Hi!
<h3>The correct options would be:</h3>
1. Many molecules are moved through the body by proteins.
Molecules are transported throughout the body through special types of proteins that are known as transport proteins. These proteins are known as carrier proteins, and assist the movement of large molecules across membranes (which cannot otherwise diffuse through it).
2. Carbohydrates provide structures for plants.
Cellulose, hemi-cellulose, and pectin (not lignin) are polysaccharides that compose the cell wall that is the outermost layer in plant cells. The cell wall determines the structures that make up a plant, and these are predominantly carbohydrates (polysaccharides).
3. Nucleic acids determine what people look like.
Deoxyribonucleic acid, or DNA, is the molecule that determines the phenotype of an individual. This DNA molecule is essentially comprised of nucleic acids and a deoxyribose sugars linked through phosphate bonds. Three nucleic acid encodes for a gene, and each gene is particular for a specific characteristics. So it would be right to say nucleic acids determine what people look like.
4. Cells are surrounded and protected by lipids.
The surrounding layer that protects the cell and is responsible for holding it together is the cell membrane. The cell membrane is essentially a partially permeable membrane that is composed of two lipid layers -better known as a lipid bilayer.
5. Proteins speed up the chemical reactions in a body.
Enzymes are the biological catalysts for the chemical reactions that take place in the body. These are protein in nature, and they can influence a rate of a reaction by lowering the activation energy, or the energy needed for the reaction to begin.
6. Hemoglobin is a protein that is built by proteins.
Hemoglobin is a proteins that serves to transport oxygen around the body. It has a Quaternary structure -meaning that involves protein subunits (2 alpha and 2 beta globin protein chains in hemoglobin) coiled into a multi-subunit protein complex.
7. The human body is insulated by lipids.
Lipids play different roles throughout the body. Though the immediate function of lipids is to provide energy to the body, they also function as an energy reserve for the body and are stored in the adipose tissue, found beneath the skin. This lipid layer can act as an insulating layer for the body, protecting excessive heat loss.
<h3>Hope this helps!</h3>
