Biology Chapter on Mutations and Lab Safety

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Questions and Answers

Which type of mutation results in a premature stop codon?

Silent mutation

Nonsense mutation (correct)

Synonymous mutation

Missense mutation

A silent mutation changes the amino acid sequence of a protein.

False

A mutation that results in the loss of a portion of a chromosome is called a ______.

deletion

Match the types of mutations with their definitions:

Point mutation = A change in a single nucleotide Chromosomal mutation = Involves changes in chromosome structure Loss-of-function mutation = Causes a decrease or loss of gene product Gain-of-function mutation = Increases the gene product or its activity Signup and view all the answers

Which type of point mutation does not affect the amino acid sequence?

Synonymous mutation Signup and view all the answers

What is an example of a chromosomal mutation?

Duplication Signup and view all the answers

What should be done with gloves worn during exercises with biohazardous materials?

Place them in a biohazard bin Signup and view all the answers

Reusable materials that require sterilization should be washed in the sink after use.

False Signup and view all the answers

What should you never do with a wrong or unmarked reagent?

Use it Signup and view all the answers

When pouring concentrated acids, always pour the acid into ___ and stir continuously.

water Signup and view all the answers

Match the waste type with its proper disposal method:

Broken glass = Sharps container Non-contaminated waste paper = Regular trash Used scalpel blades = Sharps container Bacterial culture tubes = Autoclave Signup and view all the answers

What must be done with chemical bottles during transport?

Use appropriate carrying arrangements Signup and view all the answers

It is safe to pour any chemical into a bottle regardless of the label.

False Signup and view all the answers

Why is good hand washing technique important during laboratory exercises?

To prevent contamination and contact with hazardous materials Signup and view all the answers

Items that are to be sterilized should be placed in the ___ after use.

autoclave Signup and view all the answers

What is meant by 'parfocal' in relation to microscopes?

The object will remain in focus when switching from low to high power. Signup and view all the answers

The field of view is square in shape when looking through a microscope.

False Signup and view all the answers

What should you do to find an object before viewing it under high power?

Always find the object under the low power field first. Signup and view all the answers

The limit of resolution for a microscope using visible light is approximately _____ nm.

300 Signup and view all the answers

Match the following types of sections with their descriptions:

Longitudinal section = A cut through the long axis of an organ Transverse section = A cut along a horizontal plane dividing an organ into superior and inferior parts Signup and view all the answers

What is the purpose of using the fine adjustment knob when focusing a microscope?

To precisely focus the specimen at high power. Signup and view all the answers

The field of view increases as you switch from low power to high power lenses.

False Signup and view all the answers

How do you calculate the size of a single cell using the low power field diameter?

Diameter of the field of view divided by number of cells that fit. Signup and view all the answers

Using _____ light as a light source can improve resolution to 100 nm.

ultraviolet Signup and view all the answers

What is the recommended procedure for moving to a higher power objective?

Check if the object is centered and adjust if necessary. Signup and view all the answers

What does gene amplification refer to?

The number of tandem copies of a locus is increased Signup and view all the answers

Translocation involves the exchange of broken pieces between non-homologous chromosomes.

True Signup and view all the answers

What are mutation hotspots characterized by?

Elevated rates of recombination and higher susceptibility to mutations. Signup and view all the answers

Inherited changes in ______ DNA can disrupt the mitochondria's energy generation.

mitochondrial Signup and view all the answers

Match the following genetic concepts with their definitions:

Interchromosomal insertion = Insertion on another non-homologous chromosome Intrachromosomal insertion = Insertion in a different region of the same chromosome Expanding trinucleotide repeat = Normal number of repeated sequences is increased Copy number variation = Alteration in the number of copies of a particular gene or locus Signup and view all the answers

What are the two main types of nucleic acids?

DNA and RNA Signup and view all the answers

Adenine always binds to uracil in RNA.

False Signup and view all the answers

What is the role of ATP in cellular processes?

ATP provides energy for cellular processes. Signup and view all the answers

In DNA, cytosine always binds with ______.

guanine Signup and view all the answers

What is the primary focus of molecular biology methods?

Explore molecular activity Signup and view all the answers

Match the following terms with their definitions:

Technique = A man-made strategy or tactic Method = An approach or pathway Nucleic acids = Molecules that store and transmit genetic information CRISPR-Cas9 = A technology for editing genes Signup and view all the answers

DNA synthesis involves the creation of RNA molecules.

