Lecture 7: Cells and tissues Flashcards
Which one is an animal cell, a plant cell, and a bacteria? How do you know which kind of cell is each one?
Plant, animal, bacteria
(bacteria have fewer organelles and no nucleus)
- How you can visualize the details of organelles in cells? And why?
You see membranes, lipids, and proteins depending on what stains are used
The stains bind to each of these for different reasons
E.g. membranes it’s the double bond on one of the tails causing a kink which the stain binds to (unsaturated so = double bond)
- Can you see organelles with optical microscopes? How? Explain you answer.
Yes
Use stains
Many organelles are membrane-bound (and see above)
- What is the main component of membranes in animal cells? What else can you find in animal cell membranes?
Main component is phospholipids
Also find:
- Proteins
- Globular proteins
- Protein channels
- Glycoproteins
- Glycolipids
- Cholesterols
- Draw a representation of the molecular components of a cell membrane, indicating each component. And if you had a double membrane, how should the drawing be?
Include:
- Integral (globular) protein
- Protein channel
- Glycoprotein
- Glycolipid
- Peripheral protein
- What is the consistency/molecular mobility of the membrane in cells and what is the consequence for the proteins in it?
Fluid
Proteins move around??
- In general terms, how do cells transport ions, proteins and molecules in and outside?
Active transport (uses ATP) - against concentration gradient
Passive transport (diffusion)
- Explain the phrase: Proteins are constituted only of L-Amino acids.
Amino acids are chiral: L and D versions
Protein interaction is lock and key with specific shape, so the exact shape matters
In biology the amino acids used happen to be the L version
- What does primary, secondary and tertiary structure of a protein mean?
Primary = sequence of amino acids
Secondary = folding of the chain into alpha helix or beta pleat(ed sheet)
Tertiary = 3D shape with ionic, disulphide, H- bonds etc.
- What would you consider the primary, secondary and tertiary structure of collagen?
Primary: 3 polypeptide chains of amino acids in specific sequence
Secondary: 3 chains folded around each other (procollagen)
Tertiary: removed loose ends (tropocollagen)
- What is a alpha-helix and a beta-helix?
Secondary protein structures
alpha is spiralbeta is zigzag
- What are the three major components of the cytoskeleton of animal cells?
3 components:
Actin filament
Microtubule
Intermediate filament
- Name two major components of the extracellular matrix in animals.
Extracellular matrix for animals:
Collagen fibre
Proteoglycan complex
- What are the major components of the extracellular matrix in bone?
ECM for bone = collagen and calcium phosphate
- Name three organs and say which one is the most stiff and the softest.
Lung softest
Brain
Heart stiffest
- How many kinds of cells does bone have, name them and write their functions in bone.
Osteoblasts = form new bone (secrete the ECM = collagen and calcium phosphate) then become osteocytes
Osteoclasts = resorb old bone
Osteocytes = bone cells
Osteoprogenitor = divide and differentiate into osteoblasts
- In general terms, how do osteoclasts reabsorb bone?
Osteoclasts pump HCl onto bone to dissolve and resorb it
Because hydroxyl group on calcium phosphate, dissolve bone
- List, in general terms, what is needed to be able to culture cells.
Steps for culturing cells
- Extract cells from ECM
- Cells need a substrate to grow
- Well plate used - polyethylene coated with collagen
- Cell culture media:
- pH color indicator
- Red at pH 7.4
- Buffer to keep pH constant
- Ions
- FBS/FCS = fetal calf/bovine serum
- Filtered blood from fetal calves
- pH color indicator
- 5% CO2
- 37 degrees
- 95% humidity
