Download KEY - C2.1 The Cell as an Efficient Open System

Unit C: Biology (Cycling of Matter in Living Systems) – Assignment Answer Key
C2.1 Check and Reflect #1, 2, 4, 5, 7, 8, 10
1. A system is any unit, structure, or process that has many parts that work together for a
particular goal.
2. The cell is considered an open system because it exchanges energy and matter with its
surroundings.
4. a) The cell membrane consists of a double layer of lipids with a phosphate group
attached to each. It functions as a protective barrier around a cell, allowing
substances to enter and leave the interior of the cell.
b) Vacuoles are storage sites for nutrients, secretions, fats, and water. In plant cells,
the central vacuole is a large storage area for water that swells to create turgor
pressure.
c) Mitochondria are rod-like structures where cellular respiration takes place.
d) Chloroplasts contain chlorophyll and are the site of photosynthesis in plant cells.
5. The associated organelles are:
intake of nutrients – cell membrane
exchange of gases – cell membrane
removal of wastes – lysosomes and cell membrane
The identification of the cell membrane as being associated with each of the processes
shows the important roles that it plays in the function of the cell.
7. Answers will vary, but may include:
Three similarities in the chemical composition of plant and animal cells are:
• both contain DNA
• both have a cell membrane
• both have an internal cytoskeleton made up of proteins and lipids
Three differences are:
• plant cells have a cell wall made of cellulose, animal cells do not
• plant cells contain chlorophyll for photosynthesis
• plant cells store energy in the form of starch or oils, while animal cells store
energy in glycogen or lipids
Unit C: Biology (Cycling of Matter in Living Systems) – Assignment Answer Key
8.
Cell Structure
cell membrane
nucleus
vacuole
lysosome
endoplasmic reticulum
ribosomes
Golgi apparatus
mitochondrion
Body Organ
skin/lungs
brain
no equivalent organ; fat storage tissues
stomach/digestive system
digestive system/circulatory system
no equivalent organ
digestive system
muscles
10. Both plant and animal cells have a cell membrane, nucleus, cytoplasm, mitochondria,
ribosomes, endoplasmic reticulum, vacuoles, and vesicles. The plant cell has a rigid cell
wall that encloses the cell and gives support. Plant cells (in green tissue) have
chloroplasts and can produce their own food through the process of photosynthesis.
Animal cells need support from other structures, such as skin cells and bone cells, and
cannot produce their own food. Plant cells have a large central vacuole, while animal
cells have small vacuoles.