2020 will be remembered as the Year of the Virus – the first year of the
COVID-19 pandemic. By early 2021 the COVID virus had truly left its mark on our
population, lifestyle, and biosphere, but the universe is complicated,
and viruses can be good guys too.
G’day, Dr Karl here.
2020 will go down in history as the Year of the Virus. It was the first
year of the COVID-19 pandemic. By early 2021, the COVID virus - SARS-CoV-2 -
had well and truly left its mark on our population, lifestyle, and biosphere.
Cities got emptier, and animals came back. Canada geese waddled
with their goslings along Las Vegas Boulevard, jackals occupied a city park in
Tel Aviv while coyotes walked the streets of San Francisco. Animals don’t
usually wander up and down modern city streets.
Even the chemistry and temperature of the atmosphere changed. Factory
production and transport numbers dropped so much that air pollution
plummeted. Not only did ozone levels in the lower atmosphere drop by 7%,
but so did generalised air pollution. The air became clearer, so more heat from
the Sun hit the ground and was re-emitted upwards. This led to a jump in air
temperature of about a fifth of a degree.
In the USA, the life expectancy of Black Americans suddenly dropped by
2.7 years. While world-wide, over 2.5 million people died from COVID-19.
All this turmoil was caused by a quantity of virus so small that
it would definitely fit into a milk container, and probably even a soft drink
can – just several hundred grams. It makes you want to agree with the British
biologist Peter Medawar and his wife, Jean, who said that a virus is, “a
piece of bad news wrapped up in protein”. And the Latin root is blatant -
the word “virus” means “poison”.
But you guessed it, the Universe is complicated, and viruses can be good
guys as well.
For one thing, about 8% of our human DNA is made up of viruses that
invaded us in the past – from the recent present way back to several hundred
million years ago. Some of these virus invaders are absolutely essential for a
fertilised egg to turn into a baby human some nine months later. These viruses
in human DNA make human reproduction possible.
So let's dive into virus 101.
Both a bacterium and a virus have all the genetic instructions needed to
make another bacterium or a virus.
But the big difference is that bacteria (and practically all other life
forms) also have two extra capabilities. First, they have microscopic
biological factories that can turn food into energy. And second, they have
another set of mini-factories that use this energy to physically manufacture
another baby from scratch.
But a virus has neither. By itself, it can’t make energy and it can’t
make babies.
A virus has to get itself inside the cell of a living creature – and
then take over their systems to make more viruses.
Think of a small backyard swimming pool filled with water plus all the
chemicals and elements that living creatures need to live and to make babies.
This water carries the basic macronutrients of fats, proteins and carbohydrates
as well as all the necessary micronutrients (elements such as iron, cobalt,
magnesium and the rest, along with all the vitamins). Let’s do a few mind
experiments.
Experiment 1. Put a single bacterium into that pool. About 20 minutes
later, there are two bacteria, and another 20 minutes later there are four, and
so it repeats Within a day, the pool is jam-packed with bacteria.
Experiment 2. Start with your pool loaded with water and various
chemicals and elements – and add one single virus. Nothing happens. Come back
10 years later, and still, all you have is that one single virus.
Experiment 3. Start with a fresh pool, add a few dozen bacteria and one
single virus. The bacteria start doubling in number every 20 minutes - and the
virus gets eaten by one of the bacteria. But the virus is not your average
inert meal. No, the virus takes over the biological factories inside that
bacterium, and very soon hundreds of viruses are getting squirted out into the
pool, and the bacterium probably dies. As long as the virus has at least a
single living cell that it can take over, it will - and then make more copies
of itself.
So a virus can
reproduce, but not by itself. Does that make it alive or not? That’s really
complicated, and we'll talk more about that next time.
Comprehension
1. What changes happened to city streets
in the year of COVID?
2. What changes happened to the
atmosphere in the year of COVID?
3. Explain the language feature “a piece of bad news wrapped up in protein”.
4. How much of human DNA is made up of viruses?
5. What are two things a bacterium can do?
6. How does a virus reproduce?
7. What is the effect of the rhetorical
question Does that make it alive or not?
Note singular
– bacterium plural bacteria ( from Latin)
Vocabulary
explain the
meaning of the following words or phrases ads used in the passage
waddled
wander
plummeted
turmoil
blatant
jam-packed
inert
Summary
In 300 – 500 words write a summary of
Dr Karl’s talk.