Guyton Chapter 1 and 2 - Functional Organization

Question 1

How does the ECF differ from the ICF regarding electrolytes and nutrients?

Answer 1

The ECF contains large amounts of sodium, chloride and bicarbonate ions plus nutrients for the cells such as oxygen, glucose, fatty acids and amino acids. It also contains carbon dioxide that is transported from the cell to the lungs to be excreted.

The ICF contains large amounts of potassium, magnesium and phosphate ions.

Question 2

What types of cell membrane proteins are there?

Answer 2

Integral proteins that protrude all the way through the membrane

Peripheral proteins that are attached only to one surface of the membrane and do not penetrate all the way through.

Question 3

What is the loose carbohydrate coat called on the outer surface of the cell?

Answer 3

Glycocalyx

Question 4

What is the cytosol?

Answer 4

The clear fluid portion of the cytoplasm in which the particles are dispersed. This contains mainly dissolved proteins, electrolytes and glucose.

Question 5

What is granular endoplasmic reticulum?

Answer 5

It’s where large numbers of minute granular particles called ribosomes are present on the endoplasmic reticulum.

Question 6

What is the smooth endoplasmic reticulum?

Answer 6

The part of the endoplasmic reticulum that has no attached ribosomes

Question 7

What are lysosomes and what are their functions?

Answer 7

They are vesicular organelles that form by breaking of from the Golgi apparatus and then dispersing through the cytoplasm. The lysosomes provide an intracellular digestive system that allows the cell to digest 1. Damaged cellular structures, 2. Food particles that have been ingested by the cell, 3. Unwanted matter such as bacteria

Question 8

How does peroxisomes differ from lysosomes?

Answer 8

They are believed to be formed by self replication rather than from the Golgi apparatus.
They contain oxidases rather than hydrolysed

Question 9

Are mitochondria self replicative?

Answer 9

Yes

Question 10

Where are secretory substances made in the cell?

Answer 10

They are formed by the endoplasmic reticulum - Golgi apparatus system and the released from the Golgi apparatus into the cytoplasm in the form of storage vesicles called secretory vesicles.

Question 11

What is the basic structure of the mitochondria?

Answer 11

It’s composed mainly of two lipid bilayer protein membranes: an outer membrane and an inner membrane. Many infoldings of the inner membrane form shelves onto which oxidative enzymes are attached. In addition, the inner cavity of the mitochondria is filled with a matrix that contains large quantities of dissolved enzymes that are necessary for extracting energy from nutrients. These enzymes operate in association with the oxidative enzymes on the shelves to cause oxidation of the nutrients thereby forming carbon dioxide and water and at the same time releasing energy.

Question 12

Are mitochondria self replicative?

Answer 12

Yes, they can form a second one, third one and so on whenever there is a need in the cell for increased amounts of ATP.

Question 13

The fibrillae proteins of the cell are usually organised into filaments or tubules - where are they made?

Answer 13

These originate as precursor protein molecules synthesised by ribosomes in the cytoplasm.

Question 14

How is the nuclear membrane composed?

Answer 14

The nuclear membrane is an actually two separate bilayer membranes - one inside the other. The outer membrane is continuous with the endoplasmic reticulum of the cell cytoplasm and the space between the two nuclear membranes is also continuous with the space inside the endoplasmic reticulum. The nuclear membrane is penetrated by several thousand nuclear pores.

Question 15

What is the nucleoli?

Answer 15

It’s an accumulation of large amounts of RNA and proteins of the types found in ribosomes. The nucleolus becomes considerably enlarged when the cell is actively synthesising proteins.
Formation of the nucleoli begins in the nucleus.

Question 16

Describe the steps of pinocytosis?

Answer 16

The molecules usually attach to specialised protein receptors on the surface of the membrane that are specific for the type of protein that is to be absorbed. The receptors are generally concentrated in small pits on the outer surface of the cell membrane called coated pits. On the inside of the cell membrane, beneath these pits is a latticework of fibrillation protein called clathrin as well as other proteins perhaps including contractile filaments of actin and myosin.

The process requires energy from within the cell in form of ATP. It also requires the presence of calcium ions in the ECF which probably reacts with contractile protein filaments beneath the coated pits.

Question 17

What is opsonisation?

Answer 17

In the case of bacteria, each bacterium is usually already attached to a specific antibody and it’s the antibody that attached to the phagocyte receptors, dragging the bacterium along with it.

Question 18

What is the function of lysosomes when pinocytic or phagocytosis vesicles appears inside a cell?

