Answer:
Because DNA molecules are extremely long.
Explanation:
DNA molecule is made up of only four types of nucleotides that are adenine, guanine, cytosine, and thymine. These four types of nucleotide encode all the information necessary for the formation and working of the entire organism because each DNA strand is as long as 2 meter which contains millions of base pairs.
The four nucleotides are arranged in the DNA strand with many different combinations which results in the formation of codons sequence that contains all the information about the cell. This long DNA is compressed several times to fit in the nucleus.
<span>Enzymes</span> are proteins that allow certain chemical reactions to take place much quicker than the reactions would occur on their own. Enzymes function as catalysts, which means that they speed up the rate at which metabolic processes and reactions occur in living organisms. Usually, the processes or reactions are part of a cycle or pathway, with separate reactions at each step. Each step of a pathway or cycle usually requires a specific enzyme. Without the specific enzyme to catalyze a reaction, the cycle or pathway cannot be completed.
Answer:
See the answer below
Explanation:
The central dogma gives a description of how genetic information travels in biological cells from DNAs to proteins. DNAs are first transcribed into messenger RNAs in a process known as transcription and the resulting mRNAs are used in the synthesis of proteins in a process known as translation.
In eukaryotic cells, transcription process happens within the confines of the nucleus because the genetic material in the form of DNAs are always located in the nucleus. Thereafter, the mRNAs generated from transcription are transported to the cytoplasm of the cell where they become translated into proteins.
Hence;
- <em>T</em><em>ranscription</em><em> happens in the </em><em>nucleus</em><em> of the cell.</em>
- <em>Translation </em><em>happens in the </em><em>cytoplasm</em><em> of the cell.</em>
Answer:
See below.
Explanation:
A star's energy comes from the combining of light elements into heavier elements in a process known as fusion, or "nuclear burning". It is generally believed that most of the elements in the universe heavier than helium are created, or synthesized, in stars when lighter nuclei fuse to make heavier nuclei. The process is called nucleosynthesis.
Our Sun is currently burning, or fusing, hydrogen to helium. This is the process that occurs during most of a star's lifetime. After the hydrogen in the star's core is exhausted, the star can burn helium to form progressively heavier elements, carbon and oxygen and so on, until iron and nickel are formed. Up to this point the process releases energy. <u>The formation of elements heavier than iron and nickel requires the input of energy. </u>Supernova explosions result when the cores of massive stars have exhausted their fuel supplies and burned everything into iron and nickel. The nuclei with mass heavier than nickel are thought to be formed during these explosions.
