Nerdy Jeopardy Trivia Quiz

Answer: Why is oil liquid, but butter solid?

Whether something is liquid or solid (or a gas) is dependent on the number and strength of intermolecular interactions between its molecules/atoms. The more strongly the molecules/atoms interact, the less fluid the substance is. The temperature of the surroundings "tries" to break these interactions, and the more heat there is, the more likely the interactions are to be broken, allowing the substance to have more fluidity. This explains why, at low temperature, water (as ice) is solid, but as the temperature increases, the ice melts. If the temperature is increased yet further, even more interactions between the water molecules are broken and the water becomes steam (which is even more fluid!).

Both oil and butter (as you'd find in any kitchen) are made up predominantly of triglycerides. Triglycerides consist of a central glycerol molecule, which is then attached to three fatty acids - long hydrocarbon chains. The chains in oils are said to be more unsaturated, meaning they contain several double bonds. Solid fats such as butter, however, contain few double bonds in their fatty acid chains and are described as saturated. Saturated chains are linear and so can pack closely together, forming many intermolecular interactions between them. Unsaturated chains, however, are kinked and so can't pack together as tightly and so form fewer intermolecular interactions. Less thermal energy is therefore required to "melt" oil than butter, which is why oil is a liquid at room temperature, and butter is solid.

Answer: How does the flu make us ill?

The flu is caused by the influenza virus, which contains RNA rather than DNA. It enters the cell via endocytosis and ultimately manipulates the cell's machinery to translate its viral RNA into viral proteins which can be used to make more viruses. This rapid replication within a cell is typical of the lytic cycle of viral replication, but the flu virus does not cause cell lysis. Instead, it leaves the cell in a process similar to exocytosis.

As stated in the question, the symptoms experienced during a flu infection are almost entirely directly caused by the body's attack on the virus, rather than the virus's attack on the body. The inflammatory response is beneficial as it increases blood flow to infected areas, allowing pathogen-fighting equipment to be delivered, but the inflammation it is associated with can be disruptive to tissue function, and so causes fatigue and pain. The increased production of mucus to prevent entry of yet more viral particles into the body is manifest in what we call a runny nose.

Answer: Why does exercise make me tired?

The reason for that tired feeling can be broken down to three main reasons.

The first is that, during exercise, you use a readily available pool of glucose in your blood, which can rapidly diffuse into the muscle cells when needed. When this begins to be used up, glucose then must be generated from other sources (e.g. via the breakdown of glycogen). This takes time, and so the supply of glucose is lower, therefore putting a limit on its metabolism.

The second reason is simply that anaerobic respiration does not yield as much ATP (energy) as aerobic respiration. If pyruvate is not converted into acetyl-coA, it does not enter the citric acid cycle and so the ATP usually generated here is not available to the cell.

The third reason, and that which is most directly addressed in the question section, is the effect of lactic acid build up. As its name suggests, lactic acid is an acid and so reduces the pH of the muscle cells in which it is made. This can potentially denature proteins, impairing their function, as well as giving a burning feeling.

Answer: Why do we tan in the sun?

Melanin is a dark pigment produced via melanocytes in a process called melanogenesis. Because of its darkness, melanin absorbs many wavelengths of visible light, as well as light in the ultraviolet region of the spectrum. This is a form of defence, since by absorbing UV light, melanin prevents the radiation penetrating deeper into the skin and causing damage to DNA. UV light can cause covalent bonds to form between adjacent thymine nucleotides in our DNA (called thymine dimers).

These can cause DNA polymerase to "hiccup" during DNA replication and so increases the chance of mutation and, therefore, cancer. People who have a high exposure to UV light are therefore more likely to develop skin cancer.

Answer: What does "blood type" mean?

The text above refers specifically to the ABO grouping system of blood, which is seen as most important. The Rhesus blood group system is also often taken into consideration (this is the "+" or "-" of blood groups). All red blood cells have a standard glycan chain known as the H antigen attached to their cell surface. This H antigen can have other sugars added to it. If the person possesses an enzyme which adds N-acetylgalactosamine, they have type A blood. If they have an enzyme which adds a D-galactose sugar to the chain, they have type B blood. If both enzymes are present, they are AB. If neither enzyme is present, the H antigen remains unmodified and the person has type O blood.

As well as possessing antigens on the surface of their red blood cells, people may also possess antibodies in the blood. People with type A blood possess type B antibodies, meaning that if type B blood cells enter a type A person's body, the antibodies will attack the type B cell and get rid of it quickly. This is why people with type A blood cannot accept blood from type B people (and vice versa). People with type O blood, however, have cells which will not be attacked by either type A or type B antibodies, and so may be donated to a person of any blood type. They are therefore called "universal donors".

