Lecture 16 study guide

Question 1

Define tissue

Answer 1

Groups of cells that act together to perform a specific function

Question 2

Definition of Gap junction

Answer 2

directly link cytoplasm of neighboring cells

Question 3

Definition of desmosome

Answer 3

form strong physical connections between cells

Question 4

Definition of tight junction

Answer 4

Seals neighboring cells together in an epithelial sheet to prevent leakage between the cells.

Question 5

Definition of adherens junction

Answer 5

Joins an actin bundle in one cell to a neighboring bundle in another cell.

Question 6

Definition of hemidesmosome

Answer 6

Anchors intermediate filaments in a cell to the basal lamina.

Question 7

Researchers studying the molecular makeup of a structure packed near the surface of a sheet of cells in tissue determine it to be made up mostly of collagen, polysaccharides, and other proteins. What is the name of this structure?

Answer 7

Extracellular matrix

Question 8

4. What is the function of integrin?

Answer 8

links the cells to collagen of the ECM

Question 9

Explain why a vitamin C deficiency leads to the weakening of cell tissue?

Answer 9

Vitamin C is necessary for the hydroxylation of proline- a post translational modification necessary for the construction of collagen.

Question 10

True or False: Excluding predation or other external factors that could cause death, most microbial organisms like yeast are immortal

Answer 10

true

Question 11

What percent of the proteins in a cell are dedicated to regulation?

Answer 11

90%

Question 12

Name the 8 main types of protein regulation we have covered in class so far.

Answer 12

Product inhibition, feedback regulation, covalent modifications, localization, assembly, protein synthesis, protein degradation, cell communication and signaling

Question 13

Product inhibition is able to regulate proteins as a direct consequence of what?

Answer 13

reversibility of the reaction

Question 14

Methionine can inhibit a protein involved in the synthesis of methionine precursor molecules. This is what kind of regulation?

Answer 14

Feedback regulation

Question 15

Name two types of covalent modifications used to regulate proteins.

Answer 15

Phosphorylation
ubiquitination
Acetylation

Question 16

What are proteins called that phosphorylate other proteins?

Answer 16

Kinase

Question 17

What are proteins called that dephosphorylate other proteins?

Answer 17

Phosphorylases

Question 18

True or false: ubiquitination is only used as a way to target a protein for degradation?

Answer 18

false

Question 19

What is the “ultimate turnoff mechanism?”

Answer 19

degradation

Question 20

Fill in the blank: Some proteins require several modifications before they can execute a specific function. This process functions as a _______ and the combination of several modifications alters protein activity.

Answer 20

coincidence detector

Question 21

Sar1 is only able to drive vesicle formation when it is localized to the ER membrane. What type of regulation is this?

Answer 21

Localization

Question 22

What type of protein drives the process described in question 17?

Answer 22

GTPase

Question 23

Sec23/24 coat proteins must bind to Sar1 and a cargo receptor protein before they are able to effectively drive vesicle formation. What kind of regulation is this?

Answer 23

assembly

Question 24

What is the main form of regulation driving actin dynamism?

Answer 24

assembly

Question 25

Which of the following is not a possible place to regulate protein synthesis?
a. Transcription
b. Translation
c. mRNA processing
d. mRNA export
e. mRNA stability
f. All of the above are possible place

Answer 25

All of the above

Question 26

What are the two most important domains on transcription factors?

Answer 26

• protein binding domains
• transcription regulator domains

Question 27

What are homeodomains?

Answer 27

Containing transcription factor

Question 28

Homeodomains form _____ with nucleobases mostly via the major groove of the DNA

Answer 28

1. hydrogen bonds

Question 29

True or false: homeodomains are specific in the DNA sequences they can bind

Answer 29

TRUE

Question 30

What is the basic structure and function of a leucine zipper?

Answer 30

each subunit provides an alpha helix for the formation of the DNA binding domain

Question 31

Where do transcription factors usually bind in simple eukaryotes?

Answer 31

upstream close to the transcription site

Question 32

True or False: In higher eukaryotes transcriptional factors can act from farther away and not specifically in the promoter region?

Answer 32

true

Question 33

In higher eukaryotes, what is the name of the region that activator proteins bind to?

Answer 33

enhancers

Question 34

What is the name of the complex in higher eukaryotes that contains several transcription factors, chromatin remodeling complexes, etc?

Answer 34

mediator

Question 35

What is the term for a protein that inhibits transcription of DNA? What are the two mechanisms by which they usually act?

Answer 35

Repressor proteins, physically competing with the DNA binding region or suppressing translation via the mediator complex

Question 36

What is the name of the region of DNA that can be bound by a repressor?

Answer 36

silensor region