Bio Lab Flashcards
All science is ….
provisional
arranged or existing for the present, possibly to be changed later.
Null hypothesis
Just by chance
Theory stands the test of time it becomes
a law
Analysis
Reject or accept the hypothesis
Negative control group
Do not receive the manipulation of the experimental variable
Positive control group
Do not receive the manipulation either, but they do receive a different kind of manipulation one whose effects are known.
Confounding variables
Any variables that make the experimental and control groups dissimilar
Blind experiment
When patients do not know whether they are in the experimental or control group
Double blind experiment
When the person who administers the treatment doesn’t know which one contains actual medicine and which are placebo’s. It is a standard procedure for testing the efficacy of new drugs.
A graph which is used when the experiment of variable is a continuous range of numbers with no discreet lumping of the numbers into categories.
Line graph
A graph that is used when the experimental variable is composed of categories rather than a continuous range of number numbers.
Bar graph
The range of the pH scale
0 - 14
Equation of water dissociating
H20 ⇌ H+ +OH-
What is dissociating
when a molecule breaks apart into smaller components, like atoms or ions, usually happening when a substance dissolves in water; essentially, it’s the process of a compound splitting into its individual parts
What does it mean for an acid to be strong?
pH between 0 and 2
More Hydrogen Ions
What does it mean for an acid to be weak?
pH between 3 and 6.
Fewer Hydrogen Ions: Partially ionizes, resulting in a lower concentration of H+
What does it mean for a base to be strong?
Higher pH between 12 and 14
More OH- ions
Complete ionization, produces high concentration of hydroxide ions in water it is a
Strong Base
Strong Dissociation example
NaOH –> Na+ +OH-
What does it mean for a base to be weak?
pH around 8 to 11
Produces fewer OH−OH− ions compared to a strong base at the same concentration.
How does a buffer work?
any substance that picks up or releases hydrogen ions
Buffers rely on substances that can accept or donate hydrogen ions (H+) to maintain a stable pH.
A neutral substance of 50% H+ and 50% OH-
Water
Weak acids
dissociate slightly, most molecules stay together
Strong acids
have more dissociation of hydrogen ions
All acids, bases, salts are
ionic
When a strong acid reacts with a strong base, they
neutralize each other to form a salt and water:
Strong Acid+Strong Base→Salt+Water
If blood becomes too basic (alkaline), the body will
work to lower the pH back to normal (around 7.4) by releasing hydrogen ions (H+H+) to restore the balance.
if blood becomes too acidic (a condition called acidosis) the body will
works to raise the pH by removing excess hydrogen ions (H⁺) to restore the balance.
Blood contains chemical systems that resist changes in pH. Called
Buffers
How is pure water always neutral?
It is 50-50 hydrogen and hydroxide not favoring acidity or basicity
How does a solution become acidic
When there is an increase in H+
Explain how a solution can become basic
When there is an increase in hydroxide ions
The body always strives to maintain pH around-/——- to keep biological processes stable.
7.35–7.45
Reagent for lipids is
Sudan III
Sudan III tests for
Presence of lipids.
It is a fat-soluble dye that stains fat cells.
If fat cells are present the paper will turn dark orange
If Fat are present, the Sudan III will turn
Dark Orange. Orange colored spots
The color red in Sundan III indicates that
triglycerides or fats are not present
Benedicts solution tests for
the presence of reducing sugars such as monosaccharides, and dissaccahires
Why will polysacchirides not react to Benedict’s solution?
because they are not reducing sugars.
They have few free aldehyde or ketone groups to react with the reagent
“Benedict’s test detects reducing sugars, which have free aldehyde or ketone groups that can donate electrons to the reagent, causing a color change. Polysaccharides have few free groups available, so they do not react.”
Reducing sugars such as monosachharides or disacchirides will have a ______ that can be oxidized. Therefor, Benedict’s solution is used.
aldehyde group (-CHO)
If no reducing sugars are present Benedict’s solution stays
Blue
In the presence of reducing sugars, the Benedicts solution turns
Red-orange, orange, yellow, or green.
From Blue.
Lugol’s iodine test for
the presence of starch in carbohydrates
If starch is present, Lugol’s solution will turn from
yellow-orange to deep blue-black
The test for the presence of proteins and short peptides is
Biuret
In the presence of proteins the Biuret will turn from
blue to violet
A blue biuret indicates
negative results. No presence of proteins
Smallest molecule for each macromolecule:
Fats:
Carbohydrates:
Proteins:
Nucleic Acid:
Fats: fatty acids
Carbohydrates: monosacchires
Proteins: amino acids
Nucleic Acid: nucleotide
Proteins are considered polar molecules because they contain both polar and nonpolar regions within their structure, with the polar regions generally facing outward and the nonpolar regions usually tucked inside the protein’s core when folded in an aqueous environment; this is due to the different polarities of the amino acid side chains that make up the protein.
