Chapter 1: The Cell

Question 1

State the 4 basic tenets of the cell theory

Answer 1

1. All living things are composed of cells.
2. The cell is the basic functional unit of life.
3. Cells arise only from preexisting cells.
4. Cells carry genetic information in the form of DNA. This genetic material
   is passed on from parent to daughter cell.

Question 2

In which region of the cell is rRNA synthesized?

Answer 2

nucleolus

Question 3

Microfilaments

Answer 3

• Composed of actin
• Provide structural support to the cell
• Can cause muscle contraction through interactions with myosin.
• Help form the cleavage furrow during cytokinesis.

Question 4

Describe what happens in G0

Answer 4

The cell is just living and serving its function. No preparation for division.

Question 5

Describe what happens in G1

Answer 5

The cell is getting ready to divide - it is producing organelles for energy and protein production, and it increases in size.

Question 6

Describe what happens in G2

Answer 6

Mainly serves as a quality control check - it make sure the cell duplicated its DNA correctly and that it has the necessary organelles and cytoplasm to undergo cellular division.

Question 7

Describe what happens in S

Answer 7

The cell replicates its genetic material so that each cell will have identical copies.

Question 8

What is the genotypic result of recombination between homologous chromosomes?

Answer 8

Increased genetic diversity; potential unlinking of linked genes.

Question 9

What protein, at the G1/S checkpoint, is responsible for entering into cell-cycle arrest if there has been damage to the DNA? Also in the G2/M

Answer 9

p53
(when mutated, this gene does not promote apoptosis when needed, which can cause cancer); looses capacity as tumor suppressor

Question 10

Microtubules

Answer 10

• Composed of tubulin
• Create pathways for motor proteins (kinesin and dynein) to carry vesicles
• Contribute to the structure of cilia and flagella.

Question 11

Intermediate filaments

Answer 11

• Involved in cell-cell adhesion or maintenance of the cytoskeleton
• Help anchor organelles
• Examples include keratin and desmin.

Question 12

Parenchyma

Answer 12

The functional parts of the organ.

Question 13

The stroma is formed out of _________, and it is the __________ to form the extracellular matrix.

Answer 13

• Connective tissue

- support structure

Question 14

• Gram+ bacteria turn _____ when stained with crystal violet and safranin.
• Its cell wall is composed of __________ + _________.

Answer 14

• Purple

- Peptidoglycan and lipoteichoic acid

Question 15

• Gram- bacteria turn _____ when stained with crystal violet and safranin.
• Its cell wall is composed of __________ + _________.

Answer 15

• Red/pink

- Thin wall of peptidoglycan. It has an outer membrane made up of phospholipids and lipopolysaccharides.

Question 16

What is binary fission?

Answer 16

• How prokaryotes multiply.
• Consists of replication of the chromosome while the cell grows in size. Then the cell grows inward along the midline and divides into 2 identical cells.

Question 17

Episomes

Answer 17

Plasmids that can integrate into the genome.

Question 18

Transformation

Answer 18

The acquisition of genetic material from the environment, which can be integrated into the bacterial genome.

Question 19

Conjugation

Answer 19

The transfer of genetic material from one bacterium to another across a conjugation bridge; a plasmid can be transferred from F +
cells to F – cells, or a portion of the genome can be transferred from an Hfr cell to a recipient.

Question 20

Transduction

Answer 20

The transfer of genetic material from one bacterium to another using a bacteriophage as a vector.

Question 21

Virions

Answer 21

Individual virus particles

Question 22

Positive sense RNA viruses

Answer 22

Can be translated by the host cell

Question 23

Negative sense RNA viruses

Answer 23

A complimentary DNA strand must be synthesized using reverse transcriptase. The DNA strand can then be integrated into the genome.

Question 24

Viroids

Answer 24

Plant pathogens that are small circles of complementary RNA that can turn off genes, resulting in metabolic and structural derangements of the
cell and—potentially—cell death.