Tissues 1

Question 1

What can be found in cytoplasm?

Answer 1

• Organelles
• Proteins and macromolecules
• Cytoskeleton filaments

Question 2

What is found in the nucleoplasm?

Answer 2

Heterochromatin

Question 3

What is the function of the nucleolus?

Answer 3

Ribosome synthesis.

Question 4

What size ribosomes do prokaryotes have?

Answer 4

70S (50S and 30S)

Question 5

What size ribosomes do eukaryotes have?

Answer 5

80S (60S and 40S)

Question 6

What size ribosomes do mammalian mitochondrial have?

Answer 6

55S (39S and 28S)

Question 7

What is the nuclear lamina?

Answer 7

A specialised cytoskeleton on the internal surface of the nuclear envelope.

Question 8

What is the function of the nuclear lamina?

Answer 8

Controls the assembly and disassembly of the nuclear envelope in cell division.

Question 9

Is rough ER granular or agranular?

Answer 9

Granular - smoothER is agranular

Question 10

What is the function of the rough ER?

Answer 10

Synthesis of membrane proteins and proteins which are membrane-bound.

Question 11

What is the function of the smooth ER?

Answer 11

Controls lipid metabolism and detoxification, as well as calcium storage.

Question 12

What does a high presence of mitochondria indicate?

Answer 12

Highly metabolic activity.

Question 13

What are peroxisomes?

Answer 13

Involved in lipid and oxygen metabolism. A by-product of their catalysis is peroxide.

Question 14

What is the cytoskeleton?

Answer 14

A system of filaments formed by the polymerisation of protein monomers in three main forms.

Question 15

What are the three forms of the cytoskeleton?

Answer 15

• Microfilaments
• Microtubules
• Intermediate filaments

Question 16

What are microtubules made up of?

Answer 16

Polymers of alpha and beta tubulin heterodimers.

Question 17

How thick are microtubules?

Answer 17

20nm

Question 18

What is the function of microtubules?

Answer 18

Involved in cell shape and act as tracks for the movement of organelles around the cell.

Question 19

Where are MTOCs normally found?

Answer 19

Near the nucleus of a cell

Question 20

How think are intermediate filaments?

Answer 20

10-15nm

Question 21

What is the function of intermediate filaments?

Answer 21

Mechanical strength

Question 22

Example of microtubules in biology?

Answer 22

Flagella and cilia

Question 23

Example of intermediate filaments in biology?

Answer 23

Nuclear lamina

Question 24

What are microfilaments made up of?

Answer 24

Polymers of actin

Question 25

What is the function of microfilaments?

Answer 25

Associated with cell shape and movement in muscle cells.

Question 26

How thick are microfilaments?

Answer 26

5-9nm

Question 27

What is the extracellular matrix?

Answer 27

Material deposited by cells which forms an insoluble part of the extracellular environment. Often poorly organised. Made up of fibrillar and reticular proteins.

Question 28

Why are cell-cell junctions important?

Answer 28

Allow the formation of continuous and cohesive layers, giving mechanical strength and sealing the intracellular pathways.

Question 29

What are zonulae?

Answer 29

Belts

Question 30

What are maculae?

Answer 30

Spots

Question 31

What are desmosomes?

Answer 31

Found throughout lateral membrane to provide mechanical continuity between cells. Linked to intermediate filaments.

Question 32

What are gap junctions?

Answer 32

Clusters of pores that are continuous in the adjacent cell membrane. Allows the passage of ions and small molecules between cells.

Question 33

What factors affect movement via gap junctions?

Answer 33

- pH - Calcium concentration - Voltage - Signalling molecules