The first cells were formed 750 million years ago.
Light speed, or 300,000 kilometers a second, might seem like a speed
limit, but this is just an example of 3 + 1 thinking – where we still
haven’t got our heads around the concept of four dimensional space-time
and hence we think in terms of space having three dimensions and think
of time as something different.
For example, while it seems to us
that it takes a light beam 4.3 years to go from Earth to the Alpha
Centauri system, if you were to hop on a spacecraft going at 99.999 per
cent of the speed of light you would get there in a matter of days,
hours or even minutes – depending on just how many .99s you add on to
that proportion of light speed.
This is because, as you keep
pumping the accelerator of your imaginary star drive system, time
dilation will become increasingly more pronounced and you will keep
getting to your destination that much quicker. With enough .999s you
could cross the universe within your lifetime – even though someone you
left behind would still only see you moving away at a tiny bit less than
300,000 kilometres a second. So, what might seem like a speed limit at
first glance isn’t really a limit at all.
To try and comprehend
the four dimensional perspective on this, consider that it’s impossible
to move across any distance without also moving through time. For
example, walking a kilometer may be a duration of thirty minutes – but
if you run, it might only take fifteen minutes.
Read more at: <span>https://phys.org/news/2011-10-light-speed.html#jC</span>
Answer:
Cytoplasm: Fluid between the cell membrane and the nucleus. helps protect organelles
Nucleus: A part of the cell containing hereditary information and is responsible for growth and reproduction; the "command center" of the cell.
Ribosome: A small particle in the cell that can make proteins.
Endoplasmic Reticulum: A cell structure that forms a maze of passageways in which proteins and other materials are carried from one part of the cell to another.
Golgi Apparatus: A cell structure that helps make and package materials to be transported out of the cell or for storage inside the cell.
Lysosome: Cell organelle filled with enzymes needed to break down certain materials in the cell, such as large food particles or old parts of the cell. May be found only in animal cells.
Vacuole: Saclike storage structure in the cell. can store water, nutrients, and even toxic substances.
Mitochondrion: An organelle containing enzymes responsible for producing energy. (Metabolism/respiration)
Chloroplast: An organelle found in the cells of plants and some other organisms that captures the energy from sunlight and converts it into chemical energy (photosynthesis).
Cell membrane: The thin, flexible barrier around a cell; controls what enters and leaves the cell.
Cell wall: The structure outside of the cell membrane that is used to provide support and protection. Present in plants, algae, fungi, and many prokaryotes.
Answer:
Explanation: The nucleotide triplet that encodes an amino acid is called a codon. Each group of three nucleotides encodes one amino acid. Since there are 64 combinations of 4 nucleotides taken three at a time and only 20 amino acids, the code is degenerate (more than one codon per amino acid, in most cases)