False Signup and view all the answers

Name one common method used in molecular biology.

Nucleic acid methods Signup and view all the answers

The process of ______ involves the extraction of DNA from cells.

DNA extraction Signup and view all the answers

Which of the following is NOT a type of DNA mutation?

Protein mutation Signup and view all the answers

What is the total magnification when using a 10X ocular lens with a 40X objective lens?

400 Signup and view all the answers

Immersion oil is required when using lower magnification lenses.

False Signup and view all the answers

What is the main purpose of a stereomicroscope?

To observe the surfaces of large specimens and provide 3D information. Signup and view all the answers

The field of view is the area of the slide that you see when looking through the microscope's ______.

eyepiece Signup and view all the answers

Match the following objective lenses with their respective magnifications:

Scanning Power = 4X Low Power = 10X High Power = 40X Oil Immersion = 100X Signup and view all the answers

Which statement correctly describes the use of immersion oil in microscopy?

Only necessary for high power objectives Signup and view all the answers

The eyepiece lens is responsible for projecting the image onto the detector.

True Signup and view all the answers

What is the primary purpose of a phase contrast microscope?

To enhance contrast in transparent specimens Signup and view all the answers

Fluorescent microscopy uses light from below the sample to excite fluorescent molecules.

False Signup and view all the answers

What type of light source is commonly used in fluorescence microscopy?

UV light, high-pressure mercury or xenon vapor lamps, lasers, or LED sources Signup and view all the answers

In a phase contrast microscope, light that passes through thicker parts of the cell is held up relative to the light that passes through thinner parts of the __________.

cytoplasm Signup and view all the answers

Match the microscopy method with its main characteristic:

Phase Contrast Microscopy = Enhances contrast in transparent specimens Fluorescent Microscopy = Uses specific wavelengths to excite fluorophores Epifluorescence Microscopy = Light source from above the sample Light Microscopy = Basic visualization of stained specimens Signup and view all the answers

What is the benefit of using fluorescent microscopy over traditional light microscopy?

It has a superior signal to noise ratio Signup and view all the answers

Phase contrast microscopy requires standard light objective lenses without any special modifications.

False Signup and view all the answers

What allows a fluorescent molecule to emit light after absorbing it?

The ability to absorb light at a specific wavelength and then emit it at a higher wavelength Signup and view all the answers

Fluorescent microscopes often use __________ of filters to separate excitation and emission wavelengths.

combinations Signup and view all the answers

What bond occurs between a slightly positive hydrogen and a slightly negative oxygen or nitrogen?

Hydrogen bond Signup and view all the answers

Nonpolar molecules attract water, making them hydrophilic.

False Signup and view all the answers

What is the pH value of a neutral solution?

7 Signup and view all the answers

Acids release ______ ions when dissolved in water.

hydrogen Signup and view all the answers

Match the following types of biomolecules with their main components:

Carbohydrates = Monosaccharides Proteins = Amino acids Lipids = Fatty acids Nucleic acids = Nucleotides Signup and view all the answers

Which of the following describes a buffer?

A solution that resists changes in pH Signup and view all the answers

The pH scale ranges from 1 to 10.

False Signup and view all the answers

What ion is a characteristic of strong bases when dissolved in water?

hydroxide ion (OH−) Signup and view all the answers

Water is often referred to as a universal ______ because of its ability to dissolve many substances.

solvent Signup and view all the answers

What is the main purpose of a DNA microarray?

To detect the expression of thousands of genes simultaneously Signup and view all the answers

Somatic mutations cannot be inherited by offspring.

True Signup and view all the answers

What type of mutation occurs due to environmental factors and increases mutation frequency?

Induced mutations Signup and view all the answers

The cost of gene synthesis is approximately $_____ per base pair.

0.09 Signup and view all the answers

Match the following types of mutations with their characteristics:

Germline mutations = Occur in gametes and can be inherited Somatic mutations = Occur in body cells and are not inherited Spontaneous mutations = Arise naturally during DNA replication Induced mutations = Result from environmental factors Signup and view all the answers

What type of reaction links subunits together into macromolecules?

Dehydration reaction Signup and view all the answers

Lactose is a polysaccharide.

False Signup and view all the answers

What are the three components of an amino acid?

