Biology Lab Exam Study Notes PDF

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Professor: Frank Mallory...

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Biology 1 Lab Exam Study Notes Microscopy Microscopy is the use and examination of a specimen with a microscope. Types of Microscope

The resolving power is what distinguishes these three types of microscopes. The resolving power is the smallest distance at which two adjacent points can be distinguished as separate.

The dissection microscope or stereoscope is designed to study entire objects at low power. Features: -

The light compound microscope is used to study finer details which are not visible under the dissection microscope.

Image is not inverted Good depth perception (stereoscopic vision)

Objectives of the light compound microscope: -

4X (scanning) 10X (low power) 40X (high power) 100X (oil immersion)

100X objective: Immersion oil is used to prevent the loss of light rays due to refraction. Parfocal feature: Image stays in approximate focus when magnification is changed. Resolving power: The smallest distance at which two adjacent points can be distinguished as separate. Magnification: Apparent increase in size due to the use of lenses (ocular power x objective power)

Classification Taxonomy The science of naming and classifying organisms is called taxonomy. Each group of classification is called a taxon. The Domain is the broadest taxon and the species is the most specific taxon. Domain  Kingdom  Phylum  Class  Order  Family  Genus  Species The 3 Domains: Archaea & Bacteria: includes prokaryotic organisms Eukarya: includes eukaryotic organisms (Protista, Fungi, Plantae and Animalia Kingdoms) Binomial nomenclature: Homo sapiens (Italicized when types) Homo sapiens Genus Species (capitalized)

(lower case)

Underlined with two separate lines when handwritten Homo sp. Genus identified

Species not specified

Prokaryotic cells:   

Very small Lack a nuclear membrane Lack membrane-bound cytoplasmic organelles

Prokaryotic Domains: Archaea 

 

Live in extreme environments - Extreme heat (extreme thermophiles) - High salt (extreme halophiles) Similar to bacteria but have biochemical differences Not visible when looking through a microscope

Bacteria    

Some can be pathogenic while others can be very beneficial Heterotrophs (organisms using organic compounds as a source of carbon) Autotrophs (organisms using CO2 as a source of carbon) Cyanobacteria (blue-green algae) contain a blue-green pigment called cyan

Bacterial Shapes and arrangements:

External features: 



Flagella: hair-like appendages which are responsible for the motility of bacteria. - Peritrichous arrangement: flagella are projected in every direction around the bacterium - Polar arrangement: flagella are placed at the poles of the bacterium Capsules: made of a viscous substance that surrounds the bacteria cell. These capsules allow the bacteria to cling to a substrate or to each other. Also to protect themselves from attacks by an organisms immune system.

Features found in plant cells but not animal cells:   

Cell wall Chloroplast Vacuole

Plasmolyzed plant cell:

Cells are said to be plasmolyzed when the cell membrane detaches from the cell wall due to the movement of water out of the cell by osmosis.

Microbiology Culture medium:    

Contain nutrients (proteins, carbohydrates, mineral salts) Used to cultivate microorganisms Fastidious microorganisms are those that have unusual or complex nutritional needs Can be prepared as a broth or an agar

Aseptic technique A procedure which prevents or minimized contamination by microorganisms. Bacteria have a ubiquitous nature meaning they are found almost everywhere. Types of Hemolysis Many pathogenic bacteria are capable of producing and releasing substances called hemolysins which cause the destruction of lysis or red blood cells. This process is referred to as hemolysis.

Alpha-hemolytic: partial clearing Beta-hemolytic: complete clearing Gamma-hemolytic:

incapable of lysis

Antibiotics Antibiotics are substances produced by microorganisms which inhibit the growth of or kill other microorganisms. The zone of inhibition is the area where the antibiotic ha inhibited the bacterial growth.

The Laboratory Report Title   

Informative Precise statement relating to the experiment Includes important taxonomic information

Title Page      

Title Name of the author Name of the author’s work partners Course Code Lab session Date of submission

Abstract 

Brief summary of the article



One can read it quickly and see whether or not one wants to read it in more detail

Introduction   

Background information on the subject of the experiment The majority of your references will be found here The objective or purpose of the experiment - Last paragraph of intro. - Very specific - It needs to ask a questions that can be answered in the conclusion

Objective/purpose vs. hypothesis: A purpose (objective) tells the reader why you want to do the experiment whereas the hypothesis tells the reader what you think the results will be. Materials and Methods   

A clear descriptions of the precise methodology used to do the experiment Precise enough that the reader can replicate the experiment Paragraph format

Results    

Summary of important trends Presented prior to any graphs or tables No explanations of results Figures: - Graphs - Maps - Sketches - Photos

The title of a figure is placed at the bottom. The tile of a table is placed at the top. Independent variable: factor manipulated by the researcher (x-axis). Dependant variable: factor that is the focus of the experiment (y-axis). Line graphs:

Dot to dot is used when interested in what’s happening between the dots. Line of best fit is used when you want to know a trend

Discussion    

Most important part of the report Explain, analyze, and interpret the significance or meaning of the results Past tense Conclusion - Last paragraph of the discussion - Not titled - Brief - Highlights the major points of the report - Specifically answers the purpose (objective) stated in the introduction

Diffusion and Osmosis Diffusions is the net movement of a substance from a region of higher concentration to a region of lower concentration. Temperature increase and a larger concentration difference will increase the rate of diffusion.

