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Flashcards in Histology Deck (76)
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1

The plasmalemma is known by which other name

Cell membrane

2

Many proteins are anchored into the cell membrane, what functions may they have?

Receptors
Enzymes
Channels
Transporters

3

What are the three types of filaments that make up the cytoskeleton of a cell?

Microfilaments
Intermediate filaments
Microtubles

4

What are the smallest type of filaments that made up the cytoskeleton?

Microfilaments (7 nm diameter)

5

Microfilaments are composed of what?

Actin

6

There are more than 50 classes of intermediate filaments, what can each class give an indication of?

origin of the cell in the body
(can help when locating tumours)

7

What are microtubules composed of?

Alpha and Beta tubular subunits

8

Which two proteins can use microtubules as a transport network and which direction does each travel?

Kinesin- An ATPase transport compounds towards the cell periphery
Dynein- An ATPase that transports compounds towards the cell centre

9

The nucleus is surrounded by an ______ and ______ membrane

inner and outer

10

The outer membrane of the nucleus shares a common border with what?

The rough endoplasmic reticulum

11

What is between the inner and outer membranes?

Perinuclear cisterna

12

There are three types of RNA- which two are transcribed in the nucleus and which is transcribed in the nucleolus

nucleus- mRNA, tRNA
nucleolus- rRNA

13

The nucleus contains two states of DNA, what are these states?

1. Heterochromatin- DNA condensed and not undergoing transcription
2. Euchromatin- DNA untwisted and undergoing transcription

14

Where are the ribosomes formed?

Nucleolus

15

What two subunits make up a ribosome?

1. Small subunit- binds to mRNA
2. Large subunit- catalyses formation of peptide bonds

16

What are the two types of endoplasmic reticulum?

1. Rough
2. Smooth

17

What are polysomes?

Cluster of free ribosomes in the cytoplasms surrounding mRNA which is being transcribed

18

What is the role of the smooth endoplasmic reticulum?

Processing proteins after passage through the rough endoplasmic reticulum and also for the synthesis of lipids

19

What is the role of the rough endoplasmic reticulum?

The synthesis of membrane bound proteins or secretions.
Also the site of glycoprotein formation

20

What is the role of the Golgi apparatus?

The packaging and processing of proteins for export to their destinations

21

The Golgi apparatus is made up of flattened sacs resembling plates, what is each sac called?

A cisterna

22

How do proteins arrive at the Golgi apparatus?

In transport vesicles from the rough endoplasmic reticulum

23

What is the inner membrane of the mitochondria called?

The Cristae
This is folded to increase surface area

24

DNA can be found in which locations within a cell?

1. Nucleus
2. Mitochondria - they have their own DNA

25

Which type of muscle will have many mitochondria and which type will have few?

1. many mitochondria- slow twitch muscle- generally aerobic
2. few mitochondria- fast twitch muscle- generally anerobic

26

What are intercellular junctions?

Structures specialised to join cells into groups to from a functional unit

27

Where are intercellular junctions most prominent?

Epithelial cells

28

What are the three types of intercellular junctions?

1. Occluding
2. Anchoring
3. Communicating

29

Occluding junctions can have which other name?

Tight junctions
(or zonula occludens)

30

What do occluding junctions function to do?

Link cells together to form a diffusion barrier