Amino group, carboxyl group, R group Signup and view all the answers

Triglycerides are composed of one glycerol and ______ fatty acids.

three Signup and view all the answers

Match the following types of carbohydrates with their descriptions:

Monosaccharides = Single sugar molecules like glucose Disaccharides = Two sugar molecules joined together Polysaccharides = Long chains of glucose units Oligosaccharides = Short chains of monosaccharides Signup and view all the answers

Which structure is primarily found in plasma membranes?

Phospholipids Signup and view all the answers

Denaturation of a protein can occur at normal physiological temperatures.

False Signup and view all the answers

What is the primary function of carbohydrates?

Energy source Signup and view all the answers

Lipids are generally soluble in ______ solvents.

nonpolar Signup and view all the answers

What bonds amino acids together in a protein?

Peptide bonds Signup and view all the answers

Which type of muscle is involuntarily controlled and found in the walls of hollow organs?

Smooth Muscle Signup and view all the answers

What feature of cardiac muscle fibers helps prevent fatigue during contractions?

Complete relaxation between contractions Signup and view all the answers

Skeletal muscles are primarily responsible for which of the following functions?

Supporting the body against gravity Signup and view all the answers

Which type of muscle tissue is characterized by tubular and striated fibers that are voluntarily controlled?

Skeletal Muscle Signup and view all the answers

What is the role of calcium ions (Ca2+) in muscle contraction?

They activate troponin, causing tropomyosin to uncover myosin-binding sites. Signup and view all the answers

What is the shape of smooth muscle fibers?

Cylindrical with pointed ends Signup and view all the answers

What is the first step in the sliding filament theory of muscle contraction?

The myosin heads attach to actin, forming cross-bridges. Signup and view all the answers

What structural feature distinguishes skeletal muscle fibers from other types?

Cross-striations Signup and view all the answers

What happens to acetylcholine (ACh) after it is released into the synaptic cleft?

It diffuses across the cleft and binds to receptors on the sarcolemma. Signup and view all the answers

Which statement best explains a general feature of muscle tissue?

Muscle tissue is essential for movement of the organism and internal materials. Signup and view all the answers

What is the consequence of ATP binding to myosin heads during muscle contraction?

It causes myosin to release from actin. Signup and view all the answers

What is the primary function of the neuromuscular junction?

To transmit nerve signals from motor neurons to muscle fibers. Signup and view all the answers

What is the term for the muscle that is relaxing during a contraction?

Antagonist Signup and view all the answers

Which of the following is NOT a cellular component of a muscle fiber?

Cardiomyocytes Signup and view all the answers

What provides energy for muscle contraction within muscle fibers?

Glycogen Signup and view all the answers

Which component of a muscle fiber serves as the plasma membrane?

Sarcolemma Signup and view all the answers

Thick myofilaments within muscle fibers are primarily composed of which protein?

Myosin Signup and view all the answers

What is the role of myoglobin in muscle fibers?

To bind oxygen Signup and view all the answers

Which muscle type is responsible for voluntary movements in the body?

Skeletal muscle Signup and view all the answers

What would happen if both the agonist and antagonist muscles contracted simultaneously?

No movement Signup and view all the answers

What is the main function of the sarcoplasmic reticulum in muscle fibers?

Calcium storage Signup and view all the answers

In a skeletal muscle fiber, myofibrils are made up of smaller units called what?

Myofilaments Signup and view all the answers

What is the primary role of fascia in the muscular system?

To cover muscles and extend to become tendons Signup and view all the answers

What describes the relationship between agonist and antagonist muscles?

Agonists are responsible for the primary movement while antagonists perform the opposite action. Signup and view all the answers

Which structure serves to protect internal organs from physical damage?

Muscles Signup and view all the answers

What happens to ATP during muscle contraction?

It breaks down, releasing heat. Signup and view all the answers

Where is the origin of a muscle typically located?

On the stationary bone Signup and view all the answers

Which structure often acts as a cushion between tendons and bones?

Bursae Signup and view all the answers

In the context of muscle pairs, what does the term 'insertion' refer to?

The attachment on the moving bone Signup and view all the answers

What is the function of small, fluid-filled sacs known as bursae?

To provide lubrication and reduce friction Signup and view all the answers

Which of the following best describes a fascicle?

A bundle of muscle fibers surrounded by connective tissue Signup and view all the answers

What is the primary function of myoglobin in muscle fibers?

