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Flashcards in 1. Epithelial cells Deck (53)
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1

Where are ribosomes found and what do they do there?

Free in cytoplasm: synthesise cytoplasmic proteins
OR
Attached to outer membrane of nuclear envelope and ER: make membrane proteins and proteins to be packaged in membranous organelles.

2

What is the function of nuclear pores?

control import and export of macromolecules into and out of nucleus

3

What is the relationship between nuclear envelope and endoplasmic reticulum?

There is physical continuity between nuclear envelope and ER

4

Describe the rough endoplasmic reticulum

Stacks of flattened membrane leaflets (cisternae), studded on outer face with ribosomes

5

What is the RER the site of?

protein synthesis and packaging in membrane-bound structures, e.g. secretory vesicles, lysosomes

6

What is the function of the smooth endoplasmic reticulum?

Detoxification
Lipid metabolism
Enzymes involved are typically associated with the membranes.
Site of Ca2+ storage in cells (important in cell-signalling)

7

What is the Golgi apparatus and what does it do?

System of stacked, membrane bound, flattened sacs
Modifies, sorts and packages macromolecules for secretion/ delivery to other organelles

8

How is are the faces of the Golgi apparatus aligned?

Cis: to ER
Trans: to cell periphery

9

What are peroxisomes?

Single membrane bound organelles
Contain enzymes involved in lipid and oxygen metabolism, e.g. oxidases, catalases, peroxidases

10

What is the cytoskeleton?

A system of filaments formed by the polymerisation of protein monomers

11

What 3 types of filament constitute the cytoskeleton?

Microtubules
Intermediate Filaments
Microfilaments

12

What are microtubules made of and what is the diameter of a microtubule?

Polymers of alpha and beta tubulin heterodimers
20nm thick

13

What are microtubules used for?

Movement of organelles through the cell
Involve motor proteins
Involved in spindle fibre formation

14

What are microtubules major components of?

Cilia and flagellae
Form 9 + 2 arrangement in the core
(9 doublets + 2 central singlets)

15

Describe the organisation of microtubules in cells.

Originate from a point within the cell called the microtubule organising centre (MTOC)

16

Describe structure of intermediate filaments

Group of polymers of filamentous proteins
Form rope-like filaments
10-15nm diameter

17

Which component of the cytoskeleton distinguishes different cell types?

Intermediate Filaments are different for different cell types

18

What is the function of intermediate filaments?

Give mechanical strength to cells

19

What are desmosome cell-cell adhesions connected by?

Intermediate Filaments

20

Where else are intermediate filaments found other than in the cytoplasm?

Nuclear lamins are IF's found on the internal surface of the nuclear envelope
Provide support

21

What are microfilaments made of and what is their diameter?

Polymers of Actin (filamentous actin, F-actin)
5-9nm diameter

22

What do microfilaments associate with?

Adhesion belts in epithelia and endothelia

23

What are microfilaments involved in?

cell shape and movement
major component of contractile apparatus of muscle and involved in contraction of non muscle cells

24

What is the monomer of microfilaments?

G-actin (globular actin)

25

How is the cytoskeleton dynamic?

Various elements are subject to rapid re-modelling, stimulated by biochemical and bio-mechanical signals.

26

What are the 5 major groups of cell type?

Connective tissue
Contractile tissue
Haematopoietic
Neural
Epithelial

27

Give 3 examples of connective tissue cells

Fibroblasts
Chrondocytes
Osteocytes

28

Give 3 examples of contractile tissue cells

Skeletal muscle
Cardiac muscle
Smooth muscle

29

Give 3 examples of haematopoietic cells

Blood cells
Tissue-resident immune cells
Cells of the bone marrow from which they're derived

30

Give 2 examples of neural cells

Neurones
Glial cells