Unit 4: Cell Communication and Cell Cycle

Question 1

Target Cell

Answer 1

final destination cell for a ligand

Question 2

Signal Amplification

Answer 2

the process by which a ligand signal is amplified via many relay proteins which can more quickly spread the signal out

Question 3

negative feedback

Answer 3

cell response of inhibiting a particular action

Question 4

cyclin

Answer 4

a molecule used to monitor and control the cell’s procress through the cell cycle

Question 5

telophase

Answer 5

part of the cell cycle where the cell “tears”, the microtubules detatch, and the nucleus reforms

Question 6

kinase

Answer 6

enzymes that activate or inactivate other proteins by phosphorylating them

Question 7

phosphorylation

Answer 7

adding a phosphate group to another molecule

Question 8

secondary messenger

Answer 8

small, non-protein molecules that can transfer a signal throughout the cell

Question 9

cell cycle

Answer 9

the life of a cell from creation to division

Question 10

cancer

Answer 10

unregulated cell growth

Question 11

cytokinesis

Answer 11

actual splitting of the cell

Question 12

receptor

Answer 12

the protein that a ligand binds onto in order to send a signal to the cell

Question 13

signal transduction

Answer 13

domino-effect resulting from ligand binding onto a receptor that relays a signal to the cell

Question 14

response

Answer 14

the cell’s response to a signal

Question 15

mitosis

Answer 15

process by which the cell chromosomes split into two cells

Question 16

prophase

Answer 16

DNA condenses into chromosomes

Question 17

interphase

Answer 17

G1, S, and G2 phases; where the cell spends most of its time

Question 18

gap 1 (G1) phase

Answer 18

initial growth of the cell

Question 19

synthesis (S) phase

Answer 19

duplication of genome

Question 20

gap 2 (G2) phase

Answer 20

futher growth and preparation for cell division

Question 21

ligand

Answer 21

molecule that binds to a receptor protein to initiate a signal transduction pathway

Question 22

feedback

Answer 22

response by the cell to encourage a particular activity

Question 23

metaphase

Answer 23

when the chromosomes “meet” in the middle and microtubules attatch to the chromosomes

Question 24

spindle fibers

Answer 24

microtubules released by the centrioles of the centrosome that pull apart the chromosomes in mitosis

Question 25

homeostasis

Answer 25

state of stability in a cell in multiple variables (temperature, salinity, etc)

Question 26

negative feedback

Answer 26

cell response of inhibiting a particular action

Question 27

anaphase

Answer 27

sister chromatids are pulled away from each other to opposite sides of the cell and cleavage furrow forms

Question 28

cyclin dependent kinases (CDKs)

Answer 28

an enzyme that utilizes cyclins to regulate the cell cycle

Question 29

In what ways can cells communicate with one another?

Answer 29

Local signaling:
autocrine (communication in the same cell), paracrine (nearby signaling), and juxtacrine (signaling by touching)

Long-distance signaling:
endocrine (hormones)

Question 30

What are the components of a signal transduction pathway, and what do they do?

Answer 30

Reception: receptor protein and ligand
Transduction: kinases, secondary messengers, protein phosphates, G-protein coupled receptors
Response: ribosomes, new proteins, feedback activation or inhibition

Question 31

What is the role of the environment in initiating a cellular response?

Answer 31

The changes in the environment in the form of new ligands prompt the cell to initiate an appropriate response

Question 32

What are the different types of cellular responses elicited by a signal transduction pathway?

Answer 32

Molecular response (DNA expression or cytoplasmic response)
Cellular response
Physiological response (initiate symptoms)

Question 33

How does a change in the structure of any signaling molecule affects the activity of the signaling pathway?

Answer 33

any change to the ligand will deem it nonfunctional to its appropriate receptor protein, which will not signal an STP at all

Question 34

What positive and negative feedback mechanisms do we use to maintain homeostasis?

Answer 34

negative feedback mechanisms: stabilization around a set point
positive feedback mechanisms: amplification

Question 35

How does negative feedback maintain homeostasis?

Answer 35

By constantly making sure that a variable in the body is at a set point which is called homeostasis

Question 36

How does positive feedback maintain homeostasis?

Answer 36

by quickly amplifying a signal that benefits the body

Question 37

What are the stages of the cell cycle?

Answer 37

G1, S, G2, Mitosis, Cytokinesis

Question 38

How does mitosis work?

Answer 38

Mitosis clones cells exactly so the chromosome composition is the same in each daughter cell.

Question 39

What is the role of checkpoints in the cell cycle?

Answer 39

Checkpoints are there to ensure that the cell is doing its job correctly and meeting its requirements. These are done by cyclins and CDKs.

Question 40

What happens if the cell cycle is disrupted?

Answer 40

The cell will go to the G_0 phase. If not, the cell will become cancerous.