Lecture 2 (Cell Introduction)

Question 1

Cell Theory

Answer 1

• All organisms are composed of one or more cells.
• The cell is the structural unit of life.
• Cells arise only by division from a pre-existing cell.
* Cells contain genetic information (DNA) passed to next cell generation.

Question 2

Genes store information and instructions for:

Answer 2

▪ Constructing cellular structures, the directions for
▪ Running cellular activities, and then program for
▪ Making more of themselves.

Question 3

metabolism is:

Answer 3

The sum total of the chemical reactions in a cell represents that cell’s

Question 4

Characteristics That Distinguish Prokaryotic and Eukaryotic Cells

Answer 4

▪ Genetic material is membrane-bound in eukaryotes (nucleus),
in nuclear area of cytosol in
prokaryotes.

Eukaryotic cells are
much more complex,
both structurally and
functionally, than
prokaryotic cells.

Prokaryotes – relatively small
amounts of DNA; 600-8,000 Mb.
▪ Eukaryotes – simple yeast cells
have 12 Mb DNA, most
eukaryotic cells possess more.

cytoplasm: Eukaryotes have membranebound organelles and complex
cytoskeletal proteins. Both have
ribosomes but they differ in size.

▪ Cellular reproduction: Eukaryotes divide
by mitosis; prokaryotes divide by simple
fission.

▪ Locomotion: Eukaryotes use both
cytoplasmic movement, and cilia and
flagella; prokaryotes have flagella, but
they differ in both form and mechanism.

Question 5

Types of Prokaryotic Cells

Answer 5

Archaea are evolutionarily related species that live in extremely
inhospitable environments, often referred to as “extremophiles.”

Bacteria are present in every conceivable
habitat on Earth, even found in rock layers
kilometers beneath the Earth’s surface.

Question 6

The cell size is limited by:

Answer 6

Volume of cytoplasm that can be supported by
the genes in the nucleus.
• Volume of cytoplasm that can be supported by
exchange of nutrients.
• Distance over which substances can efficiently
travel through the cytoplasm via diffusion

Question 7

Virus types:

Answer 7

virion is a virus particle outside the
host cell

Viruses that infect bacteria are
bacteriophages

Viroids are pathogens, each consisting of
a small, naked RNA molecule

Question 8

Viral infection types

Answer 8

Lytic infection: the virus redirects the host into making more virus particles,
the host cell lyses and releases the viruses.

2. Integration: the virus integrates its DNA (called a provirus) into the host
   cell’s chromosomes.

Question 9

Identify the four tenets of cell theory.
▪ Explain the importance of the fundamental properties
shared by all cells.
▪ Compare the structures and functions of prokaryotic and
eukaryotic cells.
▪ Know the structures and function of viruses.