Chapter 2 - The Cell

Question 1

Identify the cell structure of the cell ?

Answer 1

1. Plasma Membrane
2. Fluids (Intercellular and Extracellular )
3. Membrane proteins
4. Microvilli
5. Cytoplasm
6. Cytoskeleton

Question 2

what are the characteristics of the Plasma membrane/Cell Membrane ?

Answer 2

1. Flexible, sturdy barrier surrounding the cell contents.
2. Separate the cell from the external environment.
3. Contains membrane protein that ;
   
   • identify the cell,
   • strengthen the membrane
   • move substances in/out the cell
4. Selectively permeable;
   
   • allows some substances to pass through , in/out and not others.
5. Involved in communication;
   between cells and between cells and their environment.

Question 3

What is the intercellular fluid called and where is it found ? Is the content of the fluid regulated?

Answer 3

• It is called Cytosol
• It is found inside the cell
• Contents of the fluid is regulated

Question 4

What is the Extracellular fluid? Where is located? and how many types of fluids are located?

Answer 4

1. Extracellular fluid is a fluid that is located outside the cell.
2. Contains lots of substances;
   
   • cells extract what they need when they need it (O2 needed)
     There are 3 kinds of Extracellular fluids:
     1. Interstitial fluid (fluid between the cells)
     2. Plasma ( fluid in the blood vessels)
     3. Cerebrospinal (fluid that sourround the brains and spinal cord)

Question 5

What is a bilayer lipid?

Answer 5

• It is a component of the cell membrane.
• It is composed of two layers of fatty acids organized in two
  sheets.
• The lipid bilayer is typically about five nanometers to ten nanometers
  thick and surrounds all cells providing the cell membrane structure.

Question 6

Define the Cell?

Answer 6

It is the smallest functional unit that can retain the necessary characteristics for life.

Question 7

What is the membrane protein ?

Answer 7

• Proteins that are embedded within the membrane or attached
  to one side of the membrane (inside or outside)
• It is associated with the lipid bilayer.

Question 8

What are the functions of the membrane proteins ? (HINT: SSIR)

Answer 8

1. Selective channels that allow and/or move molecules from
   one side of the membrane to the other.
2. Receptors that recognize specifics molecules.
3. Identify the cell e.g blood type
4. Strengthen, support, and connect adjacent cell
   membranes.

Question 9

What is Microvilli? and what it is function ?

Answer 9

• Microvilli is a finger like projections of the plasma membrane
• Function; is to increase surface area ( no movement)
  e.g, the intestine is lined with Microvilli to increase the amount of
  absorption.

Question 10

What is Glycolysis?

Answer 10

• Glycolysis breaks down glucose and forms pyruvate with the
  production of two molecules of ATP.
• The pyruvate end product of glycolysis can be used in either
  - anaerobic respiration if no oxygen is available or
  
  • in aerobic respiration via the TCA cycle which yields much more
    usable energy for the cell.

Question 11

What is the cytoplasm ? What its structure ? and Its function?

Answer 11

- It is the content of the cell (everything inside the plasma 
    membrane and outside the nucleus)
- Structure - 2 components 
    1. intercellular fluid/Cytosol (water, dissolved substances)
    2. organelles
- Function  ; e.g Glycolysis 
   1. cell metabolism
   2. storage

Question 12

Cytoskeleton provides structure for the cell, what is it made of an its function ?

Answer 12

• It is a network of protein filaments within the Cytosol.
• Function;
  
  1. provides a structural framework for cell shape
  2. scaffold for the organization/placement and movement of
     cell contents(organelles)
  3. force transmission
  4. aids in cell movement

Question 13

What are the organelles of the cell?

Answer 13

1. Nucleus (pl.nuclei)
2. Ribosomes
3. Rough Endoplasmic Reticulum
4. Smooth Endoplasmic Reticulum
5. Golgi complex (apparatus, body)
6. Lysosome
7. Mitochondria (sing.Mitochondrium)
8. Cilia (sing. cilium)
9. Flagella (sing. flagellum)

Question 14

Identify the name of the organelle of the cell that present in all human cells except RBCs , structure and function ?

Answer 14

Nucleus (pl.nuclei)

Structure ;  1. rounded and elongated 
                    2. located near the Centre of the cell
Function;
1. control the Centre of the cell 
2. Responsible for the cell metabolism
3. Growth
4. Reproduction 
5. contains the genetic material DNA

Question 15

What is the name of the organelle that is considered the site of the protein synthesis ?

Answer 15

Ribosomes - site of protein synthesis

- helps synthesis of the filament of the cytoskeleton

Question 16

Name the organelle site of protein synthesis where Ribosomes are attached ?