To store oxygen for muscle contraction Signup and view all the answers

What structure releases Ca2+ in response to impulses conveyed by T tubules?

Sarcoplasmic reticulum Signup and view all the answers

Which statement describes the role of the sliding filament model in muscle contraction?

Thin filaments slide past thick filaments, causing sarcomeres to shorten. Signup and view all the answers

What is the composition of thick myofilaments in skeletal muscle?

Myosin with a head structure Signup and view all the answers

Which statement correctly defines the Z lines in a sarcomere?

They represent the end of the myofibril segments. Signup and view all the answers

What happens to the I band during muscle contraction according to the sliding filament model?

It shortens as the sarcomere contracts. Signup and view all the answers

How are sarcomeres organized within myofibrils?

Linearly, extending between Z lines Signup and view all the answers

What is the main energy source that supports muscle contraction?

ATP that is regenerated during contraction Signup and view all the answers

What is the primary role of thin myofilaments in muscle contraction?

To enable cross-bridge formation with myosin Signup and view all the answers

What is the H band within the A band of a sarcomere composed of?

Only thick myofilaments Signup and view all the answers

Study Notes

Biotechniques (BMS 34010A)

Course offered Fall semester 2023-2024
Instructor: Dr. Tania Tahtouh
Email: [email protected]

Basic Principles: Biosafety in the Laboratory

The lab setting presents hazards that need consideration during any exercise.
Laboratory safety ensures protection of all personnel and safe equipment use.
The disposal of contaminated materials and chemicals follows strict protocols.

Potential Laboratory Hazards

Science labs present hazards like corrosive chemicals, sharp tools/glass, and open flames.
Extreme caution is needed when handling open flames (e.g., Bunsen burners).
Attention should be paid to materials near the flame.
Infectious organisms also pose a threat; microorganisms are classified into biosafety levels (BSL).
BSL levels (1, 2, 3, 4) are based on transmission ease and pathogenicity.
Most undergraduate labs use BSL 1 organisms (cause no disease).
Working with BSL 4 organisms demands extensive safety measures (e.g., specialized labs).

Standard Practices in the Laboratory

Lab coats are crucial for contamination protection (microorganisms or corrosive substances).
Coats should be appropriately sized for coverage without restricting movement.
Lab coats are not chemical suits; remove immediately if on fire.
Gloves should not touch surfaces outside the lab (door handles, etc.).
Do not consume food, drink, or chew gum in the lab.
Eating and drinking in a lab is prohibited to avoid hazardous substances.
Do not apply makeup or adjust contacts while in a lab.
The lab bench must remain clean.
Cell phones, purses, bags, and other personal items must be stowed away from the benchtop.
Never leave active experiments unattended, especially if they involve heating or visible reactions.
Disinfect the lab bench before and after each experiment to prevent contamination.
Correct hand washing techniques are essential; review module techniques.
Follow correct hygiene procedures. Do not run or sit on benches.
Tie back long hair and secure loose clothing when working with open flames.
Goggles, safety glasses, or face shields are compulsory during UV light or chemical procedures.
Safety glasses should be worn over glasses.
Always wear closed-toed shoes to prevent chemical spills or dropped sharp objects from injuring feet.
Know the location of lab safety equipment (eyewash, chemical shower, first aid kit, fire extinguisher).
Adhere to chemical hygiene plans and policies.

Laboratory Safety Equipment

Chemical hygiene plans protect personnel from potential health hazards of using chemicals.
Fume hoods or biosafety cabinets must be used according to instructions or lab procedures.

Lab Emergencies

In the event of a lab emergency (spill, injury, accidents), immediately notify the instructor.
Report any spills, injuries, broken equipment, or other emergencies.

Biohazard Bin

Biohazardous waste (non-reusable items, infectious organisms, body fluids) must be placed in appropriately-labelled bins or bags.
Gloves worn while handling the biohazardous waste must also be disposed of in the bin.
Sterilization using an autoclave is an option before final disposal.

Sharps Containers & Trash Cans

Sharps containers are for disposing of broken glass, needles, used scalpel blades, or other sharp objects.
Non-contaminated waste (paper, etc.) should be put in regular trash cans.

Reusable Materials

Reusable materials requiring sterilization should be placed into the autoclave after use.
These include tubes, glass rods or instruments requiring sterility for use.
Materials not requiring sterilization can be washed in the sink (dissection tools, glassware, staining trays, etc).

