Early life likely began a. in the atmosphere b. in the ocean c. on the Earth’s surface
All kinds of life are made of a. very similar chemicals b. very different chemicals c. an equal mix of similar and different chemicals
Life probably began when molecules bonded to form a. RNA b. DNA c. mRNA
Discussion/essay questions
The origin of life on Earth is one of humanity’s most important and controversial questions. Why do you think this is? Do you think religion and science have the same purpose?
Transcript
Abiogenesis is the process that causes non-living materials to become living things. Abiogenesis is one of the greatest mysteries in science. Early life likely began in a “chemical soup” in the ocean. Scientists have observed that all kinds of life are made of very similar chemicals. People, plants, animals, and bacteria all share a common ancestor, which lived about 4.2 billion years ago. Most scientists agree that life probably began when molecules in the chemical soup bonded to create RNA. RNA can cause the chemical reactions that made early life possible, and it can also store information. This allows it to replicate itself. Some scientists have tried to begin the process of RNA bonding in labs. However, no one has ever observed abiogenesis. Because all life is made of the same chemicals, many scientists believe that abiogenesis has only happened once on Earth.
Joseph von Fraunhofer discovered that a. passing light through a prism would create a rainbow b. light could behave as a particle c. there were dark lines in the colour spectrum made by the Sun
Absorption lines happen when a. a cool gas absorbs photons b. a hot gas releases photons c. photons pass through empty space
Scientists can study absorption lines to find out a. the masses of stars b. the distances between stars c. the chemicals present in stars
Discussion/essay questions
Do you know any interesting facts about light? What optical illusions or “tricks of the light” have you seen?
Transcript
In 1814, a German physicist named Joseph von Fraunhofer passed light from the Sun through a prism to create a colour spectrum. He noticed that there were dark lines blocking out certain colours in the spectrum. Today, scientists call these lines absorption lines. Absorption lines happen when particles of light, called photons, move through a cool gas. The atoms and molecules in the gas absorb some of the photons and block certain colours of light. When an atom absorbs a photon, it shows up as a dark line in the colour spectrum. The photons that get absorbed are not random. Every element absorbs specific wavelengths of light, which means every element also has a unique pattern of absorption lines. Scientists can study these lines to find out which chemicals are present in stars and planets.
The most abundant elements in the universe are a. hydrogen and helium b. hydrogen and carbon c. helium and oxygen
During its life, a star can’t use nuclear fusion to create a. helium b. iron c. gold
Heavy elements can be made in a collision between two a. planets b. comets c. neutron stars
Discussion/essay questions
Scientists are beginning to experiment with nuclear fusion as a possible power source. Current nuclear power plants use a process called nuclear fission, which does not produce as much energy. What do you think about nuclear power? Do you think it will help or harm the environment? Why?
Transcript
The simplest chemical elements in the universe, hydrogen and helium, originally formed during the Big Bang. These are the most abundant elements out there. The cores of stars can make more helium through a process called nuclear fusion, where enough energy forces the centres of atoms together to make more complex atoms. Other light elements, like oxygen and carbon, also originate from this process. Iron is the heaviest element that a star can fuse. This usually happens near the very end of the star’s life. There are two ways that heavier elements are made. The first is when stars, especially massive stars, collapse and die. The second is in a collision between two extremely dense star remnants, called neutron stars. These events create enough energy to fuse elements like lead and gold.
The cells that make neurotransmitters are a. nerve cells b. blood cells c. skin cells
There are at least a. 100 known neurotransmitters b. 200 known neurotransmitters c. 1000 known neurotransmitters
Serotonin is responsible for a. regulating emotions b. responding to rewards c. responding to danger
Discussion/essay questions
Brain chemistry is something scientists are continuing to learn more about. Why is it important to understand the brain?
Transcript
Neurotransmitters are chemicals that nerve cells use to communicate with other parts of the body. When a nerve cell releases a chemical, it is detected by a receptor in a different cell. This gives the body a signal to do something. Some neurotransmitters control functions like moving or breathing. Others control emotions and learning processes. There are over 100 known types of neurotransmitters, all with different purposes. An imbalance of neurotransmitters can cause both mental and physical illnesses. For example, people who struggle with depression may have low levels of the chemical called serotonin, which helps to regulate emotions. Other commonly known neurotransmitters include dopamine, which responds to rewards, and adrenaline, which responds to danger.