Proteins are considered polar molecules because they contain both polar and nonpolar regions within their structure, with the polar regions generally facing outward and the nonpolar regions usually tucked inside the protein’s core when folded in an aqueous environment; this is due to the different polarities of the amino acid side chains that make up the protein.
Are call carbohydrates polar?
Yes
Are all lipids are non-polar?
Yes. All lipids are non-polar
A molecule that has a nitrogenous base, a pentose sugar, and a phosphate would be?
A nucleotide
-Base Unit for DNA and RNA
Protein identifying features
Amino (NH3),Carboxyl (C=00), R Group, Hydrogen (H)
Carbohydrate identifying features:
Carbon, Oxygen, Hydrogen. Straight or Ringed.
Lipid features:
Hydrocarbon chain, Carboxyl group, Alcohol
How does Lugol’s iodine test for polysaccharides but not monosacahrides?
iodine binds to the helical structure of polysaccharides, not individual sugar molecules.
An easy test answer:
“Lugol’s iodine binds to the coiled structure of polysaccharides like starch, causing a color change. Monosaccharides lack this structure, so no reaction occurs.”
Why will polysaccharides not react wirh Sundan III?
Sudan III is specifically designed to detect lipids, which are nonpolar.
polysaccharides are polar carbohydrates.
Why is water often use as a control in scientific experiments
It provides a neutral baseline with minimal potential for interfering reactions, allowing for accurate comparison.
What happens to the field of view when switching from the scanning lens (4x) to the low-power lens(10x)?
A: The field of view shrinks (gets smaller).
Keep both eyes open when using an ocular lens microscope (10x)?
It reduces eye strain and helps with depth perception.
What is the magnification of the red scanning lens?
A: 4x
What is the function of the rheostat on a microscope?
It controls the light intensity.
Why should the coarse adjustment knob never be used with low, high, or oil immersion lenses?
It can damage the slide or objective lens due to large, sudden movements.
How do you calculate total magnification?
A: Multiply the ocular lens (usually 10x) by the objective lens
What is the total magnification for the scanning lens (4x)?
A: 40x (4x * 10x)
What is the total magnification for the low-power lens (10x)?
A: 100x (10x * 10x)
What is the total magnification for the high-power lens (40x)?
A: 400x (40x * 10x)
What do all cells have in common?
A: Plasma membrane, cytoplasm, ribosomes, and DNA.
What is the difference between animal and plant cells?
Animal cells have lysosomes and centrioles.
Plant cells have chloroplasts, a cell wall, and a central vacuole.
What is an organelle?
A specialized structure inside a cell that performs a specific function.
What are the three domains of life?
A: Bacteria, Archaea, and Eukarya.
What are the six kingdoms of life?
Bacteria, Archaea, Protista, Fungi, Plantae, and Animalia.
Which kingdom contains unicellular organisms?
A: Bacteria, Archaea, and Protista.
Which kingdoms contain multicellular organisms?
Fungi, Plantae, and Animalia.
Part of the domain Eukarya
Which domains do prokaryotes belong to?
A: Bacteria and Archaea.
Which domain do eukaryotic organisms belong to?
A: Eukarya.
Why do humans belong to the domain Eukarya?
Because our cells have a nucleus and membrane-bound organelles.
What is the difference between a scanning electron microscope (SEM) and a transmission electron microscope (TEM)?
SEM creates a 3D surface image by scanning with electrons.
TEM provides detailed internal structures by passing electrons through the sample.
When would you use a compound microscope?
When viewing small, thin, transparent specimens like cells and tissues.
When would you use a dissecting microscope?
A: When viewing larger, 3D objects such as insects, plants, or small dissections.
What is the difference between a microscope’s magnification and field of view?
Magnification enlarges the image.
Field of view is the area visible through the lens and decreases as magnification increases.
Why is staining necessary when making a slide?
A: To increase contrast and make cell structures more visible.
Why is the iris diaphragm important on a microscope?
A: It controls how much light passes through the specimen, affecting contrast.
Why do scientists use microscopes?
A: To study structures too small to see with the naked eye.
Why is it important to understand depth of field in microscopy?
A: It allows you to focus on different layers of a specimen, especially when it is thick.
How are cells similar to bricks in a building?
A: Cells build up tissues and organisms just like bricks form a structure.
What is a cell?
A: The basic unit of life in all living organisms.
