ESS
What is the difference between biotic and abiotic factors?
Biotic factors are alive while abiotic factors are not.
State the factors that affect the time period of a pendulum.
pendulum length and gravity
Write a word equation for the combustion of methane.
Methane + oxygen → carbon dioxide + water + heat energy
State the full name for DNA.
Deoxyribonucleic Acid
The length of DNA in one cell?
2 m
What percentage of energy is transferred from one trophic level to the next (within an ecosystem)?
10%
Describe the movement of particles and energy in a longitudinal wave.
In a longitudinal wave, the particles of the medium move parallel to the direction the energy travels
What is the difference between exothermic and endothermic reactions?
an exothermic reaction as one where heat is transferred from the system to the surroundings.
an endothermic reaction as one where heat is transferred from the surroundings to the system.
Define the term diploid.
A cell with two copies of each chromosome
How many bones in the human body?
206
How do the levels of biological organisation progress from one organism to the biosphere?
organism, population, community, ecosystem, biome, biosphere
Outline why light is refracted when it changes medium.
Light is refracted (bent) when it changes medium because its speed changes due to a difference in the optical density of the two materials.
describe the flow of electrons in a voltaic cell
From the anode (negative electrode) to the cathode (positive electrode) through the external circuit
Outline the purpose of mitosis.
to produce two genetically identical daughter cells from a single parent cell.
For growth, repair or replacement of cells.
Average number of hairs on a human head?
Bonus which hair colour has the most?
100 000
Blondes
Why is eating at a lower trophic level more sustainable?
90% of energy is lost between trophic levels, eating at a lower trophic level would reduce this lost energy and more organisms would be able to be fed with less energy
Describe what happens to a ray of light when the critical angle of a medium is exceeded.
No refraction occurs — the light ray does not pass into the second medium.
Instead, the ray is completely reflected back into the original (denser) medium.
This phenomenon is called total internal reflection.
Ionic bond is Between metals and non-metals
Covalent bond is Between non-metals only
Ionic bonds - Electrons are transferred from one atom to another
Covalent bonds Electrons are shared between atoms
Ionic bond Forms ions: cations (+) and anions (−)
Covalent bond Forms molecules
Summarise how meiosis leads to variation.
Crossing Over (Prophase I)
Independent Assortment (Metaphase I)
Random Fertilisation
After meiosis, any sperm can fertilise any egg, further increasing the possible combinations of alleles in the offspring.
Number of hearbeats in a lifetime?
3 billion
How are the organisms in a sealed mesocosm able to stay alive?
Light energy must be allowed to enter the mesocosm. Then photosynthesis could occur using water, CO2 and the light energy producing glucose and oxygen.
Respiration could then occur using glucose and oxygen and producing water and CO2 as waste. This cycle can continue indefinitely.
Relate the frequency of electromagnetic radiation to the amount of energy it transfers.
The frequency of electromagnetic (EM) radiation is directly proportional to the amount of energy it transfers.
Higher frequency = higher energy
(e.g., gamma rays, X-rays)
Lower frequency = lower energy
(e.g., radio waves, microwaves)
Compare and contrast oxidation and reduction.
OIL – Oxidation Is Loss (of electrons)
RIG – Reduction Is Gain (of electrons)
A color blind woman marries a man with normal vision. She becomes pregnant. What are the genotype and phenotype frequencies of their possible children.
Genotype: 50% XN Xn 50% Xn Y
Phenotype: Females - carriers Males - colour blind
Number of bacteria in your mouth
6 billion