Answer: Why do people become addicted to cocaine?

Cocaine is described as a stimulant. By preventing re-uptake of dopamine (a neurotransmitter) it means that the dopamine is forced to linger in the synapse and so it continues to bind to receptors on the post-synaptic membrane. The resulting feelings of reward associated with this "happiness molecule" are therefore enhanced upon taking cocaine. The enhanced signalling is only temporary, however. The synapses in our body are plastic (i.e. they can change) and the response induced at the post-synaptic membrane will eventually return to basal levels even in the face of this enhanced exposure to dopamine. What this does mean, however, is that when cocaine is no longer used, there is only a minimal response to the small amounts of dopamine that are released, leading to feelings of depression typical of withdrawal.

Cocaine was originally used as an anaesthetic, and this can also be explained by observing its molecular interactions. Cocaine binds and inhibits sodium ion channels in our neurones. This prevents the influx of sodium ions, which are needed for the transmission of nerve impulses. A lack of nerve impulses means the brain is oblivious to painful stimuli.

Answer: Why are leaves green?

The first part of the statement can be explained by optics. If an object is red, it is because it absorbs light of every wavelength *apart* from around 620-750 nanometres (red light), which it reflects. Similarly, leaves tend to absorb light mainly in the red and blue regions of the visible light spectrum, and so reflect light of wavelength in between these two points, which corresponds to green light.

But if leaves were black, they could absorb red, blue AND green light. Since plants use the light they absorb to gain food via photosynthesis, why do they not maximise their intake and become black? The reason is the enzyme RuBisCo (ribulose-1,5-bisphosphate carboxylase oxygenase). This enzyme catalyses the fixation of carbon dioxide, allowing more complex molecules such as glucose to be formed. However, this enzyme is so inefficient that it would not be able to deal with an increased workload. It struggles as it is now - it sometimes incorporates oxygen when it should incorporate carbon dioxide. RuBisCo compensates for its inefficiency by being produced in vast amounts. It is believed to be the most abundant protein on Earth.

Answer: How can someone "inherit" cancer?

Cancer is primarily a genetic disease and so when people talk about "heritable" cancers, they are cancers that are contributed to by faulty genes that are passed from the parent to the offspring in the same way that we inherit every other gene.

The p53 protein is the "Guardian of the Genome" and is one of the most commonly mutated proteins in cancer patients. When fully functional, the p53 protein detects whenever there is genetic damage and thereafter exerts a number of effects which culminate in the correction of this damage.

Rb is similar in some ways to p53. Rb controls the progression of the cell cycle, and so sets the rate at which our cells divide. It normally functions as a break on this cycle, but is inhibited when everything is "okay" and so allows the cell cycle to progress.

The Myc protein is a transcription factor. It binds to and activates genes involved in promoting cell proliferation. Mutations which enhance the amount of Myc in the cell therefore also have the effect of enhancing cell proliferation, which is what leads to the masses of cells we call tumours.

Answer: Why do we stop growing?

In childhood and adolescence, our long bones grow (sometimes rapidly!). This is mainly due to the effect of hormones such as growth factor, which is secreted by the pituitary gland in the brain. Such growth hormones promote the rapid division of cartilage cells (known as chondrocytes) which exist at the ends of long bones in a region known as the epiphyseal plate.

These rapidly dividing chondrocytes stack on top of older cells, which eventually become ossified (turned to bone) by osteoblasts. At the end of this rapid growth period (which we call puberty) the levels of estrogen in the body increase, leading to apoptosis of the chondrocytes at the epiphyseal plate, the remains of which are ossified, effectively sealing the ends of the bone and preventing further linear growth.

Answer: What happens when we are scared?

As stated in the question, adrenaline is a major reason behind many of the things which happen when we are scared. Other catecholamines such as noradrenaline are also involved in this so called "Fight-or-Flight" response. The release of these chemicals is linked to the sympathetic nervous system - one of the branches of the autonomic nervous system. Another branch is the parasympathetic nervous system, which is more active during times of rest.

Adrenaline creates a huge number of responses and acts via several signal cascades to bring about its desired effects. For example, adrenaline activates protein kinase A, which activates phosphorylase kinase, which activates glycogen phosphorylase, which then breaks down glycogen (phew). The take home message here is that adrenaline increases the ability to "fight" or "fly". By inducing glycogen breakdown, it increases the amount of glucose available to muscles. It also dilates blood vessels in the muscles, providing them with greater amounts of this glucose, as well as oxygen.