Lab Final Flashcards
What are the actual diameter field of view sizes for each lens?
4x - 4.40mm
10x - 1.75mm
40x - 0.44mm
What is the formula for the acutal size of a cell/organism?
(Diameter of field of view of selected objective) / (# of times the cell/organism can fit across the field of view)
All living organisms are made of cells and all living cells share four basic structural features: ______?
Plasma membrane
Cytoplasm
DNA
Ribosomes
Prokaryotic cells lack a _____ nucleus, but have a central area that contains the DNA called the ____.
Membrane-bound, nucleoid
True or False: Prokaryotic organisms have organelles.
False
What is the glycocalyx?
The gelatinous outer covering of bacterial cells which traps water and protects the bacterium from desiccation
What is a thick glycocalyx called?
A capsule, which serves to prevent the bacteria from being destroyed by an animal’s immune system when ingested or inhaled, or help the bacteria to adhere to surfaces
True or False: eukaryotic organisms are only multicellular
False. Eukaryotic organisms range from unicellular to multicellular.
What are colonial organisms?
They are the half-way point between unicellular and multicellular, they may be composed of a group structurally and functionally similar cells adhere to each other and may communicate with each other.
Which of the two are bigger: eukaryotes or prokaryotes?
Eukaryotes
True or False: all eukaryotic organisms do not have a cell wall?
False. Some eukaryotic organisms do not have a cell wall (animal cells), whereas others do (plant cells)
How do you calculate the Relative Total Pollution Index (rTPI)?
Multiply the Population Index (PI) by the frequency
What does each Total Pollution Index (TPI) range indicate?
< 2: Low organic pollution
2 - 4: Probable organic pollution
4 - 5: High organic pollution
What are the two types of light microscopy?
Fluorescence microscopy and Confocal Laser Scanning
What is fluorescence microscopy?
Fluorescent dyes or antibody-dye complexes are used to label specific molecules or organelles within the cell. In this type of microscopy, the resulting fluorescence is viewed on a black background
What is confocal laser screening microscopy?
Where a laser light source is focused onto a very thin plane within either a naturally fluorescent specimen or one treated with commercial fluorescent dyes. This type of microscopy is used to examine specimens that are too thick to be examined with fluorescence microscopy.
What is electron microscopy?
Where the imaged produced by a beam of high velocity electrons instead of a beam of light. Are useful for examining very small objects, such as the internal structure of cells. These microscopes also have a greater resolving power than light microscopes
Resolution vs. Magnification
Resolution is the ability to detect/distinguish structures that are very close together; magnification is the ability to make small objects appear larger.
What are the two types of electron microscopes?
- Transmission Electron Microscopy (TEM)
- Scanning Electron Microscopy (SEM)
Describe TEM microscopy.
A beam of electrons is transmitted through an extremely thin section of a specimen. The TWM has the best resolution of the internal organization of cells and their organelles
Describe SEM microscopy.
A beam of electrons is scanned over the surface of a specimen resulting in a detailed three-dimensional image of the surface of a specimen.
Prokaryotic organisms include two major groups: ___?
Bacteria and archaea
Eukaryotic organisms include four major groups: ___?
Plants, animals, fungi, and protists.
What are three structures that are present in plant cells but not animal cells?
Cell wall, plastids (chloroplasts), and a large central vacuole
What are the three main types of plastids?
Chloroplasts, chromoplasts, and leucoplasts
The colour of chloroplasts is due to the predominance of green pigments called ___?
Chlorophyll
Chlorophylls are located on a set of membranes inside the chloroplast called ___?
Thylakoid membranes
Chromoplasts contain what kind of pigment?
Carotenoids, which are typically yellow, orange, red, or dark purple in colour.
True or False: chromoplasts are present in both animals and plants
False, chromoplasts are only present in plants
What is the main function of chromoplasts?
It helps attract animals for pollination, as well as speed dispersal
Why are leucoplasts often difficult to distinguish with light microscopy?
Due to their small size and lack of pigment
Describe plasmids.
Smaller pieces of circular DNA
What are cyanobacteria?
Photosynthetic bacteria that contain the pigment chlorophyll as well as a blue-green pigment called phycocyanin. While this bacteria may be unicellular, they commonly form filaments or colonies. They also have a thick gelatinous sheath exterior to their cell walls.
What is ATP?