Answer 16

Rough Endoplasmic Reticulum ; the sister of protein Synthesis where ribosomes are attached.

Question 17

Name the organelle that ;

1. regulate calcium within the cell
2. regulates metabolism, and
3. makes lipid molecules ?

Answer 17

Smooth Endoplasmic Reticulum (sER)

1. regulate calcium within the cell
2. regulates metabolism
3. makes lipid molecules

Question 18

An organelle that is called the Packaging department, what is the name of the organelle and its function?

Answer 18

Golgi Complex (aka apparatus , body)

1. processes
2. sorts
3. packages
4. delivers molecules to the plasma membrane or around the cell

Question 19

An organelle that break down substances that the cell has taken in or normal part of the cell that are damaged , name the organelle?

Answer 19

Lysosome breaks down substances that the cell has taken in or normal part of the cell that are damaged

Question 20

What is the function of the mitochondria?

Answer 20

Mitochondria (sing. mitochondrium)
1. power plants of the cell
2. transfer organize compounds into energy (ATP) that is easily
accessible to the cell.

Question 21

Identify the difference between Cilia and Microvilli?

Answer 21

Cilia(Saint. Cilium) e.g; respiratory tract
Structure:
-short hair-like projection ,
- extending from the surface of the cell
Function
- movement of the cilia causes a steady movement of fluid/particles
along the cell surface.

Microvilli: e.g; intestines is lined up with Microvilli
- to increase the amount of absorption.
Structure;
-finger like projections of the plasma membrane
Function;
-no movement , they increase the surface area

Question 22

An organelle that is similar to Cilia but longer and moves the cell ? available only in the sperm cell

Answer 22

Flagella (sing.flagellum)/ e.g. sperm cells

• structure; similar to cilia but longer
• function; move the cell

Question 23

The role of proteins in the cell membrane is to _____.

Answer 23

-allow molecules to enter and exit the membrane

Question 24

The role of peripheral membrane proteins?

Answer 24

1. Maintaining the cell shape and structure
2. Transportation to various locations in the cell
3. Cell signaling

Question 25

Peripheral proteins _____.?

Answer 25

• attach to the plasma membrane but do not go through it

Question 26

What peripheral membrane protein is most similar to snake venom?

Answer 26

phospholipase A2

Question 27

Which peripheral membrane protein is involved in attaching the plasma membrane to the cytoskeleton?

Answer 27

spectrin - is a cytoskeletal protein that lines the Intercellular
side of plasma membrane.

Question 28

What is the role of the plasma membrane ?

Answer 28

It is to form a barrier and protect the cell from the environment.

Question 29

What are the peripheral proteins ?

Answer 29

1. Peripheral proteins don’t cross the membrane.
2. They hang out on either side of cell membranes.
3. They are loosely attached to other proteins or the membrane itself
   through hydrogen bonds.
4. They’re called ‘peripheral proteins’ because they sit on the outside
   of the membrane and do not integrate into the membrane.

Question 30

List the names of the Integral proteins membrane ? and its functions ?

Answer 30

1. Ion Channel - form a pore through which a specific ion can
   flow to get across the membrane.
   most membrane include specific channels for
   several common ions.
2. Carrier - Transports a specific substance across membrane
   by undergoing change in shape.
   e.g. amino acids needed to synthesize new proteins, so it
   enter the body cell via carriers.
   Carrier proteins are also known as transporters.
3. Receptor - recognize specific ligand and alters cell’s function in
   some way.
   e.g. antidiuretic hormone binds to receptors in the kidney
   and changes the water permeability of certain
   plasma membrane.
4. Enzyme (can be integral and Peripheral)-
   Catalyzes reaction inside or outside the cell.
   e.g lactase protruding from the epithelial cells lining your small
   intestine splits the disaccharide lactose in the milk you drink.
5. Linker (Integral and Peripheral)-
   
   • Anchors filaments inside and outside the plasma membrane.
   • Provide structural stability and shape for the cell.
   • Participate in movement of the cell
   • Link 2 cells together.
6. Cell Identity marker (glycoprotein)
   -distinguishes your cell from anyone else’s.
   MCH (Major Histocompatibility Proteins)

Question 31

The cell has 3 junctions please list the name of the junctions and what they do ?

Answer 31

1. Tight junctions - prevent the passage of substances between
   cells. e.g skin
2. Anchoring junctions - (anchor cells to one another)
3. Gap junctions - provide channels to allow substances to pass
   between cells.
   e.g. heart with its electrical communication.