General Guidelines for Handling Chemicals

Keep chemical containers closed (dust, vapor escape).
Never use wrong or unmarked reagents. If unsure, dispose of properly.
Do not carry chemicals by their neck, instead use appropriate containers (e.g., buckets, trolleys).
Always ensure labels face upward to prevent spills damaging the label.
Never put a chemical into a container unless it is the correct chemical type.
Handle concentrated acids with specialized precautions; add acid to water, gently stir.

The Importance of Hand Washing

Good hand washing practices are essential in lab settings, especially in microbiology.
Hands can be contaminated by infectious organisms, chemicals, stains, and potentially dangerous materials.
Wash hands before, after, and whenever there's possible contamination.

Steps for Correct Hand Washing

Remove all jewelry (rings, bracelets, etc.).
Wet hands with clean running water and apply soap.
Rub hands together to generate a lather.
Scrub hands thoroughly, including fingers, backs of hands, and under nails (20 seconds).
Rinse hands.
Dry hands using a clean towel or air drying.

Metric Systems

The SI (International System of Units) system is the preferred measurement system used by scientists.
The English system is still used in the US and uses different units of measurement.
The SI system is based on the number 10.
SI system prefixes (e.g., kilo, hecto, deca, deci, centi, milli, micro) indicate multiples or fractions of 10.
Units are essential in specifying measurements.

Microscopy: Types and Principles

Biological objects, viewed with microscopes, vary in scale.
Microscopes allow observation of small biological objects.
Microscopy comes in various types, including:
Light microscopy (compound, binocular dissecting/stereomicroscope, phase contrast, fluorescent, confocal)
Electron microscopy (transmission electron, scanning electron).

Learning Outcomes: Microscopy

Students should identify and understand the function of compound light microscope parts.
Calculate total magnification using objective and ocular lenses.
Follow microscope use procedures.
Recognize the difference between low power and high power microscopy.
Define field of view (at low and high power), longitudinal & cross sections, and resolution.

Light Microscope

The simplest light microscope is a single magnifying glass.
The specimen requires minimal preparation.
Focusing is done via moving the lens/specimen relative to each other.
Light source can typically be the sun, ambient indoor light.
Detection mechanism is the human eye.
Recording involves hand-drawing.

Compound Light Microscope

Modern light microscopes have multiple combined lenses (condenser, objective, and eyepiece).
Light source is often a lamp, focused onto the specimen.
The image is magnified through the objective lens, and then projected onto an eye or digital camera.

The Parts of the Microscope and Their Function

Functions of various microscope components (body tube, arm, stage, stage clips, coarse adjustment knob, fine adjustment knob, base, etc.).

Lenses and Their Magnifications

Scanning (4x), low (10x), high (40x), oil immersion (100x).
Total magnification is calculated by multiplying the ocular and objective lens magnifications.

Field of View

The field of view is the observable area when looking through the microscope.
The FOV is circular and its size varies based on the objective lens magnification.

Microscope Immersion Oil

Immersion oil is typically needed with high magnification objective lenses.

Stereomicroscope, Phase Contrast, Fluorescent Microscope

Stereomicroscope: used for observing large specimens, suitable for micromanipulation and dissection.
Phase contrast microscope: enhances contrast for transparent/colorless samples (e.g., viewing unstained cells).
Fluorescent microscope: widely used for highly specific labelling of cellular components. Microscopy method with typically white (fluorescent) on a black (non-fluorescent) background.

Fluorescent Proteins & Stains

Fluorescent proteins and stains are used to specifically label and visualize components of the cells.

Immunofluorescence

Technique involving specific antibodies conjugated with fluorescent dyes.

Confocal Microscopes

Laser scanning confocal microscopes create optical sections of the specimen by scanning point by point.

Electron Microscopes

Electron microscopes use electron beams for magnifying and focusing on the sample.

Rules for Microscope Use

Keep both eyes open when viewing.
Avoid touching the eyepiece with eyelashes.
The lowest power objective should be positioned at the start and end of the observation.
Use regular paper tissue/wipes for cleaning lenses.
The microscope should not be tilted while viewing.
Parts of the microscope should not be removed.
Always find the object under low power before viewing using high power.