Adenosine tri-phosphate, energy-rich molecules. It is the primary source of energy used for cellular processes.
Describe chlorophyll
Green pigment, responsible for the absorption of light to provide energy for photosynthesis.
Describe plasmodesmata
Cytoplasmic connections through which plant cells communicate. Numerous plasmodesmata run through perforations and connect adjacent cells
In a single starch grain, there is a layered appearance, these layers are called _____, usually each striation corresponds to a day of starch deposition.
Striations
Describe anthocyanins and how they differ from chromoplasts
Anthocyanins are a calss of blue, purple and red pigments that occur in the central vacuoles of some plant cells. They are water soluble. This pigment comes from the central vacuole, not from plasmids.
What are the two basic types of epidermal cells?
Non-specialized cells (irregularly shaped cells that fit together like jigsaw pieces
Guard cells (regulate the opening and closing of the stomata)
Describe the stomata
Small pores through which gas exchange occurs.
What type of cytoskeletal fiber is present in cilia and flagella?
Microtubules
Describe photosynthesis
The process which uses light energy to synthesize sugars from carbon dioxide and water, while releasing oxygen as a by-product. 6CO2 + 6H2O –> C6H12O6 + 6O2
What is the function of the oculars on the compound microscope?
The viewpoint of the microscope
What is the function of the objective lenses on the compound microscope?
The primary optical lenses for specimen visualization on a microscope. Objective lenses collect the light passing through the specimen and focus the light beam to form a magnified image.
What is the function of the coarse/fine focus adjustment knobs on the compound microscope?
Two adjustment knobs are used to focus the microscope.
Coarse: brings the specimen into approximate or near focus.
Fine: sharpen the focus quality of the image. When viewing with a high-power objective lens, carefully focus by only using the fine knob.
What is the function of the condenser adjustment knob on the compound microscope?
Condensers are lenses that are used to collect and focus light from the illuminator into the specimen.
What is the function of the iris diaphragm on the compound microscope?
Changes the intensity and size of the light projected through the slide.
What is the function of the iris diaphragm on the compound microscope?
What is a flagella used for?
Locomotion.
What is the cell wall’s function?
Found immediately outside the plasma membrane, provides support and protection.
What is the mitochondria’s function?
Carries out cellular respiration and supplies most of the cell’s ATP.
What is the nucleolus’ function?
Where ribosome subunit assembly occurs.
What is the central vacuole’s function?
In plant cells, it is responsible for the storage of water, enzymes, ions, proteins, supports plant cell through maintenance of turgor pressure.
What is the nucleus’ function?
Contains most of the cell’s genetic material, controls cell function, site of DNA synthesis and RNA transcription.
What is the cilia’s function?
Facilitates locomotion, or to sweep fluid over the surface of the cell.
What is the plasma membrane’s function?
Regulates passage of substances in/out of the cell, and is selectively permeable.
What is the microtubules’ function?
Structure and movement of cilia and flagella, cell organization, and shape.
What is the contractile vacuole’s function?
Osmoregulation in animal-like protists.
What is the rough ER’s function?
Initial synthesis and sorting of proteins for export.
What is the Golgi apparatus’ function?
Modify, store, and ship products of the endoplasmic reticulum.
What is the ribosome’s function?
Synthesizes proteins.
True or false: animal cells are usually smaller than plant cells.
True
Why is it necessary to stain your cheek epithelial cells?
The cheek cells, like most animal cells are colorless. Stain is used to increase contrast, which allows you to the cell and its components more clearly.
What is a solute?
A substance that is dissolved in a solvent
What is a solvent?
A liquid that has dissolved or can dissolve one or more solutes
What is a solution?
a solvent and its dissolved solutes
Plasma membranes are selectively permeable; they allow certain kinds of relatively small molecules to pass through them freely in both directions by _____ and _____.
Diffusion and osmosis
Diffusion and osmosis are both what kinds of transport?
Passive transport processes
Describe diffusion
The random movement of molecules from an area of high concentration to low concentration of a substance
Describe osmosis
The movement of a solvent(usually water) through a selectively permeable membrane from an area of low solute to high solute concentration
Osmosis is an important process that affects all living organisms. What does it affect in plant/animal cells?
Plant: maintains turgor pressure
Animals: kidney function, exchange of fluids
What is isotonic?
