Ch. 11-12 Quiz

Question 1

What is local signaling?

Answer 1

Local signaling is communicating with an adjacent or nearby cell

Question 2

What are examples of local signaling?

Answer 2

Paracrine, synaptic

Question 3

What is long-distance signaling?

Answer 3

Long-distance signaling is communicating with cells that may be further away

Question 4

What are examples of long distance signaling?

Answer 4

Endocrine (hormonal)

Question 5

What is paracrine signaling?

Answer 5

Numerous cells simultaneously receive and respond to molecules of growth factor
Occurs between cells very close by
Signal only lasts a short amount of time because the signaling molecules degrade quickly or cannot travel far

Question 6

What is reception?

Answer 6

The target cell’s detection of a signal molecule coming from outside the cell. A chemical signal is detected when it binds to a receptor protein located at the cell’s surface or inside cell.

Question 7

What is transduction?

Answer 7

Membrane protein may have a binding site w/specific shape that fits chemical messenger
Binding of the signal molecule changes the receptor protein in some way
External messenger may cause conformational change in protein that relays message to inside of cell
Converts signal to a form that can bring a specific response
Sometimes occurs in single step but more often requires a sequence of changes

Question 8

What is response?

Answer 8

Transduced signal triggers a specific cellular response. The response may be almost any cellular activity, such as catalysis by an enzyme, rearrangement of cytoskeleton, or activation of specific genes in nucleus.

Question 9

What is a ligand?

Answer 9

Ligands are molecules that specifically and reversibly bind to another molecule or receptor

Question 10

What is testosterone?

Answer 10

Testosterone is a hormone secreted by testis and travels through the blood to enter cells throughout the body

Question 11

Describe testosterone’s reception, transduction, and response.

Answer 11

Cytosol of target cells contains receptor molecules that bind testosterone, activating receptor.
These activated proteins enter the nucleus and turn on specific genes that control male sex characteristics.

Question 12

What is a phosphorylation cascade?

Answer 12

Basically, an enzyme phosphorylates (adds a phosphate to) a protein, which causes a reaction to have another protein phosphorylated and so on and so on.

Question 13

How are kinases involved in phosphorylation cascades?

Answer 13

A protein kinase is the enzyme that transfers phosphate groups from ATP to the protein while the protein phosphatase is the enzyme that removes phosphate groups.

Question 14

Name the events of the cell cycle in order.

Answer 14

Interphase (G1, S, G2) and mitosis (prophase, prometaphase, metaphase, anaphase, telophase) cytokinesis

Question 15

Describe the chromosome structure.

Answer 15

The DNA is wrapped around proteins called histones to create chromatin
The chromatin is tightly coiled to form a chromosome

Question 16

What are the phases of cell division and what happens in each?

Answer 16

Interphase - cell prepares to divide
Mitosis - the nucleus divides
Cytokinesis - A cleavage furrow forms and pinches the cell in two

Question 17

What are the stages of mitosis?

Answer 17

Prophase
Prometaphase
Metaphase
Anaphase
Telophase
Cytokinesis

Question 18

What happens in prophase?

Answer 18

Chromatin condenses into chromosomes 
Nucleoli disappear
Each duplicated chromosome appears as two identical sister chromatids
Mitotic spindle forms
Centromeres move away from each other

Question 19

What happens in prometaphase?`

Answer 19

The nucleus envelope fragments
Chromosomes are condensed
Microtubules extend to the middle of the cell
Kinetochores (protein structure attached to the centromere of the chromosome) attach to the microtubules to move them around

Question 20

What happens in metaphase?

Answer 20

Centromeres at the opposite end of the cell
Chromosomes convene (line up) on the metaphase plate
The kinetochores of the sister chromatids are attached to kinetochore microtubules  (protein structure attached to the centromere of the chromosome) coming from opposite poles (The sister chromatids are attatched to the microtubules, AKA the spindle)

Question 21

What happens in anaphase?

Answer 21

Chromatid pairs are pulled apart by microtubules to each end of the cell
By the end of anaphase, the ends have complete collections of chromosomes

Question 22

What happens in telophase?

Answer 22

Two daughter nuclei form
nuclear envelopes begin to form
chromosomes become less dense

Question 23

What is the primary difference between animal and plant cells?

Answer 23

Animal Cells:

- pinching inward of cell membrane
- center of cell
- ”cleavage furrow”

Plant cells:

- no pinching inward
- cell plate form in center of cell
- cell membranes and cell walls form on each side of the cell plate

Question 24

What is the mitotic spindle?

Answer 24

-the mitotic spindle separates the two sister chromatids during mitosis

Question 25

What are the three checkpoints?

Answer 25

G1, G2, and S

Question 26

What is G1 checkpoint?

Answer 26

Cyclically operating set of molecules in the cell that trigger and coordinate events of the cell cycle

Question 27

What is the Mitosis checkpoint?

Answer 27

Internal signal (between metaphase and anaphase) sent by kinetochores, signals that it is okay to begin anaphase once all chromosomes are properly attached