Biology Unit 3

Which historical event most directly contributed to the development of the cell theory?

• The discovery that DNA is the genetic material.

• The development of theories of natural selection on evolution of organisms.

• The development of microscopes and higher powered lenses.

• The discovery and classification of thousands of species of organisms.

According to the cell theory —

• animals are composed of cells, but plants are not

• the smallest unit of life is an atom

• new cells arise only from other cells

• all organisms are composed of tissues

The smallest unit that can carry out all activities associated with life is —

• a tissue

• the atom

• the cell

• the organelle

Who was one of the first people to identify and observe cells from cork?

• Rudolf Virchow

• Robert Hooke

• Charles Darwin

• Anton von Leeuwenhoek

If a toxic chemical destroys the ribosomes, which cellular activity would be affected first ?

• DNA synthesis

• Energy storage

• Protein production

• Movement

The process by which a nucleus divides into two new identical nuclei is called —

• mitosis

• cell division

• interphase

• meiosis

The cell in this figure is in which stage of mitosis?

• Metaphase

• Prophase

• Anaphase

• Telophase

The process of mitosis ensures that each daughter cell has a copy of every chromosome present in the parent cell. What is the use of this process?

• It creates reproductive cells.

• It helps each new cell perform the same function.

• It helps in multiplication of DNA.

• It helps replace old, worn out cells.

Which of the following has the correct order of phases of mitosis?

• Prophase, metaphase, anaphase, telophase

• Telophase, prophase, metaphase, anaphase

• Telophase, metaphase, anaphase, prophase

• Metaphase, prophase, anaphase, telophase

A teacher explains to her students that during mitosis, all the cells divide into two daughter cells and each daughter cell has the same number of chromosomes. The teacher asks her students to support this explanation. What statements should the students give?

• Each daughter cell receives half the chromosomes and the cytoplasmic organelles from the parent cell and then duplicates.

• During the growth phase between two mitotic divisions of a cell, chromosomes and the cytoplasmic organelles duplicate.

• During mitosis, cells divide continuously without growing.

• Each daughter cell receives exactly half the number of duplicated chromosomes.