The Cell

Question 1

4 Tenets of Cell Theory?

Answer 1

1. All living things are composed of cell
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

Eukaryotes?

Answer 2

Membrane-bound organelles, a nucleus, and may form multicellular organisms

Question 3

Nucleus

Answer 3

contains DNA organized into chromosomes, surrounded by nuclear membrane or envelope, a double membrane that contains nuclear pores for two-way exchange of materials between the nucleus and cytosol, DNA is organized into coding regions called genes

Question 4

Nucleolus

Answer 4

subsection of the nucleus in which ribosomal RNA is synthesized

Question 5

Mitochondira

Answer 5

Outer membrane forms a barrier with the cytosol, inner membrane is folded into cristae and contains enzymes for the electron transport chain, between the membranes is the inter membrane space, inner mitochondrial membrane is the mitochondrial matrix; can trigger apoptosis by releasing enzymes, can divide independently of the nucleus via binary fission

Question 6

Lysosomes

Answer 6

contain hydrolytic enzymes that break down substances ingested by endocytosis, when these enzymes are released, autolysis can occur

Question 7

Rough endoplasmic reticulum vs smooth endoplasmic reticulum

Answer 7

Rough ER–> studded with ribosomes, permit translation of proteins destined for secretion
Smooth ER–> used for lipid synthesis and detoxification

Question 8

Golgi apparatus

Answer 8

stacked membrane-bound sacs in which cellular products can be modified, packaged and directed to specific locations

Question 9

Peroxisomes

Answer 9

contain hydrogen peroxide and can break down very long chain fatty acids via B-oxidation, participate in phospholipid synthesis and the pentose phosphate pathway

Question 10

microfilaments are composed of??

Answer 10

actin, they provide structural protection for the cell and cause muscle contraction thorough interactions with myosin, help form the cleavage furrow during cytokinesis in mitosis

Question 11

Microtubules are composed off??

Answer 11

tubulin, they create pathways for motor proteins like kinesin and dynein to carry vesicles. They also contribute to the structure of cilia and flagella, where they are organized into 9 pairs of microtubules in a ring with two microtubules at the center; centrioles are found in centrosomes and are involved in microtubule organization in the mitotic spindle

Question 12

intermediate filaments are involved in…

Answer 12

cell-cell adhesion and maintenance of the integrity of the cytoskeleton, help anchor organelles; ex. keratin and desmin

Question 13

epithelial tissues for the….

Answer 13

parenchyma, the functional part of the organ, may be polarized, line its cavities

Question 14

Types of epithelia (layers)

Answer 14

1. simple epithelia (one layer)
2. stratified epithelia (many layers)
3. pseudo-stratified epithelia (appear to have multiple layers due to differences in cell heights, but actually have one layer)

Question 15

Types of epithelia (by shape)

Answer 15

1. cuboidal cells–> cube-shaped
2. columnar cells–> long and narrow
3. squamous cells–> flat and scale like

Question 16

connective tissues

Answer 16

support the body and provide a framework for epithelial cells; form the stroma, or support structures, by secreting materials to form an extracellular matrix

bone, cartilage, tendons, ligaments, adipose tissues, and blood

Question 17

prokaryotes

Answer 17

don’t contain membrane-bound organelles, contain their genetic material in a single, circular molecule of DNA located in the nucleoid region

ex. bacteria and archaea

Question 18

shape of bacteria?

Answer 18

1. cocci- spherical
2. bacilli- rod-shaped
3. spirilli- spiral-shaped

Question 19

obligate aerobes

Answer 19

require oxygen for metabolism

Question 20

obligate anaerobes

Answer 20

can’t survive in oxygen-containing environments and can only carry out anaerobic metabolism

Question 21

facultative anaerobes

Answer 21

can survive in environments with or without oxygen and will toggle between metabolic processes based on environment

Question 22

aerotolerant anaerobes

Answer 22

can’t use oxygen for metabolism, but can survive in an oxygen-containing environment

Question 23

gram-positive bacteria

Answer 23

have a thick cell wall composed of peptidoglycan and lipoteichoic acid

turns purple with safranin/violet crystal stain

Question 24

gram-negative bacteria

Answer 24

have a thin cell wall composed of peptidoglycan and an outer membrane containing phospholipids and lipopolysaccharides

turns pink-red with crystal violet stain

Question 25

chemotaxis

Answer 25

moving in response to chemical stimuli, bacteria flagella contain a filament composed of flagellin, a basal body that anchors and rotates the flagellum, and a hook that connects the two

Question 26

how do prokaryotes multiply?

Answer 26

binary fission

Question 27

How can extrachromosomal material enter a prokaryote?

Answer 27

through plasmids, can contain antibiotic resistance genes or virulence factors

Question 28

what are plasmids called that integrate with the genome?

Answer 28

episomes

Question 29

4 ways bacteria go through genetic recombination?

Answer 29

transformation, conjugation, transduction, transposons

Question 30

transformation

Answer 30

when genetic material from the surroundings is taken up by the cell, which can incorporate this material into its genome

Question 31

conjugation

Answer 31

is 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 Hfr cell to recipient

Question 32

transduction

Answer 32

transfer of genetic material from one bacterium to another via a bacteriophage vector

Question 33

transposons

Answer 33

genetic elements that can insert into or remove themselves from the genome

Question 34

Bacterial growth pattern

Answer 34

1. adapt to conditions–> lag phase
2. exponential growth in –> exponential (log) phase
3. growth levels off in the stationary phase
4. resources are depleted, goes through death phase

Question 35

What are bacteriophages?

Answer 35

viruses that target bacteria
viruses contain genetic material, a protein coat (capsid), sometimes a lipid-containing envelope
bacteriophages specifically have a tail sheath and tail fibers

Question 36

Positive sense RNA viruses?

Answer 36

Can be translated by the host cell

Question 37

Negative sense RNA viruses?

Answer 37

Requires a complementary strand to be synthesized by RNA replicase before translation

Question 38

What are retroviruses?

Answer 38

Contain a single-stranded RNA genome, of which a complementary DNA strand is made using reverse transcriptase, the DNA can then be integrated into the genome

Question 39

Lytic cycle?

Answer 39

The bacteriophage produces massive numbers of new virions until the cell lyses, bacteria in the lytic phase are termed virulent

Question 40

Lysogenic cycle?

Answer 40

The virus integrates into the host genome as a pro-virus or prophage, which can then reproduce along with the cell, provirus can remain in the genome indefinitely, or may leave the genome in response to a stimulus and enter the lytic cycle

Question 41

What are prions?

Answer 41

infectious proteins that trigger misfolding of other proteins, usually converting alpha-helical structure to beta-pleated sheet, decreases the solubility of the protein and increases its resistance to degradation

Question 42

What are viroids?

Answer 42

plant pathogens that are small circles of complementary RNA that can turn off genes, resulting in metabolic and structural changes and potentially, cell death