Impact of Microscope on Disease Understanding

Question 1 How did the invention of the microscope impact society's understanding of disease? A. Scientists were able to view microorganisms that were previously unknown. B. Microscopes were invented after the development of the cell theory. Section 1 Check

Question 1 How did the invention of the microscope impact society's understanding of disease? C. It was once believed that viruses, not bacteria, caused diseases. D. Scientists could view membrane-bound organelles of prokaryotes. Section 1 Check

The answer is A. Before microscopes were invented, people believed that curses and supernatural spirits caused diseases. Microscopes enabled scientists to view cells, which led to the discovery that microorganisms cause some diseases. Section 1 Check

Question 2 Which of the following uses a beam of light and a series of lenses to magnify objects in steps? A. compound light microscope B. scanning electron microscope Section 1 Check C. transmission electron microscope D. simple light microscope

The answer is A. Most microscopes use at least two convex lenses. Compound light microscopes use a light beam and a series of lenses and can magnify objects up to about 1500 times. Electron microscopes use a beam of electrons and can magnify structures up to 500 000 times. Section 1 Check

Question 3 What makes this cell eukaryotic? Nucleus A. Because it has a cell wall. Nucleolus Chromosomes B. Because it contains DNA. Organelles Section 1 Check Plasma membrane

Question 3 What makes this cell eukaryotic? C. Because it has membrane-bound organelles. Nucleus Nucleolus Chromosomes D. Because it does not have DNA. Organelles Section 1 Check Plasma membrane

Question 3 The Answer is C. Eukaryotic cells contain membrane-bound organelles that have specific functions in the cell; prokaryotic cells do not. Nucleus Nucleolus Chromosomes Section 1 Check Organelles Plasma membrane

Question 1 Which of the following best describes the plasma membrane's mechanism in maintaining homeostasis? A. protein synthesis B. selective permeability C. fluid composition Section 2 Check D. structural protein attachment

The answer is B. Selective permeability is the process in which the membrane allows some molecules to pass through, while keeping others out. Section 2 Check

Question 2 Describe the structure of the plasma membrane. Section 2 Check

The plasma membrane is composed of a phospholipid bilayer, which has two layers of phospholipids back-to-back. The polar heads of phospholipid molecules contain phosphate groups and face outward. Section 2 Check

Question 3 Phospholipid molecule Why is the phosphate group of a phospholipid important to the plasma membrane? Polar head (includes phosphate group) Nonpolar tails (fatty acids) Section 2 Check

When phospholipid molecules form a bilayer, the phosphate groups lie to the outside. Because phosphate groups are polar, they allow the cell membrane to interact with its watery (polar) environments inside and outside the cell. Phospholipid molecule Polar head (includes phosphate group) Nonpolar tails (fatty acids) Section 2 Check

Question 4 Explain why the model of the plasma membrane is called the fluid mosaic model. Section 2 Check

It is fluid because the phospholipid molecules move within the membrane. Proteins in the membrane that move among the phospholipids create the mosaic pattern. Section 2 Check

Question 1 What is the primary function of the cell wall? A. act as selectively permeable membrane B. provide support C. control activity of organelles Section 3 Check D. acquire nutrients from environment

The answer is B.The cell wall is an inflexible, porous barrier that provides support but does not select which molecules can enter the cell. Section 3 Check

Question 2 Describe the control center of a prokaryotic cell. Plasma membrane Ribosomes DNA Cell wall Section 3 Check

Prokaryotic cells do not have true nuclei; their DNA is not separated from the rest of the cell by a membrane. Plasma membrane Ribosomes DNA Cell wall Section 3 Check

Question 3 Which of the following structures is the site of protein synthesis? A. Golgi apparatus B. Ribosome Section 3 Check C. Vacuole D. Lysosome

The answer is B.Ribosomes are the sites where the cell produces proteins according to the directions of DNA. They can be attached to the surface of the endoplasmic reticulum or float freely in the cytoplasm. Section 3 Check

Question 4 What is the advantage of having numerous folds in the ER? A. It enables the ER to lie snugly against the nucleolus. B. It can create more vesicles in a smaller space. Section 3 Check

Question 4 What is the advantage of having numerous folds in the ER? C. It can capture more light energy with more folds. D. A large amount of work can be done in a small space. Section 3 Check

The answer is D. The ER is arranged in a series of folded membranes, which, if spread out, would take up tremendous space. Section 3 Check

Question 5 What could you predict about a plant cell that contains fewer chloroplasts than other plant cells? A. It contains less chlorophyll. B. It contains a greater number of plastids. C. It will have an increased rate of light energy capture. Section 3 Check D. It will appear darker green in color.