Osmosis is the diffusion of a solvent (water) through a semi-permeable membrane. Osmosis is a type of passive diffusion.

Tonicity Hypertonic: the solution around the cell has a higher solute concentration than the cell. Isotonic: the solutions around the cell has an equal solute concentration to the cell. Hypotonic: the solutions around the cell has a lower solute concentration than the cell.

Water Movement: Hypertonic: water moves out of the cell and into the surrounding solution, causing the cell to shrivel. Isotonic: water moves into and out of the cell equally, causing no change to the cell.

Hypotonic: water moves from the surrounding solution into the cell, causing the cell to swell and potentially burst.

Cells that take in water and swell will often lyse. Red blood cells contain hemoglobin, an oxygen carrying protein that is released when the cells lyse. This is referred to as hemolysis. Cells that lose water will crenate.

A plasmolyzed cell is characterized as being flaccid due to the loss of turgor pressure. A cell in this condition is described as a turgid cell.

Cellular Respiration Cellular respiration is essentially the oxidation of organic molecules with the release of energy (ATP). Cellular respiration can be broken down into: 1. Glycolysis 2. Pyruvate oxidation and the citric acid cycle 3. Oxidative phosphorylation Aerobes: organisms which depend on oxygen Anaerobes: organisms that live without oxygen Alcohol fermentation: pyruvate  CO2 + ethanol (plants and microorganism) Lactic acid fermentation: pyruvate  CO2 + lactic acid (animals and microorganisms)

Photosynthesis

Photosynthesis: autotrophic green plants absorb carbon from the earth’s atmosphere and, with the help of light, convert it into organic compounds. The Chloroplasts Chloroplasts are cellular organelles at the center of photosynthesis. Most concentrated in the leaves.

Thylakoid: contains chlorophyll, light reaction occurs here.

Stroma: fluid surrounding granum, Calvin cycle occurs here.

Granum

Paper Chromatography

Chlorophyll: a pigment that gives chloroplasts their green appearance. Chlorophyll a is the primary pigment which participates directly in the light reactions. Chlorophyll b is an accessory pigment. Carotene and xanthophyll are accessory pigments.

The necessity of chlorophyll in photosynthesis

White area: no chlorophyll, no starch

Cell Cycle Cell Cycle: a mechanism which allows for the multiplication of cells in an organism. Cell Cycle Functions:    

Growth Repair of managed tissues Replacement of cells that have a short life span Production of gametes for reproduction

Cell Cycle Phases: 



Interphase: cell prepares for cell division and the duplication of the chromosomes. - G1 (first gap) - S (synthesis) - G2 (second gap) Mitosis or meiosis

Mitosis: where a diploid (2N) mother-cell nucleus subdivides into two genetically identical diploid daughter-nuclei. Mitosis Phases:    

Prophase Metaphase Anaphase Telophase

Meiosis:   

Begins the process of sexual reproduction by forming gametes (sperm and egg) Results in the production of haploid cells (1N) which contain a single set of chromosomes which is different from the mother cell Reproductive division: produces daughter cells with half the number of chromosomes as the parent cell

Meiosis Cell Divisions: 



Meiosis 1 - Prophase 1 - Metaphase 1 - Anaphase 1 - Telophase 1 Meiosis 2 - Prophase 2 - Metaphase 2 - Anaphase 2 - Telophase 2

Cytokinesis:  

Final step after the division of the nuclear material Division of the cell cytoplasm

Terminology:       

    

Gene: unit on a chromosome, containing the genetic code for a particular trait Chromatin: loose arrangement of DNA within the nucleus of a cell during interphase Chromosome: condensed strands of genetic information, composed of DNA and proteins Chromatid: one half of a duplicated chromosomes Sister chromatids: the two chromatids which make up one duplicated chromosome Centromere: chromosomal region where the sister chromatids are linked and where the spindle fibers attach via the kinetochore Homologous pair of chromosomes: the two representatives of the same chromosome in a diploid cell, one is the paternal chromosome and the other is the maternal chromosome. Both chromosome have the same genes in the same order Centrioles: cylindrical organelles found in animal cells that play a role in the organization of the spindle fibers, centrioles come in pairs Haploid (1N): one copy of each chromosomes in the nucleus Diploid (2N): two copies of each chromosome in the nucleus Gamete: haploid (1N) cell such as the egg or sperm Zygote (2N): formed from two gametes fused together. The zygote contains one unduplicated chromosome from each of the paternal chromosomes and one unduplicated chromosome of each of the maternal chromosome

Humans have 23 pairs of chromosomes.

Meiosis 1:

Meiosis 2:

Plant Mitosis:

   

Most mitotic activity occurs in specific areas, called meristems The apical meristem is responsible for growth of the apex or stem tip The axillary bud meristem is responsible for later growth of a side branch or of a flower bud The leaf primordia is responsible for the growth of new leaves

Genetics

Cotyledon: allows for the transfer of nutrients from the endosperm to the embryo Triploid endosperm: a source of nutrients for the developing embryo Aleurone: outer layer of the endosperm, responsible for the seed color

Chi-squared test: designed to deal with differences between observed and expected traits Autosomal traits (non-sexual): -

Attached ear lobes Hitch-hiker’s thumb Tongue rolling...