4. how does a cell membrane retain its shape?
a. the forces of polar molecules pushing on one another
b. the force of water molecules pushing on the lipids of the bilayer
c. the attractive forces of the lipid tails
d. the repellant forces between the heads and tails of the bilayer
5. what molecules are embedded within a cell membrane that allow needed materials to pass through?
a. dna
b. rna
c. proteins
d. carbohydrates

Approximately what portion of the foods that we eat have been genetically modified in some way? a.fewer than 10% b.about 50% c.nearly 100%

The relationship between intron and exon

Suppose a particular species of tulip plant has three alleles for the gene that codes for flower color. the cr allele produces red tulips, the cp allele produces purple tulips, and the cw allele produces white tulips. cr is dominant over cp and cw, and cp is dominant over cw. for each of the following crosses, determine the expected ratio of offspring for each flower color. cr cp x cp cw cr cw x cp cw 1 red: 1 purple : 0 white, 1 red: 2 purple: 1 white, 2 red: 1 purple 1 white, 1 red: 3 purple : 0 white, 2 red: 0 purple : 2 white, 2 red: 2 purple : 0 white