Answer 18

One or more lysosomes become attached to the vesicles and empty their acid hydrolases to the inside of the vesicle. Thus a digestive vesicle is formed inside the cell cytoplasm in which the vesicular hydrolases begin beginning to hydrolysing the proteins, carbohydrates, lipids and other substances in the vesicle.

Question 19

What is responsible for regression of tissues and autolysis of cells?

Answer 19

Lysosomes are responsible for much of this regression.

Question 20

How are damaged cells removed?

Answer 20

By lysosomes. Damage to cells by heat, trauma etc. induces lysosomes to rupture. The released hydrolases immediately begin to digest the surrounding organic substances.

Question 21

What is autolysis?

Answer 21

If cell damage is severe, the entire cell is digested - a process called autolysis.

Question 22

Which bactericidal agents does lysosomes contain (that can kill phagocytized bacteria before they can cause cellular damage?

Answer 22

1. Lysozyme which dissolves the bacterial cell membrane
2. Lysoferrin which binds iron and other substances before they can promote bacterial growth
3. Acid at pH of about 5.0 which activates the hydrolases and inactivates bacterial metabolic systems

Question 23

Where are the proteins formed?

Answer 23

By the granular endoplasmic reticulum. Protein molecules are synthesised within the structures of the ribosomes.

Question 24

Where does the synthesis is lipids occur?

Answer 24

By the smooth endoplasmic reticulum

Question 25

Besides lipid synthesis, what are the functions of the endoplasmic reticulum?

Answer 25

1. It provides the enzymes that control glycogen breakdown when glycogen is to be used for energy.
2. It provides a vast number of enzymes that are capable od detoxifying substances such as drugs that might damage the cells.

Question 26

Where are hyaluronic acid and chondroitin sulfate synthesised?

Answer 26

Golgi apparatus

Question 27

Name a few function of hyaluronic acid and chondroitin sulfate in the body?

Answer 27

1. They are the major components of proteoglycans secreted in the mucus and other glandular secretions
2. They are the major components of the ground substance outside the cells in the interstitial spaces acting as fillers between collagen fibers and cells
3. Principal components of the organic matrix in both cartilage and bones
4. Important in many cell activities including migration and proliferation.

Question 28

What is exocytosis in most cases stimulated by?

Answer 28

The entry of calcium ions into the cells

Question 29

What is exocytosis in most cases stimulated by?

Answer 29

The entry of calcium ions into the cells

Question 30

What is ATP composed of?

Answer 30

1. The nitrogenous base adenine
2. The Pentose sugar ribose
3. Three phosphate radicals

Question 31

What is glycolysis?

Answer 31

On entry into the cells, glucose is subjected to enzymes in the cytoplasm that convert it into pyruvic acid.

Question 32

Where does 95% of the ATP formation occur?

Answer 32

In the mitochondria

Question 33

What is pyruvic acid derived from carbohydrates, fatty acids from lipids and amino acids from proteins, eventually converted to in the matrix of the mitochondrion?

Answer 33

Acetyl co-A

Question 34

What 3 categories of cellular functions is the energy from ATP used for?

Answer 34

1. Transport of substances through multiple membranes in the cell
2. Synthesis of chemical compounds throughout the cell
3. Mechanical work

Question 35

What is ameboid movement?

Answer 35

It’s the movement of an entire cell in relation to its surroundings such as movement of white blood cells through the tissue.
It begins with protrusion of a pseudopodium from one end of the cell - it projects far out away from the cell body and partially secures itself in a new tissue area. Then the remainder of the cell is pulled toward the pseudopodium.

Question 36

What are the most common cells to exhibit locomotion in the body?

Answer 36

The white blood cells when they move out of the blood into the tissues to form tissue macrophages

Question 37

What is the most important initiator of ameboid locomotion?

Answer 37

Chemotaxis

This results from the appearance of certain chemical substances in the tissues. Most cells that exhibit ameboid locomotion move toward the source of a chemotactic substance

Question 38

Where does ciliary movement occur?

Answer 38

On the surface of the respiratory airways and on the inside of the uterine tubes

Question 39

Describe the structure of a cilia

Answer 39

The cilium is covered by an outcropping of the cell membrane and is supported by 11 mictrotubules: 9 double tubules located around the periphery of the cilium and 2 single tubules down the centre. Each cilium is an outgrowth of a structure that lies immediately beneath the cell membrane called the basal body of the cilium.

Question 40

What is the axoneme?

Answer 40

Cilium: The nine double tubules and the two single tubules are all linked to one another by a complex of protein cross linkages. The total complex of tubules and cross linkages is called the axoneme.