L8: Cell Organelles

Question 1

Which disease is caused by the absence of Hex-A?

Answer 1

Tay-Sachs disease

Question 2

What are the symptoms of Tay-Sachs?

Answer 2

Seizures, muscle rigidity, blindness. Death often before the age of 5

Question 3

Tay-Sachs is caused by the absence of a single lysosomal enzyme, Hex-A. What does Hex-A break down?

Answer 3

Ganglioside GM2, prevalent in nerve cells

Question 4

How does Tay-Sachs disease work?

Answer 4

Lack of Hex-A results in a build up of ganglioside GM2 in nerve cells, destroying nerve function

Question 5

What is Cytoplasm?

Answer 5

Contains cellular components outside the nucleus and within the plasma membrane.

• cytosol
• organelles

Question 6

Describe the cytoskeleton. What are the 3 main types?

Answer 6

Network of protein filaments throughout the cytoplasm.

1. Microfilaments
2. Intermediate filaments
3. Microtubules

Question 7

Where would you most likely find ACTIN and MYOSIN?

Answer 7

Microfilaments

Question 8

Where would you find the microfilaments?

Answer 8

Surrounding the edge of the cell

Question 9

What are the key functions of the microfilaments?

Answer 9

1. Generate movement
2. Structural support and shape
3. Create microvilli

Question 10

Which structure is made up of keratin, vimentin, and lamin?

Answer 10

Intermediate filaments

Question 11

What are the characteristics of the intermediate filaments?

Answer 11

1. Very strong
2. Found in parts of the cell subject to high stress
3. Stabilise the organelles

Question 12

What structure is formed of Tubulin?

Answer 12

Microtubules

Question 13

What are the physical features of microtubules?

Answer 13

1. Long
2. Unbranched
3. Hollow

Question 14

Where do the microtubules form?

Answer 14

Centrosomes

Question 15

List the functions of the microtubules.

Answer 15

1. Structural support and shape
2. Movement of organelles during division
3. Provide structure for the flagella

Question 16

What components form a centrosome?

Answer 16

2 centrioles

Question 17

Where are centrosomes located?

Answer 17

Proximal to the nucleus

Question 18

What are centrioles made up of?

Answer 18

A circle of 9 triplets of microtubules (27 altogether) at right-angles to each other. The clusters are bound together by tubulin rings

Question 19

What is the function of the centrosomes?

Answer 19

Growth of mitotic spindle during cell division

Question 20

How many centrosomes are present at division stage G0?

Answer 20

Only 1, it will replicate early in G1 stage of division and the spindles will form

Question 21

What is a common way to increase the risk of ectopic pregnancy?

Answer 21

Smoking, as it destroys the cilia that would normally pass the oocyte towards the uterus

Question 22

What are cilia primarily made from?

Answer 22

Microtubules

Question 23

What is the function of the cilia?

Answer 23

Transport fluids along the cells surface

Question 24

What is the functional difference between cilia and flagella?

Answer 24

Cilia pass fluids across the surface of a stationary cell; flagella transport the cell through a substrate.

Question 25

What are the roles of myosin, actin, and tubulin?

Answer 25

Myosin and actin: form microfilaments Tubulin: forms microtubules

Question 26

The surface of which organelle is covered in ribosomes?

Answer 26

Rough Endoplasmic Reticulum

Question 27

What is the function of the ribosomes?

Answer 27

Synthesise proteins

Question 28

What happens next to proteins after they are processed by the rough ER?

Answer 28

They are sent to the Golgi apparatus (entry or cis face) in a transport vesicle

Question 29

Where could synthesised proteins end up?

Answer 29

1. Sent to organelles in the cell 2. Incorporated into the plasma membrane 3. Excreted via exocytosis 4. Remain in the cytoplasm

Question 30

How many subunits are ribosomes made up of?

Answer 30

Two; one larger and one smaller

Question 31

How many proteins are in each ribosome?

Answer 31

Over 50 proteins, plus lots of ribosomal RNA

Question 32

Where are ribosomes formed?

Answer 32

Nucleolus

Question 33

What is the role of the Smooth ER in the liver?

Answer 33

1. Release glucose from gluc-6-p | 2. Detoxify lipid soluble drugs, such as alcohol and pesticides

Question 34

What is the role of the Smooth ER in muscles?

Answer 34

Store Ca2+ ions

Question 35

What part of the cell does eosin stain? What colour will it be dyed?

Answer 35

Proteins in the cytoplasm - red or pink

Question 36

What part of the cell does haematoxylin stain? What colour will it be dyed?

Answer 36

DNA, RNA, and other negatively charged compounds - dark blue/ violet

Question 37

What are the granular leukocytes?

Answer 37

Eosinophil, Basophil, Neutrophil

Question 38

What are the agranular leukocytes?

Answer 38

Lymphocyte, monocyte

Question 39

Which leukocyte is associated with anaphylaxis?

Answer 39

Basophils, as it releases histamines

Question 40

Which leukocyte is stored in the spleen?

Answer 40

Monocytes

Question 41

Which leukocyte represent 50-60% of all leukocytes in the body?

Answer 41

Neutrophils

Question 42

Which leukocyte is responsible mainly for for defence against parasites?

Answer 42

Basophils

Question 43

Which leukocyte causes tissue damage by releasing toxins that kill bacteria and parasites?

Answer 43

Eosinophil