The cell membrane forms a protective barrier between the external and internal environments. it is referred to as because it allows some substances to cross more easily than others and blocks other substances from crossing into the cell. a) impermeable b) a fluid mosaic c) a plasma membrane d) selectively permeable

Environmental impacts on evolution : mastery test

Step 1 review the imaginary strand of dna below. note the complementary base pairs. a g c a a t c c g t c t t g g t c g t t a g g c a g a a c c step 2 to begin replicating this strand of dna, draw the two sides of the strand separating. step 3 now, draw the free-floating bases linking up with the separate sides. remember to follow the rules of complementary base pairing. step 4 draw the two resulting dna strands.

Describe your dna model. which part do the straws represent? the pushpins? the paper clips and the black dots you made with the marker?