Focusing the Microscope

Always begin focusing with the scanning power objective (4x).
Use the coarse adjustment knob to lower the stage and slowly raise the stage while looking through the eye piece until the object comes into view.
Use the fine adjustment knob to sharpen focus if needed.

Low Power Field Diameter (LPD)

Measure the diameter of the field of view using the 10x (low power) objective and a ruler.
Convert the measurement to micrometers (mm to µm).
Calculate the size of a single cell by dividing the LPD by the number of cells.

Longitudinal Section vs Cross Section

Longitudinal sections: cut through the long axis of an organ/structure.
Transverse (cross) sections: cut through a horizontal plane.

Resolution

Resolution is its ability to distinguish between two close objects in the specimen.
Shorter wavelengths allow higher resolution.
Visible light has a limit of about 300 nm, oil immersion allows 200 nm.

DNA Synthesis

Artificial gene synthesis allows making DNA molecules without relying on natural DNA templates.
Exact nucleotide sequence can be designed.
Gene synthesis is often priced per base pair.

DNA Microarray

DNA microarray (microarray) is a laboratory tool for analyzing gene expression with high throughput.
The technique uses labeled DNA or RNA probes to detect target genes at different expression levels in the genome. Complementary sequences within a DNA molecule tend to bind one another.

Mutations and Causes

Mutations are alterations within DNA sequences that change the structure of a gene.
Mutations can be spontaneous (chemical instability or errors during replication) or induced by environmental factors, such as chemical mutagens or ionizing radiation.

Main Types of Mutations

By the cell type, mutations can be classified as germline (in gametes, inheritable) or somatic (in other body cells).
By size, mutations can be classified as point mutations (substitutions, insertions, deletions), chromosomal (deletion, duplication, inversion, translocation), and copy number variations (CNVs).

Point Mutations:

Substitution (incorrect base added during replication).
Insertion (one or more extra nucleotides).
Deletion (one or more nucleotides skipped during replication).
Types of point mutations (missense, nonsense, synonymous, and neutral).

Point Mutations: Types

Missense (codon codes for a different amino acid).
Nonsense (premature stop codon).
Synonymous (same amino acid).
Neutral (no change to function).

Point Mutations: Categorization

Loss-of-function mutations: reduced/absent gene product or activity.
Gain-of-function mutations: increased gene product or activity, causing potentially new or harmful traits.

Chromosomal Mutations:

Deletion: a part of the chromosome is lost.
Duplication: a part of the chromosome is repeated.
Inversion: a region of the chromosome is flipped and reinserted.
Insertion: the insertion of DNA sequence into a chromosome.
Translocation: the exchange of chromosomes' segments.

Copy Number Variation (CNV)

Gene amplification (increased number of tandem copies).
Trinucleotide repeat expansion.
Classification as forms of genome structural variation.

Mutation Hotspots

Genomic areas prone to more mutations.
Usually due to high accessibility to mutagens.

Mitochondrial DNA Mutations

Inherited changes in mitochondrial DNA can cause problems in growth, development, and functioning.
MtDNA mutations impact the mitochondria, affecting energy production.

PCR & Electrophoresis

Techniques used in molecular biology for DNA amplification and analysis.

PCR Technique

PCR is a technique for amplifying short DNA sequences.
The method uses primers that target DNA sections for amplification.
DNA polymerase is used to create numerous copies of the target sequence.

PCR Enzymes

DNA polymerases, such as Taq and Pfu, are used to synthesize new DNA strands in PCR reactions.

TA Cloning

TA cloning uses the non-template activity (TAq DNA polymerase) to add a single adenine nucleotide after the 3' end of a DNA fragment.
Cloning vector with single 5' thymine overhang at each end is used.
Enables cloning of amplified DNA products.

Gel Electrophoresis

Method to separate DNA, RNA, or proteins according to size.
DNA is negatively charged, so it moves towards the positive electrode.
Separated molecules are observable based on their distinct sizes in a gel matrix.

DNA/RNA Ladders

DNA/RNA ladders are reference mixtures.
Commonly include standard sized DNA molecules of varying lengths.
Used in gel electrophoresis to estimate the sizes of unknown samples.

Loading Buffer

Used in gel electrophoresis to load DNA samples into wells.
Usually contains a colored dye and a reagent to increase sample density.

