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Pregunta	Respuesta
The number of mitochondria in the cytoplasm depends on the activity of the cell. Why?	This is because of respiration occurs in mitochondria. Cells such as liver or muscle cells have large number of mitochondria. This is because the liver carries out many functions and muscle cells need to conract. Both types of cells therefore need lots of energy.
Why are ribosomes smaller than mitochondria and are found in the cytoplasm?	They are to small to be seen with a microscope. They are also the site of protein synthesis.
What is DNA made of?	Two strands coiled to form a double helix. Each strands contains chemicals called bases.
How many types of bases are there?	Four types with cross links between the strands formed by pairs of bases.
What are the four bases in DNA called?	A,T,C and G.
What is complementary base pairing?	Cross links holding two stands together are always between the same bases. A-T, G-C.
What does the DNA base code control and why?	Controls which protein is made. This is because the base sequence in the DNA codes for the amino acid sequence in the protein. Each amino acid is coded for by a sequence of three bases.
What does the RNA or mRNA molecule do?	It carries a code needed to produce a protein from the DNA to the ribosomes.
What did Watson and crick build?	A model of DNA using data from other scientists. They used photographs taken using x-rays showing two chains wound in a helix. Data indicating that the bases occurred in pairs.

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	Creado por fahimarehman04 hace más de 10 años