When two solutions have the same solute concentration
What is hypertonic?
When a solution has a high solute concentration. Since the concentration of solutes is higher within the cell, water moves into the cell by osmosis
What is hypotonic?
When a solution has a low solute concentration. Since the concentration of solutes is lower within the cell, the water moves out of the cell by osmosis
The normal environment for a read blood cell is the liquid component of blood called plasma. Is the cytoplasm of the red blood cell hypo/hyper/or isotonic to the plasma?
Isotonic
What cellular structure prevents the plant cells from taking in too much water and bursting?
The cell wall
The contractile vacuole removes excess water that flows into the cell. Is the cytoplasm of Amoeba hypo/hyper/or isotonic to its environment?
Hypertonic
Describe turgor pressure
The hydrostatic pressure that increases as water enters plant cells by osmosis, because cell walls restrict the expansion of the cell
Describe plasmolysis
Shrinkage of algal/plant cytoplasm that occurs when water leaves the cell by osmosis; central vacuole decreases in volume and plasma membrane no longer presses against the cell wall
Describe binary fission
A means of asexual reproduction in prokaryotes in which a cell divides to form two identical organisms
Recall that the major characteristic that distinguishes eukaryotic from prokaryotic cells in the presence of a ____?
Membrane bound nucleus
Describe chromatin
The combination of DNA and associated proteins
Describe DNA
Deoxyribonucleic acid. The genetic material of an organism; a double stranded helical acid
Describe chromosome
A unit of genetic material composed of DNA and associated proteins, found in the nuclei of eukaryotic cells and in the nucleoid region of prokaryotic cells
Describe gene
A unit of hereditary information that contributes to the inherited characteristics or traits of an organism; composed of a specific organized sequence of DNA
What is the chloroplast’s function?
Where photosynthesis occurs, found only in plants/algae.
Chromoplasts contain pigments called..?
Carotenoids.
Why do cells from onion scales lack green pigments?
Due to the absence of chloroplasts, as they do not get direct sunlight often.
What is cytoplasmic streaming?
When cellular granules move within the cytoplasmic strands.
What is the food vacuole’s function?
Contains food particles engulfed by the cell.
What is the leucoplast’s function?
Type of plastid that lacks pigment, produces and stores different macromolecules like starch, proteins, or lipids.
What is the lysosome’s function?
Contains hydrolytic enzymes that digest a cell’s food and waste.
What is the cytoskeleton’s function?
The network of protein filaments.
What is the cytoplasm’s function?
Fluid region, for creating an environment for the processes that take place in the cell.
What is the chromoplast’s function?
Plastid that contains pigments to give coloration.
What is the vesicle’s function?
Contains macromolecules for storage, transport, or secretion.
What is the microfilaments’ function?
Important in cell strength, shape, and movement. Responsible for pseudopodia formation in amoeba.
What is the smooth ER’s function?
Lipid synthesis and modification, detoxification of drugs and alcohol, Ca 2+ storage and glycogen breakdown.
What is phagocytosis?
Encircling and entrapping animals and food particles to be packaged into food vacuoles.
What is the longest phase in the cell cycle?
Interphase
Describe interphase
The cell grows and synthesizes new organelles and proteins in preparation for the next cell division
Describe the S stage
Each chromosome produces an exact copy of itself, forming a replicated chromosome
Describe a replicated chromosome
Chromosome that has two identical sister chromatids, resulting from DNA replication of the S stage
Describe chromatids
One of two identical copies of DNA that make up a replicated chromosome, and are joined at the centromere; known as sister chromatids
Describe centromere
Region in a chromosome where the two sister chromatids are tightly associated; point of attachment of spindle microtubules during cell division
Describe mitosis
Division of a nucleus to produce two genetically identical daughter nuclei, each with the same complement of chromosomes
What are some of the major functions of mitosis?
- The production and maintenance of multicellularity
- Asexual reproduction
- Replacement of old/damaged tissues
True of False: The length of time taken to complete the cell cycle varies depending on the cell type and environment.
True
What is notable about Volvox?
Multicellular motile photosynthetic protist
Describe the root apical meristem
The region of rapidly dividing cells near the tip of the root
What is a blastodisc?
