Unit 4

Question 1

Quorum Sensing

Answer 1

The ability of bacteria to sense local population densities if they have a concentration of signaling molecules

Question 2

Cell Junctions

Answer 2

Sections that can directly connect the cytoplasm of adjacent cells in plants and animals

Question 3

Paracrine Signaling

Answer 3

Type of local signaling in animals that relies on growth factors to stimulate nearby cells to grow and divide; occurs when signal molecules bind to receptors

Question 4

Synaptic Signaling

Answer 4

Local signaling in animals that occurs when a neurotransmitter is released in response to an electric signal

Question 5

Hormones

Answer 5

Type of long distance signaling chemical; endocrine signaling

Question 6

Ligand

Answer 6

The specific signal molecule that attaches to its receptor on or in the target cell

Question 7

G Protein-Coupled Receptors (GPCRs)

Answer 7

Lie on the cells’ surface and work with G Proteins to transduce signals across the plasma membrane

Question 8

GTP

Answer 8

Type of cellular energy that plays a role in signaling pathways

Question 9

Receptor Tyrosine Kinases (RTKs)

Answer 9

Membrane receptors that attach phosphates to tyrosines; can trigger multiple pathways at once

Question 10

Ligand-Gated Ion Channels

Answer 10

Act as a gate that opens/closes when receptor changes shape due to binding

Question 11

Transcription Factor

Answer 11

Certain complexes that can turn specific genes on/off

Question 12

Phosphorylation

Answer 12

Process by which phosphates are transferred from ATP to protein which yields ADP

Question 13

Phosphorylation Cascade

Answer 13

System of “passing down the phosphate” in which many relay molecules work together with one signal

Question 14

Dephosphorylation

Answer 14

Process that removes phosphates from proteins

Question 15

Second Messengers

Answer 15

Small, nonprotein, water-soluble molecules/ions that spread throughout cell by diffusion and participate in signaling pathways

Question 16

Scaffolding Proteins

Answer 16

Large relay proteins to which other relay proteins are attached that increase signal transduction efficiency by grouping together related proteins within the same pathway

Question 17

Apoptosis

Answer 17

Process of “programmed cell death” that is carried out by cells that have reached the end of their lifespan or have irreparable damage

Question 18

Cell Cycle

Answer 18

Duration of a cell’s life from formation to division

Question 19

Genome

Answer 19

All the DNA that can be found in each species

Question 20

Somatic Cells

Answer 20

Nonreproductive cells that have 2 sets of chromosomes that exist as a pair

Question 21

Gametes

Answer 21

Reproductive cells that have a single set of chromosomes

Question 22

Centromere

Answer 22

Narrow junction point of duplicated chromosomes where chromatids attach

Question 23

Sister Chromatids

Answer 23

The two identical copies of a chromosome resulting from DNA replication before mitosis

Question 24

Cohesions

Answer 24

Areas where sister chromatids are attached

Question 25

Mitosis

Answer 25

The division of genetic material in the nucleus which conserves the number of chromosomes in its daughter cells

Question 26

Cytokinesis

Answer 26

The division of the cytoplasm

Question 27

Mitotic Spindle

Answer 27

A structure made of microtubules that control chromosome movement during mitosis

Question 28

Centrosome

Answer 28

Organelle in animal cells were the mitotic spindles are formed

Question 29

Kinectochores

Answer 29

Protein complexes associated with centromeres where spindle microtubules attach to

Question 30

Metaphase Plate

Answer 30

Horizontal plane between spindle poles where chromosomes align during Metaphase

Question 31

Separase

Answer 31

Enzyme that cleaves cohesions between sister chromatids during anaphase

Question 32

Cleavage Furrow

Answer 32

The splitting/formation of the new plasma membrane in animal cells undergoing cytokinesis

Question 33

Cell Plate

Answer 33

The new cell wall formed in plant cells undergoing cytokinesis

Question 34

Binary Fission

Answer 34

Method of prokaryotic reproduction in which the 2 daughter chromosomes actively move apart (requires no spindles, microtubules, or centromeres)

Question 35

"Checkpoints"

Answer 35

Specific places in the cell cycle that require a signal for the cell to move into the next phase of division

Question 36

Maturation-Promoting Factor (MPF)

Answer 36

A protein signal that triggers cell's passage past G2 checkpoint; cell enters M phase

Question 37

Growth Factors

Answer 37

External signals released by certain cells that stimulate cell division

Question 38

Density-Dependent Inhibition

Answer 38

When a crowded cellular environment stops cells from dividing

Question 39

Anchorage Dependence

Answer 39

Cells must be attached to a substratum (surface) in order to divide