The Fundamental Units of Life Classwork Name: ______
7th Grade PSI
1. Using the four characteristics of living things, explain whether plants are living things or not.
2. Cells are microscopic. What does this mean?
3. Are you an organism? Explain how you know.
4. Are rocks living or nonliving? Justify your answer using the cell theory.
5. Bacteria are each composed of one cell that does not have a membrane-bound organelle. What two terms characterize bacteria?
The Fundamental Units of Life Homework Name: ______
7th Grade PSI
6. Where are cells found? Provide two examples of where cells are found.
7. Explain whether each of the following statements is correct or incorrect using the cell theory:
a. Even very simple organisms like bacteria are composed of cells.
b. The basic building blocks of a starfish are its spine, which give it its unique shape.
c. When you heal from a cut, new skin cells are created from existing cells.
8. Are leaves living or nonliving? Justify your answer using the cell theory.
9. Explain the difference between unicellular and multicellular organisms. Give an example of each.
10. Describe the differences between prokaryotes and eukaryotes.
Cell Structure and Function Classwork Name: ______
7th Grade PSI
11. The liver is an organ that is responsible for detoxification. This means that it breaks down toxins in the body. Explain which organelle is important for the function of the liver.
12. Proteins are important molecules in the body. Some proteins help to speed up reactions; others aid in DNA replication; still others are a source of structure, such as hair and nails. Name three organelles that work with proteins in the cell.
13. The leaves of an oak tree and a rabbit’s fur are both part of living organisms. They are both multicellular and eukaryotic. Despite these similarities, however, there are also some differences between the two. Name three things that would be found in cells of an oak tree leaf but not in the cells of rabbit’s fur? What accounts for these differences?
Cell Structure and Function Homework Name: ______
7th Grade PSI
Fill out the chart by describing each function and noting in what type of cell the structure is found.
Structure / Function / Animal Cell / Plant CellCell membrane
Cytosol
Nucleus
Ribosomes
Endoplasmic
Reticulum
Golgi apparatus
Lysosomes
Mitochondria
Cell wall
Vacuoles
Chloroplasts
Cell Structure and Function Classwork Name: ______
7th Grade PSI
Each of the following statements is an example of a type of tissue. Label each statement with the type of tissue described.
14. ______Our skin cells form tissue that protect our bodies from injury and infection.
15. ______When you put your hand on a hot stove, this type of tissue communicates with your brain and makes you quickly jerk your hand away.
16. ______The walls of the small intestine move food through the digestive system.
17. ______The pancreas is an example of an endocrine gland. This gland secretes insulin, a hormone that helps to regulate sugar in the blood.
18. ______Adipose cells compose this type of tissue that stores fat.
19. ______The heart pumps blood throughout the body and is composed of this type of tissue.
20. ______The Achilles tendon attaches the calf muscles to the heel bone.
21. ______The tissue of the brain controls various functions, such as breathing.
Fill out the flowchart with the correct order of organization in the body, from smallest to largest. Define each level and include at least two examples of each. Use the following terms: tissue, organism, organ system, cell, organ.
Cell Structure and Function Homework Name: ______
7th Grade PSI
Each of the following statements describes a component of an organ system. Label each statement with the type of system described.
22. ______When food is digested in the small intestine, nutrients pass into blood vessels, called capillaries, in the lining of the intestine. The capillaries transport the nutrients to other cells in the body.
23. ______The human rib cage consists of 24 ribs. One of the functions of the rib cage is to protect the heart.
24. ______The gallbladder is a small organ located below the liver. It releases bile, a substance that helps to digest fats.
25. ______Oxygen from the lungs is transported to oxygen-poor cells via the arteries.
26. ______The transverse abdominals are muscles that wrap around the waist and pull the body in and upwards. These muscles are important for good posture.
27. ______Alveoli are little sacs in the lungs where gas exchange occurs. On average, the human lungs contains 700 million alveoli.
28. ______The esophagus is a hollow tube that transports food from the pharynx to the stomach.
29. ______When playing soccer, the iliotibial band and the adductor leg muscles are essential for kicking and jumping.
30. ______Bone marrow is located in the middle of the bones and is the site of red blood cell production.
31. ______The trachea is a hollow tube that brings oxygen into the lungs.
