Heat and waves
What are the three methods of heat transfer?
Conduction, convection, radiation
What is the basic functional unit of the nervous system?
Neuron (Nerve cells)
What is a pathogen?
A microorganism that causes disease.
What are the three subatomic particles?
Protons, neutrons, electrons
Which type of radiation is used in smoke detectors?
Alpha radiation.
Which property of a wave determines its pitch?
Frequency
Which system sends messages using hormones?
Endocrine system
Name two types of pathogens.
bacteria, viruses, fungi, protozoa.
Which particle determines the identity of an element?
Proton
Explain the difference between a molecule and a compound.
A molecule contains two or more atoms bonded together; a compound contains two or more different elements chemically bonded.
A sound wave has a larger amplitude than another sound wave. What will be different?
It will be louder
After eating a large chocolate bar, which hormone is released and why?
Insulin; it lowers blood glucose levels.
Why don't antibiotics work on viral infections?
Antibiotics target bacteria, not viruses.
An atom has 11 protons and 10 electrons. What is its overall charge?
positive
Why does salt water conduct electricity but sugar water does not?
Salt forms ions in solution; sugar does not.
Why does sound travel faster through steel than through air?
Particles are closer together and transfer vibrations more quickly.
How does a neuron send message to another neuron?
It releases neuron transmitter at the axon terminal which carries the message to the dendrite of the next neuron.
Give example of each line of defence of the immune system.
1st line: skin, mucus, snot, stomach acid
2nd line: Phagocytes, inflammation
3rd line: lymphocytes, B cells, T cells.
Carbon-14 and Carbon-12 are both carbon atoms. What is different between them?
The number of neutrons.
Name 2 electromagnetic waves that is stronger than visible light.
Ultra violet
X ray
Gamma ray
A student says "Heat rises." Why is this statement not completely correct?
Heat itself does not rise. Warm fluids rise because they become less dense, causing convection currents.
Explain why the nervous system responds faster than the endocrine system.
Nervous system uses electrical impulses; endocrine system relies on hormones travelling in blood.
Explain why a vaccinated person may not become sick after exposure to a disease.
Memory cells quickly produce antibodies and destroy the pathogen.
There is a 100g of radioactive isotopes at the start of an experiment. How many grams of it remain after 4 half-lifes?
6.25g
A student touches a hot stove. Name the correct sequence:
Stimulus → ? → ? → ? → Response
Receptor → Control Centre (CNS) → Effector