The answer is A. Chloroplasts are among the plant organelles known as plastids and contain the green pigment chlorophyll. Chlorophyll traps light energy from the Sun and gives leaves and stems their green color. Section 3 Check

Question 6 A mutation results in the inner membranes of a liver cell's mitochondria being smooth, rather than folded. Which of the following would you expect? A. more efficient storage of cellular energy Section 3 Check B. It can create more vesicles in a smaller space

Question 6 A mutation results in the inner membranes of a liver cell's mitochondria being smooth, rather than folded. Which of the following would you expect? C. decreased energy available to the cell Section 3 Check D. fewer ribosomes available for protein synthesis

The answer is C.Mitochondria transform energy for the cell. A highly folded inner membrane provides a greater surface area for producing energy-storing molecules. Section 3 Check

Question 1 The diffusion of water across a selectively permeable membrane is called __________. (TX Obj 2; 4B) Water molecule Selectively permeable membrane Sugar molecule Section 1 Check A. active transport B. endocytosis

Question 1 The diffusion of water across a selectively permeable membrane is called __________. (TX Obj 2; 4B) Water molecule Selectively permeable membrane Sugar molecule Section 1 Check C. exocytosis D. osmosis

The answer is D, osmosis. Regulating the water flow through the plasma membrane is an important factor in maintaining homeostasis within the cell. Before osmosis After osmosis Section 1 Check Water molecule Selectively permeable membrane Sugar molecule

Question 2 What is the expected result of having an animal cell in a hypertonic solution? (TX Obj 2; 4B) A. The cell shrivels up. B. The plasma membrane shrinks away from the cell wall. Section 1 Check C. The cell swells up. D. The cell retains its normal shape.

The answer is A. In a hypertonic solution, cells experience osmosis of water out of the cell. Animal cells shrivel because of decreased pressure in the cells. H2O H2O Section 1 Check Water molecule Sugar molecule

Question 3 A grocer mists the celery display with water to keep it looking fresh. What type of solution is the celery now in? (TX Obj 2; 4B) A. isotonic B. hypotonic C. hypertonic Section 1 Check D. exotonic

The answer is B. Plant cells contain a rigid cell wall and do not burst even in a hypotonic solution. Section 1 Check

Question 4 Transport of materials across the plasma membrane that does not require energy from the cell but does use transport proteins is called __________. (TX Obj 2; 4B) Channel proteins A. osmosis Concentration gradient Section 1 Check Plasma membrane B. simple diffusion

Question 4 Transport of materials across the plasma membrane that does not require energy from the cell but does use transport proteins is called __________. (TX Obj 2; 4B) Channel proteins C. facilitated diffusion Concentration gradient Section 1 Check Plasma membrane D. active transport

The answer is C. Facilitated diffusion is a type of passive transport and requires no energy from the cell. Channel proteins Concentration gradient Plasma membrane Section 1 Check

Question 1 The stringy structures in the cell nucleus that contain DNA are __________. (TX Obj 2; 4B) A. centromeres B. chromosomes Section 2 Check C. genes D. chlorophylls

The answer is B. Chromosomes are the carriers of the genetic material of the cell. A gene is a segment of DNA that controls the production of a protein. Section 2 Check

Question 2 Look at the diagram and identify the stage of mitosis that is depicted. (TX Obj 2; 4B) Centromere Sister chromatids Section 2 Check A. prophase C. anaphase B. metaphase D. telophase

The answer is B. Metaphase is the short second phase of mitosis, during which the chromosomes begin to line up on the equator of the spindle. Centromere Sister chromatids Section 2 Check

Question 3 What is the process by which a cell's cytoplasm divides? (TX Obj 2; 4B) A. cytokinesis B. telekinesis C. meiosis Section 2 Check D. mitosis

The answer is A. Cytokinesis follows telophase and allows the two new cells to separate. Section 2 Check

Question 4 In multicellular organisms, groups of cells that work together to perform a specific function are called __________. (TX Obj 2; 10B) A. organ systems B. organs Section 2 Check C. tissues D. cell cycles

The answer is C. Tissues organize to form organs, which work with other organs to form organ systems. Section 2 Check

Question 1 Explain cancer in terms of cell growth. (TX Obj 2; 4B, 6C) Answer Cancer is a malignant growth resulting from uncontrolled cell division. The loss of control may be caused by environmental factors or changes in enzyme production that result from defective or changed genetic material. Cancerous cells form masses of tissue called tumors that deprive normal cells of nutrients. Section 3 Check

Question 2 A(n) __________ is a segment of DNA that controls the production of a protein. (TX Obj 2; 4B, 6C) A. gene B. cyclin C. enzyme Section 3 Check D. chromosome

Impact of Microscope on Disease Understanding

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