Select the correct answers 1. Biuret reaction is positive for all amino acids
2. The serine amino acid contains the -SH group
3. Glutathiol contains glutamic acid, glycine, histidine
4. Tripeptides and proteins always give a positive Biuret reaction

This is a situation in which genes are attached to an organism's sex chromosomes; the sex of an organism influences the expression of a gene.

Which statement is the best summary of the model? a-a series of aerobic and anaerobic reactions take place in cells b- the sun's energy moves through trophic levels in a food chain c-light energy is converted into stored chemical energy plants. d- food molecules are broken down in the cells if living things.

Explain what a zygote is. use the terms egg cell, sperm cell, and fertilization in your explanation.