Mid-Term Exam Constructed Response Questions and Answers

Question 1 What is the difference between independent variables, dependent variables, and constant variables? Be able to identify each in an example investigation.

Answer for Question 1 An independent variable is the manipulated variable. It is what you are testing. It is the variable that is changed. A dependent variable is the responding variable. It responds to what is being tested (independent variable). It is also the variable that is measured. A constant variable is a controlled variable. It stays the same throughout the investigation. ***THERE WILL BE A SIMILAR INVESTIGATION ON THE TEST. Airplane Investigation A group of students were conducting an investigation to see if the weight of an airplane affects the distance that the airplane will travel. They used a plane that weighed 2 ounces, a plane that weighed 4 ounces, and a plane that weighed 6 ounces. The size of the paper and the type of paper were both the same. The force used to throw each plane was also the same. The independent variable is the weight of the planes. The dependent variable is the distance traveled by the airplanes. The constant variables are size of the paper, the type of paper, and the force used to throw the plane.

Question 2 What are the cell parts and their functions in plant cells and animal cells?

Answer for Question 2 Type of Cell Structure Function Animal/Plant cell membrane Allows materials to enter and exit the cell Plant only cell wall Rigid outer covering with a boxy shape cytoplasm Clear jelly-like fluid in which the organelles are suspended Endoplasmic reticulum Produce many substances Ribosomes Produce proteins Golgi Apparatus Receives materials from the ER, packages them, and distributes them Nucleus Directs all activities of the cell Mitochondria The powerhouse of the cell; produces energy Chloroplast Captures energy from the sun and uses it to make food Animal only Lysosomes Break down food particles and old cell parts vacuole Stores food, water, or other materials

Question 3 Explain the processes of photosynthesis and cellular respiration. How are these processes a cycle?

Answer for Question 3 The process of photosynthesis uses energy, carbon dioxide, and water to make glucose and oxygen. The process of cellular respiration uses oxygen and glucose to make energy, water, and carbon dioxide. It is a cycle because the products from photosynthesis (glucose and oxygen) are used as the reactants during cellular respiration. The products from cellular respiration (carbon dioxide and water) are used as the reactants for photosynthesis.

Question 4 How are meiosis and mitosis different?

Answer for Question 4 ANY OF THESE THREE WILL WORK. Meiosis Mitosis 1. Makes 2 daughter cells. 2. Makes 2 diploid cells. Diploid cells are made of 46 chromosomes. 3. Parent cell splits into two exact copies of itself with the same amount of chromosomes (46 chromosomes). 4. The daughter cells have the same genetic material. 5. All human body cells divide this way except the egg and sperm cell. 6. One cell division occurs. 7. Used for growth, repair, and asexual reproduction (one parent). 1. Makes 4 sex cells (female egg cells or male sperm cells). 2. Makes four haploid cells. Haploid cells are made of 23 chromosomes. 3. Parent cell splits into a cell that has half the DNA or genetic material (23 chromosomes). 4. The daughter cells or sex cells have a blend of genes from the parents. 5. Only the egg and sperm cell are created by meiosis. 6. Two cell divisions occur. 7. Used for sexual reproduction (two parents).