Biology 1 Lab Exam

Steps to scientific method

observations, question, hypothesis, prediction, test, conclusion

Hypothesis

1. Must be able to be tested

2. Will help generate a prediction

Null hypothesis

A statement that if shown to be true, proves that a hypothesis is false; “no difference“ “no results“

Independent variable

Is the variable that a researcher selects and that is manipulated by the researcher to test a hypothesis. Ex: Plant has more soil than the other plant.”If”

Dependent variable

What is observed or measured in the experiment. Ex: Plant growth “Then“

pH solution formula

pH=-log[H^+]/ pH scales from 0-14/ 1 is acidic, 7 is neutral, 14 base

voltmeter

measures the voltage differences between two electrodes in an electrical circuit/ one electrode is called the sensing electrode - measures changed in hydrogen ion concentration. reference electrode - completes the circuit. combination electrode utilzes both

Buffers

A chemical system that resists change in pH by neutralizing small additions of acids or bases. Maintain stable concentrations of hydrogen ions and hydroxide ions

Reagant

“indicator“ which will change color upon reacting with a specific molecule (carbohydrates, lipids, proteins, nucleic acids)

negative control

ex: distilled water, it contains no organic molecules

positive control

provides an example of the color change of a regeant corresponding to the chemical that you expect it to react with under the conditions for that test.

Benedict’s Test

Tests for reducing sugars (monosaccharides, single sugars) and (disaccharides, double sugars)/ Blue=Negative, Green=Trace, Red=Alot, Yellow=Low Concentration, Orange=Little/ Monosaccharide = Glucose:Fructose/ Disaccharide = Maltose

Iodine Test for Starch

Lugol’s solution - contains iodine in an aqueous solution of potassium iodide/ starch is a polymer of Glucose/ Starch - combo of two polysaccharides, amylose and amylopectin/ Black:Blue = (positive) has starch/ Brown:rusty = no starch/ Yellow = no starch

Lipids (fats and oils)

Utilizes a red dye called Sudan IV (nonpolar)/ fats produces a greasy spot on brown paper/ Sudan will appear on fats as a floating red layer away form polar molecules/

Ninhydrin Test

Tests for amino acids (free floating)/ Purple:Violet = positive/ Yellow = Proline/ Brown = has both amino acids and proline/ Transparent = none/ positive control - Luecine

Biuret Test

Tests for Proteins (peptide bonds)/ Purple:Lavendar = Positive/ Blue = Negative

Total Magnification

Ocular magnification x objective magnification

plasma membrane

all bacterial cells have a plasma membrane; outermost boundry of the cytoplasm and controls the transport of items coming in and out of the cell

cytoplasm

made up of the cytosol and a few organelles

cytosol

liquid part of the cell consisting mostly of water and dissolved proteins

chromatin

generally consists of one circular, double stranded DNA molecule; its function is to control the cells metabolic functions and maintain the genetic material for reproduction

Plasmids

Often protect the bacteria in adverse environments by having genes that provide antibiotic resistance or giving them the capacity to metabolize new forms of nutrients.

Peptidoglycan

Only found in bacteria cells/ Two types and can be distinguished with a staining technique called the Gram Stain; Gram positive - Thick peptidoglycan outer cell wall stain purple. Gram negative - thin peptidoglycan cell wall sandwiched between two layers of plasma membrane stain red.

Plant cell walls

provides support when too much water is to prevent over absorption of water/ made of cellulose

Plasmodesmata

Between two plant cells walls, cytoplasmic strands (channels) that transfer material from one plant cell to another.

middle lamella

Between the cell walls of adjacent cells, sticky substance that cements cell walls together.

plasma membrane (plants)

selectively permeable membrane that controls the transport of substances into the living cell part of the plant cell (protoplast)

Anthocyanins

Within the cytosol combination of sugars, salts, plant pigements (anthocyanins)

Plastids

variety of storage vesicles, Ex: chloroplasts store the green pigment chlorophyll

Chromoplasts

Another plastid (storage vesicle) store red to orange pigments called Carotenoids.

Leucoplasts

another plastid (storage vesicle) are clear and store lipids and other clear substances

amyloplasts

are a specific time of leucoplasts that store starch

Erythrocytes

are red blood cells (RBC) and the most numerous in the blood smear; can be detected since they do not have a nucleus in “mammals.“ Function is to carry oxygen to all the tissues of the body and carbon dioxide out to the lungs.

Neutrophils

A white blood cell type (1 of the 5) most numerous, identified by their multi-lobed nucleus and their lavender to pink cytoplasmic granules. Function is to remove foreign organisms by phagocytosis.

Lymphocytes

second most abundant white blood cell (1 out of 5) have a single dark nucleus and lack cytoplasmic granules. fucntion is to control cell-mediated immunity.

Platlets

Not cells, small sacs in the blood that store clotting factors. Coagulate blood.

skeletal muscle cells

appear as multinuicleated cells in long fibers with striations

cardiac muscle cells

are branched cells, with striations and 1-2 nuclei per cell. also have intercalated discs which connect and synchonize cells

smooth muscle cells

spindle shaped, non-striated only have 1 nucleus per cell.

Nuerons

nervous tissue, large cell type with dendrites (extensions), function is to receive incoming nervous impulses

cynobacteria

type of prokaryote, found in hot springs, fresh and salt water. able to use photosynthesis.

Thylakoids

Photosynthesis happens in the Thylakoid of cynobacteria. The principal photosynthetic pigment in bacterial thylakoids is the green pigment (chlorophyll a).

Nostoc

is a filamentous (cells linked in a string) found in water or moist soil, covered by a gelatinous protective matrix.

heterocysts

large clear cells, found with Nostoc cells, function is to absorb atmospheric nitrogen and convert it to nitrate.

nitrogen fixation

absorb atmospheric nitrogen and convert it into nitrate