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Description

This quiz covers various types of mutations, their effects, and essential laboratory safety practices related to handling chemicals and biohazardous materials. It includes multiple-choice questions and matching exercises to reinforce understanding of genetic mutations and safe lab procedures.

Biology Chapter on Mutations and Lab Safety

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Questions and Answers

Which type of mutation results in a premature stop codon?

A silent mutation changes the amino acid sequence of a protein.

A mutation that results in the loss of a portion of a chromosome is called a ______.

Match the types of mutations with their definitions:

Which type of point mutation does not affect the amino acid sequence?

What is an example of a chromosomal mutation?

What should be done with gloves worn during exercises with biohazardous materials?

Reusable materials that require sterilization should be washed in the sink after use.

What should you never do with a wrong or unmarked reagent?

When pouring concentrated acids, always pour the acid into ___ and stir continuously.

Match the waste type with its proper disposal method:

What must be done with chemical bottles during transport?

It is safe to pour any chemical into a bottle regardless of the label.

Why is good hand washing technique important during laboratory exercises?

Items that are to be sterilized should be placed in the ___ after use.

What is meant by 'parfocal' in relation to microscopes?

The field of view is square in shape when looking through a microscope.

What should you do to find an object before viewing it under high power?

The limit of resolution for a microscope using visible light is approximately _____ nm.

Match the following types of sections with their descriptions:

What is the purpose of using the fine adjustment knob when focusing a microscope?

The field of view increases as you switch from low power to high power lenses.

How do you calculate the size of a single cell using the low power field diameter?

Using _____ light as a light source can improve resolution to 100 nm.

What is the recommended procedure for moving to a higher power objective?

What does gene amplification refer to?

Translocation involves the exchange of broken pieces between non-homologous chromosomes.

What are mutation hotspots characterized by?

Inherited changes in ______ DNA can disrupt the mitochondria's energy generation.

Match the following genetic concepts with their definitions:

What are the two main types of nucleic acids?

Adenine always binds to uracil in RNA.

What is the role of ATP in cellular processes?

In DNA, cytosine always binds with ______.

What is the primary focus of molecular biology methods?

Match the following terms with their definitions:

DNA synthesis involves the creation of RNA molecules.

Name one common method used in molecular biology.

The process of ______ involves the extraction of DNA from cells.

Which of the following is NOT a type of DNA mutation?

What is the total magnification when using a 10X ocular lens with a 40X objective lens?

Immersion oil is required when using lower magnification lenses.

What is the main purpose of a stereomicroscope?

The field of view is the area of the slide that you see when looking through the microscope's ______.

Match the following objective lenses with their respective magnifications:

Which statement correctly describes the use of immersion oil in microscopy?

The eyepiece lens is responsible for projecting the image onto the detector.

What is the primary purpose of a phase contrast microscope?

Fluorescent microscopy uses light from below the sample to excite fluorescent molecules.

What type of light source is commonly used in fluorescence microscopy?

In a phase contrast microscope, light that passes through thicker parts of the cell is held up relative to the light that passes through thinner parts of the __________.

Match the microscopy method with its main characteristic:

What is the benefit of using fluorescent microscopy over traditional light microscopy?

Phase contrast microscopy requires standard light objective lenses without any special modifications.

What allows a fluorescent molecule to emit light after absorbing it?

Fluorescent microscopes often use __________ of filters to separate excitation and emission wavelengths.

What bond occurs between a slightly positive hydrogen and a slightly negative oxygen or nitrogen?

Nonpolar molecules attract water, making them hydrophilic.

What is the pH value of a neutral solution?

Acids release ______ ions when dissolved in water.

Match the following types of biomolecules with their main components:

Which of the following describes a buffer?

The pH scale ranges from 1 to 10.

What ion is a characteristic of strong bases when dissolved in water?

Water is often referred to as a universal ______ because of its ability to dissolve many substances.

What is the main purpose of a DNA microarray?

Somatic mutations cannot be inherited by offspring.

What type of mutation occurs due to environmental factors and increases mutation frequency?

The cost of gene synthesis is approximately $_____ per base pair.

Match the following types of mutations with their characteristics:

What type of reaction links subunits together into macromolecules?

Lactose is a polysaccharide.

What are the three components of an amino acid?

Triglycerides are composed of one glycerol and ______ fatty acids.

Match the following types of carbohydrates with their descriptions:

Which structure is primarily found in plasma membranes?