This Week's Science Trivia Question:

Living in mostly in water but returning to land to feed, what animal is the closest living relative to whales?

 

Trivia Questions Archive

12/13/10
As they evolved, what is unique about whales?

A: They made an evolutionary u-turn
Modern whales are descended from land mammals that once walked on all fours. The common ancestor to whales and all other land mammals is a flat-headed salamander-shaped tetrapod that hauled itself out of the sea 360 million years ago.

Ancestors to whales walked, trotted, and galloped on land but ~55 million years ago, they did an about face and returned to the sea. As these animals slowly became more aquatic, their hind legs dwindled and their front legs morphed into flippers. Tails grew in size to power them through the water.

In 2000, researchers found a whale fossil in a Pakistani desert with an ankle and functional feet and toes. This appendage was too delicate to support a whale’s body on land but was an evolutionary leftover from its days on land, a missing link giving evidence of the whale’s earlier terrestrial days.

 

12/6/10
Which is larger: a blue whale or the largest dinosaur?

A: A blue whale
Some dinosaurs were the size of small buildings. The Ultrasaurus is believed to have stood 55 feet above the ground, and the Seismosaurus could have been 130 feet long. However, for sheer magnitude, no dinosaur comes close to the size of a blue whale. Blue whales grow to 82 – 105 feet and can weigh up to 200 tons.

Gravity places physical constraints on land animals. Their bones must be able to support their bulk. In comparison, whales’ bodies are supported by water so no such limitation exists.

To quote David Attenborough on the size of a blue whale, “its tongue weighs as much as an elephant, its heart is the size of a car, and some of its blood vessels are so wide that you can swim through them.” As far as we know, the blue whale is the largest creature ever to have lived on Earth.

 

11/29/10
How much ATP is in your body at one time?

A: ~2 ounces
Humans have ~2 ounces of ATP in their entire body. Most of that amount is used and regenerated within one minute. Cells use ATP to drive hundreds of different reactions. However, large stores of it are not needed because it is recycled so efficiently.

In a typical day you produce about three times your own weight in ATP and use it up just as quickly.

 

11/22/10
What is the name of the energy created by the cells after photosynthesis (and respiration)?

A: Adenosine tri-phosphate or ATP
Life depends on electron transfer in respiration and photosynthesis. Electron transfer drives the generation of a proton gradient that in turn powers the ATP-ase enzyme to make ATP.

ATP, adenosine tri-phosphate is the chemical energy source of all cellular reactions. Energy is released when ATP gives up one of its phosphates to form ADP, adenosine di-phosphate.

 

11/15/10
Who discovered superoxide in 1974?

A: Britton Chance, along with Alberto Boveris
In 1973, Boveris and Chance published “The Mitochondrial Generation of Hydrogen Peroxide” in the Biochemical Journal. They explained that animal mitochondria can generate superoxide. Superoxide molecules will bang into themselves to form one peroxide molecule and one oxygen molecule.

Peroxide molecules can directly or indirectly interact with superoxide molecules to form hydroxyl radicals and the water anion, hydroxide. Of all the reactive oxygen species (ROS) the hydroxyl radical is the villain because it is extremely reactive and oxidizing and indiscriminately attacks key cellular materials such as carbohydrates, proteins, fats, and DNA.

Chance and Boveris were the first to associate these reactions with respiration.

11/08/10
What chemical is the main culprit for our aging?

A: Oxygen
The exploitation of oxygen by our bodies is not perfect. The same chemical that helps to create energy and defend our immune system in the short term will cause us to age in the long term.

Toxic forms of oxygen can damage proteins and DNA. Superoxides, peroxides, and hydroxyl radicals are all forms of oxygen that damage our cells over time.

11/1/10
What chemical do our white blood cells use to fight off infection?

A: Oxygen
White blood cells in our immune system fight off disease and foreign materials. These cells use highly reactive molecules of superoxide (O₂-) along with other types of molecules to defend our bodies from infection.

Oxygen is stable in the atmosphere but once it accepts electrons in our cells it becomes fundamentally toxic. Fortunately, our bodies have evolved to exploit it for energy and many cellular activities.

10/25/10
In the process of photosynthesis, carbon dioxide and water are converted to oxygen and glucose. During photosynthesis, where does the oxygen emitted come from, carbon dioxide or water?

A: Water
In plants, a photon of light initiates a series of electron transfers between molecules that begins photosynthesis. Plants split water as a source of electrons and release oxygen as a waste product.

Oxygen is an excellent electron acceptor. In cellular respiration in both plants and animals, oxygen pulls electrons through a chain of molecules in a membrane that creates electrical and chemical energy. This phenomena has provided animals and plants with enough energy to power large complex creatures. Without oxygen we were destined to remained small, even single-celled organisms.

