Lab Practical Flashcards
(47 cards)
Blood
Tissue consisting of 50% plasma and 50% cells
Three major groups of blood cells
Erythrocytes (red blood cells)
Leukocytes (white blood cells)
Thrombocytes (platelets)
Most common blood cell
Erythrocytes (over 90% of blood cells)
Types of leukocytes
Granulocytes
- eosinophils
- neutrophils
- basophils
Agranulocytes
- monocytes
- lymphocytes
What type of blood cell gets stained and with what type of stain?
Leukocytes get stained with Wright’s stain
Erythrocytes
Smallest blood cell (7.5 micrometers)
Appear pink in Wright’s stain
Lack organelles and contain abundance of hemoglobin
Neutrophils
Most common white blood cell
55-75% of leukocytes
9-12 micrometers with dark purple lobed nucleus
Cytoplasms stains pale pink
Body’s first defense against invading microorganisms
Eosinophils
Cytoplasmic granules stain with acidic dyes
Only 1-5% leukocytes
10-14 micrometers w/ dark purple nucleus
True lysosomes bc they contain hydrolases that selectively phagocytize foreign proteins conjugated with antibodies.
Basophils
Named after tendency of cytoplasmic granules to stain w/ basic dyes
Least frequent cell (0.5% of leukocytes)
~10 microm. w/ purple nucleus and large dark purple granules in cytoplasm
Basophil granules contain histamine and heparin
Lymphocytes
2nd most common white blood cell (20-40% leukocytes)
7-10 microm, sometimes 15
Nucleus large, dark purple w/ blue cytoplasm
Primary function to produce antibodies in immune response
Monocytes
12-15 microm
3-8% of leukocytes
Round or oval with blunt pseudopods
Monocyte nucleus stains lightly; cytoplasm dull grey-blue w/ small lilac stained granules
Transient; remain in blood for only 1-2 days to function in phagocytizinf foreign material
Thrombocytes
Small, irregularly shaped cell fragments that broke away from cells in bone marrow
1-4 microm; stain blue or purple
Function in blood clotting
Three reasons for tissue sample to be treated with chemical fixative
- To kill the cell and leave internal structures in some approximation of their natural state
- To render cell components water-insoluble; less likely to lee h out of cell during subsequent handling
- To facilitate uptake or stains into cytoplasm
Fixation is affected by:
pH, temperature, osmotic balance and duration of fixation
Wright’s stain
Mix of methylene blue, methylene azure, and eosinate of both
Red for acidic
Blue for basic
Final color of cell dependent on pH; includes hues of pink, purple, blue, and red
Periodic acid - Schiff (PAS) reaction
Reacts with aldehyde group
Produce reddish-purple color
Effective as plasma membrane stain
Counter stain
Used after PAS stain to stain nucleic acids/nucleus
Harris’ hematoxylin used to stain nuclear material dark blue
Enzymes
Agent that speeds up chemical processes in animal cells
Proteins that accelerate all reactions that occur in biological systems including breakdown, synthesis, and chemical transfers
Specific to substrates
- denoted by name of substrate acted upon
- end in suffix -ase
- ex. Protein splitting enzyme: protease; hydrolyzing lipids: lipase
Substrate
Compound that’s acted upon by enzyme
Enzyme-specific (enzymes can only catalyze single chem. reaction)
Factors that influence rates of enzyme catalyze reactions
Temp
pH
Substrate concentration
Temperature in relation to enzymes
Denature and inactivate at 50-70°C
Increased temp can also speed up chem rxn
Temp optimum: max rxn rate; usually in the range found in cells (20-40°C)
pH in relation to enzyme rxn
Denatures and inactivation with excess acidity or basicity
Most enzymes operate at neutral pH
Enzyme used in lab was acid phosphatase and has pH optimum of 4.5
Substrate concentration
Low substrate = enzyme not fully saturated, not working as fast as it could be
At saturation, no more binding sites available, enzyme works at full capacity and max velocity of rxn seen
3 parts of wheat kernels
- Embryo or germ that produces new plant
- Starchy endosperm which serves as food source for the embryo
- Covering layers which protect the grain