Information Processing in Name: ______
Living Systems Classwork
7th Grade PSI
32. Why are sensory receptors important?
33. Describe the two parts of the nervous system.
34. Sunlight shines in your window and wakes you up early Saturday morning. What type of stimulus is this and why?
35. What makes a reflex different from other stimuli?
36. You walk into the kitchen in the evening and smell food in the oven. A moment later, you start to salivate. Identify the sensory input, integration, and motor output components of this reaction.
Information Processing in Name: ______
Living Systems Homework
7th Grade PSI
37. Bundles of nerve cells that relay information from your fingers to your spinal cord would be part of which component of the nervous system?
38. Where in the body is sensory information integrated?
39. Upon hearing a sudden, loud noise, you instantaneously startle. What type of stimulus is this and why?
40. A toddler falls down and scrapes his knee, causing him to curl into a ball and to start crying. What type of stimulus is this and why?
41. What are the three steps describing how the nervous system functions?
42. Describe an everyday example of the three steps involved in the function of the nervous system.
Answer Key
1. Plants are living things because they
· grow; they may start as seeds and grow
· respond to stimuli; they may start to wilt if exposed to too much sun or harsh weather
· reproduce through pollination
· use the sun’s energy for growth and reproduction
2. Cells cannot be seen by the naked eye. They can only be seen using a microscope.
3. Yes; humans exhibit the four characteristics of living things (growth, respond to stimuli, reproduce, use energy for growth and reproduction) AND humans can function on their own.
4. Rocks are nonliving. They are not composed of cells.
5. Bacteria are unicellular and prokaryotic.
6. Cells are found in living organisms. Two examples where cells are found are humans and starfish.
7. a) Correct; All living things are composed of one or more cells even unicellular organisms. b) Incorrect; Cells are the basic unit of structure and function in living things. c) Correct; Cells arise from other cells.
8. Leaves are living because they are composed of cells, which are the basic unit of structure and function. All leaf cells arise from other leaf cells.
9. Unicellular organisms are composed of one cell; bacteria. Multicellular organisms are composed on multiple cells; humans.
10. Prokaryotes are unicellular and have no membrane-bound organelles. They are usually smaller than eukaryotes. Eukaryotes are unicellular or multicellular, have membrane-bound organelles, and are usually much larger than prokaryotes.
11. Lysosomes because they contain enzymes that breakdown and recycle material.
12. Ribosomes, golgi apparatus, endoplasmic reticulum
13. Cell wall, vacuole, chloroplast; a rabbit contains animal cells while the oak tree contains plant cells.
Structure / Function / Animal Cell / Plant CellCell membrane / Regulates what goes in and out of the cell. / X / X
Cytosol / Holds organelles in place inside the cell. / X / X
Nucleus / Controls the cell and houses DNA. / X / X
Ribosomes / Makes proteins. / X / X
Endoplasmic
Reticulum / Serves as a pathway around the cell. / X / X
Golgi apparatus / Packages and ships proteins out of the cell. / X / X
Lysosomes / Breaks down materials. / X / X
Mitochondria / Powers the cell. Creates energy. / X / X
Cell wall / Outer covering that supports and protects the cell. / X
Vacuoles / Stores water and salt and supports the structure. / X
Chloroplasts / Photosynthesis – creates energy out of sunlight. / X
14. Epithelial tissue
15. Nervous tissue
16. Muscle tissue
17. Epithelial tissue
18. Connective tissue
19. Muscle tissue
20. Connective tissue
21. Nervous tissue
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22. Circulatory
23. Skeletal
24. Digestive
25. Circulatory
26. Muscular
27. Respiratory
28. Digestive
29. Muscular
30. Skeletal
31. Respiratory
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32. Sensory receptors respond to stimuli and send signals to the brain for processing. This is important to protect organisms from harm.
33. The central nervous system is composed of the brain and spinal cord. The peripheral nervous system connects the central nervous system to limbs and organs.
34. Electromagnetic because sunlight is a source of light and heat.
35. A reflex does not travel to the brain. It only travels to the spinal cord.
36. Sensory input: chemical stimulus of the smell of food. Integration: sensory receptors send information to brain. Motor output: mouth starts to salivate.
37. Peripheral nervous system
38. Brain
39. Reflex- it happens instantaneously meaning it bypasses brain processing.
40. Mechanical stimulus- because it involves pressure
41. Sensory input, integration, motor output
42. Answers will vary.
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