Most of life on Earth consists of two kinds of organisms, those that use carbon dioxide and expel oxygen, and those that use oxygen and expel carbon dioxide.

10/18/10
Why are plants green?

A: Plants use light in the visible region of the spectrum to drive photosynthesis
Sunlight contains the full spectrum of colors. The part of the spectrum we can see is between the wavelengths 380 nm (violet) – 750 nm (red).

Like sound, light has frequency. When light falls on some material substance, it can be reflected, transmitted, or absorbed. Substances that absorb visible light are known as pigments. The pigments within chlorophyll absorb those frequencies of the visible spectrum that are in the red and violet areas. Chlorophyll then reflects and transmits green because it does not absorb or use that frequency of light.

10/11/10
What part of a plant contains the machinery for photosynthesis?

A: Chloroplast
Chloroplasts are the sites for photosynthesis within plants and algae. Within these organelles energy from sunlight splits molecules of carbon dioxide and water to form organic compounds.

In the early evolution of plants, a photosynthetic free-living cyanobacteria was engulfed by another larger cell. The bacteria continued to photosynthesize within the cell. Chloroplasts are derived from these captured bacteria. They continue to have their own DNA separate from the genome in the nucleus.

10/04/10
What is the percentage of oxygen in our atmosphere today?

A: 20%
2.4 billion years ago, atmosphere levels of oxygen rose dramatically from 0% to 35% in what was called the Great Oxidation Event (GOE), although this occurred over a long period of time. This event changed the chemistry of the climate and dramatically altered the balance of Earth’s life forms. Life forms without oxygen were doomed to remain small, even single-celled.

Once oxygen reached the atmosphere it created an ozone layer that shields the Earth from incoming ultraviolet radiation. Unlike methane, ozone stayed in the atmosphere. The Great Oxidation Event was also the first catastrophe in the history of the Earth. Rising oxygen levels wiped out a huge portion of Earth’s anaerobic (non-oxygen using) inhabitants.

Oxygen is the signature gas of our planet, but 2.4 billion years ago it did not exist in our atmosphere.

09/29/10
What is produced when oxygen mixes with iron?

A: Rust
Rust is a general term for the mixes of oxygen with iron in the presence of water. The oxygen created by cyanobacteria combined with iron to form ferric oxide and sank to the bottom of the seas. The world literally rusted.

Eventually any minerals that could bind oxygen did. The shifting of the tectonic plates buried these compounds in the earth. When oxygen had saturated the surface and subsurface of the earth and had no place left to go, it was released into the atmosphere.

Plants didn’t invent photosynthesis. What did?

A: Bacteria. Specifically cyanobacteria.
Cyanobacteria are blue-green algae that existed in primitive seas. They harvested energy from the sun, used it to split water molecules into hydrogen and oxygen, exploited the hydrogen for metabolism, and released the oxygen.

The free oxygen created by cyanobacteria was captured by organic matter or dissolved iron. For many millions of years, cyanobacteria dominated earth’s ecology while having no effect on its atmosphere.

Hydrogen is the lightest of all the elements and when it rises into the upper atmosphere it is tends to escape into space. Why is it harder for hydrogen to be sent on a cosmic journey after oxygen entered the atmosphere?

A: Hydrogen combines with oxygen and makes water.
When water molecules rise into the atmosphere, they freeze and fall back to earth as rain or snow.

The earliest creatures on Earth were archaea, one-celled organisms that emit a strong greenhouse gas which warmed our very cold planet. What gas do archaea release into the atmosphere?

A: Methane
Archaea are superficially similar to bacteria. They are single-celled organisms with no nucleus. They can survive and even thrive in extreme environments. For energy production, archaea absorb CO₂, N₂, or H₂S and give off methane as a waste product. Methane is a strong greenhouse gas, more powerful than carbon dioxide, and it helped warm up the huge lump of ice that was Earth.

Methane is light and has a low freezing point. As it rises to the top of the atmosphere, incoming radiation strips its hydrogen atoms and they escape into space. The carbon left behind oxidized the environment and paved the way for atmospheric oxygen.

Before photosynthesis there was no free oxygen in the Earth’s atmosphere. Our atmosphere was mostly hydrogen, methane, and ammonia. What planet has a similar type of atmosphere today?

A: Jupiter.
When we consider the probable history of our planet, we can refer to other palnets in our solar sysstem that may be like our own. If all of the planets formed from the same stuff at the same time, it is not unreasonable to think that that the biggest coldest planet – Jupiter – may still preserve the conditions that existed for a time on Earth.

Jupiter is composed mostly of hydrogen and helium and contains small amounts of methane, water, and ammonia, which in themselves do not favor the production of life. Unlike Jupiter, the chemicals in Earth’s atmosphere favored production of reduced organic molecules which are essential for the creation of life.