Structure and Diversity of Cells

Question 1

What are the three major points of the cell theory?

Answer 1

1. All organisms are composed of one or more cells
2. The cell is the structural and functional unit of life
3. Cells can arise only by division of preexisting cells

Question 2

What four basic macromolecules are cells comprised of?

Answer 2

1. nucleic acids
2. proteins
3. lipids
4. carbohydrates

Question 3

What were the requirements for the formation of the first cells?

Answer 3

• organic molecules (carbon, hydrogen, nitrogen, oxygen, phosphorous, and sulphur)
• molecules for catalysis of chemical reactions and self-replication
• a barrier between the internal cell environment and the external environment

Question 4

What is the only molecule able to both catalyze chemical reactions and self replicate?

Answer 4

RNA
catalyzes chemical reactions with ribozymes
self replicates through nucleotide base pairing

Question 5

Prokaryotic cells vs eukaryotic cells

Answer 5

Prokaryotes lack a nuclear envelope (no internal membranes)

Eukaryotes have a nucleus (do have internal membranes)

Question 6

What kind of DNA is present in eukaryotic cells?

Answer 6

linear DNA

Question 7

What is the function of mitochondria in eukaryotic cells?

Answer 7

Site of oxidative metabolism

Question 8

What do lysosomes provide in eukaryotic cells?

Answer 8

specialized metabolic compartments for digestion of macromolecules

Question 9

What do peroxisomes perform in eukaryotic cells?

Answer 9

Various oxidative reactions

Question 10

What is the endoplasmic reticulum? What is its function?

Answer 10

An extensive network of intracellular membranes.

Functions in the processing and transporting of proteins, and the synthesis of lipids.

Question 11

What is the function of the golgi apparatus in animal cells vs plant cells?

Answer 11

In animal cells: sorts and transports proteins destined for secretion and serves as a site for lipid synthesis.
In plant cells: synthesis of some of the polysaccharides that compose the cell wall.

Question 12

What is the function of the cytoskeleton?

Answer 12

Provides the structural framework of the cell and it responsible for the movement of entire cells, as well as intracellular transport/positioning of organelles and other structures.

Question 13

What is the cytoskeleton composed of?

Answer 13

Actin filaments, intermediate filaments, and microtubules

Question 14

What are the three main tissue systems of plant cells?

Answer 14

1. ground tissue
2. dermal tissue
3. vascular tissue

Question 15

What are the five main tissue systems of animal cells?

Answer 15

1. epithelial tissue
2. connective tissue
3. blood tissue
4. nervous tissue
5. muscle tissue

Question 16

What do epithelial cells form? What is their function?

Answer 16

Form sheets that cover the surface of the body and line internal organs.
Specialized for protection, secretion, and absorption

Question 17

What do connective tissues include?

Answer 17

Bone, cartilage, and adipose tissue.

Question 18

What are fibroblasts?

Answer 18

A cell type that fill the spaces between organs and tissues in the body

Question 19

What does blood tissue contain?

Answer 19

Red blood cells (erythrocytes) and white blood cells (granulocytes, monocytes, macrophages, and lymphocytes)

Question 20

What is nervous tissue composed of?

Answer 20

Supporting cells and nerve cells, or neurons, which are highly specialized to transmit signals throughout the body.

Question 21

What is muscle responsible for? What are the 3 types of muscle?

Answer 21

Responsible for the production of force and movement.

3 types: skeletal, cardiac, and smooth

Question 22

What is bright-field microscopy? What does it require?

Answer 22

Light passes directly through the cell.
Requires fixation (killing) of cells/tissues, cutting a thin cross section of tissue, and a variety of stains to provide contrast between subcellular organelles in order to be visualized.

Question 23

What is phase-constrast and differential interference-contrast microscopy?

Answer 23

Optical systems that convert variations in density and thickness into contrast that can be seen in the final image without staining.
Allows visualization of living cells.

Question 24

What is fluorescence microscopy used for?

Answer 24

It is a very sensitive method used to study intracellular distribution of molecules.

Question 25

What is confocal microscopy? What is it used for?

Answer 25

A specialized form of fluorescence microscopy that allows for focus on a single plane in the specimen.
Provides a much sharper image, and multiple images can be reconstructed into a 3D image.

Question 26

Transmission electron microscopy vs scanning electron microscopy

Answer 26

Transmission electron microscopy: passes a beam of electrons through a thinly sliced, fixed specimen to form an image on a fluorescent screen.
Scanning electron microscopy: electron beam reflects off sample surface - coated with metal.

Question 27

What does differential centrifugation do? What is it used for?

Answer 27

Separates and isolates organelles (size and density) for use in biochemical studies