Most of the time but not always. When it doesn't, it results in a gene mutation.
During DNA replication, the two strands separate as the hydrogen bonds connecting the parent strands are broken by an enzyme called helicase. In the DNA molecule (double strand) complementary bases are joined by hydrogen bonds; that is; Adenine paired to thyamine and guanine to cytosine; during replication the enzyme helicase separates the double helix by breaking the hydrogen bonds between the complementary bases.
The correct answer is pretest and posttest .
A pretest/posttest experiment is an experiment that includes double measurements at multiple points in time. In this kind of test, measurements (measurement of dependent variable) are taken both before and after a treatment.
Answer:
The cell membrane is semi-permeable. It allows some molecules to enter easily inside the cell whereas some molecules are blocked from entering the cell.
Small, polar molecules and hydrophobic molecules enter easily through the cell membrane. But large molecules and ions cannot easily move inside the cell membrane.
A hydrophilic substance like the substance L mentioned in the question enters the cell membrane through the help of carrier proteins. The substance attached to the large protein might enter through active or passive diffusion but it can only enter the cell by attaching to carrier proteins.
Plants are NOT heterotrophs. Heterotrophs are organisms that cannot produce their own food; generally these are animals.