A multicellular embryonic stage
Unicellular vs multicellular vs colonial organisms
Unicellular: one cell can live on its own
Colonial: localized population of microorganisms derived from a single cell; adhere to each other
Multicellular: has cells which are specialized for different functions
Describe the eyespot
Light-sensitive organelle that orients certain organisms towards light
Describe pyrenoid
Structure associated with the chloroplast of some algae; site where the sugar produced by photosynthesis is converted to starch for storage purposes
Describe recombinant DNA
DNA molecule carrying genes derived from two or more sources (e.g., two species)
The techniques used in recombinant DNA technology employ the same _____ as those used in forensic biology and paternity testing
Restriction enzymes
Describe restriction enzymes
An enzyme that recognizes specific DNA sequences and cleaves the DNA molecule at this recognition site
What is a transgenic organism?
Organism that has acquired genes from another source through an artificial molecular technique (a.k.a - a genetically modified organism (GMO))
What are the steps involved in processing and analyzing crime scene DNA?
- DNA extraction
- Polymerase Chain Reaction (PCR)
- Restriction Fragment Analysis
+ Restriction digest
+Gel electrophoresis - Interpreting the results
What are the steps in DNA extraction?
- Collection in an isotonic medium: use sports drink, because it can be used as a medium for collecting intact cells because it is isotonic.
- Addition of cell lysis: lysis of cell membrane and nuclear membrane
- Addition of 70% ethanol: DNA precipitates out of solution into the ethanol layer
What is PCR used for?
It is a process that rapidly makes identical copies of DNA sequences, which can be then used in subsequent analysis
What are the four ingredients required in a PCR reaction?
- DNA extract
- The 4 dtps (dNTP, dCTP, dGTP, dTTP)
- Primers
- DNA polymerase (Taq polymerase)
What are the 3 steps in each PCR cycle?
- Denaturation of DNA: heat to separate the two strands of DNA double helix
- Annealing the primers: cool so primers can bond to single strands of DNA
- Extension of primers: heat to allow Taq polymerase to add dNTPs to the end of the primers
Describe Down’s Syndrome.
There is an extra 21 autosome. Some phenotypic abnormalities associated with this syndrome: poor muscle tone, shorter neck/limbs, protruding tongue, almond shaped eyes, mild/moderate mental deficiency.
Describe Turner Syndrome.
There is only 1 X chromosome. Some phenotypic abnormalities associated with this syndrome: short stature, non-functioning ovaries, webbed neck, and a wide chest
What is a karyotype?
A photograph of the chromosomes of an actively dividing cell, showing the number, shape, and size of the chromosomes.
Heterozygous females would not exhibit a sex-linked recessive trait, but are instead called _____?
Carriers
Describe Klinefelter Syndrome.
There is an extra X chromosome. Some phenotypic abnormalities associated with this syndrome: small testes, low levels of testosterone in blood, learning disabilities.
A diploid organism is said to be _____ for a particular gene if it has two identical alleles for the gene.
Homozygous
Describe the condition Protan
A reduced or complete absence of red photoreceptors in the eye. This disorder occurs in about 2% of males and 0.04% of females
Describe red-green colorblindness
General term for a spectrum of relatively common sex-linked recessive disorders including Protan and Deutan deficiency
Why can men never be considered carriers?
Because they only have one X chromosome.
Describe the condition Deutan
A reduced or complete absence of green photoreceptors in the eye. This disorder occurs in about 6% of males and 0.4% of females.
True or False: the spindles in Metaphase II are perpendicular to those formed in Metaphase I?
True.
True or false: in traits inherited in Mendelian fashion, are dominant phenotypes always the most common in a population
False
The percentage of the offspring that are the result of recombination can be taken as ..?
A measure of the relative distance between the two genes involved
True or False: the crossover frequency between two linked genes is proportional to the distance between them?
True.
What is a pedigree chart?
The analysis of how phenotypic traits or genetic diseases (sex-linked or autosomal) are passed on from parents to offspring.
Describe polygenic traits
Phenotypic traits that involve contributions from the alleles of many genes at multiple locations and on separate chromosomes. These traits show a continuous range of phenotypes in a population that approximates a normal distribution.
What is a Punnett square?
Used to simulate all possible combinations of male and female gametes to form offspring.
Mendel’s First Law
The principle of segregation. Alleles of one gene segregate from one another during the formation of gametes. When a hybrid (heterozygous) plant reproduces, it produces two kinds of reproductive cells - half passing on the dominant character, and the other half passing on the recessive.
