2 Cells & Organelles

Question 1

Which human cells contain flagellum

Answer 1

Spermatozoa - increase motility for fertilisation

Question 2

What are flagella and cilia composed of

Answer 2

Microtubules - this allows for whipping motion. These are composed of doublets

Question 3

Which cells do not contain a nucleus

Answer 3

• Erythrocytes ( red blood cells)

Question 4

What makes the structure of red blood cells different from others

Answer 4

• biconcave shaped
• anucleate

Question 5

What is the main function of erythrocytes

Answer 5

• carry oxygen to tissues and these live for 120 days

Question 6

Which organelle is present in cells which function to produce large amounts of protein

Answer 6

Extensive rough Endoplasmic reticulum & Golgi

Question 7

Which cells produce large amounts of proteins

Answer 7

Plasma cells produce large quantities of antibodies ( proteins)

Question 8

Which cell organelle is enriched to support cells function

Answer 8

• smooth Endoplasmic reticulum

Question 9

What is the function of Hepatocytes

Answer 9

Lipid biosynthesis

Question 10

Lipid biosynthesis is carried by which type of cells

Answer 10

Hepatocytes

Question 11

What is the function of Leydig cells

Answer 11

Steroid hormone biosynthesis

Question 12

Steroid biosynthesis is carried out by which cell type

Answer 12

Leydig cells

Question 13

What is the function of muscle cells

Answer 13

Rely on availability of calcium storage

Question 14

Which cell is involved in calcium storage

Answer 14

• Muscle cells

Question 15

Which skin condition is characterised by very fragile skin

Answer 15

Epidermolysis bullosa

Question 16

List some of the characteristics of epidermolysis bullosa

Answer 16

• skin blistering
• tear of skin apon touch
• painful

Question 17

Patient presents with blistering and painful skin, which is sensitive to touch resulting in tear. The dr has diagnosed it as a type of epidermolysis bullosa.

A defect in which anchoring junction causes this ?

Answer 17

Hemidesmosomes - intermediate filaments ( Cell ECM junctions)

Question 18

List 3 cells which contain cilia

Answer 18

• Respiratory epithelial cells
• Brain Ependymal cells
• Epithelial cells ( line Fallopian tubes)

Question 19

What is function of cilia in respiratory epithelial cells

Answer 19

Clear mucus from airways

Question 20

What is the function of cilia on brain ependymal cells

Answer 20

Circulation of cerebrospinal fluid (CSF)

Question 21

What is the function of cilia on epithelial cells which line Fallopian tubes

Answer 21

Help ovum to move uterus

Question 22

What can result from a defect in cilia

Answer 22

Kartagener syndrome - absence of dynein arms

Question 23

What can a defect of cilia have on respiratory epithelial cells

Answer 23

Ineffective mucus clearance

Question 24

What can a defect of cilia have epithelial cells lining the Fallopian tubes

Answer 24

• effect on fertility

Question 25

What helps to stabilise microtubules

Answer 25

Proteins which bind to microtubules helps to stabilise them

Question 26

Which protein in particular helps to stabilise microtubules

Answer 26

TAU protein

Question 27

Describe the correlation of TAU protein to Alzheimer’s Disease

Answer 27

Tau protein dissociates from microtubules in Alzheimer’s which causes microtubule disassembly

Question 28

A 5 month old baby has been diagnosed with Tay- sachs disease ( accumulation of substrates in excess various organs). This disease arises from the build up of gangliosides ( lipid with carbohydrate portion in the brain & spinal cord).

Which organelle might be defective in this case?

Answer 28

Lysosomal storage disorders - mutation in gene which encode for lysosomal enzymes

Lysosomal enzyme breaks down excel gangliosides

Question 29

Cancer cells change and acquire mutations to enable them to grow and spread.

Can you think of any organelles or sub cellular structures which might be defective in order for the spread of cancer cells?

Answer 29

Epithelial Cadherin ( E- cadherin)

Question 30

How does a defect in E-Cadherins result in the spread of cancer cells

Answer 30

Human cancers ( carcinomas) stem from epithelial tissue for which E- cadherin is a prototypic cadherin.

During malignancy epithelial tumours lose E- Cadherins partially or completely

Question 31

Describe GAP junctions

Answer 31

Function = metabolic & electrical coupling

Components = connexins

Cytoskeleton = N/A

Example = Cardiac tissue

Question 32

Describe tight junctions

Answer 32

Function = barrier, selectively permeable, cell polarity ( apical = top & basolateral = bottom)

Components = Claudins

Cytoskeleton = actin

Example = epidermis

Question 33

Describe Adherence junctions

Answer 33

Function = tissue integrity, contractility, motility

Components = cadherins

Cytoskeleton = actin

Example = Morphogenesisx

Question 34

Describe desmosomes

Answer 34

Function = strong adhesions, resist mechanical stress

Components = desmosomal cadherins

Cytoskeleton = intermediate filaments

Example = epidermis ( keratins)

Question 35

Describe focal adhesions

Answer 35

Function = cell anchorage, mechanical and biochemical signalling

Components = intergrins

Cytoskeleton = actin

Example = cell migration

Question 36

Describe hemidesmosomes

Answer 36

Function - cell anchorage

Components = integrins

Cytoskeleton = intermediate filaments

Example = dermal- epidermal junction