An Overview of the Cell
The cell is the fundamental unit of life. In this quiz you will revisit the familiar onion peel and human cheek cell preparations, then move inward to the nucleus, chromosomes and DNA.
You will also test your grasp of:
- The difference between eukaryotic and prokaryotic cells
- Cytoplasm as the main arena of cellular activities
- Membrane-bound organelles versus ribosomes, which occur in all cells
- The centrosome of animal cells
- The size range from Mycoplasma to the ostrich egg
- How cell shape varies with function
Read each question carefully and choose the single best option. Good luck!
Q1. In an onion peel cell observed under the microscope, which structure forms the distinct outer boundary?
The onion cell is a typical plant cell with a distinct cell wall as its outer boundary, and just within it lies the cell membrane.
Q2. The cells of the human cheek have which structure as the delimiting boundary of the cell?
Human cheek cells have an outer membrane as the delimiting structure of the cell, with no cell wall beyond it.
Q3. Inside each cell there is a dense membrane bound structure that contains the chromosomes. This structure is the:
The dense membrane bound structure inside the cell is the nucleus, and it contains the chromosomes which in turn contain the genetic material, DNA.
Q4. The chromosomes present inside the nucleus contain which genetic material?
The nucleus contains the chromosomes, which in turn contain the genetic material, DNA.
Q5. Cells that have a membrane bound nucleus are called:
Cells that have membrane bound nuclei are called eukaryotic, whereas cells that lack a membrane bound nucleus are prokaryotic.
Q6. Which statement about the cytoplasm is correct according to the lesson?
A semi-fluid matrix called cytoplasm occupies the volume of the cell and is the main arena of cellular activities in both plant and animal cells, where chemical reactions keep the cell in the living state.
Q7. Which of the following is a membrane bound organelle of eukaryotic cells?
Eukaryotic cells have membrane bound organelles such as the endoplasmic reticulum, Golgi complex, lysosomes, mitochondria, microbodies and vacuoles. Ribosomes and the centrosome are non-membrane bound.
Q8. Ribosomes are best described as:
Ribosomes are non-membrane bound organelles found in all cells, both eukaryotic and prokaryotic.
Q9. Within a eukaryotic cell, ribosomes are found in the cytoplasm and also within which two organelles?
Ribosomes are found not only in the cytoplasm but also within chloroplasts (in plants) and mitochondria, and on rough ER.
Q10. Which non-membrane bound organelle is found in animal cells and helps in cell division?
Animal cells contain another non-membrane bound organelle called the centrosome, which helps in cell division.
Q11. Which organisms are described in the lesson as the smallest cells, measuring only about 0.3 micrometres in length?
Mycoplasmas are the smallest cells, only about 0.3 micrometres in length, while bacteria could be 3 to 5 micrometres.
Q12. The largest isolated single cell is:
The largest isolated single cell is the egg of an ostrich. Human red blood cells are only about 7.0 micrometres in diameter.
Q13. Which of the following is true of prokaryotic cells?
Prokaryotic cells lack membrane bound organelles, but ribosomes are found in all cells, both eukaryotic and prokaryotic.
Q14. Human red blood cells are about 7.0 micrometres in diameter and are described as:
Among multicellular organisms, human red blood cells are about 7.0 micrometres in diameter and are round and biconcave in shape.
Q15. According to the lesson, the shape of a cell may vary with:
Cells vary greatly in shape, which may be disc-like, polygonal, columnar, cuboid, thread like or irregular, and the shape of the cell may vary with the function it performs.