HW #3 Cell Parts Reading Questions HW #4 Create Your Own Cell Analogy
Hour
Hypothesis Data Table Graph Questions
____ ____ ____ ____
Accuracy
____
Completion Accuracy
____ ____
_______ / 5 possible points
Homework #2: Cell Size Lab
(from Biology: Living Systems, pg. 120-121)
Introduction: In this lab, you will determine the size of plant and animal cells. Your teacher will supply a millimeter ruler and a variety of plant and animal cells. You can measure the diameter of the field of view under low power with your millimeter ruler. It will be easier for you to make your measurements in millimeters. However, because cells are very small, convert your answers to micrometers. There are 1000 micrometers (m) in 1 millimeter (mm). (For example, 1.8 mm is equal to 1800 µm).
Problem: How big are cells?
Materials:
Microscope Ruler Slides of plant and animal cells Calculator
Methods:
1. Take out your microscope and properly set it up as we did in the Microscope Lab. 2. Set your microscope to LOW power. 3. Record the Eyepiece and Objective magnification in Table 1. 4. Mathematically, determine the Overall magnification. 5. Use your ruler to measure the diameter of the field of view in millimeters. Record your answer in Table 1. 6. Convert the diameter in millimeters to micrometers. Record your answer in Table 1. 7. Repeat steps 2 and 3 for MEDIUM and HIGH power.
8. Obtain a slide and estimate the number of cells across the field of view as in Figure 1. Record your answer in Table 2.
1
2
3
45 6 7 8 9 10
9. Individual cell size can be determined using the following equation: (Field of view diameter) ÷ (# of cells) Use your math skills to determine the estimated cells of each individual cell in micrometers. Record your answers in Table 2. Data and Observations: TABLE 1. Measuring the field of view Setting
Ex. Super Low LOW
Eyepiece magnification
Objective magnification
Overall magnification
10x
2x
20
10x
4x
40x
10x
10x
100x
10x
40x
400x
MEDIUM
HIGH
Field of View Diameter (mm) 10 mm
Field of View Diameter (m) 5,000
TABLE 2. Estimating the size of cells Cell Type
EXAMPLE: Mosquito wing
Microscope Setting
Super Low
Frog Blood Testes Corn Stem Onion Root
# of cells
10
Estimated Cell Size (m)
High High Medium High
Analysis and Conclusions: -
Prepare a bar graph that shows the relationship of cell type (X-axis) to cell size (Y-axis). Be sure to include a title, key, and labeled axis (X and Y) on your graph. DO NOT INCLUDE THE MOSQUITO WING! Neatness counts.
Post-Lab Questions: Answer the following questions using complete sentences (neatness counts!). I will be really impressed if you use what you know about cells and cell parts to answer them. 1. Which specific cell type was smallest? Speculate about why it is an advantage for that type of cell to be so small.
Testes (sperm cells) Sperm cells are so small due to the function of the cell. Their job is to fertilize eggs and they have only what is necessary to accomplish this task: little cytoplasm, many mitochondria for energy, and 23 chromosomes to pass on genetic information. 2. Which specific cell type was largest? Speculate about why it is an advantage for the cell of that type to be large.
Corn stem cells Corn stem cells are large due to the function that they perform. Their jobs include: transport of water and sugars, structural support of plant, etc.
3. Why do you think cells are different sizes?
Cells are different sizes and shapes due to the functions that they perform.
Homework #3: Chapter 5 Reading Questions (please use complete sentences)
1. One of the parts of the cell theory states that “all living things are made of cells”. Give three examples of things that would not be made of cells. A. B. Answers will vary. Anything made out of metal, plastic, etc. C.
2. Cells of the eye (page 723) are shaped like rods and cones. White blood cells (page 604) are shaped like bumpy round balls. Plant cells (page 583) tend to be more rectangular than animal cells. Why are cells of many different shapes and sizes?
Rod Cells: most sensitive; permit vision in dim light Cone Cells: distinguish color; sharpen image White Blood Cells: protect against foreign invaders Plant Cells: support; shape
The function of the cells determines the shape of the cells. 3. Complete the chart below with either the name or function of the appropriate cell structure. Structure Function Mitochondria Creates energy for the cell Ribosome Important in the creation of proteins Chromosomes Contains the hereditary information Vacuole Storage of water, undigested food, and or wastes Nuclear Semi-permeable membrane surrounding nucleus Membrane Lysosome Storage of digestive enzymes Chloroplasts Contains chlorophyll to attract sunlight energy Golgi Body
4. Fill in the following Venn Diagram to compare and contrast animal and plant cells. Which cell parts do they have in common? Which cell parts are unique?
JUST ANIMAL CELLS
BOTH Cell membrane Mitochondria Nucleus Chromosomes
JUST PLANT CELLS Chloroplasts Cell wall Large vacuoles
ER Golgi body Ribosomes
5. Predict which organ in your body is composed of cells that contain the greatest number of mitochondria. Explain your answer.
Answers will vary. Any cells that require a great amount of energy will have many mitochondria.
6. In class we learned that plants have large vacuoles. Why would plant cells have larger vacuoles than animal cells?
Vacuoles are used for storage. Because vacuoles store liquid, they help to keep cells stiff. Storage of water also allows cell to get big without using much energy (cytoplasm is metabolically costly).
Homework #4: CREATE YOUR OWN CELL ANALOGY Over the past few days, you have been learning about cells and comparing them to a factory. To help you get ready for tomorrow’s quiz, I would like you to develop a different comparison. What else is a cell like? How would those parts fit into that analogy?
Work with your partner to develop your own analogy using the chart below. You must be able to use at least 10 of the cell parts that we described in class. In the first column, write the name of a cell part. In the second column, write the job the cell part would have in your analogy. In the third column, give your rationale or reason why that particular cell part would do that job in your analogy.
