion: when a section of DNA is lost or deleted. E.g. deletion syndrome
Can be harmful, neutral or beneficial
Process of cloning
- cell removed
- DNA removed from nucleus
- egg cell removed from female
- nucleus from egg cell disposed of
- nucleus injected into egg cell
- cell given electric shock
- cell divides to form embryo (mitosis)
- embryo implanted into surrogate
- offspring identical to original organism
- nucleus injected into
Cloning adv and disadv
ADVANTAGES
- genetically identical organisms - desired characteristics
- slow breeding organisms can be reproduced quickly
DISADVANTAGES
- susceptibility to disease passed on
- less variation in species
- unable to create new varieties
Genetic modification
- involves changing or modifying DNA
- can be done by deactivating selected genes or cutting DNA from one cell and placing it into another cell
Genetic modification examples
- Roundup resistant cotton (herbicide tolerance)
- Bt cotton (produces insecticides)
- Cold temp strawberries
- Flavr Savr tomatoes (slows ripening)
Process of IVF (in-vitro fertilisation)
- stimulation of ovaries
- egg collection
- fertilisation
- embryo transfer
Types of stem cells
- adult (brain, heart and bone marrow)
- embryonic: in embryos
Uses of stem cells
- Parkinson’s disease (to produce dopamine)
- rebuilding bones and cartilage
- repairing damaged immune systems
Ethics
- a set of moral principles that guide a person’s behaviour, reflecting what is seen as right or wrong.
Atom
smallest particle of a chemical element that can exist.
Chemical formula for: water carbon dioxide glucose hydrochloric acid sulfuric acid nitric acid phosphoric acid ammonia sodium hydroxide sodium chloride
H2O CO2 C6H12O6 HCl H2SO4 HNO3 H3PO4 NH3 NaOH NaCl
Acids
- burn skin
- conduct electricity
- turn universal indicator red
- vinegar
- lemon juice
- HCl
Bases
- bitter taste
- conduct electricity
- turn universal indicator purple
- antacids
- bleach
- soap
Metal Carbonates
- consist of metal and carbonate ion (CO^3-
- reacts with acid to form salt, water and CO2
- copper carbonate (CuCO3)
- sodium carbonate (Na2CO3)
- sodium hydrogen carbonate (NaHCO3)
Salts
- soluble in water
- high melting and boiling point
- common (carbonates, phosphates, sulfates)
- sodium chloride
- magnesium chloride
- copper sulfate
Alcohols
- contain an OH group
- low melting and boiling point
- soluble in water
- ethanol
- propanol
Types of salts and the acids that influence their creation.
Chlorides - Hydrochloric acid
Nitrate - nitric acid
Phosphate - phosphoric acid
Sulfate - sulfuric acid
Combustion
Acid with Metal
Acid with metal carbonate
Corrosion
Fuel + Oxygen -> CO2 + water
Metal + acid -> salt + hydrogen
Metal carbonate + acid -> salt + CO2 + water
Iron + water + oxygen -> rust
Precipitation
Neutralisation
Decomposition
AB + CD -> AD + CB
Acid + Base -> salt + water
AB -> A + B
Balanced respiration equation
C6H12O6 + 6O2 -> 6CO2 + 6H2O
Incomplete and complete combustion reactions
Different products formed depending on how much oxygen is supplied. Complete combustion forms CO2 and water
Law of Conservation of Mass
Matter cannot be neither created nor destroyed, but merely changed from one form to another.
What occurs during a chemical reaction?
One substance is changed into another substance by forming and breaking chemical bonds between atoms.
