Block 1 - Cytology Flashcards Preview

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Flashcards in Block 1 - Cytology Deck (54):
1

What are the layers of the nuclear envelope?

Outer nuclear membrane
Perinuclear space
Inner nuclear membrane
Nuclear lamina

2

What is the perinuclear space continuous with?

The lumen of the RER

3

Are there ribosomes on the outer nuclear membrane?

Yes, this closely resembles the RER membrane and is continuous with it.

4

Is the inner nuclear membrane continuous with the ER?

No, it is distinct.

5

What is able to bind to the inner nuclear membrane?

Chromatin and lamins

6

What supports the inner nuclear membrane?

Rigid network of intermediate filaments.

7

What is the nuclear lamina?

Thin, dense protein layer continuous with the inner nuclear membrane.

8

What is the skeleton of the the nucleus made out of?

Lamins (intermediate filament). Cross-linked into an orthogonal lattice (lettuce)

9

Where is ribosomal RNA processed?

Nucleolus

10

In the nucleolus, what contains DNA loops with rRNA genes?

Fibrillar Centers

11

What is the dense fibrillar component?

In the nucleolus, it contains ribosomal genes that are being translated as well as large amounts of rRNA

12

What is the granular component?

It is the site for ribosomal assembly and is made of densely packed clusters of pre-ribosomal particles.

13

What are three major types of filaments in the cytoskeleton?

Actin, microtubles, and intermediate filaments

14

What are actin's three most important roles in the cytoskeleton?

Cell movement, shape, and organelle transport.

15

What is G-actin?

Soluble globular protein that can be polymerized into F-actin.

16

What is F-actin?

Thin filaments, a double stranded helix made out of polymerized head-to-tail g-actin.

17

What are two thin filaments?

Actin and myosin

18

What is the cortex of a cell?

cross-lined actin filaments in a thin sheath beneath cytoplasm

19

What three things to cross-lined actin filaments (cortex) do?

Resist cell deformation
Transmit forces
Restrict organelle movements

20

How does actin interact with myosin (motor)?

Generates force and movement

21

Which are the only cells that do not contain microtubules in their cytoskeleton?

Erythrocytes (RBC)

22

What are the three vital functions of microtubules?

Organelle and vesicle movement
Mitotic Spindle/chromosome movement
Beating of cilia and flagella

23

What is the structure of microtubules?

Two polymerized globular proteins, alpha-tubulin and beta-tubulin

24

Describe the two ends of a microtubule

Plus end, grows faster, toward periphery
Minus end, grows slower, towards nucleus

25

Which way do dyneins move?

Towards the minus end, in towards nucleus

26

Which way to kinesins move?

Toward the plus end, out towards periphery

27

What are 4 high order stuctures of microtubules?

Cilia, flagella, centrioles, and microtubule-organizing centers

28

What is in the core of cilia and flagella?

Axoneme

29

Describe the composition and function of an axoneme

9 doublet pairs of microtubules on outside
1 central pair
Dynein arms attach tubules of one pair to the next, causing a walking motion

30

What is at the base of cilia/flagella?

A centriole (aka basal body) consisting of 9 doublets, no central pair

31

What two cell types do not contain a microtubule-organizing center (MTOC)?

Erythrocytes and neurons

32

Where do virtually all cellular microtubules come from?

Microtubule-organizing center

33

What type of filament is between thickness of actin filaments and microtubules?

Intermediate filaments

34

What are the 6 classes of intermediate filaments and where are they found?

Lamins - Inside nuclear envelope (..)
Keratins - epithelial tissue
Vimentin - connective tissue
Desmin - muscle cells
Glial fibrillary acidic protein (glial cells) - support cells of nervous system
Neurofilaments - neurons

35

What are the 4 main purposes of cytoplasmic intermediate filaments?

Spread tensile forces
Maintain cell structure
Act as a cocoon when cell is damaged
Anchor ion channel proteins

36

What is the standard color of most tissue?

Colorless

37

What is hematoxylin?

A basic dye that stains acid structures blue

38

What is eosin?

An acid dye that stains basic structures pink

39

What are the similarities and differences of integral and transmembrane proteins?

All transmembrane proteins are integral membrane proteins, but not all integral proteins are transmembrane proteins.

Both have hydrophobic parts that anchor in the center of the plasma membrane, but transmembrane go all the way through.

40

Where do peripheral proteins attach?

To integral proteins or hydrophillic heads of membrane lipids

41

What are three classes of functional membrane proteins?

Transport, receptor, and structural

42

What is glycocalyx?

The fuzzy coating on external surface of many cells due to large amounts of carbohydrates attached to proteins and lipids on cell surface

43

What are particles and inclusions used for? What are two main types?

Synthesis and storage
Ribosomes and gylcoproteins

44

What are 3 ways ribosomes exist in cells?

In mirtochondria, in RER, or free

45

Where do proteins synthesized in the RER go?

Golgi, lysosome, secretory granules, and plasma membrane

46

Most proteins are synthesized on what type of ribosome?

Free ribosomes

47

What is a polysome?

During ribosome synthesis, string of ribosomes attached to mRNA

48

What are the 4 main functions of the SER?

Lipid and steroid synthesis
Detoxification
Glycologen Metabolism
Ca++ storage (only in sarcoplasmic reticulum of muscle cells)

49

What are 2 main functions of the golgi?

Modifications of proteins
Sorting and packing

50

What is the principal signal that directs proteins from trans golgi to the lysosome?

Mannose-6-phosphate

51

What disease is caused when mannose-6-phosphate is mutated? What happens to the proteins?

I-Cell. Proteins intended for lysosomes are secreted into the intercellular space

52

What do peroxisomes contain? What is their purpose?

Oxidative enzymes (catalase)
Oxidize/break down long chain fatty acids

53

What is Zellweger syndrome?

Mutations in proteins used for transporting enzymes to peroxisomes.
Affects brain development through improper formation of mylein sheath.
No cure. Patients die before 6 months of age.

54

What is adrenoleukodystrophy?

Disruption in fatty acid oxidation caused build up of fatty acids in brain and eventual death. X-linked