Cell Biology 1

Question 1

What are the two components of protoplasm?

Answer 1

Nucleus

Cytoplasm (where the cytosol, organelles, inclusions and protein fibers hang out)

Question 2

What cells are the exception to the general rule that most cells have only one nucleus?

Answer 2

RBC, lens fibers and cornified layers of skin have none

Osteoclasts have multiple

Question 3

Why is the fate of the cell important?

Answer 3

They determine the development, health and lifespan of an individual

Question 4

What are the 9 representative cell types of the Human body?

Answer 4

Epithelial
Support
Contractile
Nerve
Germ
Blood
Immune
Hormone secreting 
Adult stem cells

Question 5

Why are adult stem cells so interesting andI important? And where can you find some adult stem cells?

Answer 5

They are capable of activation, proliferation and differentiation in response to tissue injuries.
You can find them in Stem muscle cells and cornea epithelial stem cells

Question 6

How are the different cell types classified?

Answer 6

By function

Question 7

What are some examples of cell functions?

Answer 7

Secretory activity
Absorptive activity
High protein synthetic activity

Question 8

True or false are different cell types woven into tissues?

Answer 8

True

Question 9

Mitochondria

Answer 9

Provide energy to the cell, can release proteins that bring on cell death

Question 10

ER

Answer 10

Produces proteins and lipids; also covalent addition of sugars to proteins

Question 11

Golgi

Answer 11

Processes sugar side chains and glycoproteins and sorts proteins for transport

Question 12

Nucleus

Answer 12

The largest organelle

Stores genetic information (DNA) in chromosomes and has the machinery to express then

Question 13

Plasma Membrane

Answer 13

Encloses the entire cell and has several functions in containment and cell communication

Question 14

Cytoskeleton

Answer 14

Internally organizes the cytoplasm

Question 15

What are the five major junctions of the cell membrane?

Answer 15

Structure
Protection
Activation of cell
Transport
Cell-Cell interaction

Question 16

What is glycocalyx? What are some of its functions?

Answer 16

Carbohydrate contain region that faces outward from the plasma membrane.
Microvilli plasma membrane glycocalyx involves glycoproteins w/ digestive functions
Other functions: cell-cell adhesions, communication, proliferation, signaling and receptor sites for hormones

Question 17

Explain the Modified fluid mosaic model.

Answer 17

Membrane are composed of lipids and proteins
Phosphoric molecules make the bilayer
Cholesterol maintains structural integrity; glycolipids have protective functions

Question 18

What are the three major classes of lipids?

Answer 18

Phospholipid, cholesterol and glycolipids

Question 19

What are lipid rafts?

Answer 19

Specialized lipid domains that have high concentration of glycosphingolipids and cholesterol and membrane proteins involved in cell signaling

Question 20

Where do integral proteins lie within the membrane?

Answer 20

They penetrate the bilayer, some are linked to special lipids

Question 21

What is the function of integral proteins

Answer 21

Pumps, channels, receptors, linkers, enzymes and structural proteins

Question 22

What are gap junctions and what is there job?

Answer 22

They punctuate the plasma membrane as organized junction all complexes. And connects the cytoplasm of two adjacent cells.
Function: metabolic, ionic and low resistance electrical communication

Question 23

What are some diseases/malfunctions of the plasma membrane?

Answer 23

A mutation in connexin-26 is the most common cause of inherited deafness
A mutation in connection -50 leads to cataracts in the lens of the eye

Question 24

Where are cilia located?

Answer 24

On the apical domain of membranes/epithelial cells

Question 25

What is the structure of cilia?

Answer 25

9 microtubules doublets | There are dynein arms on cilia microtubules doublets

Question 26

What are some common diseases/malfunctions of cilia?

Answer 26

Kartagener's syndrome which happens due to lack of dynein arms on cilia microtubules

Question 27

What type of filaments to microvilli contain?

Answer 27

Actin filaments | They also have absorptive functions

Question 28

What supports the plasma membrane?

Answer 28

Membrane skeleton is found just beneath the membrane and contains actin filaments *other cytoskeleton elements are found throughout the cytoplasm*

Question 29

What is the shape of RBC's and how is it maintained?

Answer 29

They have a biconcave shape. It's maintained by fibrillar protein network or membrane skeleton underneath the plasma membrane

Question 30

What is spectrin in regards to RBC membrane skeleton?

Answer 30

They are long molecules that help maintain the biconcave shape of RBCs and gives the cell properties of elasticity and flexibility.

Question 31

What is endocytosis?

Answer 31

It's either fluid phase or receptor-mediated. Pinocytosis is the fluid phase and it's non-specific and has random uptake Receptor-Mediated is driven by specific receptors that bind ligands

Question 32

What is phagocytosis?

Answer 32

Used when cells ingest large particles Important to host defense Important in tissue remodeling and wound healing

Question 33

What are the key steps involved in receptor mediated endocytosis?

Answer 33

1) coated membrane vesicles form by invagination so plasma membrane 2) these vesicles are derived from coated pits braced by a coat of protein called Clatherin 3) Adaptins organize the cargo receptor complexes. Dynamic has a role in the pinching off of the coated pit to form vesicles 4) inside the cell Clatherin and Adaptins disassemble from a coated vesicle and are recycled

Question 34

What type of disease can come from malfunctions in receptors mediated endocytosis?

Answer 34

Familial Hypercholesterolemia. | LDL is not endocytosed but builds up in the bloodstream because of LDL receptor mutation

Question 35

What are the Key steps in Phagocytosis?

Answer 35

1) initial binding reactions between molecules and receptors on the plasma membrane 2) changes in the underlying actin membrane skeleton lead to pseudopods and formation of phagosome that will eventually fuse with a lysosomes

Question 36

What are the three components of the cytoskeleton?

Answer 36

Microtubules: non-branching, long hollow cylinders Actin microfilaments: double stranded linear helical arrays Intermediate filaments: rope-like fibers

Question 37

What are centrioles?

Answer 37

Non-membranous organelle. Composed of 9 microtubule triplets contains different forms of tubulin and centrin. They are located MTOC region of the cell. They assisting the formation of organization of microtubules and provide basal bodies for cilia and flagella

Question 38

What is the job of the cytoskeleton?

Answer 38

It determines cell shape and strength. It has a role in moving components form place to place in no dividing cells. In dividing cells, cytoskeleton microtubules make up the mitosis spindle.