In a chromosome diagram of a cell with the genotype Aa in prophase I, how many chromosomes are present, and are these chromosomes single or replicated?
There will be 4 chromosomes present, and they are replicated
What is a test cross?
Involves crossing an individual of unknown genotype with a homozygous recessive individual. Test crosses can also be used to test known genotypes to determine if the genes in question are on different chromosomes (independent assortment) or on the same chromosome (gene linkage)
When using a test cross, describe the scenario in which it is Independent Assortment
- Draw a Punnett square to predict the test cross results
- What is the genotypic ratio amongst the test cross progeny?
The ratio should be 1: 1: 1: 1 - What are the predicted phenotypic frequencies amongst the test cross progeny?
The frequencies should be 0.25, 0.25, 0.25, 0.25
Mendel’s Second Law
Law of independent assortment. Alleles of different genes assort independently of one another during gamete formation.
Mendel’s principle of dominance
When parents differ in one characteristic, their hybrid offspring resemble only one of the parents and are not a blend of the two parent phenotypes.
What is a monohybrid cross?
Is a cross between two organisms that differ with respect to one characteristic
Common examples of phenotypes determined by sex-linked recessive genes.
Red-green colour blindness
Total colour blindness
Hemophilia
True or False: many polygenic traits will also be influenced by environmental factors?
True.
The normal chromosome complements of diploid cells in the human male and female is..?
22 pairs of autosomes and 1 pair of sex chromosomes
If these two genes are close together, we would expect relatively few breakages to occur between them. What would the result of this?
Result in a relatively low number of recombinant gametes (the recombinant offspring would be closer to a frequency of 0)
In most higher plants and animals, what determines whether an individual is male or female?
The morphology of a single pair of sex chromosomes.
Genes located on the X chromosome are said to be ____ ?
Sex-linked
What is a recessive allele?
Where it is not expressed phenotypically in the heterozygous condition. They are represented by lowercase letters
What is a dominant allele?
Where the phenotypic effect is the same in both heterozygous and homozygous conditions. They are represented by uppercase letters
Which trend would most likely be the result of a polygenic trait?
Similar to an upside-down ‘u’ shape. Continuous range of phenotypes that approximate a normal distribution, mixture phenotypes
A diploid organism is said to be _____ for a particular gene if it has two different alleles for the gene.
Heterozygous
What is a genotype?
Is the genetic makeup of an organism. Genotypes are indicated by groups of letters
A gene can come in different forms called what?
Alleles.
Percentage recombination formula
= (total # of recombinants / total # of offspring) x 100
How is this continuous variation produced?
The effects of multiple alleles are additive.
If two genes are far apart, we would expect a greater chance of breakage occurring somewhere between the two genes in question. What would the result of this?
The result would be a relatively large number of recombinant gametes to be produces during meiosis.
What is crossing over in the context of genetics?
The genetic exchange that can occur between homologous chromosomes during prophase I. When nonsister chromatids physically cross over one another, and segments of the chromosomes will be enzymatically exchanged.
What are recombinant type gametes?
The combinations that aren’t present in the Parents of the F1.
When using a test cross, describe the scenario in which it is Gene Linkage
- Draw the locations of the alleles on the chromosome with a solid line across. If we assume that A and B are linked on one chromosome and a and b are linked on its homologous partner and we assume that no crossing over occurs, the heterozygous plant showing gene linkage would only produce two types of gametes: AB and ab
- Draw a Punnett square to show how the gametes of the heterozygous parent and the homozygous recessive
- With gene linkage, the predicted phenotypic frequencies amongst the test cross progeny are: 0.50, 0.50
What is gene linkage?
If two or more genes are located close together on a chromosomes, and they tend to move together during gamete formation.
What is ratio in the context of genetics?
It is the proportion of one type of thing to another. To calculate the ratio, divide all numbers in a series by the lowest number. A colon is used to separate each item.
What is a phenotype?
The physical appearance of an organism for a particular trait. They are indicated by descriptive words
What is a dihybrid cross?
A cross between two organisms that differ with respect to two characteristics
What is frequency in the context of genetics?
The proportion of one type of thing to the total population. They will range between 0 and 1, and all the frequencies must add up to 1. A comma is used to separate each item.
What is a gene?
A factor of inheritance for a particular trait or characteristic of an organism.
