Biology Exam 2 Short Answer Questions1. Define the process of facilitated diffusion, using theinsulin dependent glucose transporter as an example. What is diabetes and what are the 2 main forms of this disease?Polar or charged substances can move across a membrane with the help of specific transport proteins in a process called facilitated diffusion. Without the transport protein, the substance cannot cross the membrane or it diffuses across it too slowly to be useful to the cell. Facilitated diffusion is a type of passive transport because it does not require energy. As in all passive transport, the driving force is the concentration gradient. Glucose binds to the selective transport protein. The glucose transport proteins allow glucose to pass through the membrane and then is released into the cell. Insulin’s role is that it stimulates an increase in these transport proteins, so glucose is able to enter into the cell at a faster diffusion rate. Diabetes is a serious hormonal disease in which body cells are unable to absorb glucose from the blood. It develops when there is not enough insulin in the blood or when target cells do not respond normally to blood insulin. Type 1 (insulin-dependent) diabetes is an autoimmune disease in which white blood cells of the body’s own immune system attack anddestroy the pancreatic beta cells. As a result the pancreas doesn’t produce enough insulin and glucose builds up in the blood. Generally develops in childhood.In Type 2 (non-insulin-dependent) diabetes insulin is produced, but target cells fail to take up glucose from the blood, causing the blood glucose levels to remain elevated. This type Is almost always associated with being overweight and underactive, although whetherobesity causes diabetes remains unknown. Generally appears after age 40, but even young overweight and inactive kids can develop the disease.2. Describe how plant and animal cells react to hypotonic, hypertonic, & isotonic solutions. How doplants "exploit" hypotonicity?Their rigid cell wall helps them exploit hypotonicity by making the cell turgid instead of bursting. Although the somewhat elastic cellwell expands a bit, the pressure it exerts prevents the cell from taking in too much water and busting, as an animal cell would in a hypotonic environment. 3. Describe the characteristics and functions of ATP.ATP powers nearly all forms of cellular work. ATP is a nucleotide.The adenosine part of ATP consists of adenine, a nitrogenous base, and ribose, a 5-carbon sugar. The triphosphate part is a chain of three phosphate groups (all three are negatively charged). As a result, the bonds connecting the phosphate groups are unstable and can be readily broken by hydrolysis, the addition ofwater. A phosphate group leaves ATP and then becomes ADP, releasing energy. This makes hydrolysis exergonic-it releases energy.The cell couples this reaction to an endergonic one by transferring a phosphate group from ATP to some other molecule. This is called phosphorylation, and most cellular work depends on ATP energizing molecules by phosphorylating them.3 types of cellular work that ATP powers: chemical, mechanical, and transport. In chemical work, the phosphorylation of reactants provides energy to drive the endergonic synthesis of products. An example ofmechanical work would be the transfer of phosphate groups to special motor proteins in muscle cells that cause the proteins to change shape and pull on protein filaments causing the cells to contract. In transport work, ATP drives the active transport of solutesacross a membrane against their concentration gradient by phosphorylating transport proteins. Work can be sustained because ATP is a renewable source that cells regenerate. Exergonic processes phosphorylate ADP to form ATP. ATP transfers energy to endergonic processes by phosphorylating other molecules. 4. Describe and discuss the importance of the energy organelles (mitochondria and chloroplasts).The mitochondrion consumes oxygen to efficiently extract energy from carbon sources like glucose, producing carbon dioxide and water in the process.Mitochondrion are enclosed by two membranes. The mitochondrion has two internal compartments: the intermembrane space and the inner membrane space. The inner membrane space encloses the mitochondrial matrix, which contains mitochondrial DNA and ribosomes, as well as enzymes. The folds inside the mitochondrion are called cristae and increase the membranes surface area, enhancing its ability to produce ATP. The chloroplast consumes water and carbon dioxide as it captures energy from light and funnels it into the chemical energy of glucose, releasing oxygen in the process. Chloroplasts are enclosed by an inner and outer membraneseparated by a thin internal membrane space. The thick fluid inside the inner membrane is called stroma, which contains chloroplast DNA, and ribosomes as well as enzymes. A network of interconnected sacs called thylakoids is inside the chloroplast. A stack of thylakoids is called a granum. The grana are the chloroplast’s solar power packs-the sites where the chlorophyll molecules embedded in thylakoid membranes trap solar energy. Endosymbiotic theory proposes that these organelles were once prokaryotic cells, living inside larger host cells. 5. Review and know the equations for photosynthesis and cellular respiration.Photosynthesis6CO2 + 6H2O + Energy --> C6H12O6 + 6O2Cellular RespirationC6H12O6 + 6O2 --> 6CO2 + 6H2O +