MA1 Intro

Question 1

organelles

Answer 1

smaller domains within the cell

Question 2

common functions of cells

Answer 2

Cells must be able to:
Maintain a complete copy of the genetic code
Synthesize and sort components for use in and outside the cell
Degrade and renew constituents
Elaborate and maintain shape and movement
Recognize other cells
Establish and maintain connections with environment (other cells)
Renew separate cell populations and the whole organism

Question 3

tissue

Answer 3

an aggregation of related cells with their specific extracellular matrix

Question 4

4 body tissues and their functions

Answer 4

Epithelium (form a barrier lining free surfaces in the body)
Connective tissue (important for support, loose or dense, i.e. bone, cartilage; scattered cells)
Contractile tissue (skeletal, cardiac, smooth muscle; proteins actin and myosin arranged for movement and generating force)
Nervous tissue (densely packed cells with specializations for electrical communication)

Question 5

Organelles

Answer 5

permanent parts of the cell that are essential for survival; distinguished from inclusions, transient and non-essential cellular components

Question 6

membranes

Answer 6

establish compartments and domains, create a barrier that restricts movement in/out of cell, anchor proteins

Question 7

plasma membrane

Answer 7

separates the cytosol (organized by cytoskeletal elements) from the extracellular space

Question 8

intracisternal space

Answer 8

space within organelles that is separated from the cytoplasm by membranes

Question 9

Integral membrane proteins

Answer 9

Require detergent solubilization techniques to separate the proteins from the membrane; many contain one or more sequences of hydrophobic amino canids that insert through the lipid bilayer; transmembrane ion channel proteins of proteins linked to lipids are an example

Question 10

Peripheral membrane proteins

Answer 10

Are more loosely associated with the bilayer and can be isolated with mild biochemical treatment

Question 11

Membrane proteins

Answer 11

2 kinds - integral and peripheral; they can diffuse laterally within the plane of the membrane, however many are anchored to the cytoskeleton and/or ECM to establish functional domains in the membrane

Question 12

glycoconjugates

Answer 12

sugars associated with protein in the membrane, involved in cell-cell interactions and are almost exclusively on the non-cytosolic side of the membrane and help maintain a net negative charge, maintaining water at the cell surface to facilitate fluid uptake

Question 13

polarity

Answer 13

asymmetrical internal organization of some cells, showing that organelles are not randomly distributed

Question 14

apical surface

Answer 14

where cells line a free surface, i.e. epithelial, the apical surface is towards the free surface, opposite the basolateral side

Question 15

Fixation

Answer 15

Usually the first step in preparing a histology specimen; fixatives preserve tissue structure by cross-linking proteins to prevent degradation (best if you do this right after death). The specimen is submerged in a fixative (formaldehyde is the most common) for several hours. Glutaraldehyde or other stronger fixatives are necessary to preserve ultrastructure (fine intracellular details) for EM

Question 16

Sectioning

Answer 16

The second histologic preparation step, fixed specimens need to be thinly sectioned into sheets (<50 microns for light microscopy, 60 nanometers for EM)

Question 17

Staining

Answer 17

The last step in histologic preparation, thinly cut tissue is almost invisible without being stained. Specialized stains are applied to the tissue section, H&E is the most common.
The coverslip placed over the tissue sample on the slide protects the stained section and facilitates microscopic viewing by reducing the refractive index

Question 18

H&E Stain

Answer 18

Hematoxylin is a basic dye that turns acidic (basophilic) things blue (i.e. DNA, RNA, nucleus, RER)
Eosin is an acidic dye that turns basic (acidophilic) things pink (i.e. cytoplasm, mitochondria, connective tissue fibers)

Question 19

Trichrome Stain

Answer 19

Highlight connective tissue, which stains greenish-blue

Question 20

Periodic Acid-Schiff Stain (PAS)

Answer 20

Identifies glycogen and other carbohydrates, especially in the basement membrane

Question 21

Wright’s Stain

Answer 21

Used in blood

Question 22

Cresyl Violet

Answer 22

Commonly applied to neural tissue; for EM, lipids stain black

Question 23

Transmission Electron Microscopy

Answer 23

Shows finer detail within the cell than light microscopy, but only in black and white. The sample is placed on a copper grid and electron beam is focused on the specimen. Cell membranes are highlighted and appear as thin dark lines.

Question 24

Scanning Electron Microscopy

Answer 24

SEM is used to show the 3-D external surface structure of a cell