The Cell

Question 1

3 tenets of 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

Question 2

nuclear pores

Answer 2

in the nuclear membrane

allow for selective two-way exchange of material into and out of the nucleus

Question 3

where is rRNA synthesized?

Answer 3

nucleolus

Question 4

extranuclear inheritance

Answer 4

transmission of genetic material independent of the nucleus

eg mitochondria - contain some of their own genes and replicate independently of the nucleus via binary fission

Question 5

apopotosis

Answer 5

programmed cell death

mitochondria can kill the cell by release of enzymes from the electron transport chain

Question 6

mitochondria

Answer 6

powerhouse of the cell

Question 7

lysosomes

Answer 7

membrane-bound structures containing hydrolytic enzymes that are capable of breaking down many different substrates, including substances ingested by endocytosis and cellular waste products

Question 8

rough vs. smooth ER

Answer 8

rough endoplasmic reticulum contains ribosomes for protein synthesis
smooth ER is for lipid synthesis and transport of proteins from rough ER to Golgi apparatus

Question 9

Golgi apparatus

Answer 9

consists of stacked membrane-bound sacs
materials from the ER are transported to Golgi in vesicles
cellular products undergo modification
contents are released via exocytosis

Question 10

peroxisomes

Answer 10

primary function: breakdown of fatty acid chains via beta-oxidation

Question 11

microfilamnets

Answer 11

made up of solid polymerized rods of actin
organized into bundles and networks
resistant to compression and fracture (provide protection for the cell)

Question 12

microtubules

Answer 12

hollow polymers of tubulin proteins

radiate throughout the cell

Question 13

cilia and flagella

Answer 13

cilia primarily for movement along surface of the cell, whereas flagella primarily for movement of cell itself like sperm
9+2 structure = nine pairs of microtubules forming an outer ring with two microtubules in the center

Question 14

intermediate filaments

Answer 14

diverse group of filamentous proteins
include keratin, desmin, vimentin, lamins
involved in cell-cell adhesion or maintenance of the overall integrity of the cytoskeleton
able to withstand a tremendous amount of tension, making the cell rigid

Question 15

epithelial tissues

Answer 15

cover the body and line its cavities, providing a means for protection against pathogen invasion and desiccation
tightly joined to layer of connective tissue called basement membrane
simple/stratified/pseudostratified and squamous/cuboidal/columnar

Question 16

parenchyma

Answer 16

functional parts of an organ

made up of epithelial cells

Question 17

prokaryotic envelope

Answer 17

cell wall forms outer barrier (peptidoglycan)

plasma membrane forms inner layer

Question 18

Gram positive vs. Gram negative bacteria

Answer 18

Gram stain applied to cell walls
gram positive - lipoteichoic acid in cell wall along with peptidoglycan, very thick
gram negative - additional outer membrane containing lipopolysaccharides and phospholipids, very thin

Question 19

episomes

Answer 19

subset of plasmids capable of integrating into the genome of the bacterium

Question 20

transformation

Answer 20

integration of foreign genetic material into the host genome

most frequently comes from neighboring bacteria upon lysing

Question 21

conjugation

Answer 21

unidirectional transfer of genetic material from donor male (+) to recipient female (-)
conjugation bridge forms from sex pili on the donor male
requires sex factors such as F (fertility) factor

Question 22

Hfr

Answer 22

high frequency of recombination

bacterium with sex factor (conjugative) plasmid integrated into its genome

Question 23

transudction

Answer 23

requires a vector

viruses carry genetic material from one bacterium to another

Question 24

phases of bacterial growth

Answer 24

lag phase - bacteria adapt to new environmental conditions
exponential phase - growth increases as bacteria adapt (aka log phase)
stationary phase - reduction of resources slows reproduction
death phase - after bacteria have exceeded environment’s ability to support them

Question 25

bacteriophages

Answer 25

viruses that specifically target bacteria inject genetic material into bacterial cell without actually entering it composed of capsid (protein coat), genetic material, tail sheath, and tail fibers

Question 26

single-stranded RNA viruses

Answer 26

positive sense RNA viruses: genome may be directly translated to functional proteins by ribosomes of the host cell, just like mRNA negative sense RNA viruses: require synthesis of an RNA stand complementary to negative sense strand, which can then be used as a template for protein synthesis

Question 27

retroviruses

Answer 27

enveloped, single-stranded RNA viruses carry reverse transcriptase enzyme which can synthesize DNA from single-stranded RNA DNA then integrates into host cell genome eg HIV

Question 28

lytic cycle

Answer 28

bacteriophage makes maximal use of the cell's machinery with little regard for host cell survival host swells with new virion --> host cell lyses --> other bacteria can be infected

Question 29

lysogenic cycle

Answer 29

virus integrates into host genome as provirus/prophage and will be replicated as the bacterium reproduces will typically revert to the lytic cycle at some point

Question 30

prions

Answer 30

cause infections by triggering misfolding of other proteins usually convert protein from alpha helix to B sheet structure drastically reduces solubility of the protein and cell's ability to degrade it eg mad cow disease, Creutzfeldt-Jakob disease, familial fatal insomnia

Question 31

viroids

Answer 31

short circular single-stranded RNA that infects plants | silences genes in the plant genome