Lab Midterm Flashcards
Calculate total magnification
4 x 10 = 40
10 x 10 = 100
40 x 10 = 400
Describe how to create a wet mount
Take a glass slide
Add a drop of water to a slide and place the specimen in the water (or you may have to place the specimen first and then add the drop of water)
Place the edge of the coverslip on the slide so it touches the edge of the water
Slowly lower the coverslip to prevent the formation and trapping of air bubbles
Remove excess water from the slide using lens paper
Biological domains
LOOK AT PAGES 13 and 14 for pictures!
Archaea
Bacteria (Cocci, Bacilli, Spirilla)
Eukarya
Eukaryotic kingdoms and an example of an organism in each
LOOK AT PAGES 13-15 for pictures!
Protista - Paramecium, Amoeba, Euglena (active; single-celled; have organelles that can be observed; complex; euglena are easiest to observe; green pigments)
Fungi - Yeast and molds, Penicillium conidia (single-celled and multicelled; grow hyphae, which are long, branching filaments (thread-like) structures)
Plantae - Azolla (multicellular; photosynthetic pigments make easy to see; should not move around; can be seen with naked eye)
Animalae - Rotifers (aka wheel animals), daphnia (aka water fleas); (multi-cellular; complex structure)
Hypothesis
- Reflects a tentative answer to a question
- It restates a question with a possible explanation for the observation
Control Group
Group that is not exposed to the (independent) variable
Experimental Group
Group that is exposed to the (independent) variable
Dependent Variable vs. Independent Variable
DV: the outcome you measure (that is meant to be influenced by the IV)
IV: the characteristic you control and manipulate between groups
Differentiate the steps of the scientific method and the different approaches demonstrated in lab
Observe → Hypothesize → Test → Interpret
-Used to develop scientific knowledge
Biomolecules
Macromolecules (large molecules) found in living systems that contain five or more carbon atoms in either ting or chain formation
-We get MACROmolecules form the food we eat
4 key biomolecules essential to life?
Carbohydrates
Lipids
Proteins
Nucleic Acids
Organic Compounds
Substances that contain carbon, hydrogen, and oxygen (the 4 key biomolecules are organic compounds)
Indicators
Special chemicals that change in some way in the presence of a specific organic substance
Triglyceride
- Type of lipid
- Consist of a glycerol molecule combined with three fatty acids
Hydrophilic
- Water loving
- Polar molecules that are soluble in water
- Polar molecules tend to have slight differences in electrical charge associated with different parts of their molecular structure; this polarity is caused by unequal sharing of electrons associated with the internal bonds that hold the molecule together
Hydrophobic
- Water fearing
- Polar molecules that are not soluble in water
Recognize tests and indicators that detect the presence of carbohydrates, lipids, and proteins
- Sudan III
- The Biuret Test
- Benedict’s Reagent
- Iodine
The Biuret Test
Detects proteins and peptides
- Positive = Reactant changed from blue to violet color (pinkish-purple) because of amine groups in amino acids reacting with copper ions
- Negative = Blue color
Benedict’s Reagent
Detects reducing sugars (carbohydrates)
- Positive = Green (low concentration); Yellow, orange, or red-orange (high concentration)
- Negative = Maintains blue color
Iodine
Detects for starches (carbohydrates)
- Positive = Changes from maroon (brownish) to dark blue-black color
- Negative = Maintains brownish color
Sudan III
Detects Lipids
- Positive = orange-colored spot on the filter paper
- Negative = indicated by a spot lacking color OR one with red particles
- It’s hydrophobic
- Polar molecules won’t take up this dye
Amino Acid
- Basic unit of protein
- Bond between amino acids is called a peptide bonds
Monosaccharide
- One-sugar or singular sugar
- Basic building blocks for carbohydrates (simple sugars)
- Ex: glucose and fructose
Polysaccharide
- Sugars containing several to many monosaccharides linked together (many-sugars)
- Ex: starch
Describe the controls used in the biochemical tests
- The control for all the tests was distilled water (dH2O) because it does not contain any macromolecules
- If control gives you a positive result, test is invalid (because solutions likely to be contaminated)
Recognize the typical structures in human cells
- Structure of a typical cell is divided into three major parts:
1) Plasma membrane (cell membrane), which envelops (or encloses) the rest of the cell
2) Cytoplasm, which is comprised of a liquid medium known as cytosol containing the functional subunits called organelles
3) A membrane-bound structure that contains DNA, the nucleus - Each cell is a membrane-enclosed sac containing smaller subunits that perform cellular function
Plasma Membrane
- Structure: lipids and proteins, with some carbohydrates
- Location: Envelopes entire cell
- Primary Functions: Provides selectively-permeable barrier for cell; regulates movement of material in and out of cell
Cytoplasm
- Structure: Mixture of water, salts, and organic molecules that form a thick fluid (cytosol) and organized structures (organelles)
- Location: Interior of cell
- Primary Function: Region of cellular metabolism and other activities that maintain the cell
Cytosol
- Structure: Thick, gel-like fluid mostly made up of water; also contains salts, protein filaments (making up cytoskeleton), soluble proteins, and other organic molecules
- Location: Interior of cell; surrounds organelles
- Primary Function: Allows transport of substances within cell
Centrioles
- Structure: Composed of microtubules forming cylinders (often starburst-like in appearance)
- Location: Near nucleus in the centrosome
- Primary Function: Participates in cell division
Cilia
- Structure: Short, slender projections in certain cells
- Location: Extended outward away from cell surface
- Primary Function: Motile cilia are used to propel fluids or small particles
Flagella
- Structure: Composed of bundles of fused microtubules
- Location: Tail-like appendage that protrudes through cell membrane to the exterior of the cell
- Primary Function: Movement of cell
Ribosomes
- Structure: Very small, spherical structures composed of RNA and protein
- Location: Often attached to the ER or unattached in cytoplasm
- Primary Function: Sites of protein synthesis
Rough ER
- Structure: Large, branching, membrane bound structure that may be flatted or tubular
- Location: Extends from nuclear envelope within the cytoplasm
- Primary Function: Sites of protein synthesis