Chapter 2 - Basic components of living

Question 1

What does cell theory state ?

Answer 1

• Both plants and animal tissues are made up of cells
• Cells arise from division of pre-existing cells
• Cells are the basic unit of life

Question 2

Why is staining used ?

Answer 2

1 - Increases contrast
2 - Makes ultrastructure more visible
3 - Allows for differentiation

Question 3

What are the two types of staining ?

Answer 3

Acid-Fast technique
Gram staining

Question 4

What are the steps of gram staining ?

Answer 4

1 - Add Crystal Violet dye
2 - Grams iodine is used to fix the dye
3 - Alcohol is then added to decolourise and get rid of excess dye
4 - Safranin is applied

Question 5

How can you identify gram positive and gram negative bacteria ?
Why is this the case ?

Answer 5

Gram Positive - absorbs crystal violet dye, due to the thick peptidoglycan layer, hence turns purple

Gram Negative - absorbs Safranin and not Crystal violet dye, due to the thin peptidoglycan layer and thick phospholipid bilayer. Hence turns pink

Question 6

What are the steps of Acid fast technique ?

Answer 6

1 - Lipid solvent carries carbolfuschin dye
2 - Heat is then applied to fix dye
3 - Alcohol is then applied
4 - Methylene blue is then added as a counterstain

Question 7

How can you identify mycobacterium from other bacteria using acid fast ?

Answer 7

Mycobacterium, stains red

Regular bacteria, stains blue

Question 8

What are the differences between a light and electron microscope ?

Answer 8

Light
- 2000x magnification
- 200nm resolution
Electron
- 500,000x magnification
- 0.5 - 3-10 nm resolution

Question 9

Definition of magnification and resolution ?

Answer 9

Magnification - How many times larger an image is than the actual size of the object

Resolution - Ability to see individual objects as separate entities

Question 10

How does a Laser Conofocal Microscope work ?
What are its features ?

Answer 10

Works by using a single spot of focused light across a specimen causing flouresence
- uses flourescent dyes that can target specific proteins
- non invasive

Question 11

What is the role of cytoplasm within the cell ?

Answer 11

To compartmentalise ultrastructures, and provide specific environments in correlation with their function

Question 12

What are the functions of the nucleus within Eukaryotes ?

Answer 12

• Contains coded for genetic information in the form of DNA
• Directs protein synthesis
• Contained within nucleur envelope

Question 13

What is the function of the nucleoulus ?
What is it made up of ?

Answer 13

Made up of proteins and produces ribosomes

Question 14

What is the structure and functions of the mitochondria ?

Answer 14

• Site of final stages of cellular respiration
• Double membrane
• Folds of cristae with matrix fluid
• Enzymes within the cristae used in respiration
• Contain DNA and can produce their own enzymes

Question 15

What are vesicles ?

Answer 15

• Membranous sacs that are used to store and transport molecules

Question 16

What are lysosomes ?

Answer 16

• Special forms of vesicles that contain hydrolytic enzymes
• Responsible for breaking down waste
• Play an important role in apoptosis

Question 17

What is the cytoskeleton comprised of ?

Answer 17

1. Microfilaments
2. Microtubules
3. Intermediate fibres

Question 18

What are the features of Microfilaments ?

Answer 18

• Formed of actin
• Responsible for cell movement/cell contraction

Question 19

What are the features of Microtubules ?

Answer 19

• Globular tubulin proteins
• Form tubes that determine the shape of a cell
• Act as tracks to direct cell movement of organelles

Question 20

What are the features of intermediate fibres ?

Answer 20

• Provide mechanical strength to cells

Question 21

What are centrioles ?

Answer 21

• Component of cytoskeleton
• Composed of microtubules
• Two associated centrioles form the coentrosome
• Involved in the assembly and organisation of the spibdle fibres

Question 22

What are the features of flagella and functions ?

Answer 22

The flagella are extensions that protrude from some cell types.
- Longer than cillia
- Used for cell motility

Question 23

What are the features of Cillia and how does it work ?

Answer 23

Used to move mucus and clean air passages

Contain a 9+2 arrangement as pairs of parallel microtubules slide over eachother causing cilia to move in a beating motion

Question 24

What is the function of the SER ?

Answer 24

• Responsible for lipid and carbohydrate synthesis and storage

Question 25

What is the function of the RER ?

Answer 25

• Contains ribosomes bound to its surface and is responsible for the synthesis and trasport of proteins

Question 26

What are the functions of ribosomes ?
What is it made out of ?

Answer 26

• Constructed of RNA
• Site of protein synthesis

Question 27

What is the function of Golgi apparatus ?

Answer 27

• Formed of Cisternae
• Modifies and packages proteins into vesicles

Question 28

How does simple protein production occur ?

Answer 28

1. Proteins are synthesised on RER
2. They then pass into cisternae and are packaged into vesicles
3. These vesicles move towards the Golgi apparatus
4. Vesicles fuse with cis-face of Golgi apparatus and leave out the trans-face of the Golgi apparatus
5. Secretory Vesicles then carry the proteins from Golgi to plasma membrane where they are released via exocytosis